Graduate School of Biomedical Engineering, The University of New South Wales, Level 5 Samuels Building, Sydney, New South Wales 2052, Australia.
Biotechnol Bioeng. 2012 Jun;109(6):1561-70. doi: 10.1002/bit.24430. Epub 2012 Jan 11.
Microencapsulation within hydrogel microspheres holds much promise for drug and cell delivery applications. Synthetic hydrogels have many advantages over more commonly used natural materials such as alginate, however their use has been limited due to a lack of appropriate methods for manufacturing these microspheres under conditions compatible with sensitive proteins or cells. This study investigated the effect of flow rate and voltage on size and uniformity of the hydrogel microspheres produced via submerged electrospray combined with UV photopolymerization. In addition, the mechanical properties and cell survival within microspheres was studied. A poly(vinyl alcohol) (PVA) macromer solution was sprayed in sunflower oil under flow rates between 1-100 µL/min and voltages 0-10 kV. The modes of spraying observed were similar to those previously reported for electrospraying in air. Spheres produced were smaller for lower flow rates and higher voltages and mean size could be tailored from 50 to 1,500 µm. The microspheres exhibited a smooth, spherical morphology, did not aggregate and the compressive modulus of the spheres (350 kPa) was equivalent to bulk PVA (312 kPa). Finally, L929 fibroblasts were encapsulated within PVA microspheres and showed viability >90% after 24 h. This process shows great promise for the production of synthetic hydrogel microspheres, and specifically supports encapsulation of cells.
微胶囊化在水凝胶微球中具有很大的潜力，可用于药物和细胞输送应用。与更常用的天然材料（如海藻酸盐）相比，合成水凝胶具有许多优势，然而，由于缺乏在与敏感蛋白质或细胞相容的条件下制造这些微球的合适方法，其应用受到限制。本研究调查了流速和电压对通过浸没式电喷雾与 UV 光聚合结合生产的水凝胶微球的大小和均匀性的影响。此外，还研究了微球内的机械性能和细胞存活率。将聚（乙烯醇）（PVA）大分子溶液在流速为 1-100 μL/min 和电压为 0-10 kV 的葵花籽油中喷雾。观察到的喷雾模式与以前报道的在空气中进行电喷雾的模式相似。流速越低，电压越高，产生的球体越小，平均尺寸可从 50 至 1500 µm 进行调整。微球呈现出光滑的球形形态，不聚集，并且球体的压缩模量（350 kPa）与块状 PVA（312 kPa）相当。最后，L929 成纤维细胞被封装在 PVA 微球内，在 24 小时后存活率>90%。该工艺显示出用于生产合成水凝胶微球的巨大潜力，特别是支持细胞的封装。
