Li Hong-Bo, Jiang Hong, Wang Chang-Yong, Duan Cui-Mi, Ye Ye, Su Xiao-Ping, Kong Qing-Xue, Wu Jing-Fang, Guo Xi-Min
Department of Tissue Engineering, Beijing Institute of Basic Medical Sciences, 27 Taiping Road, Beijing 100850, People's Republic of China.
Biomed Mater. 2006 Mar;1(1):42-7. doi: 10.1088/1748-6041/1/1/007. Epub 2006 Mar 15.
Transplantation of encapsulated living cells is a promising approach for the treatment of a wide variety of diseases, especially diabetes. Range-scale application of the technique, however, is hampered by insufficient stability of the capsules. It is difficult to find the optimal membrane to meet all the properties required for cell transplantation. To overcome these difficulties, it is necessary to compare characteristics such as mechanical strength, cell proliferation and biocompatibility of different membranes. We prepared Ca-alginate-poly-L-lysine-alginate (APA) and Ba-alginate-poly-L-lysine-alginate (BPA) microcapsules using the electrostatic droplet method. The integrity of the microcapsules was measured by suspending them in a saline buffer and shaking at 150 rpm for 48 h. The microcapsules were cultured in simulated body fluid to analyze the osmotic pressure stability and implanted in the leg muscle pouch of SD rats to test in vivo transplantation stability. The microcapsules were implanted in the intraperitoneal cavity; then the biocompatibility of microcapsules was identified through analyzing fibrosis formation of microcapsules. The proliferation of cells (Cos-7 and HL-60) cultured in the microcapsules was measured by MTT assay. After 48 h shaking at 150 rpm, the percentages of intact microcapsules of BPA and APA microcapsules were 98.5 +/- 0.248% and 95.7 +/- 0.221% (p < 0.05), respectively. The intact percentages of APA and BPA microcapsules were 96.9% and 97.7%, respectively, after being soaked in SBF at 37 degrees C for 15 days. The empty APA and BPA microcapsules were not adhered to the muscle and there was light cellular overgrowth. There is no difference on biocompatibility in implantation into peritoneal cavities. After the cells were cultured in microcapsules, A(490 nm) of the 8th week was significantly higher than that of 1 day, and the 4th week was at the peak of the cell proliferation curve. After culture for 2 to 6 weeks, spheroids started to develop gradually within the beads. The mechanical strength of BPA microcapsules was higher than that of APA microcapsules. However, there was no difference between the two kinds of capsules in biocompatibility. Microencapsulation did not affect cell proliferation or increase the quantity of cells. In conclusion, BPA microcapsules were more suitable for transplantation in vivo.
封装活细胞移植是治疗多种疾病，尤其是糖尿病的一种很有前景的方法。然而，该技术的大规模应用受到胶囊稳定性不足的阻碍。很难找到能满足细胞移植所需所有特性的最佳膜。为克服这些困难，有必要比较不同膜的机械强度、细胞增殖和生物相容性等特性。我们采用静电滴液法制备了钙 - 海藻酸盐 - 聚 -L - 赖氨酸 - 海藻酸盐（APA）和钡 - 海藻酸盐 - 聚 -L - 赖氨酸 - 海藻酸盐（BPA）微胶囊。通过将微胶囊悬浮在盐缓冲液中并在150 rpm下振荡48小时来测量微胶囊的完整性。将微胶囊在模拟体液中培养以分析渗透压稳定性，并植入SD大鼠的腿部肌肉袋中以测试体内移植稳定性。将微胶囊植入腹腔；然后通过分析微胶囊的纤维化形成来确定微胶囊的生物相容性。通过MTT法测量在微胶囊中培养的细胞（Cos - 7和HL - 60）的增殖情况。在150 rpm下振荡48小时后，BPA和APA微胶囊完整微胶囊的百分比分别为98.5±0.248％和95.7±0.221％（p <0.05）。在37℃下于模拟体液中浸泡15天后，APA和BPA微胶囊的完整百分比分别为96.9％和97.7％。空的APA和BPA微胶囊未粘附于肌肉，且细胞过度生长较轻。植入腹腔后的生物相容性没有差异。细胞在微胶囊中培养后，第8周的A（490 nm）显著高于第1天，第4周处于细胞增殖曲线的峰值。培养2至6周后，微珠内开始逐渐形成球体。BPA微胶囊的机械强度高于APA微胶囊。然而，两种胶囊在生物相容性方面没有差异。微囊化不影响细胞增殖或增加细胞数量。总之，BPA微胶囊更适合体内移植。
