title: Synthesis and characterization of a novel chitosan-gelatin bioconjugate with fluorescence emission.
abstract: Polysaccharide-protein conjugations have generated increasing interests for biomedical applications in recent years. A naturally occurring cross-linking reagent, genipin, which has been used in herbal medicine, was employed to cross-link chitosan and gelatin for the preparation of a novel chitosan-gelatin conjugate. The primary amine groups on chitosan and gelatin were covalently linked with genipin, leading to the formation of a chitosan-gelatin conjugate with nitrogen-containing heterocycle units, the pyrindine-like derivatives. The FT-IR and UV-vis studies revealed that chitosan could react with genipin via a nucleophilic ring-opening reaction to construct more sufficient and extensive cross-link networks, as compared with its gelatin counterpart. The UV-vis absorption properties of the chitosan-gelatin conjugates were strongly related to the chitosan-to-gelatin weight ratio in the compositions. It is worth noting that the conjugation process endows the special emission properties of the chitosan-gelatin conjugates, which depends on the cross-linking reaction and the formation of hydrogen bonding involved chitosan-gelatin complex. Fluorescence quenching or enhancement was observed from the chitosan-gelatin conjugates upon coordinated with a wide variety of heavy metal ions (Ag+, Cu2+, Fe2+, and Co2+). This study also examined the possibility of covalent coupling the capture chelator (chitosan) with bioactive protein (e.g., albumin, alpha-globulin, and fibrinogen) to create fluorescence emission. These findings may provide a novel way to deliver therapeutic radionuclides for immuno-targeting purposes in the future.
authors.affiliation: Division of Applied Chemistry, Department of Applied Science, Chinese Naval Academy, 669 Jiun Shiaw Road, Kaohsiung, Taiwan 813, ROC. flmi@cna.edu.tw
authors.forename: Fwu-Long
authors.initials: FL
authors.lastname: Mi
mesh_terms: D000276:Adjuvants, Immunologic / Q000138:chemical synthesis; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents; D016503:Drug Delivery Systems; D005453:Fluorescence; D005780:Gelatin / Q000737:chemistry*; D057889:Iridoid Glycosides; D039823:Iridoids; D008670:Metals; D011714:Pyrans; D013057:Spectrum Analysis
chemical_list: D000276:Adjuvants, Immunologic; D003432:Cross-Linking Reagents; D057889:Iridoid Glycosides; D039823:Iridoids; D008670:Metals; D011714:Pyrans; D005780:Gelatin; D048271:Chitosan; C007834:genipin