Hydrogel having anti-microbial properties

A method of making a hydrogel having antimicrobial properties. The hydrogel includes a hydrogel-forming polymer and an anti-microbial agent. The method includes mixing a hydrogel-forming polymer, such as a hydrophilic polymer, with water and cross-linking the polymer and water using an energy source. The method does not require any chemical additive to affect the cross-linking. The anti-microbial agent may be mixed with the hydrogel-forming polymer and water prior to cross-linking. Alternatively, the anti-microbial agent may be applied to a substrate onto which the hydrogel is placed such that the anti-microbial agent or the properties of the agent, or both, migrate into the hydrogel. The substrate may be a liner onto which the hydrogel is placed, a scrim located on or in the hydrogel, or other appropriate device.