SCIENTIFIC PUBLICATIONS

You are researching: Tissue and Organ Biofabrication
Matching entries: 224 /224
All Groups
AUTHOR Daghrery, Arwa and Ferreira, Jessica A. and Xu, Jinping and Golafshan, Nasim and Kaigler, Darnell and Bhaduri, Sarit B. and Malda, Jos and Castilho, Miguel and Bottino, Marco C.
Title Tissue-specific melt electrowritten polymeric scaffolds for coordinated regeneration of soft and hard periodontal tissues [Abstract]
Year 2023
Journal/Proceedings Bioactive Materials
Reftype
DOI/URL URL DOI
Abstract
Periodontitis is a chronic inflammatory condition that often causes serious damage to tooth-supporting tissues. The limited successful outcomes of clinically available approaches underscore the need for therapeutics that cannot only provide structural guidance to cells but can also modulate the local immune response. Here, three-dimensional melt electrowritten (i.e., poly(ε-caprolactone)) scaffolds with tissue-specific attributes were engineered to guide differentiation of human-derived periodontal ligament stem cells (hPDLSCs) and mediate macrophage polarization. The investigated tissue-specific scaffold attributes comprised fiber morphology (aligned vs. random) and highly-ordered architectures with distinct strand spacings (small 250 μm and large 500 μm). Macrophages exhibited an elongated morphology in aligned and highly-ordered scaffolds, while maintaining their round-shape on randomly-oriented fibrous scaffolds. Expressions of periostin and IL-10 were more pronounced on the aligned and highly-ordered scaffolds. While hPDLSCs on the scaffolds with 500 μm strand spacing show higher expression of osteogenic marker (Runx2) over 21 days, cells on randomly-oriented fibrous scaffolds showed upregulation of M1 markers. In an orthotopic mandibular fenestration defect model, findings revealed that the tissue-specific scaffolds (i.e., aligned fibers for periodontal ligament and highly-ordered 500 μm strand spacing fluorinated calcium phosphate [F/CaP]-coated fibers for bone) could enhance the mimicking of regeneration of natural periodontal tissues.
AUTHOR Terpstra, Margo L. and Li, Jinyu and Mensinga, Anneloes and de Ruijter, Myl{`{e}}ne and van Rijen, Mattie H. P. and Androulidakis, Charalampos and Galiotis, Costas and Papantoniou, Ioannis and Matsusaki, Michiya and Malda, Jos and Levato, Riccardo
Title Bioink with cartilage-derived extracellular matrix microfibers enables spatial control of vascular capillary formation in bioprinted constructs [Abstract]
Year 2022
Journal/Proceedings Biofabrication
Reftype
DOI/URL DOI
Abstract
Microvasculature is essential for the exchange of gas and nutrient for most tissues in our body. Some tissue structures such as the meniscus presents spatially confined blood vessels adjacent to non-vascularized regions. In biofabrication, mimicking the spatial distribution of such vascular components is paramount, as capillary ingrowth into non-vascularized tissues can lead to tissue matrix alterations and subsequent pathology. Multi-material three-dimensional (3D) bioprinting strategies have the potential to resolve anisotropic tissue features, although building complex constructs comprising stable vascularized and non-vascularized regions remains a major challenge to date. In this study, we developed endothelial cell-laden pro- and anti-angiogenic bioinks, supplemented with bioactive matrix-derived microfibers (MFs) that were created from type I collagen sponges (col-1) and cartilage decellularized extracellular matrix (CdECM), respectively. Human umbilical vein endothelial cell (HUVEC)-driven capillary networks started to form 2 d after bioprinting. Supplementing cartilage-derived MFs to endothelial-cell laden bioinks reduced the total length of neo-microvessels by 29%, and the number of microvessel junctions by 37% after 14 d, compared to bioinks with pro-angiogenic col-1 MFs. As a proof of concept, the bioinks were bioprinted into an anatomical meniscus shape with a biomimetic vascularized outer and non-vascularized inner region, using a gellan gum microgel suspension bath. These 3D meniscus-like constructs were cultured up to 14 d, with in the outer zone the HUVEC-, mural cell-, and col-1 MF-laden pro-angiogenic bioink, and in the inner zone a meniscus progenitor cell (MPC)- and CdECM MF-laden anti-angiogenic bioink, revealing successful spatial confinement of the nascent vascular network only in the outer zone. Further, to co-facilitate both microvessel formation and MPC-derived matrix formation, we formulated cell culture medium conditions with a temporal switch. Overall, this study provides a new strategy that could be applied to develop zonal biomimetic meniscal constructs. Moreover, the use of ECM-derived MFs to promote or inhibit capillary networks opens new possibilities for the biofabrication of tissues with anisotropic microvascular distribution. These have potential for many applications including in vitro models of vascular-to-avascular tissue interfaces, cancer progression, and for testing anti-angiogenic therapies.
AUTHOR Dufour, A. and Gallostra, X. Barceló and O'Keeffe, C. and Eichholz, K. and Von Euw, S. and Garcia, O. and Kelly, D. J.
Title Integrating melt electrowriting and inkjet bioprinting for engineering structurally organized articular cartilage [Abstract]
Year 2022
Journal/Proceedings Biomaterials
Reftype
DOI/URL URL DOI
Abstract
Successful cartilage engineering requires the generation of biological grafts mimicking the structure, composition and mechanical behaviour of the native tissue. Here melt electrowriting (MEW) was used to produce arrays of polymeric structures whose function was to orient the growth of cellular aggregates spontaneously generated within these structures, and to provide tensile reinforcement to the resulting tissues. Inkjet printing was used to deposit defined numbers of cells into MEW structures, which self-assembled into an organized array of spheroids within hours, ultimately generating a hybrid tissue that was hyaline-like in composition. Structurally, the engineered cartilage mimicked the histotypical organization observed in skeletally immature synovial joints. This biofabrication framework was then used to generate scaled-up (50 mm × 50 mm) cartilage implants containing over 3,500 cellular aggregates in under 15 min. After 8 weeks in culture, a 50-fold increase in the compressive stiffness of these MEW reinforced tissues were observed, while the tensile properties were still dominated by the polymer network, resulting in a composite construct demonstrating tension-compression nonlinearity mimetic of the native tissue. Helium ion microscopy further demonstrated the development of an arcading collagen network within the engineered tissue. This hybrid bioprinting strategy provides a versatile and scalable approach to engineer cartilage biomimetic grafts for biological joint resurfacing.
AUTHOR Daghrery, Arwa and Ferreira, Jessica A. and de Souza Araújo, Isaac J. and Clarkson, Brian H. and Eckert, George J. and Bhaduri, Sarit B. and Malda, Jos and Bottino, Marco C.
Title A Highly Ordered, Nanostructured Fluorinated CaP-Coated Melt Electrowritten Scaffold for Periodontal Tissue Regeneration [Abstract]
Year 2021
Journal/Proceedings Advanced Healthcare Materials
Reftype
DOI/URL DOI
Abstract
Abstract Periodontitis is a chronic inflammatory, bacteria-triggered disorder affecting nearly half of American adults. Although some level of tissue regeneration is realized, its low success in complex cases demands superior strategies to amplify regenerative capacity. Herein, highly ordered scaffolds are engineered via Melt ElectroWriting (MEW), and the effects of strand spacing, as well as the presence of a nanostructured fluorinated calcium phosphate (F/CaP) coating on the adhesion/proliferation, and osteogenic differentiation of human-derived periodontal ligament stem cells, are investigated. Upon initial cell-scaffold interaction screening aimed at defining the most suitable design, MEW poly(ε-caprolactone) scaffolds with 500 µm strand spacing are chosen. Following an alkali treatment, scaffolds are immersed in a pre-established solution to allow for coating formation. The presence of a nanostructured F/CaP coating leads to a marked upregulation of osteogenic genes and attenuated bacterial growth. In vivo findings confirm that the F/CaP-coated scaffolds are biocompatible and lead to periodontal regeneration when implanted in a rat mandibular periodontal fenestration defect model. In aggregate, it is considered that this work can contribute to the development of personalized scaffolds capable of enabling tissue-specific differentiation of progenitor cells, and thus guide simultaneous and coordinated regeneration of soft and hard periodontal tissues, while providing antimicrobial protection.
AUTHOR He, Shaolong and Radeke, Carmen and Jacobsen, Jette and Lind, Johan Ulrik and Mu, Huiling
Title Multi-material 3D printing of programmable and stretchable oromucosal patches for delivery of saquinavir [Abstract]
Year 2021
Journal/Proceedings International Journal of Pharmaceutics
Reftype
DOI/URL URL DOI
Abstract
Oromucosal patches for drug delivery allow fast onset of action and ability to circumvent hepatic first pass metabolism of drugs. While conventional fabrication methods such as solvent casting or hot melt extrusion are ideal for scalable production of low-cost delivery patches, these methods chiefly allow for simple, homogenous patch designs. As alternative, a multi-material direct-ink-write 3D printing for rapid fabrication of complex oromucosal patches with unique design features was demonstrated in the present study. Specifically, three print-materials: an acidic saquinavir-loaded hydroxypropyl methylcellulose ink, an alkaline effervescent sodium carbonate-loaded ink, and a methyl cellulose backing material were combined in various designs. The CO2 content and pH of the microenvironment were controlled by adjusting the number of alkaline layers in the patch. Additionally, the rigid and brittle patches were converted to compliant and stretchable patches by implementing mesh-like designs. Our results illustrate how 3D printing can be used for rapid design and fabrication of multifunctional or customized oromucosal patches with tailored dosages and changed drug permeation.
AUTHOR Asulin, Masha and Michael, Idan and Shapira, Assaf and Dvir, Tal
Title One-Step 3D Printing of Heart Patches with Built-In Electronics for Performance Regulation [Abstract]
Year 2021
Journal/Proceedings Advanced Science
Reftype
DOI/URL DOI
Abstract
Abstract Three dimensional (3D) printing of heart patches usually provides the ability to precisely control cell location in 3D space. Here, one-step 3D printing of cardiac patches with built-in soft and stretchable electronics is reported. The tissue is simultaneously printed using three distinct bioinks for the cells, for the conducting parts of the electronics and for the dielectric components. It is shown that the hybrid system can withstand continuous physical deformations as those taking place in the contracting myocardium. The electronic patch is flexible, stretchable, and soft, and the electrodes within the printed patch are able to monitor the function of the engineered tissue by providing extracellular potentials. Furthermore, the system allowed controlling tissue function by providing electrical stimulation for pacing. It is envisioned that such transplantable patches may regain heart contractility and allow the physician to monitor the implant function as well as to efficiently intervene from afar when needed.
AUTHOR Madiedo-Podvrsan, Sabrina and Belaïdi, Jean-Philippe and Desbouis, Stephanie and Simonetti, Lucie and Ben-Khalifa, Youcef and Soeur, Jérémie and Rielland, Maïté
Title Utilization of patterned bioprinting for heterogeneous and physiologically representative reconstructed epidermal skin models [Abstract]
Year 2021
Journal/Proceedings Scientific Reports
Reftype Madiedo-Podvrsan2021
DOI/URL DOI
Abstract
Organotypic skin tissue models have decades of use for basic research applications, the treatment of burns, and for efficacy/safety evaluation studies. The complex and heterogeneous nature of native human skin however creates difficulties for the construction of physiologically comparable organotypic models. Within the present study, we utilized bioprinting technology for the controlled deposition of separate keratinocyte subpopulations to create a reconstructed epidermis with two distinct halves in a single insert, each comprised of a different keratinocyte sub-population, in order to better model heterogonous skin and reduce inter-sample variability. As an initial proof-of-concept, we created a patterned epidermal skin model using GPF positive and negative keratinocyte subpopulations, both printed into 2 halves of a reconstructed skin insert, demonstrating the feasibility of this approach. We then demonstrated the physiological relevance of this bioprinting technique by generating a heterogeneous model comprised of dual keratinocyte population with either normal or low filaggrin expression. The resultant model exhibited a well-organized epidermal structure with each half possessing the phenotypic characteristics of its constituent cells, indicative of a successful and stable tissue reconstruction. This patterned skin model aims to mimic the edge of lesions as seen in atopic dermatitis or ichthyosis vulgaris, while the use of two populations within a single insert allows for paired statistics in evaluation studies, likely increasing study statistical power and reducing the number of models required per study. This is the first report of human patterned epidermal model using a predefined bioprinted designs, and demonstrates the relevance of bioprinting to faithfully reproduce human skin microanatomy.
AUTHOR Browning, James R. and Derr, Paige and Derr, Kristy and Doudican, Nicole and Michael, Sam and Lish, Samantha R. and Taylor, Nicholas A. and Krueger, James G. and Ferrer, Marc and Carucci, John A. and Gareau, Daniel S.
