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AUTHOR Leu Alexa, Rebeca and Iovu, Horia and Ghitman, Jana and Serafim, Andrada and Stavarache, Cristina and Marin, Maria-Minodora and Ianchis, Raluca
Title 3D-Printed Gelatin Methacryloyl-Based Scaffolds with Potential Application in Tissue Engineering [Abstract]
Year 2021
Journal/Proceedings Polymers
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The development of materials for 3D printing adapted for tissue engineering represents one of the main concerns nowadays. Our aim was to obtain suitable 3D-printed scaffolds based on methacrylated gelatin (GelMA). In this respect, three degrees of GelMA methacrylation, three different concentrations of GelMA (10%, 20%, and 30%), and also two concentrations of photoinitiator (I-2959) (0.5% and 1%) were explored to develop proper GelMA hydrogel ink formulations to be used in the 3D printing process. Afterward, all these GelMA hydrogel-based inks/3D-printed scaffolds were characterized structurally, mechanically, and morphologically. The presence of methacryloyl groups bounded to the surface of GelMA was confirmed by FTIR and 1H-NMR analyses. The methacrylation degree influenced the value of the isoelectric point that decreased with the GelMA methacrylation degree. A greater concentration of photoinitiator influenced the hydrophilicity of the polymer as proved using contact angle and swelling studies because of the new bonds resulting after the photocrosslinking stage. According to the mechanical tests, better mechanical properties were obtained in the presence of the 1% initiator. Circular dichroism analyses demonstrated that the secondary structure of gelatin remained unaffected during the methacrylation process, thus being suitable for biological applications.
AUTHOR Leu Alexa, Rebeca and Iovu, Horia and Trica, Bogdan and Zaharia, Catalin and Serafim, Andrada and Alexandrescu, Elvira and Radu, Ionut-Cristian and Vlasceanu, George and Preda, Silviu and Ninciuleanu, Claudia Mihaela and Ianchis, Raluca
Title Assessment of Naturally Sourced Mineral Clays for the 3D Printing of Biopolymer-Based Nanocomposite Inks [Abstract]
Year 2021
Journal/Proceedings Nanomaterials
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The present study investigated the possibility of obtaining 3D printed composite constructs using biomaterial-based nanocomposite inks. The biopolymeric matrix consisted of methacrylated gelatin (GelMA). Several types of nanoclay were added as the inorganic component. Our aim was to investigate the influence of clay type on the rheological behavior of ink formulations and to determine the morphological and structural properties of the resulting crosslinked hydrogel-based nanomaterials. Moreover, through the inclusion of nanoclays, our goal was to improve the printability and shape fidelity of nanocomposite scaffolds. The viscosity of all ink formulations was greater in the presence of inorganic nanoparticles as shear thinning occurred with increased shear rate. Hydrogel nanocomposites presented predominantly elastic rather than viscous behavior as the materials were crosslinked which led to improved mechanical properties. The inclusion of nanoclays in the biopolymeric matrix limited hydrogel swelling due the physical barrier effect but also because of the supplementary crosslinks induced by the clay layers. The distribution of inorganic filler within the GelMA-based hydrogels led to higher porosities as a consequence of their interaction with the biopolymeric ink. The present study could be useful for the development of soft nanomaterials foreseen for the additive manufacturing of customized implants for tissue engineering.
AUTHOR Curti, Filis and Drăgușin, Diana-Maria and Serafim, Andrada and Iovu, Horia and Stancu, Izabela-Cristina
Title Development of thick paste-like inks based on superconcentrated gelatin/alginate for 3D printing of scaffolds with shape fidelity and stability [Abstract]
Year 2021
Journal/Proceedings Materials Science and Engineering: C
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Shape fidelity and integrity are serious challenges in the 3D printing of hydrogel precursors, as they can influence the overall performance of 3D scaffolds. This work reports the development of superconcentrated inks based on sodium alginate and fish gelatin as an appealing strategy to satisfy such challenges and dictate the quality of the printed scaffolds, without using crosslinking strategies during 3D printing. SEM micrographs and micro-CT images indicate the homogeneous distribution of the polysaccharide in the gelatin-based matrix, suggesting its potential to act as a reinforcing additive. The high concentration of gelatin aqueous solution (50 wt%) and substantial incorporation of alginate have facilitated the highly accurate printability and influence the in vitro stability and mechanical properties of the printed scaffolds. An improvement of the stiffness is dictated by the increase of alginate concentration from 20 wt% to 25 wt%, and an increase of Young modulus with about 46% is reached, confirming the reinforcing effect of polysaccharide. This study highlights the potential of paste-type inks to provide high resolution 3D printed structures with appealing structural and dimensional stability, in vitro degradability and mechanical properties for biomedical applications.
