Injectable Thermosensitive Hydrogel (Chitosan/Gelatin/β-Glycerol Phosphate) Reinforced with Polyaniline/Carboxylated Carbon Nanotube/Gelatin Containing Stem Cells for Cardiac Tissue Engineering

Injectable hydrogels that mimic heart tissues can be considered a promissing perspective towards the future developments of cardiac tissue engineering. This study aims to fabricate an injectable, thermosensitive hydrogel consisting of chitosan/gelatin/glycerol phosphate. Due to their unique electro-conductivity characteristic, hydrogels can provide a suitable environment to accelerate cardiac cell proliferation. Polyaniline/multi-walled carboxylated carbon nanotube (PAni/c-MWNT) was prepared using Sodium Dodecyl Sulfate (SDS) emulsion. To prevent the interaction between the PAni/c-MWNT nanocomposite and hydrogel, the nanocomposite was coated with gelatin to form polyaniline/carboxylated carbon nanotube/gelatin (PAni/c-MWNT/G). The PAni/c-MWNT/G nanocomposite was then dispersed to provide electrical signals throughout the hydrogel. The gelation time, gel temperature, and mechanical properties of the hydrogel were measured using a rheometer. FTIR spectroscopy results revealed that the interaction between the aniline and c-MWNT/G could change the position of the quinone and benzene peaks. The conductivity of hydrogel-containing nanocomposite was found to be higher than that of c-MWNT and PAni. Scanning Electron Microscopy (SEM) confirmed the uniform distribution of PAni/c-MWNT/G nanocomposite throughout the hydrogel. The degradation rate of conductive hydrogel is lower than that of pure hydrogel. The MTT assay test showed the biocompatibility of the cell-hydrogel. Finally, Mesenchymal Stem Cells (MSCs) were cultured in the hydrogels for 14 days. Cell adhesion, cell viability, and proliferation were also examined. This study utilized PAni/c-MWNT/G, for the first time, to enhance the electro-conductivity of chitosan/gelatin/glycerol phosphate hydrogel. This conductive thermosensitive injectable hydrogel can be used to regenerate cardiac tissue and other electroactive tissues.