Open-source hybrid 3D-bioprinter for simultaneous printing of thermoplastics and hydrogels

3D-bioprinting is a promising technology applicable in areas such as regenerative medicine or in vitro organ model development. Various 3D-bioprinting technologies and systems have been developed and are partly commercially available. Here, we present the construction and characterization of an open-source low-cost 3D-bioprinter that allows the alternated microextrusion of hydrogel and fused deposition modeling (FDM) of thermoplastic filaments. The presented 3D-bioprinter is based on a conventional Prusa i3 MK3 printer and features two independent printheads: the original FDM-head and a piston-driven microextrusion system for soft materials. Modifications were designed modularly to fit various syringe formats or heating elements to the device. The bioprinter is the first hybrid DIY 3D-bioprinter that allows switching between materials as often as required during a print run to produce complex multi-material constructs with arbitrary patterns in each layer. For validation of the printer, two designs suitable for relevant bioprinting applications were realized. First, a porous plastic construct filled with hydrogel was printed, serving as a mechanically stable bone replacement tissue model. Second, a plastic chamber, which might be used in organ-on-a-chip applications, was printed with an extruded silicone sealing that enables the liquid-tight attachment of glass slides to the top and bottom of the chamber.3D生物打印（3D-bioprinting）是一项极具应用前景的技术，可覆盖再生医学、体外器官模型开发等诸多领域。目前已有多种3D生物打印技术与系统被开发出来，且部分已实现商业化应用。在此，我们介绍一款开源低成本3D生物打印机的构建与性能表征方案，该设备可实现水凝胶的交替微挤出与热塑性丝材的熔融沉积建模（FDM）打印。 这款3D生物打印机基于常规Prusa i3 MK3打印机打造，配备两个独立打印头：原厂FDM打印头，以及用于软质材料的活塞驱动式微挤出系统。其改造设计采用模块化思路，可适配多种注射器规格或加装加热元件。该生物打印机是首款混合型自制（DIY）3D生物打印机，支持在打印过程中按需频繁切换打印材料，从而制备每层具有任意图案的复杂多材料结构。 为验证该打印机的实际性能，我们实现了两款适配主流生物打印应用的设计方案。其一为填充水凝胶的多孔塑料结构，可用作机械稳定性优异的骨替代组织模型；其二为可应用于器官芯片（organ-on-a-chip）领域的塑料腔室，该腔室搭配挤出成型的硅胶密封件，可实现载玻片与腔室上下表面的液密连接。