Flexible Patterned Fuel Cell Patches Stimulate Nerve and Myocardium Restoration

The distribution of electrical potentials and current in exogenous electrostimulation has significant impacts on its effectiveness in promoting tissue repair. However, there is still a lack of a flexible, implantable power source capable of generating customizable patterned electric fields for in situ electrostimulation(electrical stimulation). Herein, this study reports a fuel cell patch (FCP) that can provide in situ electrostimulation and a hypoxic microenvironment to promote tissue repair synergistically. Stable and highly efficient PtNi nanochains and PtNi nanocages electrocatalysts with anti-interference properties catalyze glucose oxidation and oxygen reduction respectively in an encapsulation-free fuel cell. The laser-induced graphene (LIG) electrode loaded with PtNi electrocatalysts is transferred to the surface of a flexible chitosan hydrogel. The resulting flexible FCP can adapt to tissues with different morphologies, firmly adhere to prevent suturing, and provide potent electrostimulation (0.403 V, 51.55 µW cm^-2). Additionally, it consumes oxygen in situ to create a hypoxic microenvironment, increasing the expression of hypoxia-inducible factor-1α (HIF-1α). Based on the different pattern requirements of exogenous electrostimulation during the repair of various types of tissue, an axial FCP for peripheral nerves and a flower-patterned FCP for myocardial tissue are constructed and transplanted into animals, showing significant tissue repair in both models.