Insulin delivery and the artificial beta cell: luminal obstructions in capillary conduits.

Insulin delivery mechanisms in which the polypeptide is conducted through the fine bore tubes develope luminal occlusions after 2-6 weeks. Scanning electron micrographs of the ends of such capillaries reveal that the usual methods of sectioning these tubes produces barbed and distorted exits on which aggregates of insulin appear to be localized. This paper addresses a novel technique for sectioning teflon (PTFE) capillary bore tubing which avoids this problem.