Title A 3D biofabricated cutaneous squamous cell carcinoma tissue model with multi-channel confocal microscopy imaging biomarkers to quantify antitumor effects of chemotherapeutics in tissue [Abstract]
Year 2020
Journal/Proceedings Oncotarget; Vol 11, No 27
Reftype
DOI/URL URL
Abstract
// James R. Browning 1 , Paige Derr 2 , Kristy Derr 2 , Nicole Doudican 3 , Sam Michael 2 , Samantha R. Lish 1 , Nicholas A. Taylor 3 , James G. Krueger 1 , Marc Ferrer 2 , John A. Carucci 3 and Daniel S. Gareau 1 1 Laboratory for Investigative Dermatology, The Rockefeller University, New York, New York, USA 2 National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland, USA 3 The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York, USA Correspondence to: Daniel S. Gareau, email: dgareau@rockefeller.edu Keywords: squamous cell carcinoma; screening; 3D printing; in vitro model; confocal microscopy Received: January 05, 2020     Accepted: April 03, 2020     Published: July 07, 2020 ABSTRACT Cutaneous squamous cell carcinoma (cSCC) causes approximately 10,000 deaths annually in the U. S. Current therapies are largely ineffective against metastatic and locally advanced cSCC. There is a need to identify novel, effective, and less toxic small molecule cSCC therapeutics. We developed a 3-dimensional bioprinted skin (3DBPS) model of cSCC tumors together with a microscopy assay to test chemotherapeutic effects in tissue. The full thickness SCC tissue model was validated using hematoxylin and eosin (H&E) and immunohistochemical histological staining, confocal microscopy, and cDNA microarray analysis. A nondestructive, 3D fluorescence confocal imaging assay with tdTomato-labeled A431 SCC and ZsGreen-labeled keratinocytes was developed to test efficacy and general toxicity of chemotherapeutics. Fluorescence-derived imaging biomarkers indicated that 50% of cancer cells were killed in the tissue after 1?M 5-Fluorouracil 48-hour treatment, compared to a baseline of 12% for untreated controls. The imaging biomarkers also showed that normal keratinocytes were less affected by treatment (11% killed) than the untreated tissue, which had no significant killing effect. Data showed that 5-Fluorouracil selectively killed cSCC cells more than keratinocytes. Our 3DBPS assay platform provides cellular-level measurement of cell viability and can be adapted to achieve nondestructive high-throughput screening (HTS) in bio-fabricated tissues.
AUTHOR Benmeridja, Lara and De Moor, Lise and De Maere, Elisabeth and Vanlauwe, Florian and Ryx, Michelle and Tytgat, Liesbeth and Vercruysse, Chris and Dubruel, Peter and Van Vlierberghe, Sandra and Blondeel, Phillip and Declercq, Heidi
Title High-throughput fabrication of vascularized adipose microtissues for 3D bioprinting [Abstract]
Year 2020
Journal/Proceedings Journal of Tissue Engineering and Regenerative Medicine
Reftype
DOI/URL DOI
Abstract
Abstract For patients with soft tissue defects, repair with autologous in vitro engineered adipose tissue could be a promising alternative to current surgical therapies. A volume-persistent engineered adipose tissue construct under in vivo conditions can only be achieved by early vascularization after transplantation. The combination of 3D bioprinting technology with self-assembling microvascularized units as building blocks can potentially answer the need for a microvascular network. In the present study, co-culture spheroids combining adipose-derived stem cells (ASC) and human umbilical vein endothelial cells (HUVEC) were created with an ideal geometry for bioprinting. When applying the favourable seeding technique and condition, compact viable spheroids were obtained, demonstrating high adipogenic differentiation and capillary-like network formation after 7 and 14 days of culture, as shown by live/dead analysis, immunohistochemistry and RT-qPCR. Moreover, we were able to successfully 3D bioprint the encapsulated spheroids, resulting in compact viable spheroids presenting capillary-like structures, lipid droplets and spheroid outgrowth after 14 days of culture. This is the first study that generates viable high-throughput (pre-)vascularized adipose microtissues as building blocks for bioprinting applications using a novel ASC/HUVEC co-culture spheroid model, which enables both adipogenic differentiation while simultaneously supporting the formation of prevascular-like structures within engineered tissues in vitro.
AUTHOR Dubey, Nileshkumar and Ferreira, Jessica A. and Daghrery, Arwa and Aytac, Zeynep and Malda, Jos and Bhaduri, Sarit B. and Bottino, Marco C.
Title Highly Tunable Bioactive Fiber-Reinforced Hydrogel for Guided Bone Regeneration [Abstract]
Year 2020
Journal/Proceedings Acta Biomaterialia
Reftype
DOI/URL URL DOI
Abstract
One of the most damaging pathologies that affects the health of both soft and hard tissues around the tooth is periodontitis. Clinically, periodontal tissue destruction has been managed by an integrated approach involving elimination of injured tissues followed by regenerative strategies with bone substitutes and/or barrier membranes. Regrettably, a barrier membrane with predictable mechanical integrity and multifunctional therapeutic features has yet to be established. Herein, we report a fiber-reinforced hydrogel with unprecedented tunability in terms of mechanical competence and therapeutic features by integration of highly porous poly(ε-caprolactone) fibrous mesh(es) with well-controlled 3D architecture into bioactive amorphous magnesium phosphate-laden gelatin methacryloyl hydrogels. The presence of amorphous magnesium phosphate and PCL mesh in the hydrogel can control the mechanical properties and improve the osteogenic ability, opening a tremendous opportunity in guided bone regeneration (GBR). Results demonstrate that the presence of PCL meshes fabricated via melt electrowriting can delay hydrogel degradation preventing soft tissue invasion and providing the mechanical barrier to allow time for slower migrating progenitor cells to participate in bone regeneration due to their ability to differentiate into bone-forming cells. Altogether, our approach offers a platform technology for the development of the next-generation of GBR membranes with tunable mechanical and therapeutic properties to amplify bone regeneration in compromised sites.
AUTHOR Peiffer, Quentin C. and de Ruijter, Mylène and van Duijn, Joost and Crottet, Denis and Dominic, Ernst and Malda, Jos and Castilho, Miguel
Title Melt electrowriting onto anatomically relevant biodegradable substrates: Resurfacing a diarthrodial joint [Abstract]
Year 2020
Journal/Proceedings Materials & Design
Reftype
DOI/URL URL DOI
Abstract
Three-dimensional printed hydrogel constructs with well-organized melt electrowritten (MEW) fibre-reinforcing scaffolds have been demonstrated as a promising regenerative approach to treat small cartilage defects. Here, we investige how to translate the fabrication of small fibre-reinforced structures on flat surfaces to anatomically relevant structures. In particular, the accurate deposition of MEW-fibres onto curved surfaces of conductive and non-conductive regenerative biomaterials is studied. This study reveals that clinically relevant materials with low conductivities are compatible with resurfacing with organized MEW fibres. Importantly, accurate patterning on non-flat surfaces was successfully shown, provided that a constant electrical field strength and an electrical force normal to the substrate material is maintained. Furthermore, the application of resurfacing the geometry of the medial human femoral condyle is confirmed by the fabrication of a personalised osteochondral implant. The implant composed of an articular cartilage-resident chondroprogenitor cells (ACPCs)-laden hydrogel reinforced with a well-organized MEW scaffold retained its personalised shape, improved its compressive properties and supported neocartilage formation after 28 days in vitro culture. Overall, this study establishes the groundwork for translating MEW from planar and non-resorbable material substrates to anatomically relevant geometries and regenerative materials that the regenerative medicine field aims to create.
AUTHOR Afanasenkau, Dzmitry and Kalinina, Daria and Lyakhovetskii, Vsevolod and Tondera, Christoph and Gorsky, Oleg and Moosavi, Seyyed and Pavlova, Natalia and Merkulyeva, Natalia and Kalueff, Allan V. and Minev, Ivan R. and Musienko, Pavel
Title Rapid prototyping of soft bioelectronic implants for use as neuromuscular interfaces [Abstract]
Year 2020
Journal/Proceedings Nature Biomedical Engineering
Reftype Afanasenkau2020
DOI/URL DOI
Abstract
Neuromuscular interfaces are required to translate bioelectronic technologies for application in clinical medicine. Here, by leveraging the robotically controlled ink-jet deposition of low-viscosity conductive inks, extrusion of insulating silicone pastes and in situ activation of electrode surfaces via cold-air plasma, we show that soft biocompatible materials can be rapidly printed for the on-demand prototyping of customized electrode arrays well adjusted to specific anatomical environments, functions and experimental models. We also show, with the monitoring and activation of neuronal pathways in the brain, spinal cord and neuromuscular system of cats, rats and zebrafish, that the printed bioelectronic interfaces allow for long-term integration and functional stability. This technology might enable personalized bioelectronics for neuroprosthetic applications.
AUTHOR Noor, Nadav and Shapira, Assaf and Edri, Reuven and Gal, Idan and Wertheim, Lior and Dvir, Tal
Title 3D Printing of Personalized Thick and Perfusable Cardiac Patches and Hearts [Abstract]
Year 2019
Journal/Proceedings Advanced Science
Reftype
DOI/URL DOI
Abstract
Abstract Generation of thick vascularized tissues that fully match the patient still remains an unmet challenge in cardiac tissue engineering. Here, a simple approach to 3D-print thick, vascularized, and perfusable cardiac patches that completely match the immunological, cellular, biochemical, and anatomical properties of the patient is reported. To this end, a biopsy of an omental tissue is taken from patients. While the cells are reprogrammed to become pluripotent stem cells, and differentiated to cardiomyocytes and endothelial cells, the extracellular matrix is processed into a personalized hydrogel. Following, the two cell types are separately combined with hydrogels to form bioinks for the parenchymal cardiac tissue and blood vessels. The ability to print functional vascularized patches according to the patient's anatomy is demonstrated. Blood vessel architecture is further improved by mathematical modeling of oxygen transfer. The structure and function of the patches are studied in vitro, and cardiac cell morphology is assessed after transplantation, revealing elongated cardiomyocytes with massive actinin striation. Finally, as a proof of concept, cellularized human hearts with a natural architecture are printed. These results demonstrate the potential of the approach for engineering personalized tissues and organs, or for drug screening in an appropriate anatomical structure and patient-specific biochemical microenvironment.
AUTHOR Daly, Andrew C. and Kelly, Daniel J.
Title Biofabrication of spatially organised tissues by directing the growth of cellular spheroids within 3D printed polymeric microchambers [Abstract]
Year 2019
Journal/Proceedings Biomaterials
Reftype
DOI/URL URL DOI
Abstract
Successful tissue engineering requires the generation of human scale implants that mimic the structure, composition and mechanical properties of native tissues. Here, we report a novel biofabrication strategy that enables the engineering of structurally organised tissues by guiding the growth of cellular spheroids within arrays of 3D printed polymeric microchambers. With the goal of engineering stratified articular cartilage, inkjet bioprinting was used to deposit defined numbers of mesenchymal stromal cells (MSCs) and chondrocytes into pre-printed microchambers. These jetted cell suspensions rapidly underwent condensation within the hydrophobic microchambers, leading to the formation of organised arrays of cellular spheroids. The microchambers were also designed to provide boundary conditions to these spheroids, guiding their growth and eventual fusion, leading to the development of stratified cartilage tissue with a depth-dependant collagen fiber architecture that mimicked the structure of native articular cartilage. Furthermore, the composition and biomechanical properties of the bioprinted cartilage was also comparable to the native tissue. Using multi-tool biofabrication, we were also able to engineer anatomically accurate, human scale, osteochondral templates by printing this microchamber system on top of a hypertrophic cartilage region designed to support endochondral bone formation and then maintaining the entire construct in long-term bioreactor culture to enhance tissue development. This bioprinting strategy provides a versatile and scalable approach to engineer structurally organised cartilage tissues for joint resurfacing applications.
AUTHOR Derr, Kristy and Zou, Jinyun and Luo, Keren and Song, Min Jae and Sittampalam, G. Sitta and Zhou, Chao and Michael, Samuel and Ferrer, Marc and Derr, Paige
Title Fully 3D Bioprinted Skin Equivalent Constructs with Validated Morphology and Barrier Function [Abstract]
Year 2019
Journal/Proceedings Tissue Engineering Part C: Methods
Reftype
DOI/URL DOI
Abstract
Development of high throughput, reproducible, three-dimensional bioprinted skin equivalents that are morphologically and functionally comparable to native skin tissue is advancing research in skin diseases, and providing a physiologically relevant platform for the development of therapeutics, transplants for regenerative medicine, and testing of skin products like cosmetics. Current protocols for the production of engineered skin rafts are limited in their ability to control three dimensional geometry of the structure and contraction leading to variability of skin function between constructs. Here we describe a method for the biofabrication of skin equivalents that are fully bioprinted using an open market bioprinter, made with commercially available primary cells and natural hydrogels. The unique hydrogel formulation allows for the production of a human-like skin equivalent with minimal lateral tissue contraction in a multiwell plate format, thus making them suitable for high throughput bioprinting in a single print with fast print and relatively short incubation times. The morphology and barrier function of the fully three-dimensional bioprinted skin equivalents are validated by immunohistochemistry staining, optical coherence tomography, and permeation assays.
AUTHOR Gonzalez-Fernandez, T. and Rathan, S. and Hobbs, C. and Pitacco, P. and Freeman, F. E. and Cunniffe, G. M. and Dunne, N. J. and McCarthy, H. O. and Nicolosi, V. and O'Brien, F. J. and Kelly, D. J.
