Disclosed herein is a composition comprising a crosslinked hydrogel where the hydrogel comprises a polymer having a cleavable bond along a backbone of the polymer, along a substituent that undergoes crosslinking, or along the backbone of the polymer and along the substituent that undergoes crosslinking where the cleavable bond is operative to be cleaved by an enzyme released in the body of a living being and a semiconducting quantum dot that emits light in the visible portion of the electromagnetic spectrum.
