Patent ID: 7619009

Claim:
A method of making an injectable thetagel solution for injection into a region, wherein the method comprises the steps of: dissolving polyvinyl alcohol (PVA) molecules in a first solution to form a PVA solution, wherein the first solution has a Flory interaction parameter (chi value) that is not sufficient for gelation; contacting the PVA solution with a second solution in a controlled manner, wherein after the contacting the combination of both solutions has a Flory interaction parameter (chi value) that is sufficient for gelation, and thereby forms an injectable thetagel solution; and maintaining for a period of time the injectable thetagel solution at a temperature such that it is in a workable state, wherein the injectable thetagel solution can be injected into a region, and therein gel in situ after the injection to form in the region a polymer hydrogel that has physical crosslinks between PVA molecules, wherein the polymer hydrogel is formed without chemical crosslinkers, irradiation or thermal cycling.