Raddatz Lukas, Lavrentieva Antonina, Pepelanova Iliyana, Bahnemann Janina, Geier Dominik, Becker Thomas, Scheper Thomas, Beutel Sascha
Institut für Technische Chemie, Leibniz Universität Hannover, Callinstraße 5, 30167 Hannover, Germany.
Lehrstuhl für Brau- und Getränketechnologie, Technische Universität München, Weihenstephaner Steig 20, 80354 Freising, Germany.
J Funct Biomater. 2018 Nov 9;9(4):63. doi: 10.3390/jfb9040063.
Three-dimensional (3D)-bioprinting enables scientists to mimic in vivo micro-environments and to perform in vitro cell experiments under more physiological conditions than is possible with conventional two-dimensional (2D) cell culture. Cell-laden biomaterials (bioinks) are precisely processed to bioengineer tissue three-dimensionally. One primarily used matrix material is sodium alginate. This natural biopolymer provides both fine mechanical properties when gelated and high biocompatibility. Commonly, alginate is 3D bioprinted using extrusion based devices. The gelation reaction is hereby induced by a CaCl₂ solution in the building chamber after material extrusion. This established technique has two main disadvantages: (1) CaCl₂ can have toxic effects on the cell-laden hydrogels by oxygen diffusion limitation and (2) good printing resolution in the CaCl₂ solution is hard to achieve, since the solution needs to be removed afterwards and substituted by cell culture media. Here, we show an innovative approach of alginate bioprinting based on a CaCl₂ nebulizer. The device provides CaCl₂ mist to the building platform inducing the gelation. The necessary amount of CaCl₂ could be decreased as compared to previous gelation strategies and limitation of oxygen transfer during bioprinting can be reduced. The device was manufactured using the MJP-3D printing technique. Subsequently, its digital blueprint (CAD file) can be modified and additive manufactured easily and mounted in various extrusion bioprinters. With our approach, a concept for a more gentle 3D Bioprinting method could be shown. We demonstrated that the concept of an ultrasound-based nebulizer for CaCl₂ mist generation can be used for 3D bioprinting and that the mist-induced polymerization of alginate hydrogels of different concentrations is feasible. Furthermore, different cell-laden alginate concentrations could be used: Cell spheroids (mesenchymal stem cells) and single cells (mouse fibroblasts) were successfully 3D printed yielding viable cells and stable hydrogels after 24 h cultivation. We suggest our work to show a different and novel approach on alginate bioprinting, which could be useful in generating cell-laden hydrogel constructs for e.g., drug screening or (soft) tissue engineering applications.
三维（3D）生物打印使科学家能够模拟体内微环境，并在比传统二维（2D）细胞培养更接近生理条件的情况下进行体外细胞实验。载有细胞的生物材料（生物墨水）经过精确处理，以三维方式对组织进行生物工程构建。一种主要使用的基质材料是海藻酸钠。这种天然生物聚合物在凝胶化时既具有良好的机械性能，又具有高生物相容性。通常，海藻酸钠是使用基于挤出的设备进行3D生物打印的。在此过程中，材料挤出后，通过构建腔内的CaCl₂溶液引发凝胶化反应。这种成熟的技术有两个主要缺点：（1）CaCl₂可能通过氧气扩散限制对载有细胞的水凝胶产生毒性作用；（2）在CaCl₂溶液中难以实现良好的打印分辨率，因为之后需要去除该溶液并用细胞培养基替代。在此，我们展示了一种基于CaCl₂雾化器的海藻酸钠生物打印创新方法。该设备向构建平台提供CaCl₂雾气以引发凝胶化。与先前的凝胶化策略相比，所需的CaCl₂量可以减少，并且可以减少生物打印过程中氧气传输的限制。该设备是使用MJP - 3D打印技术制造的。随后，其数字蓝图（CAD文件）可以轻松修改并通过增材制造，然后安装在各种挤出式生物打印机中。通过我们的方法，可以展示一种更温和的3D生物打印方法的概念。我们证明了基于超声的雾化器产生CaCl₂雾气的概念可用于3D生物打印，并且不同浓度的海藻酸钠水凝胶的雾气诱导聚合是可行的。此外，可以使用不同的载有细胞的海藻酸钠浓度：细胞球状体（间充质干细胞）和单细胞（小鼠成纤维细胞）成功进行了3D打印，培养24小时后产生了活细胞和稳定的水凝胶。我们建议我们的工作展示了一种不同的、新颖的海藻酸钠生物打印方法，这可能有助于生成用于例如药物筛选或（软）组织工程应用的载有细胞的水凝胶构建体。
