Bioartificial devices for treatment of neurologic diseases

据报道，通过移植多巴胺释放细胞可以治疗帕金森病，并且通过移植吗啡释放细胞可以减轻晚期癌症患者的剧烈疼痛。免疫反应是移植同种异体和异种细胞时最有可能失败的原因。为了克服这个问题，将细胞装入半渗透性聚合物膜后进行移植，该膜必须对小分子如氧气，营养物质和生物活性物质具有渗透性，但对淋巴细胞和免疫球蛋白和补体蛋白不可渗透。此外，在中枢神经系统中很难找到大量移植的空间。因此，研究了离心微囊化细胞聚集体以解决这些问题。将球形细胞聚集体悬浮于藻酸盐溶液中。0.4在内径为14 mm的12 ml玻璃试管中，将10 ml悬浮液覆盖在由2.5 ml 7重量%葡聚糖层、0.5 ml BaCl 2溶液层和0.5 ml 13重量%葡聚糖层组成的三层的顶部。将试管在170 x g下离心10 min，以将聚集体旋转至试管底部。该方法能有效地将细胞聚集体包裹在微囊内，微囊壁很薄，不会污染空微囊，试管法不适用于大量细胞聚集体的微囊化。研制了一种特殊的离心机。该方法操作简单，可有效地微囊化大量细胞聚集体，但从离心机中收集微囊化细胞聚集体存在一个问题。

It has been reported that Parkinson's disease can be treated by transplantation of dopamine releasing cells and sever pain of end stage cancer patients can be alleviated by transplanting morphine releasing cells. Immunological reactions are most likely to be the reason for failure when transplanting allogeneic and xenogeneic cells. To overcome this problem, cells are transplanted after they are enclosed into a semipermeable polymer membrane, which must be permeable to small molecules such as oxygen, nutrients and bioactive substances, but impermeable to lymphocytes and immunoglobulins and complement proteins. In addition, it is difficult to find space for a large volume of transplant in central nerve system. Therefore, cen trifugal microencapsulation of cell aggregates was examined to solve these problems. Spherical cell aggregates were suspended into the alginate solution. 0.4 ml of the suspension was over-layed on the top of three layers composed of a 2.5 ml layer of 7 wt% dextran, a 0.5 ml layer of BaCl2 solution and a 0.5 ml layer Of 13 wt% dextran from the top in a 12 ml glass test-tube of 14 mm inner diameter. The test-tube was centrifuged at 170 x g for 10 min to spin the aggregates to the bottom of the tube. This procedure can effectively enclose cell aggregates in microcapsules with a very thin wall without contamination of empty microcapsules.The test-tube method can't be applied to microencapsulation of a large number of cell aggregates. A special centrifuge was developed. It can easily be operate and effectively microencapsulate a large number of cell aggregates, but there is a problem to solve in collecting microencapsulated aggregates from the centrifuge.