The invention disclosed is a hydrogel composition for use as dural substitute, for wound closure of cleft palate and regeneration, and as substrate for cell delivery to the eye. 1 to about 30% by weight of synthetic mica. This invention also provides a method to determine whether or not a tumor is likely to be a responder to chemotherapy. A rotor is connected to the hub and supports a compressor section. A catalyst is injected into the site and is permitted to diffuse through the site.