Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, Illinois, USA.
J Biomed Mater Res A. 2010 Nov;95(2):632-40. doi: 10.1002/jbm.a.32883.
Alginate microcapsules coated with a permselective poly-L-ornithine (PLO) membrane have been investigated for the encapsulation and transplantation of islets as a treatment for type 1 diabetes. The therapeutic potential of this approach could be improved through local stimulation of microvascular networks to meet mass transport demands of the encapsulated cells. Fibroblast growth factor-1 (FGF-1) is a potent angiogenic factor with optimal effect occurring when it is delivered in a sustained manner. In this article, a technique is described for the generation of multilayered alginate microcapsules with an outer alginate layer that can be used for the delivery of FGF-1. The influence of alginate concentration and composition (high mannuronic acid (M) or guluronic acid (G) content) on outer layer size and stability, protein encapsulation efficiency, and release kinetics was investigated. The technique results in a stable outer layer of alginate with a mean thickness between 113 and 164 μm, increasing with alginate concentration and G-content. The outer layer was able to encapsulate and release FGF-1 for up to 30 days, with 1.25% of high G alginate displaying the most sustained release. The released FGF-1 retained its biologic activity in the presence of heparin, and the addition of the outer layer did not alter the permselectivity of the PLO coat. This technique could be used to generate encapsulation systems that deliver proteins to stimulate local neovascularization around encapsulated islets.
用具有选择透过性的聚-L-鸟氨酸（PLO）膜包被的藻酸盐微胶囊已被用于胰岛的封装和移植，作为 1 型糖尿病的治疗方法。通过局部刺激微血管网络来满足被包裹细胞的质量传输需求，可以提高这种方法的治疗潜力。成纤维细胞生长因子-1（FGF-1）是一种有效的血管生成因子，当以持续的方式给药时效果最佳。本文描述了一种生成具有藻酸盐外层的多层藻酸盐微胶囊的技术，该外层可用于递送 FGF-1。研究了藻酸盐浓度和组成（高甘露糖醛酸（M）或古洛糖醛酸（G）含量）对外层大小和稳定性、蛋白质包封效率和释放动力学的影响。该技术可得到稳定的藻酸盐外层，其平均厚度在 113 至 164μm 之间，随着藻酸盐浓度和 G 含量的增加而增加。外层能够封装和释放 FGF-1 长达 30 天，1.25%高 G 藻酸盐显示出最持久的释放。在肝素存在的情况下，释放的 FGF-1 保持其生物学活性，并且外层的添加不会改变 PLO 涂层的选择透过性。该技术可用于生成封装系统，以递送蛋白质来刺激包裹胰岛周围的局部新生血管形成。
