Injectable Hydrogels Encapsulating Dual-Functional Au@Pt Core–Shell Nanoparticles Regulate Infarcted Microenvironments and Enhance the Therapeutic Efficacy of Stem Cells through Antioxidant and Electrical Integration

[Image: see text] Injectable functional biomaterials have made significant progress in cardiac regenerative. In addition, how to adjust the abominable infarction microenvironment and introduce therapeutic stem cells to improve the healing effect has become a hotspot. Herein, injectable stem cell vector is prepared by combining natural alginate hydrogel and Au@Pt nanoparticles (Au@Pt/Alg hydrogel) to encapsulate brown adipose stem cells (BASCs). Au@Pt nanoparticles with both antioxidative and conductive properties could effectively eliminate reactive oxygen species, enhance the frequency of action potential release of cardiomyocytes, and further reduce the inflammatory factors of macrophage in vitro. The Au@Pt/Alg hydrogel enhances the antioxidant, differentiation, and paracrine capability of BASCs. The effect of BASCs loaded Au@Pt/Alg hydrogel is evaluated in a rat myocardial infarction (MI) model. The antioxidant, anti-inflammatory, and heart electrical integration are showed in the MI model. More interestingly, Au@Pt/Alg hydrogel can effectively maintain the paracrine efficiency and pro-angiogenesis effects of BASCs in the infarcted area. This study led us to recognize the great value of Au@Pt/Alg hydrogels for their ability to actively regulate the microenvironment and carry stem cells for MI treatment.