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.

Fabrication of porous chitosan scaffolds for soft tissue engineering using dense gas CO2

“…GP-crosslinked hydrogels also exhibited a peak shift from 1640 to 1648 cm À1 , due to the crosslinking reaction between chitosan and GP ( Fig. 4d and e) [47]. No significant difference was observed between hydrogels produced at atmospheric (1 bar) and dense gas (60 bar) conditions using GA and GP, respectively.…”

Graphene oxide-reinforced biodegradable genipin-cross-linked chitosan fluorescent biocomposite film and its cytocompatibility

“…Abbreviations: gcs, genipin-cross-linked chitosan; GO, graphene oxide; PBS, phosphate-buffered saline. 38 It appears that a large conjugated system, possibly the π-π* conjugation, is formed by this reaction, thus resulting in the fluorescence in the cross-linked CS. 39 In our study, genipin was added after the GO sheets were blended into the CS solution.…”

Incorporation of PLGA nanoparticles into porous chitosan–gelatin scaffolds: Influence on the physical properties and cell behavior

“…The mechanical properties and water stability of CH-G blend can be increased by crosslinking with suitable non cytotoxic crosslinking agents. In this work, genipin, an aglycone derived from geniposide which is extracted from the fruit of Gardenia Jasminoides Ellis, was selected as a crosslinker for CH-G blend (Mi, 2005). PLGA nanoparticles were selected as they have a recognized biocompatibility and efficiency in the delivery of growth factors, proteins or drugs, in a time dependent manner, both in vitro and in vivo (Muthu, 2005).…”