REGENHU-Switzerland-3d-bioprinting-instrument-bio-3d-bioprinter-DevelopmentTeam-0006

SCIENTIFIC PUBLICATIONS

You are researching: Karlsruhe institute of technology
Matching entries: 4 /4
All Groups
AUTHOR Steier, Anke and Schmieg, Barbara and Irtel von Brenndorff, Yannic and Meier, Manuel and Nirschl, Hermann and Franzreb, Matthias and Lahann, Joerg
Title Enzyme Scaffolds with Hierarchically Defined Properties via 3D Jet Writing [Abstract]
Year 2020
Journal/Proceedings Macromolecular Bioscience
Reftype
DOI/URL DOI
Abstract
Abstract The immobilization of enzymes into polymer hydrogels is a versatile approach to improve their stability and utility in biotechnological and biomedical applications. However, these systems typically show limited enzyme activity, due to unfavorable pore dimensions and low enzyme accessibility. Here, 3D jet writing of water-based bioinks, which contain preloaded enzymes, is used to prepare hydrogel scaffolds with well-defined, tessellated micropores. After 3D jet writing, the scaffolds are chemically modified via photopolymerization to ensure mechanical stability. Enzyme loading and activity in the hydrogel scaffolds is fully retained over 3 d. Important structural parameters of the scaffolds such as pore size, pore geometry, and wall diameter are controlled with micrometer resolution to avoid mass-transport limitations. It is demonstrated that scaffold pore sizes between 120 µm and 1 mm can be created by 3D jet writing approaching the length scales of free diffusion in the hydrogels substrates and resulting in high levels of enzyme activity (21.2% activity relative to free enzyme). With further work, a broad range of applications for enzyme-laden hydrogel scaffolds including diagnostics and enzymatic cascade reactions is anticipated.
AUTHOR Strauß, Svenja and Meutelet, Rafaela and Radosevic, Luka and Gretzinger, Sarah and Hubbuch, Jürgen
Title Image analysis as PAT-Tool for use in extrusion-based bioprinting [Abstract]
Year 2020
Journal/Proceedings Bioprinting
Reftype
DOI/URL URL DOI
Abstract
The technology of bioprinting is arousing a growing interest in biopharmaceutical research and industry. In order to accelerate process development in the field of bioprinting, image-based analysis methods are non-invasive, time- and cost-saving tools which are usable for printer characterization, bioink printability evaluation, and process optimization. Image processing can also be used for the study of reproducibility, since reliable production is important in the transition from research to industrial application, and more precisely to clinical studies. This study revolves around the establishment of an automated and image-based line analysis method for bioprinting applications which enables an easy comparison of 3D-printed lines. Diverse rheological properties of bioinks and the printing process affect the geometry of the resulting object. The line represents a simple geometry, where the influence of the rheological properties and printing parameters is directly apparent. Therefore, a method for line analysis was developed on the basis of image recognition. At first, the method is tested for several substances such as Nivea®, pure and colored Kolliphor solutions, and two commercially available hydrogel formulations which can be used as bioinks. These are Biogelx™-ink-RGD by Biogelx and Cellink® Bioink by Cellink. The examination of limitations showed that transparent materials such as Kolliphor-based solutions cannot be analyzed with the developed method whereas opaque materials such as Nivea® and both bioinks can be analyzed. In the course of process characterization, the method was used to investigate the shrinkage behavior for both bionks. With the help of the line analysis tool, a shrinkage behavior of both bioinks was demonstrated and thus, process time could be identified as a critical process parameter.
AUTHOR Gretzinger, Sarah and Beckert, Nicole and Gleadall, Andrew and Lee-Thedieck, Cornelia and Hubbuch, Jürgen
Title 3D bioprinting – Flow cytometry as analytical strategy for 3D cell structures [Abstract]
Year 2018
Journal/Proceedings Bioprinting
Reftype
DOI/URL URL DOI
Abstract
The importance of 3D printing technologies increased significantly over the recent years. They are considered to have a huge impact in regenerative medicine and tissue engineering, since 3D bioprinting enables the production of cell-laden 3D scaffolds. Transition from academic research to pharmaceutical industry or clinical applications, however, is highly dependent on developing a robust and well-known process, while maintaining critical cell characteristics. Hence, a directed and systematic approach to 3D bioprinting process development is required, which also allows for the monitoring of these cell characteristics. This work presents the development of a flow cytometry-based analytical strategy as a tool for 3D bioprinting research. The development was based on a model process using a commercially available alginate-based bioink, the β-cell line INS-1E, and direct dispensing as 3D bioprinting method. We demonstrated that this set-up enabled viability and proliferation analysis. Additionally, use of an automated sampler facilitated high-throughput screenings. Finally, we showed that each process step, e.g. suspension of cells in bioink or 3D printing, cross-linking of the alginate scaffold after printing, has a crucial impact on INS-1E viability. This reflects the importance of process optimization in 3D bioprinting and the usefulness of the flow cytometry-based analytical strategy described here. The presented strategy has a great potential as a cell characterisation tool for 3D bioprinting and may contribute to a more directed process development.
AUTHOR Schmieg, Barbara and Schimek, Adrian and Franzreb, Matthias
Title Development and performance of a 3D‐printable Polyethylenglycol‐Diacrylate hydrogel suitable for enzyme entrapment and long‐term biocatalytic applications [Abstract]
Year 2018
Journal/Proceedings Engineering in Life Sciences
Reftype
DOI/URL DOI
Abstract
Physical entrapment of enzymes within a porous matrix is a fast and gentle process to immobilize biocatalysts to enable their recycling and long‐term use. This study introduces the development of a biocompatible 3D‐printing material suitable for enzyme entrapment, while having good rheological and UV‐hardening properties. Three different viscosity‐enhancing additives have been tested in combination with a polyethylenglycol‐diacrylate‐based hydrogel system. The addition of polyxanthan or hectorite clay particles results in hydrogels that degrade over hours or days, releasing entrapped compounds. In contrast, the addition of nanometer‐sized silicate particles ensures processability while preventing disintegration of the hydrogel. Lattice structures with a total height of 6 mm consisting of 40 layers were 3D‐printed with all materials and characterized by image analysis. Rheological measurements identified a shear stress window of 200 < τ < 500 Pa at shear rates of 25 s−1 and 25°C for well‐defined geometries with an extrusion‐based printhead. Enzymes immobilized in these long‐term stable hydrogel structures retained an effective activity of approximately 10% compared to the free enzyme in solution. It could be shown that the reduction of effective activity isn't caused by a significant reduction of the intrinsic enzyme activity but by mass transfer limitations within the printed hydrogel structures. This article is protected by copyright. All rights reserved