Self-Powered Bioelectrical Materials for Tissue Repair: A Charge-Centered Perspective

Electrical cues are essential regulators of tissue repair processes such as wound healing, nerve regeneration, and bone remodeling. Implantable electrical stimulation systems have therefore attracted increasing interest; however, conventional devices typically rely on external power supplies or batteries, leading to limitations including bulky system integration, finite lifetime, mechanical mismatch, and elevated risks of infection and revision surgery. Herein, we propose a conceptual classification of implantable electrical stimulation materials based on their relationship with electric charges, categorizing them into charge-storing materials, charge-conducting materials, and charge-generating materials. Among these, charge-generating materials represent an emerging class capable of autonomously converting endogenous mechanical, chemical, thermal, or optical energy into electrical signals, enabling self-powered and self-sustained electrical stimulation without external energy input. This review systematically summarizes the underlying mechanisms, material design strategies, and recent advances of representative charge-generating systems, including piezoelectric, triboelectric, and electrochemical materials. Their applications in tissue repair are critically discussed, highlighting unique advantages in device miniaturization, long-term operation, and intelligent responsiveness. Finally, current challenges and future perspectives are outlined to guide the development of next-generation self-powered bioelectronic therapies.