3-D Life CD-Link is a component of the 3-D Life Hydrogel system. The CD-Link molecule consists of a polyethylene glycol-peptide conjugate carrying a thiol at each end. When combined with polymers of the 3-D Life Hydrogel system, thiol groups on CD-Link form stable thioether bonds with the thiol-reactive groups on the polymers, which results in the formation of the hydrogel. CD-Link can be used with 3-D Life functionalised polymers Mal-PVA, Mal-Dextran, SG-PVA and SG-Dextran. CD-Link contains a matrix metalloproteinase (MMP)-cleavable peptide sequence (Pro-Leu-Gly-Leu-Trp-Ala), which is cleaved by a broad range of MMPs including MMP1, MMP3, MMP7 and MMP9 . It allows cells to locally degrade the polymer network, if they produce the indicated MMPs.For instructions, please consult General Protocols GP-1 "Preparation of 3-D Life Fast Gelling Hydrogels" or GP-2 "Preparation of 3-D Life Slow Gelling Hydrogels" and the 3-D Life Hydrogels User Guide.