Title Pore-forming bioinks to enable Spatio-temporally defined gene delivery in bioprinted tissues [Abstract]
Year 2019
Journal/Proceedings Journal of Controlled Release
Reftype
DOI/URL URL DOI
Abstract
The regeneration of complex tissues and organs remains a major clinical challenge. With a view towards bioprinting such tissues, we developed a new class of pore-forming bioink to spatially and temporally control the presentation of therapeutic genes within bioprinted tissues. By blending sacrificial and stable hydrogels, we were able to produce bioinks whose porosity increased with time following printing. When combined with amphipathic peptide-based plasmid DNA delivery, these bioinks supported enhanced non-viral gene transfer to stem cells in vitro. By modulating the porosity of these bioinks, it was possible to direct either rapid and transient (pore-forming bioinks), or slower and more sustained (solid bioinks) transfection of host or transplanted cells in vivo. To demonstrate the utility of these bioinks for the bioprinting of spatially complex tissues, they were next used to zonally position stem cells and plasmids encoding for either osteogenic (BMP2) or chondrogenic (combination of TGF-β3, BMP2 and SOX9) genes within networks of 3D printed thermoplastic fibers to produce mechanically reinforced, gene activated constructs. In vivo, these bioprinted tissues supported the development of a vascularised, bony tissue overlaid by a layer of stable cartilage. When combined with multiple-tool biofabrication strategies, these gene activated bioinks can enable the bioprinting of a wide range of spatially complex tissues.
AUTHOR de Ruijter, Mylène and Ribeiro, Alexandre and Dokter, Inge and Castilho, Miguel and Malda, Jos
Title Simultaneous Micropatterning of Fibrous Meshes and Bioinks for the Fabrication of Living Tissue Constructs [Abstract]
Year 2018
Journal/Proceedings Advanced Healthcare Materials
Reftype
DOI/URL DOI
Abstract
Abstract Fabrication of biomimetic tissues holds much promise for the regeneration of cells or organs that are lost or damaged due to injury or disease. To enable the generation of complex, multicellular tissues on demand, the ability to design and incorporate different materials and cell types needs to be improved. Two techniques are combined: extrusion-based bioprinting, which enables printing of cell-encapsulated hydrogels; and melt electrowriting (MEW), which enables fabrication of aligned (sub)-micrometer fibers into a single-step biofabrication process. Composite structures generated by infusion of MEW fiber structures with hydrogels have resulted in mechanically and biologically competent constructs; however, their preparation involves a two-step fabrication procedure that limits freedom of design of microfiber architectures and the use of multiple materials and cell types. How convergence of MEW and extrusion-based bioprinting allows fabrication of mechanically stable constructs with the spatial distributions of different cell types without compromising cell viability and chondrogenic differentiation of mesenchymal stromal cells is demonstrated for the first time. Moreover, this converged printing approach improves freedom of design of the MEW fibers, enabling 3D fiber deposition. This is an important step toward biofabrication of voluminous and complex hierarchical structures that can better resemble the characteristics of functional biological tissues.
AUTHOR Cunniffe, Gráinne and Gonzalez-Fernandez, Tomas and Daly, Andrew and Nelson Sathy, Binulal and Jeon, Oju and Alsberg, Eben and J. Kelly, Daniel
Title Three-Dimensional Bioprinting of Polycaprolactone Reinforced Gene Activated Bioinks for Bone Tissue Engineering [Abstract]
Year 2017
Journal/Proceedings Tissue Engineering Part A
Reftype
DOI/URL DOI
Abstract
Regeneration of complex bone defects remains a significant clinical challenge. Multi-tool biofabrication has permitted the combination of various biomaterials to create multifaceted composites with tailorable mechanical properties and spatially controlled biological function. In this study we sought to use bioprinting to engineer nonviral gene activated constructs reinforced by polymeric micro-filaments. A gene activated bioink was developed using RGD-g-irradiated alginate and nano-hydroxyapatite (nHA) complexed to plasmid DNA (pDNA). This ink was combined with bonemarrow-derived mesenchymal stemcells (MSCs) and then co-printed with a polycaprolactone supporting mesh to provide mechanical stability to the construct. Reporter genes were first used to demonstrate successful cell transfection using this system, with sustained expression of the transgene detected over 14 days postbioprinting. Delivery of a combination of therapeutic genes encoding for bone morphogenic protein and transforming growth factor promoted robust osteogenesis of encapsulated MSCs in vitro, with enhanced levels of matrix deposition and mineralization observed following the incorporation of therapeutic pDNA. Gene activated MSC-laden constructs were then implanted subcutaneously, directly postfabrication, and were found to support superior levels of vascularization andmineralization compared to cell-free controls. These results validate the use of a gene activated bioink to impart biological functionality to three-dimensional bioprinted constructs.
AUTHOR Yao, Y. and Raymond, J. E. and Kauffmann, F. and Maekawa, S. and Sugai, J. V. and Lahann, J. and Giannobile, W. V.
Title Multicompartmental Scaffolds for Coordinated Periodontal Tissue Engineering [Abstract]
Year 2023
Journal/Proceedings Journal of Dental Research
Reftype
DOI/URL DOI
Abstract
Successful periodontal repair and regeneration requires the coordinated responses from soft and hard tissues as well as the soft tissue–to–bone interfaces. Inspired by the hierarchical structure of native periodontal tissues, tissue engineering technology provides unique opportunities to coordinate multiple cell types into scaffolds that mimic the natural periodontal structure in vitro. In this study, we designed and fabricated highly ordered multicompartmental scaffolds by melt electrowriting, an advanced 3-dimensional (3D) printing technique. This strategy attempted to mimic the characteristic periodontal microenvironment through multicompartmental constructs comprising 3 tissue-specific regions: 1) a bone compartment with dense mesh structure, 2) a ligament compartment mimicking the highly aligned periodontal ligaments (PDLs), and 3) a transition region that bridges the bone and ligament, a critical feature that differentiates this system from mono- or bicompartmental alternatives. The multicompartmental constructs successfully achieved coordinated proliferation and differentiation of multiple cell types in vitro within short time, including both ligamentous- and bone-derived cells. Long-term 3D coculture of primary human osteoblasts and PDL fibroblasts led to a mineral gradient from calcified to uncalcified regions with PDL-like insertions within the transition region, an effect that is challenging to achieve with mono- or bicompartmental platforms. This process effectively recapitulates the key feature of interfacial tissues in periodontium. Collectively, this tissue-engineered approach offers a fundament for engineering periodontal tissue constructs with characteristic 3D microenvironments similar to native tissues. This multicompartmental 3D printing approach is also highly compatible with the design of next-generation scaffolds, with both highly adjustable compartmentalization properties and patient-specific shapes, for multitissue engineering in complex periodontal defects.
AUTHOR Freeman, Fiona E. and Pitacco, Pierluca and van Dommelen, Lieke H. A. and Nulty, Jessica and Browe, David C. and Shin, Jung-Youn and Alsberg, Eben and Kelly, Daniel J.
Title 3D bioprinting spatiotemporally defined patterns of growth factors to tightly control tissue regeneration [Abstract]
Year 2020
Journal/Proceedings Science Advances
Reftype
DOI/URL URL DOI
Abstract
Therapeutic growth factor delivery typically requires supraphysiological dosages, which can cause undesirable off-target effects. The aim of this study was to 3D bioprint implants containing spatiotemporally defined patterns of growth factors optimized for coupled angiogenesis and osteogenesis. Using nanoparticle functionalized bioinks, it was possible to print implants with distinct growth factor patterns and release profiles spanning from days to weeks. The extent of angiogenesis in vivo depended on the spatial presentation of vascular endothelial growth factor (VEGF). Higher levels of vessel invasion were observed in implants containing a spatial gradient of VEGF compared to those homogenously loaded with the same total amount of protein. Printed implants containing a gradient of VEGF, coupled with spatially defined BMP-2 localization and release kinetics, accelerated large bone defect healing with little heterotopic bone formation. This demonstrates the potential of growth factor printing, a putative point of care therapy, for tightly controlled tissue regeneration.
AUTHOR Lee, Ji Seung and Park, Hae Sang and Jung, Harry and Lee, Hanna and Hong, Heesun and Lee, Young Jin and Suh, Ye Ji and Lee, Ok Joo and Kim, Soon Hee and Park, Chan Hum
Title 3D-printable photocurable bioink for cartilage regeneration of tonsil-derived mesenchymal stem cells [Abstract]
Year 2020
Journal/Proceedings Additive Manufacturing
Reftype
DOI/URL URL DOI
Abstract
Cartilage regeneration is challenging because of the poor intrinsic self-repair capacity of avascular tissue. Three-dimensional (3D) bioprinting has gained significant attention in the field of tissue engineering and is a promising technology to overcome current difficulties in cartilage regeneration. Although bioink is an essential component of bioprinting technology, several challenges remain in satisfying different requirements for ideal bioink, including biocompatibility and printability based on specific biological requirements. Gelatin and hyaluronic acid (HA) have been shown to be ideal biomimetic hydrogel sources for cartilage regeneration. However, controlling their structure, mechanical properties, biocompatibility, and degradation rate for cartilage repair remains a challenge. Here, we show a photocurable bioink created by hybridization of gelatin methacryloyl (GelMA) and glycidyl-methacrylated HA (GMHA) for material extrusion 3D bioprinting in cartilage regeneration. GelMA and GMHA were mixed in various ratios, and the mixture of 7% GelMA and 5% GMHA bioink (G7H5) demonstrated the most reliable mechanical properties, rheological properties, and printability. This G7H5 bioink allowed us to build a highly complex larynx structure, including the hyoid bone, thyroid cartilage, cricoid cartilage, arytenoid cartilage, and cervical trachea. This bioink also provided an excellent microenvironment for chondrogenesis of tonsil-derived mesenchymal stem cells (TMSCs) in vitro and in vivo. In summary, this study presents the ideal formulation of GelMA/GMHA hybrid bioink to generate a well-suited photocurable bioink for cartilage regeneration of TMSCs using a material extrusion bioprinter, and could be applied to cartilage tissue engineering.
AUTHOR Liu, Xue and Michael, Samuel and Bharti, Kapil and Ferrer, Marc and Song, Min Jae
Title A biofabricated vascularized skin model of atopic dermatitis for preclinical studies [Abstract]
Year 2020
Journal/Proceedings Biofabrication
Reftype
DOI/URL DOI
Abstract
Three-dimensional (3D) biofabrication techniques enable the production of multicellular tissue models as assay platforms for drug screening. The increased cellular and physiological complexity in these 3D tissue models should recapitulate the relevant biological environment found in the body. Here we describe the use of 3D bioprinting techniques to fabricate skin equivalent tissues of varying physiological complexity, including human epidermis, non-vascularized and vascularized full-thickness skin tissue equivalents, in a multi-well platform to enable drug screening. Human keratinocytes, fibroblasts, and pericytes, and induced pluripotent stem cell (iPSC)-derived endothelial cells were used in the biofabrication process to produce the varying complexity. The skin equivalents exhibit the correct structural markers of dermis and epidermis stratification, with physiological functions of the skin barrier. The robustness, versatility and reproducibility of the biofabrication techniques are further highlighted by the generation of atopic dermatitis (AD)-disease like tissues. These AD models demonstrate several clinical hallmarks of the disease, including: (i) spongiosis and hyperplasia; (ii) early and terminal expression of differentiation proteins; and (iii) increases in levels of pro-inflammatory cytokines. We show the pre-clinical relevance of the biofabricated AD tissue models to correct disease phenotype by testing the effects of dexamethasone, an anti-inflammatory corticosteroid, and three Janus Kinase inhibitors from clinical trials for AD. This study demonstrates the development of a versatile and reproducible bioprinting approach to create human skin equivalents with a range of cellular complexity for disease modelling. In addition, we establish several assay readouts that are quantifiable, robust, AD relevant, and can be scaled up for compound screening. The results show that the cellular complexity of the tissues develops a more physiologically relevant AD disease model. Thus, the skin models in this study offer an in vitro approach for the rapid understanding of pathological mechanisms, and testing for efficacy of action and toxic effects of drugs.
AUTHOR Colle, Julien and Blondeel, Phillip and De Bruyne, Axelle and Bochar, Silke and Tytgat, Liesbeth and Vercruysse, Chris and Van Vlierberghe, Sandra and Dubruel, Peter and Declercq, Heidi
Title Bioprinting predifferentiated adipose-derived mesenchymal stem cell spheroids with methacrylated gelatin ink for adipose tissue engineering [Abstract]
Year 2020
Journal/Proceedings Journal of Materials Science: Materials in Medicine
Reftype Colle2020
DOI/URL DOI
Abstract
The increasing number of mastectomies results in a greater demand for breast reconstruction characterized by simplicity and a low complication profile. Reconstructive surgeons are investigating tissue engineering (TE) strategies to overcome the current surgical drawbacks. 3D bioprinting is the rising technique for the fabrication of large tissue constructs which provides a potential solution for unmet clinical needs in breast reconstruction building on decades of experience in autologous fat grafting, adipose-derived mesenchymal stem cell (ASC) biology and TE. A scaffold was bioprinted using encapsulated ASC spheroids in methacrylated gelatin ink (GelMA). Uniform ASC spheroids with an ideal geometry and diameter for bioprinting were formed, using a high-throughput non-adhesive agarose microwell system. ASC spheroids in adipogenic differentiation medium (ADM) were evaluated through live/dead staining, histology (HE, Oil Red O), TEM and RT-qPCR. Viable spheroids were obtained for up to 14 days post-printing and showed multilocular microvacuoles and successful differentiation toward mature adipocytes shown by gene expression analysis. Moreover, spheroids were able to assemble at random in GelMA, creating a macrotissue. Combining the advantage of microtissues to self-assemble and the controlled organization by bioprinting technologies, these ASC spheroids can be useful as building blocks for the engineering of soft tissue implants.
