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

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.

Primary Study on Constructing Anti-cancer Drug in-situ Hydrogel by Self-assembling Peptide RAD16-Ⅰ / 中国药房

OBJECTIVE:To investigate the possibility of constructing anti-cancer drug in-situ hydrogel with self-assembling peptide RAD16-Ⅰ. METHODS:The rheological parameters as storage modulus(G′),loss modulus(G″)and phase angle(Δ)of 0.1%,0.2% and 0.5% RAD16-Ⅰ solution containing paclitaxel or not were determined by rheometer before and after mixing with isometric phosphate buffer solution (PBS);RAD16-Ⅰ solution containing paclitaxel or not were mixed with breast cancer MDA-MB-435S cells culture medium to obtain hydrogel,the status and effect of which on cell morphology were observed by in-verted microscope (compared with paclitaxel solution). RESULTS:In RAD16-Ⅰ solution containing paclitaxel or not,G′was close to or slightly higher than G″,and G′and G″had changed slightly as the concentration of peptide increased. Compared with not mixed with PBS,G′increased significantly in concentration-dependent manner after mixed with PBS,and G″also increased but was slighter than G′;Δ decreased significantly. In cell culture media,RAD16-Ⅰ solutions containing paclitaxel could form hy-drogel and maintain their gel form,cancer cells kept same morphology after treated with hydrogel and same concentration of pacli-taxel solution for same time. CONCLUSIONS:RAD16-Ⅰ solutions containing paclitaxel can form hydrogel under simulated physi-ological conditions,which can maintain their gel form and have anti-cancer effect of paclitaxel.