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Influence of Sulfur‐Containing Diamino Acid Structure on Covalently Crosslinked Copolypeptide Hydrogels
Author(s) -
Raftery Eric D.,
Gharkhanian Eric G.,
Ricapito Nicole G.,
McNamara J.,
Deming Timothy J.
Publication year - 2018
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201801031
Subject(s) - lanthionine , self healing hydrogels , cystine , covalent bond , monomer , amino acid , chemistry , thioether , polymer chemistry , copolymer , residue (chemistry) , imino acid , organic chemistry , polymer , cysteine , biochemistry , enzyme , proline
Biologically occurring non‐canonical di‐α‐amino acids were converted into new di‐ N ‐carboxyanhydride (di‐NCA) monomers in reasonable yields with high purity. Five different di‐NCAs were separately copolymerized with tert ‐butyl‐ l ‐glutamate NCA to obtain covalently crosslinked copolypeptides capable of forming hydrogels with varying crosslinker density. Comparison of hydrogel properties with residue structure revealed that different di‐α‐amino acids were not equivalent in crosslink formation. Notably, l ‐cystine was found to produce significantly weaker hydrogels compared to l ‐homocystine, l ‐cystathionine, and l ‐lanthionine, suggesting that l ‐cystine may be a sub‐optimal choice of di‐α‐amino acid for preparation of copolypeptide networks. The di‐α‐amino acid crosslinkers also provided different chemical stability, where disulfide crosslinks were readily degraded by reduction, and thioether crosslinks were stable against reduction. This difference in response may provide a means to fine tune the reduction sensitivity of polypeptide biomaterial networks.