Electrically conductive gold nanoparticle-chitosan thermosensitive hydrogels for cardiac tissue engineering

• Thermosensitive electro-conductive hydrogels were prepared from CS and GNPs.
• Gelation time and conductivity were tuned by varying concentration of GNPs.
• CS-2GNP with gelation time of 25.7 min and conductivity of 0.13 S·m− 1 was selected for in vitro studies.
• CS-2GNP supported active metabolism, migration and proliferation of MSCs.
• Expression of cardiac markers increased about two-fold in CS-2GNP compared to CS.

Injectable hydrogels that resemble electromechanical properties of the myocardium are crucial for cardiac tissue engineering prospects. We have developed a facile approach that uses chitosan (CS) to generate a thermosensitive conductive hydrogel with a highly porous network of interconnected pores. Gold nanoparticles (GNPs) were evenly dispersed throughout the CS matrix in order to provide electrical cues. The gelation response and electrical conductivity of the hydrogel were controlled by different concentrations of GNPs. The CS-GNP hydrogels were seeded with mesenchymal stem cells (MSCs) and cultivated for up to 14 days in the absence of electrical stimulations. CS-GNP scaffolds supported viability, metabolism, migration and proliferation of MSCs along with the development of uniform cellular constructs. Immunohistochemistry for early and mature cardiac markers showed enhanced cardiomyogenic differentiation of MSCs within the CS-GNP compared to the CS matrix alone. The results of this study demonstrate that incorporation of nanoscale electro-conductive GNPs into CS hydrogels enhances the properties of myocardial constructs. These constructs could find utilization for regeneration of other electroactive tissues.

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