AUTHOR Daly, Andrew C. and Pitacco, Pierluca and Nulty, Jessica and Cunniffe, Gráinne M. and Kelly, Daniel J.
Title 3D printed microchannel networks to direct vascularisation during endochondral bone repair [Abstract]
Year 2018
Journal/Proceedings Biomaterials
Reftype
DOI/URL URL DOI
Abstract
Bone tissue engineering strategies that recapitulate the developmental process of endochondral ossification offer a promising route to bone repair. Clinical translation of such endochondral tissue engineering strategies will require overcoming a number of challenges, including the engineering of large and often anatomically complex cartilage grafts, as well as the persistence of core regions of avascular cartilage following their implantation into large bone defects. Here 3D printing technology is utilized to develop a versatile and scalable approach to guide vascularisation during endochondral bone repair. First, a sacrificial pluronic ink was used to 3D print interconnected microchannel networks in a mesenchymal stem cell (MSC) laden gelatin-methacryloyl (GelMA) hydrogel. These constructs (with and without microchannels) were next chondrogenically primed in vitro and then implanted into critically sized femoral bone defects in rats. The solid and microchanneled cartilage templates enhanced bone repair compared to untreated controls, with the solid cartilage templates (without microchannels) supporting the highest levels of total bone formation. However, the inclusion of 3D printed microchannels was found to promote osteoclast/immune cell invasion, hydrogel degradation, and vascularisation following implantation. In addition, the endochondral bone tissue engineering strategy was found to support comparable levels of bone healing to BMP-2 delivery, whilst promoting lower levels of heterotopic bone formation, with the microchanneled templates supporting the lowest levels of heterotopic bone formation. Taken together, these results demonstrate that 3D printed hypertrophic cartilage grafts represent a promising approach for the repair of complex bone fractures, particularly for larger defects where vascularisation will be a key challenge.
AUTHOR Ng, Wei Long and Qi, Jovina Tan Zhi and Yeong, Wai Yee and Naing, May Win
Title Proof-of-concept: 3D bioprinting of pigmented human skin constructs [Abstract]
Year 2018
Journal/Proceedings Biofabrication
Reftype
DOI/URL DOI
Abstract
Three-dimensional (3D) pigmented human skin constructs have been fabricated using a 3D bioprinting approach. The 3D pigmented human skin constructs are obtained from using three different types of skin cells (keratinocytes, melanocytes and fibroblasts from three different skin donors) and they exhibit similar constitutive pigmentation (pale pigmentation) as the skin donors. A two-step drop-on-demand bioprinting strategy facilitates the deposition of cell droplets to emulate the epidermal melanin units (pre-defined patterning of keratinocytes and melanocytes at the desired positions) and manipulation of the microenvironment to fabricate 3D biomimetic hierarchical porous structures found in native skin tissue. The 3D bioprinted pigmented skin constructs are compared to the pigmented skin constructs fabricated by conventional a manual-casting approach; in-depth characterization of both the 3D pigmented skin constructs has indicated that the 3D bioprinted skin constructs have a higher degree of resemblance to native skin tissue in term of the presence of well-developed stratified epidermal layers and the presence of a continuous layer of basement membrane proteins as compared to the manually-cast samples. The 3D bioprinting approach facilitates the development of 3D in vitro pigmented human skin constructs for potential toxicology testing and fundamental cell biology research.
AUTHOR Kessel, Benjamin and Lee, Mihyun and Bonato, Angela and Tinguely, Yann and Tosoratti, Enrico and Zenobi-Wong, Marcy
Title 3D Bioprinting of Macroporous Materials Based on Entangled Hydrogel Microstrands [Abstract]
Year 2020
Journal/Proceedings Advanced Science
Reftype
DOI/URL DOI
Abstract
Abstract Hydrogels are excellent mimetics of mammalian extracellular matrices and have found widespread use in tissue engineering. Nanoporosity of monolithic bulk hydrogels, however, limits mass transport of key biomolecules. Microgels used in 3D bioprinting achieve both custom shape and vastly improved permissivity to an array of cell functions, however spherical-microbead-based bioinks are challenging to upscale, are inherently isotropic, and require secondary crosslinking. Here, bioinks based on high-aspect-ratio hydrogel microstrands are introduced to overcome these limitations. Pre-crosslinked, bulk hydrogels are deconstructed into microstrands by sizing through a grid with apertures of 40–100 µm. The microstrands are moldable and form a porous, entangled structure, stable in aqueous medium without further crosslinking. Entangled microstrands have rheological properties characteristic of excellent bioinks for extrusion bioprinting. Furthermore, individual microstrands align during extrusion and facilitate the alignment of myotubes. Cells can be placed either inside or outside the hydrogel phase with >90% viability. Chondrocytes co-printed with the microstrands deposit abundant extracellular matrix, resulting in a modulus increase from 2.7 to 780.2 kPa after 6 weeks of culture. This powerful approach to deconstruct bulk hydrogels into advanced bioinks is both scalable and versatile, representing an important toolbox for 3D bioprinting of architected hydrogels.
AUTHOR Kokkinis, Dimitri and Bouville, Florian and Studart, André R.
Title 3D Printing of Materials with Tunable Failure via Bioinspired Mechanical Gradients [Abstract]
Year 2018
Journal/Proceedings Advanced Materials
Reftype
DOI/URL DOI
Abstract
Abstract Mechanical gradients are useful to reduce strain mismatches in heterogeneous materials and thus prevent premature failure of devices in a wide range of applications. While complex graded designs are a hallmark of biological materials, gradients in manmade materials are often limited to 1D profiles due to the lack of adequate fabrication tools. Here, a multimaterial 3D‐printing platform is developed to fabricate elastomer gradients spanning three orders of magnitude in elastic modulus and used to investigate the role of various bioinspired gradient designs on the local and global mechanical behavior of synthetic materials. The digital image correlation data and finite element modeling indicate that gradients can be effectively used to manipulate the stress state and thus circumvent the weakening effect of defect‐rich interfaces or program the failure behavior of heterogeneous materials. Implementing this concept in materials with bioinspired designs can potentially lead to defect‐tolerant structures and to materials whose tunable failure facilitates repair of biomedical implants, stretchable electronics, or soft robotics.
AUTHOR Liu, Chun and Dai, Ting and Wu, Xiaoyu and Ma, Jiayi and Liu, Jun and Wu, Siyu and Yang, Lei and Zhao, Hongbin
Title 3D bioprinting of cell-laden nano-attapulgite/gelatin methacrylate composite hydrogel scaffolds for bone tissue repair [Abstract]
Year 2023
Journal/Proceedings Journal of Materials Science & Technology
Reftype
DOI/URL URL DOI
Abstract
Bone tissue engineering (BTE) has proven to be a promising strategy for bone defect repair. Due to its excellent biological properties, gelatin methacrylate (GelMA) hydrogels have been used as bioinks for 3D bioprinting in some BTE studies to produce scaffolds for bone regeneration. However, applications for load-bearing defects are limited by poor mechanical properties and a lack of bioactivity. In this study, 3D printing technology was used to create nano-attapulgite (nano-ATP)/GelMA composite hydrogels loaded into mouse bone mesenchymal stem cells (BMSCs) and mouse umbilical vein endothelial cells (MUVECs). The bioprintability, physicochemical properties, and mechanical properties were all thoroughly evaluated. Our findings showed that nano-ATP groups outperform the control group in terms of printability, indicating that nano-ATP is beneficial for printability. Additionally, after incorporation with nano-ATP, the mechanical strength of the composite hydrogels was significantly improved, resulting in adequate mechanical properties for bone regeneration. The presence of nano-ATP in the scaffolds has also been studied for cell-material interactions. The findings show that cells within the scaffold not only have high viability but also a clear proclivity to promote osteogenic differentiation of BMSCs. Besides, the MUVECs-loaded composite hydrogels demonstrated increased angiogenic activity. A cranial defect model was also developed to evaluate the bone repair capability of scaffolds loaded with rat BMSCs. According to histological analysis, cell-laden nano-ATP composite hydrogels can effectively improve bone regeneration and promote angiogenesis. This study demonstrated the potential of nano-ATP for bone tissue engineering, which should also increase the clinical practicality of nano-ATP.
AUTHOR Solis, Daphene Marques and Czekanski, Aleksander
Title 3D and 4D additive manufacturing techniques for vascular-like structures – A review [Abstract]
Year 2022
Journal/Proceedings Bioprinting
Reftype
DOI/URL URL DOI
Abstract
The critical shortage in organ donors is a problem facing patients and health care systems worldwide. The most promising solution to this crisis is the artificial production of organs and tissues, known as tissue engineering. Significant advances in this field have led to the commercial production of artificial skin and cartilage, but limitations remain in the production of thicker tissues (i.e., >200 μm thickness). The challenge of producing thicker tissues relates to the inability to establish and maintain a vascular system, which is the basic requirement for artificially producing any vital organ. Given the importance of these structures, a major scientific effort is underway to better understand how to reproduce a vascular system. This review presents the most recent advances in the manufacturing of vascular-like structures, especially techniques involving additive manufacturing, or 3D and 4D printing. This review starts with a primer on the classification, composition, and mechanical proprieties of blood vessels, offering the reader a better understanding of the challenges involved in the artificial production of vessels. The review then discusses the methodologies, technologies, and materials used and available for the manufacturing of the vascular system.
AUTHOR Pitacco, Pierluca and Sadowska, Joanna M. and O'Brien, Fergal J. and Kelly, Daniel J.
Title 3D bioprinting of cartilaginous templates for large bone defect healing [Abstract]
Year 2022
Journal/Proceedings Acta Biomaterialia
Reftype
DOI/URL URL DOI
Abstract
Damaged or diseased bone can be treated using autografts or a range of different bone grafting biomaterials, however limitations with such approaches has motivated increased interest in developmentally inspired bone tissue engineering (BTE) strategies that seek to recapitulate the process of endochondral ossification (EO) as a means of regenerating critically sized defects. The clinical translation of such strategies will require the engineering of scaled-up, geometrically defined hypertrophic cartilage grafts that can be rapidly vascularised and remodelled into bone in mechanically challenging defect environments. The goal of this study was to 3D bioprint mechanically reinforced cartilaginous templates and to assess their capacity to regenerate critically sized femoral bone defects. Human mesenchymal stem/stromal cells (hMSCs) were incorporated into fibrin based bioinks and bioprinted into polycaprolactone (PCL) frameworks to produce mechanically reinforced constructs. Chondrogenic priming of such hMSC laden constructs was required to support robust vascularisation and graft mineralisation in vivo following their subcutaneous implantation into nude mice. With a view towards maximising their potential to support endochondral bone regeneration, we next explored different in vitro culture regimes to produce chondrogenic and early hypertrophic engineered grafts. Following their implantation into femoral bone defects within transiently immunosuppressed rats, such bioprinted constructs were rapidly remodelled into bone in vivo, with early hypertrophic constructs supporting higher levels of vascularisation and bone formation compared to the chondrogenic constructs. Such early hypertrophic bioprinted constructs also supported higher levels of vascularisation and spatially distinct patterns of new formation compared to BMP-2 loaded collagen scaffolds (here used as a positive control). In conclusion, this study demonstrates that fibrin based bioinks support chondrogenesis of hMSCs in vitro, which enables the bioprinting of mechanically reinforced hypertrophic cartilaginous templates capable of supporting large bone defect regeneration. These results support the use of 3D bioprinting as a strategy to scale-up the engineering of developmentally inspired templates for BTE. Statement of significance Despite the promise of developmentally inspired tissue engineering strategies for bone regeneration, there are still challenges that need to be addressed to enable clinical translation. This work reports the development and assessment (in vitro and in vivo) of a 3D bioprinting strategy to engineer mechanically-reinforced cartilaginous templates for large bone defect regeneration using human MSCs. Using distinct in vitro priming protocols, it was possible to generate cartilage grafts with altered phenotypes. More hypertrophic grafts, engineered in vitro using TGF-β3 and BMP-2, supported higher levels of blood vessel infiltration and accelerated bone regeneration in vivo. This study also identifies some of the advantages and disadvantages of such endochondral bone TE strategies over the direct delivery of BMP-2 from collagen-based scaffolds.
