Sheet does not damage islets

The material used to make the immunoisolation barrier must be compatible with the cells inside as well as the host outside. The material comprising the device and all solvents and reagents used to make it must be nontoxic. For example, organic solvents can dessicate living tissue.

In addition to the material, the method must not be damaging to the islets. For example, some methods of forming droplets around islets produce high shear forces that damage islet cells. Free radical polymerization can damage the cell membrane. Here, we have specifically defined "biocompatible" as both materials and methods non-deleterious to the cells contained in the device.