Methods for sterilizing a biocompatible hydrogel polymer are provided via treating the biocompatible hydrogel polymer with a supercritical CO2 treatment composition at a treatment pressure of about 4 MPa to about 30 MPa and a treatment temperature of about 5° C. to about 75° C. The supercritical CO2 treatment composition can be substantially pure CO2 or may further include hydrogen peroxide (e.g., in an amount of about 10 ppm to about 1,000 ppm). In certain embodiments, the biocompatible hydrogel polymer can be treated with the supercritical CO2 treatment composition for about 30 minutes to about 5 hours. According to these methods, treating the biocompatible hydrogel polymer can kill about 90% or more of any S. aureus and E. coli present in the biocompatible hydrogel polymer.
