Schneider S, Feilen P, Cramer H, Hillgärtner M, Brunnenmeier F, Zimmermann H, Weber M M, Zimmermann U
Schwerpunkt Endokrinologie und Stoffwechseler Krankungen, I. Medizinische Klinik und Poliklinik, Universitäts-Klinik Mainz, Germany.
J Microencapsul. 2003 Sep-Oct;20(5):627-36. doi: 10.1080/0265204031000140796.
A key engineering challenge in designing microcapsules made from biocompatible alginate is maintaining adequate exchange of nutrients and oxygen between the entrapped cells and the environment, while simultaneously avoiding swelling and subsequent failure of the microcapsule. Approval for the use of alginate in pharmaceutical and/or biomedical applications also strictly requires that the components of the microcapsule material must meet the safety criteria of the ASTM and FDA. Incorporation of foetal calf serum (FCS) into the microcapsules for stabilization is not in accordance with the guidelines affirmed by these organizations. FCS should be substituted by microcapsule-stabilizing additives that are medically approved. In this communication, it is shown that 10% FCS can be replaced by 1% human serum albumin (i.e. by an agent for which medical approval is granted) without compromising effects on long-term in vitro stability. Furthermore, it is demonstrated that human serum albumin (HSA) significantly enhances cell survival and, particularly, insulin secretion of encapsulated rat islets over a time period of 3 weeks when incubated in culture medium. Thus, HSA-stabilized microcapsules made from UHV(Lam) alginate are apparently a promising system for immunoisolation of cells, particularly when alginate is cross-linked by injection of BaCl(2) crystals into the alginate droplets. Slight adjustments of the alginate concentration can tailor the microcapsule permeability to the released therapeutic factor.
设计由生物相容性藻酸盐制成的微胶囊时，一个关键的工程挑战是要在被包裹的细胞与环境之间维持足够的营养物质和氧气交换，同时避免微胶囊肿胀及随后的失效。在制药和/或生物医学应用中使用藻酸盐的批准严格要求微胶囊材料的成分必须符合美国材料与试验协会（ASTM）和美国食品药品监督管理局（FDA）的安全标准。将胎牛血清（FCS）加入微胶囊以实现稳定化不符合这些组织所确认的指导方针。FCS应由医学上批准的微胶囊稳定化添加剂替代。在本通讯中表明，10%的FCS可以由1%的人血清白蛋白（即一种已获医学批准的试剂）替代，而不会对长期体外稳定性产生不利影响。此外，还证明了人血清白蛋白（HSA）在培养基中孵育3周的时间段内，能显著提高被包裹大鼠胰岛的细胞存活率，尤其是胰岛素分泌。因此，由超高分子量（Lam）藻酸盐制成的HSA稳定化微胶囊显然是一种用于细胞免疫隔离的有前景的系统，特别是当藻酸盐通过向藻酸盐液滴中注入BaCl₂晶体进行交联时。对藻酸盐浓度进行轻微调整可以调整微胶囊对释放的治疗因子的通透性。