AUTHOR Leu Alexa, Rebeca and Cucuruz, Andreia and Ghițulică, Cristina-Daniela and Voicu, Georgeta and Stamat (Balahura), Liliana-Roxana and Dinescu, Sorina and Vlasceanu, George Mihail and Stavarache, Cristina and Ianchis, Raluca and Iovu, Horia and Costache, Marieta
Title 3D Printable Composite Biomaterials Based on GelMA and Hydroxyapatite Powders Doped with Cerium Ions for Bone Tissue Regeneration [Abstract]
Year 2022
Journal/Proceedings International Journal of Molecular Sciences
Reftype
DOI/URL URL DOI
Abstract
The main objective was to produce 3D printable hydrogels based on GelMA and hydroxyapatite doped with cerium ions with potential application in bone regeneration. The first part of the study regards the substitution of Ca2+ ions from hydroxyapatite structure with cerium ions (Ca10-xCex(PO4)6(OH)2, xCe = 0.1, 0.3, 0.5). The second part followed the selection of the optimal concentration of HAp doped, which will ensure GelMA-based scaffolds with good biocompatibility, viability and cell proliferation. The third part aimed to select the optimal concentrations of GelMA for the 3D printing process (20%, 30% and 35%). In vitro biological assessment presented the highest level of cell viability and proliferation potency of GelMA-HC5 composites, along with a low cytotoxic potential, highlighting the beneficial effects of cerium on cell growth, also supported by Live/Dead results. According to the 3D printing experiments, the 30% GelMA enriched with HC5 was able to generate 3D scaffolds with high structural integrity and homogeneity, showing the highest suitability for the 3D printing process. The osteogenic differentiation experiments confirmed the ability of 30% GelMA-3% HC5 scaffold to support and efficiently maintain the osteogenesis process. Based on the results, 30% GelMA-3% HC5 3D printed scaffolds could be considered as biomaterials with suitable characteristics for application in bone tissue engineering.
AUTHOR Leu Alexa, Rebeca and Cucuruz, Andreia and Ghițulică, Cristina-Daniela and Voicu, Georgeta and Stamat (Balahura), Liliana-Roxana and Dinescu, Sorina and Vlasceanu, George Mihail and Iovu, Horia and Serafim, Andrada and Ianchis, Raluca and Ciocan, Lucian-Toma and Costache, Marieta
Title 3D Printed Composite Scaffolds of GelMA and Hydroxyapatite Nanopowders Doped with Mg/Zn Ions to Evaluate the Expression of Genes and Proteins of Osteogenic Markers [Abstract]
Year 2022
Journal/Proceedings Nanomaterials
Reftype
DOI/URL URL DOI
Abstract
As bone diseases and defects are constantly increasing, the improvement of bone regeneration techniques is constantly evolving. The main purpose of this scientific study was to obtain and investigate biomaterials that can be used in tissue engineering. In this respect, nanocomposite inks of GelMA modified with hydroxyapatite (HA) substituted with Mg and Zn were developed. Using a 3D bioprinting technique, scaffolds with varying shapes and dimensions were obtained. The following analyses were used in order to study the nanocomposite materials and scaffolds obtained by the 3D printing technique: Fourier transform infrared spectrometry and X-ray diffraction (XRD), scanning electron microscopy (SEM), and micro-computed tomography (Micro-CT). The swelling and dissolvability of each scaffold were also studied. Biological studies, osteopontin (OPN), and osterix (OSX) gene expression evaluations were confirmed at the protein levels, using immunofluorescence coupled with confocal microscopy. These findings suggest the positive effect of magnesium and zinc on the osteogenic differentiation process. OSX fluorescent staining also confirmed the capacity of GelMA-HM5 and GelMA-HZ5 to support osteogenesis, especially of the magnesium enriched scaffold.
AUTHOR Yang, Xue and Li, Shuai and Ren, Ya and Qiang, Lei and Liu, Yihao and Wang, Jinwu and Dai, Kerong
Title 3D printed hydrogel for articular cartilage regeneration [Abstract]
Year 2022
Journal/Proceedings Composites Part B: Engineering
Reftype
DOI/URL URL DOI
Abstract
Tissue engineering is a promising strategy for damaged cartilage tissue repair. Three-dimensional (3D) printed hydrogel exhibits great potential in cartilage tissue engineering for fabricating 3D cell culture scaffolds, owing to its similarity to the extracellular matrix (ECM). Numerous hydrogels have been tested for 3D printing in vitro articular cartilage tissues, including natural and synthetic hydrogels that mimic their in vivo counterparts. The advancement of materials science and 3D printing techniques enables a wide range of fabrication strategies that produce cartilage tissues with delicate structures and on multiple scales. Stimuli-responsive hydrogels, which rely on the external environment to transform to a desired structure or dimension, have likewise been widely studied in tissue engineering. This review summarizes the characteristics, functions, and research conducted on 3D printed hydrogels by categorizing cutting-edge hydrogel materials commonly used in cartilage tissue engineering and their complexes. The challenges and application prospects of hydrogels in cartilage tissue engineering are described. Novel composite hydrogels must be investigated to meet the requirements of native articular cartilage in the aspects of structure, scale, mechanical properties, among others. Combining stimuli-responsive hydrogels with biological scaffolds also shows great potential in various applications, including but not limited to articular cartilage, vascularization, and osteochondral repair.
AUTHOR Hashimi, Noura Sayed Al and Soman, Soja Saghar and Govindharaj, Mano and Vijayavenkataraman, Sanjairaj
Title 3D printing of complex architected metamaterial structures by simple material extrusion for bone tissue engineering [Abstract]
Year 2022
Journal/Proceedings Materials Today Communications
Reftype
DOI/URL URL DOI
Abstract
Triply periodic minimal surfaces (TPMS) are gaining popularity as scaffolds for bioapplications due to their unique structure, offering strong mechanical properties and biomorphic surfaces which enhance cell attachment and proliferation. In this work, polymer TPMS sheet lattices were printed using a well-known yet unprecedented technique of manufacturing such structures; which is material extrusion (specifically, pneumatic melt extrusion). This method offers a one step, straightforward yet reliable way to print complex porous structures while retaining design accuracy and significantly simplifying the process. Multiple primitive, gyroid and cubic structures were designed using MSLattice and Solidworks with 70% porosity and 2×2×3 unit cells. The scaffolds were printed by melt extrusion of polycaprolactone (PCL) at different parameters to establish the optimal settings. Morphological features (pore size and strut thickness) were determined using scanning electron microscopy (SEM) and the accuracy of print was determined by comparing to the design, showing high print accuracy and minimal percentage errors of less than 15% in all prints. Uniaxial compression testing was used to demonstrate the different deformation processes of the scaffolds and evaluate their mechanical properties, with primitive having the highest modulus and gyroid the highest yield strength. Finally, cell viability was quantified by alamar blue cell viability assay and visualized by SEM, displaying significant increase in cell proliferation and attachment, specifically in the primitive structure. Herein we will explain the challenges faced with design and print optimization and how we overcame them, making this work the first of its kind in material extrusion (pneumatic melt extrusion) printing of TPMS scaffolds.
AUTHOR Hilgeroth, Philipp S. and Thümmler, Justus F. and Binder, Wolfgang H.
Title 3D Printing of Triamcinolone Acetonide in Triblock Copolymers of Styrene–Isobutylene–Styrene as a Slow-Release System [Abstract]
Year 2022
Journal/Proceedings Polymers
Reftype
DOI/URL URL DOI
Abstract
Additive manufacturing has a wide range of applications and has opened up new methods of drug formulation, in turn achieving attention in medicine. We prepared styrene–isobutylene–styrene triblock copolymers (SIBS; Mn = 10 kDa–25 kDa, PDI 1,3–1,6) as a drug carrier for triamcinolone acetonide (TA), further processed by fused deposition modeling to create a solid drug release system displaying improved bioavailability and applicability. Living carbocationic polymerization was used to exert control over block length and polymeric architecture. Thermorheological properties of the SIBS polymer (22.3 kDa, 38 wt % S) were adjusted to the printability of SIBS/TA mixtures (1–5% of TA), generating an effective release system effective for more than 60 days. Continuous drug release and morphological investigations were conducted to probe the influence of the 3D printing process on the drug release, enabling 3D printing as a formulation method for a slow-release system of Triamcinolone.
AUTHOR Kitana, Waseem and Apsite, Indra and Hazur, Jonas and Boccaccini, Aldo R. and Ionov, Leonid
Title 4D Biofabrication of T-Shaped Vascular Bifurcation [Abstract]
Year 2022
Journal/Proceedings Advanced Materials Technologies
Reftype
DOI/URL DOI
Abstract
Abstract 4D Biofabrication – a pioneering biofabrication technique – involves the automated fabrication of 3D constructs that are dynamic and show shape-transformation capability. Although current 4D biofabrication methods are highly promising for the fabrication of vascular elements such as tubes, the fabrication of tubular junctions is still highly challenging. Here, for the first time, a 4D biofabrication-based concept for the fabrication of a T-shaped vascular bifurcation using 3D printed shape-changing layers based on a mathematical model is reported. The formation of tubular structures with various diameters is achieved by precisely controlling the parameters (e.g. crosslinking time). Consequently, the 3D printed films show self-transformation into a T-junction upon immersion in water with a diameter of a few millimeters. Perfusion of the tubular T-junction with an aqueous medium simulating blood flow through vessels shows minimal leakages with a maximum flow velocity of 0.11 m s–1. Furthermore, human umbilical vein endothelial cells seeded on the inner surface of the plain T-junction show outstanding growth properties and excellent cell viability. The achieved diameters are comparable to the native blood vessels, which is still a challenge in 3D biofabrication. This approach paves the way for the fabrication of fully automatic self-actuated vascular bifurcations as vascular grafts.
AUTHOR Özcan, Mutlu and Magini, Eduarda Blasi and Volpato, Guilherme Maziero and Cruz, Ariadne and Volpato, Claudia Angela Maziero
Title Additive Manufacturing Technologies for Fabrication of Biomaterials for Surgical Procedures in Dentistry: A Narrative Review [Abstract]
Year 2022
Journal/Proceedings Journal of Prosthodontics
Reftype
DOI/URL DOI
Abstract
Abstract Purpose To screen and critically appraise available literature regarding additive manufacturing technologies for bone graft material fabrication in dentistry. Material and Methods PubMed and Scopus were searched up to May 2021. Studies reporting the additive manufacturing techniques to manufacture scaffolds for intraoral bone defect reconstruction were considered eligible. A narrative review was synthesized to discuss the techniques for bone graft material fabrication in dentistry and the biomaterials used. Results The databases search resulted in 933 articles. After removing duplicate articles (128 articles), the titles and abstracts of the remaining articles (805 articles) were evaluated. A total of 89 articles were included in this review. Reading these articles, 5 categories of additive manufacturing techniques were identified: material jetting, powder bed fusion, vat photopolymerization, binder jetting, and material extrusion. Conclusions Additive manufacturing technologies for bone graft material fabrication in dentistry, especially 3D bioprinting approaches, have been successfully used to fabricate bone graft material with distinct compositions.
AUTHOR Murab, Sumit and Gupta, Aastha and Włodarczyk-Biegun, Małgorzata Katarzyna and Kumar, Anuj and van Rijn, Patrick and Whitlock, Patrick and Han, Sung Soo and Agrawal, Garima
Title Alginate based hydrogel inks for 3D bioprinting of engineered orthopedic tissues [Abstract]
Year 2022
Journal/Proceedings Carbohydrate Polymers
Reftype
DOI/URL URL DOI
Abstract
3D printed hydrogels have emerged as a novel tissue engineering and regeneration platform due to their ability to provide a suitable environment for cell growth. To obtain a well-defined scaffold with good post-printing shape fidelity, a proper hydrogel ink formulation plays a crucial role. In this regard, alginate has received booming interest owing to its biocompatibility, biodegradability, easy functionalization, and fast gelling behavior. Hence, this review highlights the significance of alginate-based hydrogel inks for fabricating 3D printed scaffolds for bone and cartilage regeneration. Herein, we discuss the fundamentals of direct extrusion 3D bioprinting method and provide a comprehensive overview of various alginate-based hydrogel ink formulations that have been used so far. We also summarize the requirements of hydrogel inks and 3D printed scaffolds to achieve similarity to the native tissue environment. Finally, we discuss the challenges, and research directions relevant for future clinical translation.
AUTHOR Pontiggia, Luca and Hengel, Ingmar A.J. Van and Klar, Agnes and Rütsche, Dominic and Nanni, Monica and Scheidegger, Andreas and Figi, Sandro and Reichmann, Ernst and Moehrlen, Ueli and Biedermann, Thomas
Title Bioprinting and plastic compression of large pigmented and vascularized human dermo-epidermal skin substitutes by means of a new robotic platform [Abstract]
Year 2022
Journal/Proceedings Journal of Tissue Engineering
Reftype
DOI/URL URL DOI
Abstract
Extensive availability of engineered autologous dermo-epidermal skin substitutes (DESS) with functional and structural properties of normal human skin represents a goal for the treatment of large skin defects such as severe burns. Recently, a clinical phase I trial with this type of DESS was successfully completed, which included patients own keratinocytes and fibroblasts. Yet, two important features of natural skin were missing: pigmentation and vascularization. The first has important physiological and psychological implications for the patient, the second impacts survival and quality of the graft. Additionally, accurate reproduction of large amounts of patient’s skin in an automated way is essential for upscaling DESS production. Therefore, in the present study, we implemented a new robotic unit (called SkinFactory) for 3D bioprinting of pigmented and pre-vascularized DESS using normal human skin derived fibroblasts, blood- and lymphatic endothelial cells, keratinocytes, and melanocytes. We show the feasibility of our approach by demonstrating the viability of all the cells after printing in vitro, the integrity of the reconstituted capillary network in vivo after transplantation to immunodeficient rats and the anastomosis to the vascular plexus of the host. Our work has to be considered as a proof of concept in view of the implementation of an extended platform, which fully automatize the process of skin substitution: this would be a considerable improvement of the treatment of burn victims and patients with severe skin lesions based on patients own skin derived cells.
