In Situ Photocurable Janus Hydrogels with Magnetically Guided Anisotropic Conductivity for Myocardial Ischemeia–Reperfusion Injury Treatment and Tissue Adhesion Prevention

Abstract Myocardial ischemia–reperfusion (I/R) injury remains a major clinical challenge associated with reperfusion therapy, often leading to adverse cardiac remodeling and heart failure. Although cardiac patches offered a promising therapeutic strategy, the traditional designs had some limitations, such as invasive implantation, poor electrical integration, and nonspecific tissue adhesion. Here, we introduced an in situ photoinitiated Janus conductive hydrogel patch, namely, HD/G@Fe3O4-A, which integrates minimally invasive delivery, spatiotemporal programmed asymmetric adhesion, and magnetically guided anisotropic conductivity. This shear-thinning hydrogel precursor could be injected through a catheter and uniformly cover the beating heart and then achieve strong myocardial attachment on one side through rapid ultraviolet cross-linking while forming an antiadhesion interface on the other side, resulting in a 60- to 80-fold adhesion contrast. Under magnetic guidance, Fe3O4 microspheres were arranged to form conductive pathways, simulating the anisotropic conductivity of natural myocardial tissue and enhancing signal propagation and synchronous contraction. In vitro experiments showed that HD/G@Fe3O4-A exhibited excellent cell compatibility and antioxidant activity while promoting the functional maturation of neonatal rat cardiomyocytes. In a rat I/R model, the patch significantly improved cardiac function by effectively restoring electrophysiological conduction and alleviating oxidative stress, thereby reducing ventricular dilation and fibrosis. Moreover, it prevented postoperative pleural adhesions by regulating local inflammation. This multifunctional hydrogel platform provided an integrated cardiac repair solution in a minimally invasive manner, combining structural support, electrical integration, and biochemical regulation.