Lysine-functionalized chondroitin sulfate improves the biological properties of collagen/chitosan-based injectable hydrogels

Novel bioactive collagen/chitosan/lysine-functionalized chondroitin sulfate (CSmod) injectable hydrogels are presented. The modification of CS with amine groups introduced with lysine moieties (the degree of substitution about 21%) guarantees its covalent binding with the hydrogel network while genipin crosslinking. Both the physicochemical and biological features of developed hydrogels might be adjusted by playing with CSmod and crosslinking agent concentrations. It was revealed that materials became more hydrophobic with increased CSmod content, while crosslinking degree and enzymatic degradation studies established the influence of CSmod con-centration and Ch:CSmod ratio on the crosslinking process. In situ rheological experiments verified the inject-ability of resulted systems. The biological in vitro evaluation demonstrated that all designed materials are biocompatible as they supported proliferation and adhesion of MG-63 cell line. In vitro biomineralization study employing simulated body fluid model revealed CSmod-content dependent bioactivity of obtained hydrogels. Importantly for pristine collagen/chitosan materials, the formation of apatite-like structures was not observed. Our findings demonstrate that developed injectable ColChCS(mod) hydrogels particularly system with the greatest CSmod concentration exhibits high bioactive potential, without the need of applying additional inducers what renders them promising materials within tissue engineering applications.

Automated summary

This study presents a novel injectable hydrogel composed of collagen, chitosan, and lysine-functionalized chondroitin sulfate. The physicochemical and biological properties of the hydrogels can be adjusted by varying the concentrations of the components. The addition of lysine moieties to chondroitin sulfate enhances the bioactivity of the hydrogels and promotes cell proliferation and adhesion. These hydrogels have great potential for tissue engineering applications.