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Photoresponsive Peptide and Polypeptide Systems, 14. Biodegradation of Photocrosslinkable Copolypeptide Hydrogels Containing L ‐Ornithine and δ ‐7‐Coumaryloxyacetyl‐ L ‐ornithine Residues
Author(s) -
Ohkawa Kousaku,
Shoumura Kenji,
Yamada Masanori,
Nishida Ayako,
Shirai Hirofusa,
Yamamoto Hiroyuki
Publication year - 2001
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/1616-5195(20010601)1:4<149::aid-mabi149>3.0.co;2-o
Subject(s) - self healing hydrogels , chemistry , polymer chemistry , monomer , biodegradation , aqueous solution , lysine , peptide , solvent , amide , amino acid , organic chemistry , polymer , biochemistry
Copoly[Orn/Orn(Cou)] containing δ ‐7‐coumaryloxyacetyl‐ L ‐ornithine [Orn(Cou)] and L ‐ornithine (Orn) residues was synthesized by the N ‐carboxyanhydride method. When aqueous solutions of copoly[Orn/Orn(Cou)] containing 5–10 mol‐% of Orn(Cou) are irradiated, the photoinduced dimerization reaction between coumarin moieties in the side chains proceeds slowly, and after 24 h the solutions become transparent hydrogels. The gels exhibit solvent‐induced reversible expansion and contraction behavior in both water and ethanol. The biodegradation of the hydrogels by proteolytic enzymes and soil filamentous fungi is investigated using photocrosslinked copoly[Orn/Orn(Cou)] gels. The copoly[Orn 89 /Orn(Cou) 11 ] gel is degradable by protease type XXIII, but not by trypsin. In the biochemical oxygen demand test, the order of the microbial biodegradation (%) was Rhizopus sp. (92%) > A. oryzae (38%) > P. caseicolum (18%) > P. citrinum (11%) > Cladosporium sp. (6%). The order for the copoly[Orn 89 /Orn(Cou) 11 ] hydrogel is inverse to that for a polylysine/glutaraldehyde gel. These results suggest that the biodegradabilities of photocrosslinked hydrogels can be controlled by the monomer ratio of Orn, Orn(Cou) and lysine (Lys) in the parent copoly(amino acid)s of the photocrosslinked hydrogels.