Chan Hon Fai, Zhang Ying, Ho Yi-Ping, Chiu Ya-Ling, Jung Youngmee, Leong Kam W
Department of Biomedical Engineering, Duke University, 101 Science Drive, Durham, NC 27708, USA.
Sci Rep. 2013 Dec 10;3:3462. doi: 10.1038/srep03462.
An attractive option for tissue engineering is to use of multicellular spheroids as microtissues, particularly with stem cell spheroids. Conventional approaches of fabricating spheroids suffer from low throughput and polydispersity in size, and fail to supplement cues from extracellular matrix (ECM) for enhanced differentiation. In this study, we report the application of microfluidics-generated water-in-oil-in-water (w/o/w) double-emulsion (DE) droplets as pico-liter sized bioreactor for rapid cell assembly and well-controlled microenvironment for spheroid culture. Cells aggregated to form size-controllable (30-80 μm) spheroids in DE droplets within 150 min and could be retrieved via a droplet-releasing agent. Moreover, precursor hydrogel solution can be adopted as the inner phase to produce spheroid-encapsulated microgels after spheroid formation. As an example, the encapsulation of human mesenchymal stem cells (hMSC) spheroids in alginate and alginate-arginine-glycine-aspartic acid (-RGD) microgel was demonstrated, with enhanced osteogenic differentiation further exhibited in the latter case.
组织工程的一个有吸引力的选择是使用多细胞球体作为微组织，特别是干细胞球体。传统的制造球体的方法存在通量低、尺寸多分散性的问题，并且无法补充细胞外基质（ECM）的信号以增强分化。在本研究中，我们报道了利用微流控产生的水包油包水（w/o/w）双重乳液（DE）液滴作为皮升大小的生物反应器，用于快速细胞组装和对球体培养进行良好控制的微环境。细胞在150分钟内在DE液滴中聚集形成尺寸可控（30 - 80μm）的球体，并且可以通过液滴释放剂回收。此外，在球体形成后，可以采用前体水凝胶溶液作为内相来制备包裹球体的微凝胶。例如，展示了将人间充质干细胞（hMSC）球体封装在藻酸盐和藻酸盐 - 精氨酸 - 甘氨酸 - 天冬氨酸（-RGD）微凝胶中，在后一种情况下进一步表现出增强的成骨分化。