AUTHOR Cernecu, Alexandra and Lungu, Adriana and Stancu, Izabela Cristina and Vasile, Eugeniu and Iovu, Horia
Title Polysaccharide-Based 3D Printing Inks Supplemented with Additives
Year 2020
Journal/Proceedings University Politechnica of Bucharest Scientific Bulletin
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AUTHOR Iordache, F. and Alexandru, D. and Pisoschi, A. M. and PoP, A.
Title 3D Bioprinting of Blood Vessel Model Using Collagen-Hyaluronic Acid Hydrogel [Abstract]
Year 2019
Journal/Proceedings AgroLife Scientific Journal
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3D bioprinting is a technology that supports fabrication of biomimetic tissues with complex architecture. It has application in drug discovery, tissue development, and regenerative medicine. The aim of this study was to create a blood vessel model correlating properties of collagen-hyaluronic acid hydrogel with bioprinter parameters such as speed rate, pressure, number of layers, nozzle diameter, and temperature. The blood vessel model was created using BioCAD software and bioprinted by extrusion technology using collagen-hyaluronic acid hydrogel. We analyzed the water uptake, enzymatic degradation and morphology by scanning electron microscopy and after staining with Hematoxylin and Eosin (H&E) and Trichromic Masson dyes. The results showed that the blood vessel constructs have 2.46 mm (±0.41) mean diameter, 1.4 mm (±0.10) mean thick wall, and 2.8 mm (±0.05) mean height which is appropriate with the model created in the BioCAD software. The optimal parameters for these constructs were: 1.1 bar pressure, 1mm/sec speed rate, 18°C temperature, 0.2 mm nozzle diameter, and 10 numbers of layers. Increasing hydrogel weight by 22% at 2 hours after immersion in PBS suggesting that is hydrophilic. Furthermore, decreasing by up to 47.2% in the presence of collagenase (50 μg/ml) shows that is biodegradable. H&E and Trichromic Masson staining showed that collagen-hyaluronic acid hydrogel organized in a network with pores dimension that could support cells growth and differentiation. In conclusion, our scaffold mimics the blood vessel structure, further experiment will be addressed for study the biocompatibility of these scaffold with mesenchymal stem cells.
AUTHOR Cernencu, Alexandra I. and Lungu, Adriana and Stancu, Izabela-Cristina and Serafim, Andrada and Heggset, Ellinor and Syverud, Kristin and Iovu, Horia
Title Bioinspired 3D printable pectin-nanocellulose ink formulations [Abstract]
Year 2019
Journal/Proceedings Carbohydrate Polymers
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The assessment of several ink formulations for 3D printing based on two natural macromolecular compounds is presented. In the current research we have exploited the fast crosslinking potential of pectin and the remarkable shear-thinning properties of carboxylated cellulose nanofibrils, which is known to induce a desired viscoelastic behavior. Prior to 3D printing, the viscoelastic properties of the polysaccharide inks were evaluated by rheological measurements and injectability tests. The reliance of the printing parameters on the ink composition was established through one-dimensional lines printing, the base units of 3D-structures. The performance of the 3D-printed structures after ionic cross-linking was evaluated in terms of mechanical properties and rehydration behavior. MicroCT was also used to evaluate the morphology of the 3D-printed objects regarding the effect of pectin/nanocellulose ratio on the geometrical features of scaffolds. The proportionality between the two polymers proved to be the determining factor for the firmness and strength of the printed objects.