AUTHOR Saghar Soman, Soja and Govindraj, Mano and Al Hashimi, Noura and Zhou, Jiarui and Vijayavenkataraman, Sanjairaj
Title Bioprinting of Human Neural Tissues Using a Sustainable Marine Tunicate-Derived Bioink for Translational Medicine Applications [Abstract]
Year 2022
Journal/Proceedings International Journal of Bioprinting; Vol 8, No 4 (2022)DO - 10.18063/ijb.v8i4.604
Reftype
DOI/URL URL
Abstract
Bioprinting of nervous tissue is a major challenge in the bioprinting field due to its soft consistency and complex architecture. The first step in efficient neural bioprinting is the design and optimization of printable bioinks which favor the growth and differentiation of neural tissues by providing the mechanophysiological properties of the native tissue microenvironment. However, till date, limited studies have been conducted to make tissue specific bioinks. Here, we report a novel bioink formulation specifically designed for bioprinting and differentiation of neural stem cells (NSCs) to peripheral neurons, using a marine tunicate-derived hydrogel and Matrigel. The formulation resulted in seamless bioprinting of NSCs with minimal processing time from bioink preparation to in vitro culture. The tissues exhibited excellent post-printing viability and cell proliferation along with a precise peripheral nerve morphology on in vitro differentiation. The cultured tissues showed significant cell recovery after subjecting to a freeze-thaw cycle of −80 to 37°C, indicating the suitability of the method for developing tissues compatible for long-term storage and transportation for clinical use. The study provides a robust method to use a sustainable bioink for three-dimensional bioprinting of neural tissues for translational medicine applications.
AUTHOR Daskalakis, Evangelos and Huang, Boyang and Vyas, Cian and Acar, Anil A. and Liu, Fengyuan and Fallah, Ali and Cooper, Glen and Weightman, Andrew and Blunn, Gordon and Koç, Bahattin and Bartolo, Paulo
Title Bone Bricks: The Effect of Architecture and Material Composition on the Mechanical and Biological Performance of Bone Scaffolds [Abstract]
Year 2022
Journal/Proceedings ACS Omega
Reftype
DOI/URL DOI
Abstract
Large bone loss injuries require high-performance scaffolds with an architecture and material composition resembling native bone. However, most bone scaffold studies focus on three-dimensional (3D) structures with simple rectangular or circular geometries and uniform pores, not able to recapitulate the geometric characteristics of the native tissue. This paper addresses this limitation by proposing novel anatomically designed scaffolds (bone bricks) with nonuniform pore dimensions (pore size gradients) designed based on new lay-dawn pattern strategies. The gradient design allows one to tailor the properties of the bricks and together with the incorporation of ceramic materials allows one to obtain structures with high mechanical properties (higher than reported in the literature for the same material composition) and improved biological characteristics.
AUTHOR Fl{'{e}}geau, Killian and Puiggali-Jou, Anna and Zenobi-Wong, Marcy
Title Cartilage tissue engineering by extrusion bioprinting utilizing porous hyaluronic acid microgel bioinks [Abstract]
Year 2022
Journal/Proceedings Biofabrication
Reftype
DOI/URL DOI
Abstract
3D bioprinting offers an excellent opportunity to provide tissue-engineered cartilage to microtia patients. However, hydrogel-based bioinks are hindered by their dense and cell-restrictive environment, impairing tissue development and ultimately leading to mechanical failure of large scaffolds in vivo. Granular hydrogels, made of annealed microgels, offer a superior alternative to conventional bioinks, with their improved porosity and modularity. We have evaluated the ability of enzymatically crosslinked hyaluronic acid (HA) microgel bioinks to form mature cartilage in vivo. Microgel bioinks were formed by mechanically sizing bulk HA-tyramine hydrogels through meshes with aperture diameters of 40, 100 or 500 µm. Annealing of the microgels was achieved by crosslinking residual tyramines. Secondary crosslinked scaffolds were stable in solution and showed tunable porosity from 9% to 21%. Bioinks showed excellent rheological properties and were used to print different objects. Printing precision was found to be directly correlated to microgel size. As a proof of concept, freeform reversible embedding of suspended hydrogels printing with gelation triggered directly in the bath was performed to demonstrate the versatility of the method. The granular hydrogels support the homogeneous development of mature cartilage-like tissues in vitro with mechanical stiffening up to 200 kPa after 63 d. After 6 weeks of in vivo implantation, small-diameter microgels formed stable constructs with low immunogenicity and continuous tissue maturation. Conversely, increasing the microgel size resulted in increased inflammatory response, with limited stability in vivo. This study reports the development of new microgel bioinks for cartilage tissue biofabrication and offers insights into the foreign body reaction towards porous scaffolds implantation.
AUTHOR Cao, Chuanliang and Huang, Pengren and Prasopthum, Aruna and Parsons, Andrew J. and Ai, Fanrong and Yang, Jing
Title Characterisation of bone regeneration in 3D printed ductile PCL/PEG/hydroxyapatite scaffolds with high ceramic microparticle concentrations [Abstract]
Year 2022
Journal/Proceedings Biomater. Sci.
Reftype
DOI/URL DOI
Abstract
3D printed bioactive glass or bioceramic particle reinforced composite scaffolds for bone tissue engineering currently suffer from low particle concentration (100% breaking strain) by adding poly(ethylene glycol) which is biocompatible and FDA approved. The scaffolds require no post-printing washing to remove hazardous components. More exposure of HA microparticles on strut surfaces is enabled by incorporating higher HA concentrations. Compared to scaffolds with 72 wt% HA{,} scaffolds with higher HA content (90 wt%) enhance matrix formation but not new bone volume after 12 weeks implantation in rat calvarial defects. Histological analyses demonstrate that bone regeneration within the 3D printed scaffolds is via intramembranous ossification and starts in the central region of pores. Fibrous tissue that resembles non-union tissue within bone fractures is formed within pores that do not have new bone. The amount of blood vessels is similar between scaffolds with mainly fibrous tissue and those with more bone tissue{,} suggesting vascularization is not a deciding factor for determining the type of tissues regenerated within the pores of 3D printed scaffolds. Multinucleated immune cells are commonly present in all scaffolds surrounding the struts{,} suggesting a role of managing inflammation in bone regeneration within 3D printed scaffolds.
AUTHOR Clua-Ferré, Laura and de Chiara, Francesco and Rodríguez-Comas, Júlia and Comelles, Jordi and Martinez, Elena and Godeau, Amelie Luise and García-Alamán, Ainhoa and Gasa, Rosa and Ramón-Azcón, Javier
Title Collagen-Tannic Acid Spheroids for β-Cell Encapsulation Fabricated Using a 3D Bioprinter [Abstract]
Year 2022
Journal/Proceedings Advanced Materials Technologies
Reftype
DOI/URL DOI
Abstract
Abstract Type 1 Diabetes results from autoimmune response elicited against β-cell antigens. Nowadays, insulin injections remain the leading therapeutic option. However, injection treatment fails to emulate the highly dynamic insulin release that β-cells provide. 3D cell-laden microspheres have been proposed during the last years as a major platform for bioengineering insulin-secreting constructs for tissue graft implantation and a model for in vitro drug screening platforms. Current microsphere fabrication technologies have several drawbacks: the need for an oil phase containing surfactants, diameter inconsistency of the microspheres, and high time-consuming processes. These technologies have widely used alginate for its rapid gelation, high processability, and low cost. However, its low biocompatible properties do not provide effective cell attachment. This study proposes a high-throughput methodology using a 3D bioprinter that employs an ECM-like microenvironment for effective cell-laden microsphere production to overcome these limitations. Crosslinking the resulting microspheres with tannic acid prevents collagenase degradation and enhances spherical structural consistency while allowing the diffusion of nutrients and oxygen. The approach allows customization of microsphere diameter with extremely low variability. In conclusion, a novel bio-printing procedure is developed to fabricate large amounts of reproducible microspheres capable of secreting insulin in response to extracellular glucose stimuli.
AUTHOR Man, Kenny and Barroso, Inês A. and Brunet, Mathieu Y. and Peacock, Ben and Federici, Angelica S. and Hoey, David A. and Cox, Sophie C.
Title Controlled Release of Epigenetically-Enhanced Extracellular Vesicles from a GelMA/Nanoclay Composite Hydrogel to Promote Bone Repair [Abstract]
Year 2022
Journal/Proceedings International Journal of Molecular Sciences
Reftype
DOI/URL URL DOI
Abstract
Extracellular vesicles (EVs) have garnered growing attention as promising acellular tools for bone repair. Although EVs’ potential for bone regeneration has been shown, issues associated with their therapeutic potency and short half-life in vivo hinders their clinical utility. Epigenetic reprogramming with the histone deacetylase inhibitor Trichostatin A (TSA) has been reported to promote the osteoinductive potency of osteoblast-derived EVs. Gelatin methacryloyl (GelMA) hydrogels functionalised with the synthetic nanoclay laponite (LAP) have been shown to effectively bind, stabilise, and improve the retention of bioactive factors. This study investigated the potential of utilising a GelMA-LAP hydrogel to improve local retention and control delivery of epigenetically enhanced osteoblast-derived EVs as a novel bone repair strategy. LAP was found to elicit a dose-dependent increase in GelMA compressive modulus and shear-thinning properties. Incorporation of the nanoclay was also found to enhance shape fidelity when 3D printed compared to LAP-free gels. Interestingly, GelMA hydrogels containing LAP displayed increased mineralisation capacity (1.41-fold) (p ≤ 0.01) over 14 days. EV release kinetics from these nanocomposite systems were also strongly influenced by LAP concentration with significantly more vesicles being released from GelMA constructs as detected by a CD63 ELISA (p ≤ 0.001). EVs derived from TSA-treated osteoblasts (TSA-EVs) enhanced proliferation (1.09-fold), migration (1.83-fold), histone acetylation (1.32-fold) and mineralisation (1.87-fold) of human bone marrow stromal cells (hBMSCs) when released from the GelMA-LAP hydrogel compared to the untreated EV gels (p ≤ 0.01). Importantly, the TSA-EV functionalised GelMA-LAP hydrogel significantly promoted encapsulated hBMSCs extracellular matrix collagen production (≥1.3-fold) and mineralisation (≥1.78-fold) in a dose-dependent manner compared to untreated EV constructs (p ≤ 0.001). Taken together, these findings demonstrate the potential of combining epigenetically enhanced osteoblast-derived EVs with a nanocomposite photocurable hydrogel to promote the therapeutic efficacy of acellular vesicle approaches for bone regeneration.
AUTHOR Cadle, Rachel and Rogozea, Dan and Moldovan, Leni and Moldovan, Nicanor I.
Title Design and Implementation of Anatomically Inspired Mesenteric and Intestinal Vascular Patterns for Personalized 3D Bioprinting [Abstract]
Year 2022
Journal/Proceedings Applied Sciences
Reftype
DOI/URL URL DOI
Abstract
Recent progress in bioprinting has made possible the creation of complex 3D intestinal constructs, including vascularized villi. However, for their integration into functional units useful for experimentation or implantation, the next challenge is to endow them with a larger-scale, anatomically realistic vasculature. In general, the perfusion of bioprinted constructs has remained difficult, and the current solution is to provide them with mostly linear and simply branched channels. To address this limitation, here we demonstrated an image analysis-based workflow leading through computer-assisted design from anatomic images of rodent mesentery and colon to the actual printing of such patterns with paste and hydrogel bioinks. Moreover, we reverse-engineered the 2D intestinal image-derived designs into cylindrical objects, and 3D-printed them in a support hydrogel. These results open the path towards generation of more realistically vascularized tissue constructs for a variety of personalized medicine applications.
AUTHOR Ramakrishnan, Rashmi and Kasoju, Naresh and Raju, Riya and Geevarghese, Rency and Gauthaman, Ashna and Bhatt, Anugya
Title Exploring the Potential of Alginate-Gelatin-Diethylaminoethyl Cellulose-Fibrinogen based Bioink for 3D Bioprinting of Skin Tissue Constructs [Abstract]
Year 2022
Journal/Proceedings Carbohydrate Polymer Technologies and Applications
Reftype
DOI/URL URL DOI
Abstract
Designing printable bioinks for 3D bioprinting capable of supporting cellular viability with post-printing functionality remains challenging. Native ECM offers several physical, chemical, and biological cues that are difficult to restore using only a single component. Herein, we have optimized a multicomponent-based bioink formulation comprising alginate (ALG), gelatin (GEL), diethylaminoethyl cellulose (DCEL) and fibrinogen (FIB), termed as ALG-GEL-DCEL-FIB bioink for potential application in bioprinting and biofabrication of skin tissue equivalents. The designed formulation was extensively studied for its printability, physico-chemical, rheological, and biocompatibility properties. Excellent printability, shape fidelity and cell-laden tissue equivalent printing were established using the RegenHu 3D Discovery Bioprinter. The human primary fibroblast and keratinocyte-laden bioprinted constructs exhibited good cell viability. Long term culture of 4 weeks comprising 5 days of air-liquid-interphase followed by 21 days of submerged culture produced biomimetic tissue histology in the ALG-GEL-DCEL-FIB bioink printed constructs. Specific epidermal-dermal marker expressions proving functionality were evident in immunohistochemical, biochemical and gene expression analysis. The ALG-GEL-DCEL-FIB bioink may be explored further for potential biofabrication and therapeutic applications.
