Multilayer capsules: a promising microencapsulation system for transplantation of pancreatic islets
Multilayer capsules: a promising microencapsulation system for transplantation of pancreatic islets
复制标题
DOI：
10.1016/s0142-9612(00)00380-x
复制
发表时间：
2001-07-01
期刊：
影响因子：
14
通讯作者：
Pommersheim, R
中科院分区：
文献类型：
--
作者：
Schneider, S;Feilen, PJ;Pommersheim, R
1980年，Lim和Sun推出了一种包覆有海藻酸盐/聚赖氨酸复合体的微囊，用于包裹胰岛。这种类型的胶囊的特征是，它由在单个程序步骤中形成的平坦的膜组成。利用这种简单的工艺，很难立即获得针对胰岛移植所需的所有特性进行优化的膜。为了克服这些困难，建议分几个连续的步骤构建膜，每个步骤都针对特定的性能进行优化。在这项研究中，我们分析了这样的多层微囊包裹胰岛。因此，空的和含有海藻酸盐的珠子被交替地包裹着聚乙烯亚胺、聚丙烯酸或羧甲基纤维素和海藻酸盐的层。通过扫描电子显微镜，与仪器规模相比，覆盖的多层膜的厚度估计小于800 nm。椭偏仪测量表明，薄膜厚度在145 nm范围内。包埋过程和成膜步骤均不妨碍胰岛的刺激反应。在细胞培养的第三周和第五周，包裹的胰岛的刺激反应甚至明显更好。此外，多层膜不会影响移植微囊的生物相容性。根据所使用的聚阳离子-聚阴离子组合，允许轻松调节分子截止和机械稳定性。与一步包封法相比，多层膜胶囊具有明显的优势。尽管膜厚只有145纳米，但这些珠子保证了高生物兼容性、精确调整的截止值、最佳的胰岛素反应和高机械稳定性。(C)2001爱思唯尔科学有限公司。保留所有权利。
In 1980, Lim and Sun introduced a microcapsule coated with an alginate/polylysine complex for encapsulation of pancreatic islets. Characteristic to this type of capsule is, that it consists of a plain membrane which is formed during a single procedural step. With such a simple process it is difficult to obtain instantly a membrane optimized with respect to all the properties requested for islet transplantation. To overcome these difficulties, it is recommended to build up the membrane in several consecutive steps, each optimized for a certain property. In this study, we have analysed such a multilayer microcapsule for the encapsulation of pancreatic islets. Therefore, empty and islet containing alginate beads were coated with alternating layers of polyethyleneimine, polyacrylacid or caboxymethylcellulose and alginate. By scanning electron microscopy the thickness of the covering multilayer-membrane was estimated to be less than 800 nm by comparison with an apparatus scale. Ellipsometric measurements showed that the membrane thickness is in the range of 145 nm. Neither the encapsulation procedure, nor the membrane-forming step did impede the stimulatory response of the islets. The encapsulation even lead to a significantly better stimulatory response of the encapsulated islets during week three and five of cell culture. Furthermore, the multilayer-membrane did not deteriorate the biocompatibility of the transplanted microcapsules. allowing an easy tuning of the molecular cut-off and the mechanical stability depending on the polycation-polyanion combination used. The multilayer membrane capsule has obvious advantages compared to a one-step encapsulation procedure. These beads guarantee a high biocompatibility, a precisely adjusted cut-off, an optimal insulin-response and high mechanical stability although the membrane is only 145 nm thick. (C) 2001 Elsevier Science Ltd. All rights reserved.