A method of forming a polymeric, biocompatible material on tissue or cells, the method comprising applying to the tissue or cells a solution of biodegradable, polymerizable macromer having a solubility of at least about 1 g/100 ml in an aqueous solution comprising at least one water soluble region, at least one degradable region which is hydrolyzable under in vivo conditions, and free radical polymerizable end groups having the capacity to form additional covalent bonds resulting in macromer interlinking, wherein the polymerizable end groups are separated from each other by at least one degradable region, in the presence of a free radical initiator, and polymerizing the macromer.