Preparation And Properties Of Hydroxypropyl Chitosan Grafted Peptides

Hydroxypropyl chitosan?HPCS?is one of the important derivatives of chitosan,which has good solubility and retains the properties of the chitosan.Collagen peptide?COP?has good moisturizing,antioxidant activity,biocompatibility,hypoallergenic and weak antigenicity.Soybean protein peptides?SPs?have chelated metal ion and antioxidant activity.Nisin produced by microbial fermentation and is not only used for natural food preservatives but also widely used in the field of biomedical with broad-spectrum antibacterial activity.In this paper,through grafting peptides into HPCS by biocatalytic method and we get materials with excellent properties.These materials are expected to be used in the field of wound dressing.The main research of this paper is as follows:?1?Collagen peptide?COP?had been grafted to hydroxypropyl chitosan?HPCS?by using microbial transglutaminase?MTGase?as biocatalyst.The chemical structures of derivative were characterized by FT-IR and¹H NMR spectroscopy.The experimental results show that:the best reaction conditions to prepare HPCS-COP were as follows:the optimal reaction temperature was 40°C,the reaction time was 5h,the mass ratio of COP to HPCS was 1.2,the mass ratio of MTGase to HPCS was0.2;The result of moisture absorption and retention showed that HPCS-COP could serve not only to reduce the loss of moisture but also to absorb the moisture,and the moisture absorption and moisture retention abilities were closely related to the degree of substitution?DS?values;The result of antioxidant capacity experiments showed that with the increase of DS and concentration,the radical scavenging activity of?OH and DPPH?1,1-diphenyl-2-trinitrophenylhydrazine?increased;The result of NIH-3T3mouse embryos fiber cell experiments showed that the higher DS was,the higher the proliferation rate of the cells in a certain concentration range.?2?Soybean protein was hydrolyzed small molecule by papain,which we called soybean protein peptides?SPs?.SPs had been grafted to HPCS by using microbial MTGase as biocatalyst.The chemical structures of derivative were characterized by FT-IR and¹H NMR spectroscopy.The optimum conditions for the preparation of HPCS-SPs were as follows:the reaction temperature was 40°C,the reaction time was4 h,the mass ratio of SPs to HPCS was 2.0,and the mass ratio of MTGase to HPCS was 0.2.The result of moisture absorption and retention showed that HPCS-SPs has good moisture absorption and retention abilities.The result of antioxidant capacity experiments showed that the radical scavenging activity rate of?OH,DPPH and?O^2-improved with the DS and concentration of HPCS-SPs increased;The result of NIH-3T3 mouse experiments showed that the lower concentration of HPCS-SPs,the lower the toxicity of NIH-3T3 in certain DS.?3?Nisin had been grafted to HPCS by using microbial MTGase as biocatalyst.The chemical structures of derivative were characterized by FT-IR and ¹H NMR spectroscopy.The optimum reaction conditions to prepare HPCS-nisin were as follows:the reaction temperature was 50°C,the reaction time was 2 h,the mass ratio of nisin to HPCS was 1.1,the mass ratio of MTGase to HPCS was 0.25;The result of the moisture absorption and retention abilities showed that HPCS-nisin had some moisture absorption and retention abilities;The result of antibacterial experiment showed that HPCS-nisin had inhibitory effect on S.aureus and E.coli at pH=6.The result of NIH-3T3 cell experiments showed that in certain concentration,the higher DS,the relatively lower of the cell survival rate,but the cell survival rate maintained in the cytotoxic range.In vitro cytotoxicity test,HPCS-nisin in low concentration showed no toxicity.