Fluorescent Magnetic Iron Oxide NanoparticleEncapsulated Protein Hydrogel Against Doxorubicin-Associated Cardiotoxicity and for Enhanced Cardiomyocyte Survival

Doxorubicin (DOX) is a widely used and effective anticancer drug. However, it shows high cardiotoxicity in several patients. The exact biological mechanisms of DOX-induced cardiotoxicity remain unclear. In the present study, we developed and assessed novel injectable hydrogel matrices combined with nanoparticles and secretome biomolecules to reduce DOXinduced cytotoxicity in human stem cell-derived cardiomyocytes. A Fe₂O₃ nanoparticle-loaded biocompatible silk sericin nanocomposite form was fabricated and used as an injectable carrier for secretome for in vivo cardiomyocyte metabolism. The formulated hydrogels carrying secretome were analyzed in vitro for proliferation, migration, and tube formation of human stem cell-derived cardiomyocytes. Biological analyses revealed that the secretome-encapsulated florescent Fe₃O₂ Silk sericin (Sec@MSS) hydrogel markedly reduced calcein-PI dual staining in cardiomyocytes, revealing significantly induced apoptosis. Furthermore, we evaluated the mitochondrial membrane potential for DOX and Sec@MSS hydrogel, and demonstrated apoptosis of the cardiomyocytes in the DOX-alone and Sec@MSS groups. However, the cardiotoxicity of Sec@MSS sericin was much lower than that in the DOX group, and was further evaluated via VEGFR and TUNEL analyses. The results indicate that Sec@MSS hydrogel might serve as an effective treatment agent in cardiac diseases in the future.