Objective To construct a biodegradable magnetic iron oxide nanoparticles-chitosan-aloe vera composite porous scaffold, then utilize it to build up an in-vitro novel three-dimensional myocardial patch and analyze its physiological property.

Methods The iron oxide nanoparticles (IONP)-chitosan (CS)-aloe vera (AV) mixed solutions were prepared with different mass fractions of IONPs and AV. Then, these mixtures were processed through gradient lyophilization in a freeze dryer to obtain porous scaffolds. Scaffolds were characterized and examined by scanning electron microscope, dynamic thermomechanical analysis, porosity and in vitro degradation test to investigate their physical and biological properties. Then the scaffold was seeded with the immature cardiomyocytes and co-cultured for seven days to obtain an in-vitro myocardial patch. Finally, the mRNA in the tissue was extracted to analyze the expression of the cardiac-specific and apoptosis genes by quantitative polymerase chain reactions.

Results The synthesized 0.1% IONP-1% CS-0.2%AV composite porous scaffold had sizeable highly-connected surface pores and a porosity of 0.930±0.017. It also displayed a high swelling rate (>1 000%), pleasant tensile strength (0.33±0.06) mPa, as well as 0.12±0.01 extreme tensile elastic strain but diminished when AV content increased (P < 0.05). The scaffold presented a rapid in-vitro degradation (82.9±2.4% in 7 days), which was monitored under magnetic resonance imaging. The scaffold exhibited an incentive effect of rat cardiomyocytes (H9C2) proliferation without cytotoxicity. The obtained in-vitro myocardial patch not only demonstrated physiological contraction-relaxation under an extra electric field, but facilitated the expression of cardiac-specific genes (P < 0.05) and inhibited apoptosis (P < 0.05).

Conclusions Biodegradable magnetic IONP-CS-AV composite porous scaffolds have appropriate features for myocardial tissue engineering applications. The scaffold-based three-dimensional in-vitro myocardial patch can facilitate the maturation of cardiomyocytes, thus might provide a potential therapeutic method for treating post-infarct patients by implantation.