CS, BMPm (“GGGRHVRISRSL”), and NC (“GGGHAVDI”) were used as model biomolecules due to their involvement in the development of native bone and cartilage and their established usage in tissue engineering (5, 31). CS was functionalized with azide groups by attachment of the amine/azide linker ATA, using EDC/NHS chemistry in MES buffer (pH 5), as described in detail elsewhere (13). BMPm and NC were synthesized by 9-fluorenyl methoxycarbonyl–based solid-phase peptide synthesis on a rink amide MBHA (4-methylbenzhydrylamine) low-loading resin, as described elsewhere (19). To introduce N-terminal azide functionalization, 2-azidoacetic acid was added as the final “amino acid” by the same chemistry as regular amino acid addition, followed by peptide cleavage from the resin. Peptide purification was performed by precipitation in cold diethyl ether and dialysis for 24 hours at 500-Da molecular mass cutoff (MWCO), with replacement of H2O every 6 to 8 hours. After dialysis, solutions were flash-frozen in liquid N2 and lyophilized.