AUTHOR Li, Ming-Chia and Chang, Pu-Yuan and Luo, Huai-Rou and Chang, Ling-Yuan and Lin, Chuan-Yi and Yang, Chih-Yu and Lee, Oscar Kuang-Sheng and Lee, Yan-Hwa Wu and Tarng, Der-Cherng
Title Functioning tailor-made 3D-printed vascular graft for hemodialysis [Abstract]
Year 2022
Journal/Proceedings The Journal of Vascular Access
Reftype
DOI/URL DOI
Abstract
Background:The two ends of arteriovenous graft (AVG) are anastomosed to the upper limb vessels by surgery for hemodialysis therapy. However, the size of upper limb vessels varies to a large extent among different individuals.Methods:According to the shape and size of neck vessels quantified from the preoperative computed tomography angiographic scan, the ethylene-vinyl acetate (EVA)-based AVG was produced in H-shape by the three-dimensional (3D) printer and then sterilized. This study investigated the function of this novel 3D-printed AVG in vitro and in vivo.Results:This 3D-printed AVG can be implanted in the rabbit’s common carotid artery and common jugular vein with ease and functions in vivo. The surgical procedure was quick, and no suture was required. The blood loss was minimal, and no hematoma was noted at least 1 week after the surgery. The blood flow velocity within the implanted AVG was 14.9 ± 3.7 cm/s. Additionally, the in vitro characterization experiments demonstrated that this EVA-based biomaterial is biocompatible and possesses a superior recovery property than ePTFE after hemodialysis needle cannulation.Conclusions:Through the 3D printing technology, the EVA-based AVG can be tailor-made to fit the specific vessel size. This kind of 3D-printed AVG is functioning in vivo, and our results realize personalized vascular implants. Further large-animal studies are warranted to examine the long-term patency.
AUTHOR Mota, Fabio Batista and Braga, Luiza Amara Maciel and Cabral, Bernardo Pereira and Filho, Carlos Gilbert Conte
Title Future of Bioprinted Tissues аnd Organs: A Two-Wave Global Survey [Abstract]
Year 2022
Journal/Proceedings Foresight and STI Governance
Reftype
DOI/URL URL
Abstract
Technologies of 3D and 4D bioprinting make it possible to restore or replace tissues and organs, solving the problem of the lack of donor resources and reducing the risks of implant rejection. This article presents the results of a two-stage global survey of specialists in tissue engineering on the prospects of bioprinting in preclinical studies and clinical practice. A picture of possible tracks and horizons upon which the implementation of the considered solutions is possible is presented. According to the results of the survey, in the next two decades it will be possible to recreate tissues and organs suitable for implantation and drug testing. There will be a market for bioprinted products, the problem of organ shortages and adverse reactions to drugs will be solved. These changes may significantly affect not only the practice of biomedical research, drug testing, and medicine, but also the healthcare sector in general, which implies the need for a preventive review of current policies. A practical and accessible tool for identifying and interviewing a large number of experts around the world is proposed, which may be useful for new Foresight studies.
AUTHOR Yan Li and Lijing Huang and Guangpin Tai and Feifei Yan and Lin Cai and Chenxing Xin and Shamoon {Al Islam}
Title Graphene Oxide-loaded magnetic nanoparticles within 3D hydrogel form High-performance scaffolds for bone regeneration and tumour treatment [Abstract]
Year 2022
Journal/Proceedings Composites Part A: Applied Science and Manufacturing
Reftype
DOI/URL URL DOI
Abstract
The treatment of tumour-related bone defects should ideally combine bone regeneration with tumour treatment. Additive manufacturing (AM) could feasibly place functional bone-repair materials within composite materials with functional-grade structures, giving them bone repair and anti-tumour effects. Magnetothermal therapy is a promising non-invasive method of tumour treatment that has attracted increasing attention. In this study, we prepared novel hydrogel composite scaffolds of polyvinyl alcohol/sodium alginate/hydroxyapatite (PVA/SA/HA) at low temperature via AM. The scaffolds were loaded with various concentrations of magnetic graphene oxide (MGO) @Fe3O4 nanoparticles. The scaffolds were characterised by fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and thermal gravimetric analysis (TGA), which showed that the scaffolds have good moulding qualities and strong hydrogen bonding between the MGO/PVA/SA/HA components. TGA analysis demonstrated the expected thermal stability of the MGO and scaffolds. Thermal effects can be adjusted by varying the contents of MGO and the strength of an external alternating magnetic field. The prepared MGO hydrogel composite scaffolds enhance biological functions and support bone mesenchymal stem cell differentiation in vitro. The scaffolds also show favourable anti-tumour characteristics with effective magnetothermal conversion in vivo.
AUTHOR Girardeau-Hubert, Sarah and Lynch, Barbara and Zuttion, Francesca and Label, Rabab and Rayee, Chrystelle and Brizion, Sébastien and Ricois, Sylvie and Martinez, Anthony and Park, Eunhye and Kim, Changhwan and Marinho, Paulo André and Shim, Jin-Hyung and Jin, Songwan and Rielland, Maïté and Soeur, Jérémie
Title Impact of microstructure on cell behavior and tissue mechanics in collagen and dermal decellularized extra-cellular matrices [Abstract]
Year 2022
Journal/Proceedings Acta Biomaterialia
Reftype
DOI/URL URL DOI
Abstract
Skin models are used for many applications such as research and development or grafting. Unfortunately, most lack a proper microenvironment producing poor mechanical properties and inaccurate extra-cellular matrix composition and organization. In this report we focused on mechanical properties, extra-cellular matrix organization and cell interactions in human skin samples reconstructed with pure collagen or dermal decellularized extra-cellular matrices (S-dECM) and compared them to native human skin. We found that Full-thickness S-dECM samples presented stiffness two times higher than collagen gel and similar to ex vivo human skin, and proved for the first time that keratinocytes also impact dermal mechanical properties. This was correlated with larger fibers in S-dECM matrices compared to collagen samples and with a differential expression of F-actin, vinculin and tenascin C between S-dECM and collagen samples. This is clear proof of the microenvironment's impact on cell behaviors and mechanical properties. Statement of significance In vitro skin models have been used for a long time for clinical applications or in vitro knowledge and evaluation studies. However, most lack a proper microenvironment producing a poor combination of mechanical properties and appropriate biological outcomes, partly due to inaccurate extra-cellular matrix (ECM) composition and organization. This can lead to limited predictivity and weakness of skin substitutes after grafting. This study shows, for the first time, the importance of a complex and rich microenvironment on cell behaviors, matrix macro- and micro-organization and mechanical properties. The increased composition and organization complexity of dermal skin decellularized extra-cellular matrix populated with differentiated cells produces in vitro skin models closer to native human skin physiology.
AUTHOR Helaehil, Júlia Venturini and Lourenço, Carina Basqueira and Huang, Boyang and Helaehil, Luiza Venturini and de Camargo, Isaque Xavier and Chiarotto, Gabriela Bortolança and Santamaria-Jr, Milton and Bártolo, Paulo and Caetano, Guilherme Ferreira
Title In Vivo Investigation of Polymer-Ceramic PCL/HA and PCL/β-TCP 3D Composite Scaffolds and Electrical Stimulation for Bone Regeneration [Abstract]
Year 2022
Journal/Proceedings Polymers
Reftype
DOI/URL URL DOI
Abstract
Critical bone defects are a major clinical challenge in reconstructive bone surgery. Polycaprolactone (PCL) mixed with bioceramics, such as hydroxyapatite (HA) and tricalcium phosphate (TCP), create composite scaffolds with improved biological recognition and bioactivity. Electrical stimulation (ES) aims to compensate the compromised endogenous electrical signals and to stimulate cell proliferation and differentiation. We investigated the effects of composite scaffolds (PCL with HA; and PCL with β-TCP) and the use of ES on critical bone defects in Wistar rats using eight experimental groups: untreated, ES, PCL, PCL/ES, HA, HA/ES, TCP, and TCP/ES. The investigation was based on histomorphometry, immunohistochemistry, and gene expression analysis. The vascular area was greater in the HA/ES group on days 30 and 60. Tissue mineralization was greater in the HA, HA/ES, and TCP groups at day 30, and TCP/ES at day 60. Bmp-2 gene expression was higher in the HA, TCP, and TCP/ES groups at day 30, and in the TCP/ES and PCL/ES groups at day 60. Runx-2, Osterix, and Osteopontin gene expression were also higher in the TCP/ES group at day 60. These results suggest that scaffolds printed with PCL and TCP, when paired with electrical therapy application, improve bone regeneration.
AUTHOR Włodarczyk-Biegun, Małgorzata K. and Villiou, Maria and Koch, Marcus and Muth, Christina and Wang, Peixi and Ott, Jenna and del Campo, Aranzazu
Title Melt Electrowriting of Graded Porous Scaffolds to Mimic the Matrix Structure of the Human Trabecular Meshwork [Abstract]
Year 2022
Journal/Proceedings ACS Biomaterials Science & Engineering
Reftype
DOI/URL DOI
Abstract
The permeability of the human trabecular meshwork (HTM) regulates eye pressure via a porosity gradient across its thickness modulated by stacked layers of matrix fibrils and cells. Changes in HTM porosity are associated with increases in intraocular pressure and the progress of diseases such as glaucoma. Engineered HTMs could help to understand the structure–function relation in natural tissues and lead to new regenerative solutions. Here, melt electrowriting (MEW) is explored as a biofabrication technique to produce fibrillar, porous scaffolds that mimic the multilayer, gradient structure of native HTM. Poly(caprolactone) constructs with a height of 125–500 μm and fiber diameters of 10–12 μm are printed. Scaffolds with a tensile modulus between 5.6 and 13 MPa and a static compression modulus in the range of 6–360 kPa are obtained by varying the scaffold design, that is, the density and orientation of the fibers and number of stacked layers. Primary HTM cells attach to the scaffolds, proliferate, and form a confluent layer within 8–14 days, depending on the scaffold design. High cell viability and cell morphology close to that in the native tissue are observed. The present work demonstrates the utility of MEW for reconstructing complex morphological features of natural tissues.
AUTHOR Sarmin, Atiya M. and El Moussaid, Nadia and Suntornnond, Ratima and Tyler, Eleanor J. and Kim, Yang-Hee and Di Cio, Stefania and Megone, William V. and Pearce, Oliver and Gautrot, Julien E. and Dawson, Jonathan and Connelly, John T.
Title Multi-Scale Analysis of the Composition, Structure, and Function of Decellularized Extracellular Matrix for Human Skin and Wound Healing Models [Abstract]
Year 2022
Journal/Proceedings Biomolecules
Reftype
DOI/URL URL DOI
Abstract
The extracellular matrix (ECM) is a complex mixture of structural proteins, proteoglycans, and signaling molecules that are essential for tissue integrity and homeostasis. While a number of recent studies have explored the use of decellularized ECM (dECM) as a biomaterial for tissue engineering, the complete composition, structure, and mechanics of these materials remain incompletely understood. In this study, we performed an in-depth characterization of skin-derived dECM biomaterials for human skin equivalent (HSE) models. The dECM materials were purified from porcine skin, and through mass spectrometry profiling, we quantified the presence of major ECM molecules, including types I, III, and VI collagen, fibrillin, and lumican. Rheological analysis demonstrated the sol-gel and shear-thinning properties of dECM materials, indicating their physical suitability as a tissue scaffold, while electron microscopy revealed a complex, hierarchical structure of nanofibers in dECM hydrogels. The dECM materials were compatible with advanced biofabrication techniques, including 3D printing within a gelatin microparticle support bath, printing with a sacrificial material, or blending with other ECM molecules to achieve more complex compositions and structures. As a proof of concept, we also demonstrate how dECM materials can be fabricated into a 3D skin wound healing model using 3D printing. Skin-derived dECM therefore represents a complex and versatile biomaterial with advantageous properties for the fabrication of next-generation HSEs.
