Tissue-Adaptive, Adhesive, and Ultra-Conformal Polymer Nanomesh-Based Implantable Bioelectrode for Long-Term Stable Electrical Stimulation

Abstract

Electrical stimulation has emerged as a promising strategy for enhancing bone regeneration; however, its long-term effectiveness is often limited by poor electrode-tissue conformity, mechanical mismatch, and interfacial instability in the complex and heterogeneous bone environment. Here, we present a tissue-adaptive, ultra-conformal polymer nanomesh-based implantable bioelectrode designed to enable stable and reliable electrical stimulation on mechanically rigid and topographically irregular bone surfaces. Nanomesh-based bioelectrodes demonstrated superior mechanical compliance and tissue adaptability, with smaller changes in dermal (polyimide film: 1192.26 & micro;m, nanomesh: 905.56 & micro;m) and fibrotic thickness (polyimide film: 240 & micro;m, nanomesh: 49.04 & micro;m) after eight weeks of implantation. The porous nanomesh structure exhibited 2.9- and 7.3-times improved adhesive properties for sliding and peel-off, respectively. Additionally, its porosity promoted tissue growth, enhancing adhesion, mechanical compliance, and stable long-term electrical energy transfer. Finally, in a rabbit calvaria bone defect model, the nanomesh-based electroceutical system enhanced bone mineral density by 15% and bone volume by 25% compared to the control group. This work highlights the potential of nanomesh-based implantable bioelectrode as a platform for effective, long-term tissue regeneration.