Injectable and thermoresponsive pericardial matrix derived conductive scaffold for cardiac tissue engineering

Scaffolds derived from decellularized cardiac tissue offer an enormous advantage for cardiac applications as they recapitulate biophysical and cardiac specific cues. However, poor electrical conductivity and mechanical properties severely compromise the therapeutic potential of these matrices. Dispersion of multiwall carbon nanotubes (MWCTs) in these scaffolds could improve their mechanical and electrical properties. However, the inherent hydrophobicity and poor dispersibility of these materials under aqueous conditions limit their outcome. We have developed a modified MWCNT functionalized with carbodihydrazide (CDH) residues that significantly improved their dispersibility and suppressed cytotoxicity in HL-1 cardiomyocytes. We found that the doping of CDH functionalized MWCNT (CDH-MWCNT) as low as 0.5 wt% to the pericardial matrix hydrogel (PMNT) induced the necessary electrical conductivity and significantly improved the mechanical properties of the hydrogel. Cardiomyocytes cultured on a PMNT scaffold triggered proliferation and significantly increased the expression of cardiac-specific gap junction protein, namely connexin 43. Such a phenomenon was not observed when cardiomyocytes were cultured on the pericardial matrix derived gels without MWCNT or on gelatin-fibronectin coated 2D cultures. The PMNT gels displayed excellent biophysical characteristics resulting in the clustering of cardiomyocytes with synchronous contraction, which is crucial for the successful integration to the host tissue.