AUTHOR Daskalakis, Evangelos and Huang, Boyang and Vyas, Cian and Acar, Anil Ahmet and Fallah, Ali and Cooper, Glen and Weightman, Andrew and Koc, Bahattin and Blunn, Gordon and Bartolo, Paulo
Title Novel 3D Bioglass Scaffolds for Bone Tissue Regeneration [Abstract]
Year 2022
Journal/Proceedings Polymers
Reftype
DOI/URL URL DOI
Abstract
The design of scaffolds with optimal biomechanical properties for load-bearing applications is an important topic of research. Most studies have addressed this problem by focusing on the material composition and not on the coupled effect between the material composition and the scaffold architecture. Polymer–bioglass scaffolds have been investigated due to the excellent bioactivity properties of bioglass, which release ions that activate osteogenesis. However, material preparation methods usually require the use of organic solvents that induce surface modifications on the bioglass particles, compromising the adhesion with the polymeric material thus compromising mechanical properties. In this paper, we used a simple melt blending approach to produce polycaprolactone/bioglass pellets to construct scaffolds with pore size gradient. The results show that the addition of bioglass particles improved the mechanical properties of the scaffolds and, due to the selected architecture, all scaffolds presented mechanical properties in the cortical bone region. Moreover, the addition of bioglass indicated a positive long-term effect on the biological performance of the scaffolds. The pore size gradient also induced a cell spreading gradient.
AUTHOR Staubli, Flurina and Stoddart, Martin J. and D'Este, Matteo and Schwab, Andrea
Title Pre-culture of human mesenchymal stromal cells in spheroids facilitates chondrogenesis at a low total cell count upon embedding in biomaterials to generate cartilage microtissues [Abstract]
Year 2022
Journal/Proceedings Acta Biomaterialia
Reftype
DOI/URL URL DOI
Abstract
Material-assisted cartilage tissue engineering has limited application in cartilage treatment due to hypertrophic tissue formation and high cell counts required. This study aimed at investigating the potential of human mesenchymal stromal cell (hMSC) spheroids embedded in biomaterials to study the effect of biomaterial composition on cell differentiation. Pre-cultured (3 days, chondrogenic differentiation media) spheroids (250 cells/spheroid) were embedded in tyramine-modified hyaluronic acid (THA) and collagen type I (Col) composite hydrogels (four combinations of THA (12.5 vs 16.7 mg/ml) and Col (2.5 vs 1.7 mg/ml) content) at a cell density of 5 × 106 cells/ml (2 × 104 spheroids/ml). Macropellets derived from single hMSCs (2.5 × 105 cells, ScMP) or hMSC spheroids (2.5 × 105 cells, 103 spheroids, SpMP) served as control. hMSC differentiation was analyzed using glycosaminoglycan (GAG) quantification, gene expression analysis and (immuno-)histology. Embedding of hMSC spheroids in THA-Col induced chondrogenic differentiation marked by upregulation of aggrecan (ACAN) and COL2A1, and the production of GAGs . Lower THA led to more pronounced chondrogenic phenotype compared to higher THA content. Col content had no significant influence on hMSC chondrogenesis. Pellet cultures showed an upregulation in chondrogenic-associated genes and production of GAGs with less upregulation of hypertrophic-associated genes in SpMP culture compared to ScMP group. This study presents hMSC pre-culture in spheroids as promising approach to study chondrogenic differentiation after biomaterial encapsulation at low total cell count (5 × 106/ml) without compromising chondrogenic matrix production. This approach can be applied to assemble microtissues in biomaterials to generate large cartilage construct. Statement of significance In vitro studies investigating the chondrogenic potential of biomaterials are limited due to the low cell-cell contact of encapsulated single cells. Here, we introduce the use of pre-cultured hMSC spheroids to study chondrogenesis upon encapsulation in a biomaterial. The use of spheroids takes advantage of the high cell-cell contact within each spheroid being critical in the early chondrogenesis of hMSCs. At a low seeding density of 5·106 cells/ml (2 × 104 spheroids/ml) we demonstrated hMSC chondrogenesis and cartilaginous matrix deposition. Our results indicate that the pre-culture might have a beneficial effect on hypertrophic gene expression without compromising chondrogenic differentiation. This approach has shown potential to assemble microtissues (here spheroids) in biomaterials to generate large cartilage constructs and to study the effect of biomaterial composition on cell alignment and migration.
AUTHOR Wang, Ruiqi and Deng, Shuai and Wu, Yuping and Wei, Haiying and Jing, Guangping and Zhang, Bosong and Liu, Fengzhen and Tian, Hui and Chen, Xiongbiao and Tian, Weiming
Title Remodelling 3D printed GelMA-HA corneal scaffolds by cornea stromal cells [Abstract]
Year 2022
Journal/Proceedings Colloid and Interface Science Communications
Reftype
DOI/URL URL DOI
Abstract
Engineering scaffolds with a structure mimicking that of native cornea allows for addressing the severe donor shortage for the corneal blindness treatment, which, however, remains challenging. In the light that corneal stromal (CS) cells can play a key role in corneal stroma formation, in this study we incorporated CS cells into three-dimensional (3D) scaffolds printed from hyaluronic acid-modified gelatin-methacrylate (GelMA-HA) scaffolds and characterized the scaffolds in terms of remodeled extracellular matrix (ECM) in vitro. Our results illustrated that the modification of GelMA by HA allowed for 3D printing of corneal scaffolds and further improved the characteristics of primary rabbit-derived corneal stromal cells for remodelling scaffolds. After 60 days, we decellularized the remodeled corneal scaffolds and examined their optical properties; and our results demonstrated that the 3D printed corneal scaffolds provided CS cells with cues that guided them toward the directional and spatial organization and facilitated the ECM remodelling.
AUTHOR Eichholz, Kian and Freeman, Fiona and Pitacco, Pierluca and Nulty, Jessica and Ahern, Daniel and Burdis, Ross and Browe, David and Garcia, Orquidea and Hoey, David and Kelly, Daniel John
Title Scaffold microarchitecture regulates angiogenesis and the regeneration of large bone defects [Abstract]
Year 2022
Journal/Proceedings Biofabrication
Reftype
DOI/URL DOI
Abstract
Emerging 3D printing technologies can provide exquisite control over the external shape and internal architecture of scaffolds and tissue engineered constructs, enabling systematic studies to explore how geometric design features influence the regenerative process. Here we used fused deposition modelling (FDM) and melt electrowriting (MEW) to investigate how scaffold microarchitecture influences the healing of large bone defects. FDM was used to fabricate scaffolds with relatively large fibre diameters and low porosities, while MEW was used to fabricate scaffolds with smaller fibre diameters and higher porosities, with both scaffolds being designed to have comparable surface areas. Scaffold microarchitecture significantly influenced the healing response following implantation into critically sized femoral defects in rats, with the FDM scaffolds supporting the formation of larger bone spicules through its pores, while the MEW scaffolds supported the formation of a more round bone front during healing. After 12 weeks in vivo, both MEW and FDM scaffolds supported significantly higher levels of defect vascularisation compared to empty controls, while the MEW scaffolds supported higher levels of new bone formation. Somewhat surprisingly, this superior healing in the MEW group did not correlate with higher levels of angiogenesis, with the FDM scaffold supporting greater total vessel formation and the formation of larger vessels, while the MEW scaffold promoted the formation of a dense microvasculature with minimal evidence of larger vessels infiltrating the defect region. To conclude, the small fibre diameter, high porosity and high specific surface area of the MEW scaffold proved beneficial for osteogenesis and bone regeneration, demonstrating that changes in scaffold architecture enabled by this additive manufacturing technique can dramatically modulate angiogenesis and tissue regeneration without the need for complex exogenous growth factors. These results provide a valuable insight into the importance of 3D printed scaffold architecture when developing new bone tissue engineering strategies.
AUTHOR Liu, Jing and Zhou, Zhengtong and Zhang, Min and Song, Feng and Feng, Chong and Liu, Haochen
Title Simple and robust 3D bioprinting of full-thickness human skin tissue [Abstract]
Year 2022
Journal/Proceedings Bioengineered
Reftype
DOI/URL DOI
Abstract
ABSTRACTArtificial skins have been used as skin substitutes for wound healing in the clinic, and as in vitro models for safety assessment in cosmetic and pharmaceutical industries. The three-dimensional (3D) bioprinting technique provides a promising strategy in the fabrication of artificial skins. Despite the technological advances, many challenges remain to be conquered, such as the complicated preparation conditions for bio-printed skin and the unavailability of stability and robustness of skin bioprinting. Here, we formulated a novel bio-ink composed of gelatin, sodium alginate and fibrinogen. By optimizing the ratio of components in the bio-ink, the design of the 3D model and the printing conditions, a fibroblasts-containing dermal layer construct was firstly fabricated, on the top of which laminin and keratinocytes were sequentially placed. Through air-liquid interface (ALI) culture by virtue of sterile wire mesh, a full-thickness skin tissue was thus prepared. HE and immunofluorescence staining showed that the bio-printed skin was not only morphologically representative of the human skin, but also expressed the specific markers related to epidermal differentiation and stratum corneum formation. The presented easy and robust preparation of full-thickness skin constructs provides a powerful tool for the establishment of artificial skins, holding critical academic significance and application value.
AUTHOR Burdis, Ross and Chariyev-Prinz, Farhad and Browe, David C. and Freeman, Fiona E. and Nulty, Jessica and McDonnell, Emily E. and Eichholz, Kian F. and Wang, Bin and Brama, Pieter and Kelly, Daniel J.
Title Spatial patterning of phenotypically distinct microtissues to engineer osteochondral grafts for biological joint resurfacing [Abstract]
Year 2022
Journal/Proceedings Biomaterials
Reftype
DOI/URL URL DOI
Abstract
Modular biofabrication strategies using microtissues or organoids as biological building blocks have great potential for engineering replacement tissues and organs at scale. Here we describe the development of a biofabrication strategy to engineer osteochondral tissues by spatially localising phenotypically distinct cartilage microtissues within an instructive 3D printed polymer framework. We first demonstrate that immature cartilage microtissues can spontaneously fuse to form homogeneous macrotissues, and that combining less cellular microtissues results in superior fusion and the generation of a more hyaline-like cartilage containing higher levels of sulphated glycosaminoglycans and type II collagen. Furthermore, temporally exposing developing microtissues to transforming growth factor-β accelerates their volumetric growth and subsequent capacity to fuse into larger hyaline cartilage grafts. Next, 3D printed polymeric frameworks are used to further guide microtissue fusion and the subsequent self-organisation process, resulting in the development of a macroscale tissue with zonal collagen organisation analogous to the structure seen in native articular cartilage. To engineer osteochondral grafts, hypertrophic cartilage microtissues are engineered as bone precursor tissues and spatially localised below phenotypically stable cartilage microtissues. Implantation of these engineered grafts into critically-sized caprine osteochondral defects results in effective defect stabilisation and histologically supports the restoration of a more normal articular surface after 6 months in vivo. These findings support the use of such modular biofabrication strategies for biological joint resurfacing.
AUTHOR Hatt, Luan P. and Armiento, Angela R. and Mys, Karen and Thompson, Keith and Hildebrand, Maria and Nehrbass, Dirk and Müller, Werner E. G. and Zeiter, Stephan and Eglin, David and Stoddart, Martin J.
Title Standard in vitro evaluations of engineered bone substitutes are not sufficient to predict in vivo preclinical model outcomes [Abstract]
Year 2022
Journal/Proceedings Acta Biomaterialia
Reftype
DOI/URL URL DOI
Abstract
Understanding the optimal conditions required for bone healing can have a substantial impact to target the problem of non–unions and large bone defects. The combination of bioactive factors, regenerative progenitor cells and biomaterials to form a tissue engineered (TE) complex is a promising solution but translation to the clinic has been slow. We hypothesized the typical material testing algorithm used is insufficient and leads to materials being mischaracterized as promising. In the first part of this study, human bone marrow – derived mesenchymal stromal cells (hBM-MSCs) were embedded in three commonly used biomaterials (hyaluronic acid methacrylate, gelatin methacrylate and fibrin) and combined with relevant bioactive osteogenesis factors (dexamethasone microparticles and polyphosphate nanoparticles) to form a TE construct that underwent in vitro osteogenic differentiation for 28 days. Gene expression of relevant transcription factors and osteogenic markers, and von Kossa staining were performed. In the second and third part of this study, the same combination of TE constructs were implanted subcutaneously (cell containing) in T cell-deficient athymic Crl:NIH-Foxn1rnu rats for 8 weeks or cell free in an immunocompetent New Zealand white rabbit calvarial model for 6 weeks, respectively. Osteogenic performance was investigated via MicroCT imaging and histology staining. The in vitro study showed enhanced upregulation of relevant genes and significant mineral deposition within the three biomaterials, generally considered as a positive result. Subcutaneous implantation indicates none to minor ectopic bone formation. No enhanced calvarial bone healing was detected in implanted biomaterials compared to the empty defect. The reasons for the poor correlation of in vitro and in vivo outcomes are unclear and needs further investigation. This study highlights the discrepancy between in vitro and in vivo outcomes, demonstrating that in vitro data should be interpreted with extreme caution. In vitro models with higher complexity are necessary to increase value for translational studies. Statement of significance Preclinical testing of newly developed biomaterials is a crucial element of the development cycle. Despite this, there is still significant discrepancy between in vitro and in vivo test results. Within this study we investigate multiple combinations of materials and osteogenic stimulants and demonstrate a poor correlation between the in vitro and in vivo data. We propose rationale for why this may be the case and suggest a modified testing algorithm.