Synthesis and Biocompatibility Characterizations of in Situ Chondroitin Sulfate–Gelatin Hydrogel for Tissue Engineering

Abstract

Novel hydrogel composed of both chondroitin sulfate (CS) and gelatin was developed for better cellular interaction through two step double crosslinking of N-(3-diethylpropyl)-N-ethylcarbodiimide hydrochloride (EDC) chemistries and then click chemistry. EDC chemistry was proceeded during grafting of amino acid dihydrazide (ADH) to carboxylic groups in CS and gelatin network in separate reactions, thus obtaining CS-ADH and gelatin-ADH, respectively. CS-acrylate and gelatin-TCEP was obtained through a second EDC chemistry of the unreacted free amines of CS-ADH and gelatin-ADH with acrylic acid and tri(carboxyethyl)phosphine (TCEP), respectively. In situ CS-gelatin hydrogel was obtained via click chemistry by simple mixing of aqueous solutions of both CS-acrylate and gelatin-TCEP. ATR-FTIR spectroscopy showed formation of the new chemical bonds between CS and gelatin in CS-gelatin hydrogel network. SEM demonstrated microporous structure of the hydrogel. Within serial precursor concentrations of the CS-gelatin hydrogels studied, they showed trends of the reaction rates of gelation, where the higher concentration, the quicker the gelation occurred. In vitro studies, including assessment of cell viability (live and dead assay), cytotoxicity, biocompatibility via direct contacts of the hydrogels with cells, as well as measurement of inflammatory responses, showed their excellent biocompatibility. Eventually, the test results verified a promising potency for further application of CS-gelatin hydrogel in many biomedical fields, including drug delivery and tissue engineering by mimicking extracellular matrix components of tissues such as collagen and CS in cartilage.

Click Chemistry-Based Injectable Hydrogels and Bioprinting Inks for Tissue Engineering Applications

“…Bang et al reported chondroitin sulphate-based dual cross-linked hydrogels with gelatin grafting for improving the cell-adhesive properties of the chondroitin sulphate. They used the Michael type click chemistry reaction method and N-(3-diethylpropyl)-Nethylcarbodiimide hydrochloride chemistry for the gel formation and the hydrogels were tested for its application related to tissue engineering and drug delivery [100]. These different works related to thiol-based click chemistry reactions show potentials of this method in developing novel hydrogel biomaterials for tissue engineering applications.…”

Non-cytotoxic Dityrosine Photocrosslinked Polymeric Materials With Targeted Elastic Moduli

“…Hydrogels with similar G ′ that were formed by different crosslinking formulations were evaluated in cytotoxicity assays to understand changes in cytotoxicity due to differences in Ru and APS concentrations. The cytotoxicity assay tests the utility of Ru-mediated dityrosine crosslinked hydrogels in applications for which buffer exchange of the hydrogel is difficult, such as in-situ hydrogel applications (Bang et al, 2018) where crosslinking reagents necessarily come into direct contact with cells. This study demonstrates a systematic approach to prepare non-cytotoxic biomaterials with targeted elastic moduli given any appropriate tyrosyl-containing polymer by controlling the concentrations of Ru and APS used during photocrosslinking.…”

Natural hydrogels for cartilage regeneration: Modification, preparation and application

“…The grafting of ADH to chondroitin sulfate (CS) and gelatin resulted in CS-ADH and gelatin-ADH, respectively. After the subsequent reaction mediated by EDC, the in situ gelatin-CS hydrogel was obtained, which showed excellent biocompatibility, especially the application potential in cartilage tissue engineering [75].…”