Injection of cell-laden hydrogel microspheres is a minimally invasive method for tissue regeneration. However, microspheres are usually limited by structural heterogeneity, uneven size, low cell loading capacity, and poor cell survival rate. We devised a microfluidics synchronous cross-linked technology to obtain injectable homogenous porous microspheres of desired particle (50-400μm) and pore (0-50μm) size by adjusting the flow rate and concentration of gelatin methacrylamide (GelMA). The synchronous cross-linking controlled the strength of cross-linking and prevented fusion and uneven cross-linking. The freeze-dried microspheres of particle size 300μm and pore size 50μm rapidly adsorbed murine bone marrow-derived stem cells (BMSCs) and maintained their viability and osteogenic potential in vitro. In addition, the cell-loaded porous microspheres promoted tissue regeneration when injected locally into a murine bone defect model. Our results show that hydrogel microspheres generated by the microfluidics synchronous cross-linked technology are stable and biocompatible, and have strong regenerative potential when loaded with stem cells.

充满细胞的水凝胶微球的注射是用于组织再生的微创方法。然而，微球通常受到结构异质性，大小不均，细胞负荷能力低和细胞存活率低的限制。我们设计了一种微流体同步交联技术，通过调节明胶甲基丙烯酰胺（GelMA）的流速和浓度，获得所需颗粒（50-400μm）和孔（0-50μm）大小的可注射均质多孔微球。同步交联控制了交联的强度，并防止了熔融和不均匀的交联。粒径为300μm，孔径为50μm的冻干微球可快速吸附鼠骨髓来源的干细胞（BMSCs），并在体外保持其活力和成骨潜能。另外，当局部注入鼠骨缺损模型中时，细胞多孔微球促进了组织再生。我们的结果表明，由微流体同步交联技术产生的水凝胶微球稳定且具有生物相容性，并且在装载干细胞时具有强大的再生潜力。