Injectable polyaniline nanorods/alginate hydrogel with AAV9-mediated VEGF overexpression for myocardial infarction treatment.

Intramyocardial injection of hydrogels possesses great potential in the minimally invasive treatment of myocardial infarction (MI), but the current injectable hydrogels lack conductivity, long-term angiogenesis inductive ability, and reactive oxygen species (ROS)-scavenging ability, which are essential for myocardium repair. In this study, lignosulfonate-doped polyaniline (PANI/LS) nanorods and adeno-associated virus encoding vascular endothelial growth factor (AAV9-VEGF) are incorporated in the calcium-crosslinked alginate hydrogel to develop an injectable conductive hydrogel with excellent antioxidative and angiogenic ability (Alg-P-AAV hydrogel). Due to the special nanorod morphology, a conductive network is constructed in the hydrogel with the conductivity matching the native myocardium for excitation conduction. The PANI/LS nanorod network may also have large specific surfaces and effectively scavenges ROS to protect cardiomyocytes from oxidative stress damage. AAV9-VEGF transfects the surrounding cardiomyocytes for continuously expressing VEGF, which significantly promotes the proliferation, migration and tube formation of endothelial cells. After injecting the Alg-P-AAV hydrogel around the MI area in rats, the generation of gap junctions and angiogenesis are greatly improved with reduced infarct area and recovered cardiac function. The remarkable therapeutic effect indicates the promising potential of this multi-functional hydrogel for MI treatment.