Strand B L, Gåserød O, Kulseng B, Espevik T, Skjåk-Baek G
Department of Biotechnology, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
J Microencapsul. 2002 Sep-Oct;19(5):615-30. doi: 10.1080/02652040210144243.
Alginate-polylysine-alginate capsules containing insulin-producing cells have been used as a bio-artificial pancreas in the treatment of diabetes mellitus. In a search for microcapsules with improved diffusion characteristics, a high voltage system was developed that produces 250,000 beads/min with a diameter of 160 microm +/- 3-5%. The diameter of the beads could be varied between 160-700 microm depending on the needle diameter and construction, the voltage, the distance between the electrodes and the flow of alginate solution. Ca-alginate beads with diameters of 200 and 500 microm were produced by the high voltage electrostatic system. The 200 microm beads were sensitive to poly-L-lysine (PLL) exposure and had to be washed in ion-free solution to avoid collapse. The 200 microm beads swelled more than the 500 microm beads in the washing and PLL treatment. Also, the porosity of the capsules changed with size, but capsules impermeable to tumour necrosis factor (TNF) could be made by exchanging PLL with poly-D-lysine (PDL) for the 500 microm beads. The 200 microm beads were impermeable to IgG after PLL exposure. Islets of Langerhans were encapsulated in alginate-PLL-alginate capsules and evaluated by measuring protruding islets and insulin production. Islets in microcapsules made by the high voltage electrostatic system did not function differently from islets in larger microcapsules made by an air jet system. In conclusion, alginate capsules made by a high voltage electrostatic system enable large-scale production of small capsules with a narrow size distribution that can meet the functional properties of larger capsules by small changes in the encapsulation procedure.
含有产胰岛素细胞的海藻酸盐-聚赖氨酸-海藻酸盐胶囊已被用作生物人工胰腺来治疗糖尿病。为了寻找具有改善扩散特性的微胶囊，开发了一种高压系统，该系统每分钟可生产250,000个直径为160微米±3 - 5%的珠子。珠子的直径可在160 - 700微米之间变化，这取决于针的直径和构造、电压、电极之间的距离以及海藻酸盐溶液的流速。通过高压静电系统生产出了直径为200和500微米的钙海藻酸盐珠子。200微米的珠子对聚-L-赖氨酸（PLL）暴露敏感，必须在无离子溶液中洗涤以避免塌陷。在洗涤和PLL处理过程中，200微米的珠子比500微米的珠子膨胀得更多。此外，胶囊的孔隙率随尺寸而变化，但对于500微米的珠子，通过用聚-D-赖氨酸（PDL）替代PLL可以制成对肿瘤坏死因子（TNF）不可渗透的胶囊。PLL暴露后，200微米的珠子对IgG不可渗透。将胰岛包裹在海藻酸盐-PLL-海藻酸盐胶囊中，并通过测量突出的胰岛和胰岛素产量进行评估。由高压静电系统制成的微胶囊中的胰岛与由空气喷射系统制成的较大微胶囊中的胰岛功能没有差异。总之，由高压静电系统制成的海藻酸盐胶囊能够大规模生产尺寸分布狭窄的小胶囊，通过在封装过程中进行微小改变，这些小胶囊可以具备较大胶囊的功能特性。
