Abstract Addressing the spatial constraints inherent in wound therapy within narrow living organisms (e.g., intestinal tracts), the advancement of implantable micro-energy devices shows significant promise, which still faces the challenge of solving the trade-off between high energy and limited volume. Here we report a high-capacity implantable micro-supercapacitor based on the compact carbon nanotubes (CNTs) constricted by polyvinyl alcohol (PVA) framework, where the ionic conductive PVA network undergoes isotropic inward shrinkage, leading to bending deformation of CNTs and generating internal strain, thereby activating additional electrochemically active surface area. The electrochemically active surface area increases by 4000 times compared to its initial state, while the double-layer capacitance is 100 times higher than other reported carbon-based materials. Moreover, the implantable device has a small diameter of only 2.5 mm and provides sustained electrical stimulation exceeding 96 hours in simulated intestinal fluid, which is further verified in narrow intestinal sections across an experimental pig model with a 36% − 50% increase in healing rate compared to untreated wounds.
Wu et al. (2026) studied this question.