Preparation And Properties Of N-succinyl Chitosan Grafted Peptides

N-succinyl chitosan?NSC?is a novel chitosan derivative,the molecular chain is rich in carboxyl and the rest of amino.Due to superior water solubility,moisture absorption and retention abilities and greater bioactivity,it can be used as an excellent biomedical materials.Polypeptide is a compound formed by dehydration condensation of multiple amino acids.It has small molecular weight,good water solubility and more biological activity.It is becoming a hot trend among the field of cosmetic,medicine,biomaterial.In this research,N-succinyl chitosan-collagen peptide?NSC-COP?,NSC-nisin,N-succinyl chitosan-C-Phycocyanin peptide?NSC-CPC?were synthesized with Microbia transglutaminase?MTGase?as biocatalyst.The grafting of the three peptides has given NSC a special biological activity while improving the water solubility,antioxidant activity,moisture absorption and retention abilities.Collagen peptide?COP?enhances its ability to promote mouse fibroblasts,nisin enhances its antibacterial activity and C-Phycocyanin peptide?CPC?improves its antitumor activity.The study of reaction conditions and in vitro performance has laid a foundation for the research of novel biomedical materials.The main research contents are as follows:?1?Chitosan reacted with succinic anhydride to prepare N-succinyl-chitosan.NSC-COP,NSC-nisin,NSC-CPC was prepared with MTGase as biocatalyst.Then the product was characterized by Fourier transform infrared?FTIR?to confirm the goal product was successfully synthesized.?2?DS can be taken as the indexes,the reaction conditions were optimized through one-factor-at-a-time experiment.Then the water solubility,moisture absorption and retention properties,antioxidant activity?DPPH radical and hydroxyl radical scavenging activity?and cytotoxicity?L929 fibroblasts?of NSC-COP were measured.The optimum reaction conditions were as follows:the reaction time?t?was2 h,the reaction temperature?T?was 40?,the solution pH was 7.0,the mass ratio of COP and NSC(m_COP/m_NSC)was 1.4.The water solubility,moisture absorption and retention properties,antioxidant activity of NSC-COP was improved with the DS increased.The appropriate concentration of NSC-COP can promote fibroblast proliferation.?3?DS can be taken as the indexes,the reaction conditions were optimized through one-factor-at-a-time experiment.Then the antioxidant activities?hydroxyl radical scavenging activity and reducing capacity?,antibacterial properties?S.aueus and E.coli?and cytotoxicity?L929 fibroblasts?of NSC-nisin were measured.The optimum reaction conditions were as follows:the reaction time?t?was 2 h,the reaction temperature?T?was 55?,the solution pH was 4.0 and the mass ratio of MTGase and NSC(m_MTGase/m_NSC)was 1.2.The hydroxyl radical scavenging activity and reducing capacity of NSC-nisin was improved with the DS increased.Antimicrobial experiments showed the inhibitory effect of NSC-nisin on S.aueus was enhanced.The appropriate concentration and high degree of NSC-nisin can promote fibroblast proliferation.?4?DS can be taken as the indexes,the reaction conditions were optimized through one-factor-at-a-time experiment.Then the moisture absorption and retention properties,antioxidant activity?DPPH radical and hydroxyl radical scavenging activity?and cytotoxicity?L929 fibroblasts and Hela?of NSC-CPC were measured.The optimum reaction conditions were as follows:the reaction time?t?was 2.5 h,the reaction temperature?T?was 50?,the solution pH was 7.0.The moisture absorption and retention properties,antioxidant activity of NSC-CPC was improved with the DS increased.MTT assay indicated that NSC-CPC had restraining effect on Hela,and showed no toxicity.