Shao Lei, Pan Bingchu, Hou Ruxia, Jin Yuan, Yao Yudong
Research Institute for Medical and Biological Engineering, Ningbo University, Ningbo 315211, People's Republic of China.
State Key Laboratory of Fluid Power and Mechatronic Systems, College of Mechanical Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China.
Biofabrication. 2022 Mar 7;14(2). doi: 10.1088/1758-5090/ac57a5.
Hydrogel microspheres are flexible microstructures with many fascinating functions, such as three-dimensional cell culture, injection therapy, drug delivery, organoids and microtissues construction. The traditional methods of manufacturing hydrogel microspheres more or less have some shortcomings, such as atomization/emulsion method with uneven sizes; piezoelectric-/thermal-/electric-assisted inkjet with high cell damage and unknown cell growth effects; microfluidic manufacturing with sophisticated microdevices etc, which lead to poor user experiences. Here, we designed a user-friendly microfluidic device to generate hydrogel microspheres with sharp needles that can be replaced at will. Specifically, a commercial tapered opening sharp needle was inserted into a transparent silicone tube with the tapered opening facing the upper wall of the silicone tube. Then, gelatin methacrylate (GelMA) solution and paraffin oil were pumped into the sharp needle and the silicone tube respectively. GelMA microdroplets were formed under the shear stress of the silicone tube and the oil phase, and after being photo-crosslinked, GelMA microspheres with uniform and adjustable sizes can be generated. Due to the simplicity of our original device, heterogeneous microspheres such as Janus, core-shell and hollow microspheres can be easily manufactured by simple modification of the device. In addition, we demonstrated the strong flexibility and maneuverability of the microspheres through macroscopic free assembly. Finally, we prepared different cell-laden GelMA microspheres, and the cells showed stretching behavior similar to thatafter a short period culture, which indicated the high bioactivity of GelMA microspheres. Meanwhile, we cultured the Janus cell-laden GelMA microspheres and the assembly of cell-laden GelMA microspheres, where the cells stretched and interacted, demonstrating the potential of GelMA microspheres for co-culture and fabrication of large-scale tissue constructs. In view of the above results, our user-friendly microfluidic manufacturing method of hydrogel microspheres with sharp needles will provide great convenience to relevant researchers.
水凝胶微球是具有许多迷人功能的柔性微结构，如三维细胞培养、注射治疗、药物递送、类器官和微组织构建。传统的水凝胶微球制造方法或多或少都存在一些缺点，例如雾化/乳液法尺寸不均匀；压电/热/电辅助喷墨法对细胞损伤大且细胞生长效果未知；微流控制造需要精密的微器件等，这些都导致用户体验不佳。在此，我们设计了一种用户友好型微流控装置，用可随意更换的尖锐针头来生成水凝胶微球。具体而言，将一支商用的锥形开口尖锐针头插入透明硅胶管中，使锥形开口朝向硅胶管的上壁。然后，分别将甲基丙烯酸明胶（GelMA）溶液和石蜡油泵入尖锐针头和硅胶管中。GelMA微滴在硅胶管和油相的剪切应力作用下形成，经过光交联后，可生成尺寸均匀且可调的GelMA微球。由于我们原始装置的简单性，通过对装置进行简单修改，就可以轻松制造出诸如Janus、核壳和中空微球等异质微球。此外，我们通过宏观自由组装展示了微球强大的柔韧性和可操作性。最后，我们制备了不同的负载细胞的GelMA微球，细胞表现出与短期培养后相似的伸展行为，这表明GelMA微球具有高生物活性。同时，我们培养了负载Janus细胞的GelMA微球以及负载细胞的GelMA微球组件，其中细胞伸展并相互作用，证明了GelMA微球在共培养和大规模组织构建制造方面的潜力。鉴于上述结果，我们这种用户友好型的带尖锐针头的水凝胶微球微流控制造方法将为相关研究人员提供极大的便利。
