Frontier applications of piezoelectric hydrogels: principles, design strategies, and translational perspectives

Applications of piezoelectric hydrogels in four major biomedical fields: 1) Application in wound healing and tissue regeneration; 2) Application in bone and cartilage engineering; 3) Application in nerve regeneration and repair; 4) Application in wearable and implantable devices. • Piezoelectric hydrogels offer soft, self-powered stimulation for tissue regeneration. • Piezoionic effect via asymmetry mimics mechanotransduction unlike conventional piezo. • Translational progress: improve efficiency, biosafety, integration, and scalability. Piezoelectric hydrogels (PHs) are emerging smart materials that combine the tissue-like softness and biocompatibility of hydrogels with the electromechanical conversion capability of piezoelectric materials, offering new opportunities for biomedicine and flexible electronics. Their functionality arises from both the intrinsic piezoelectric effect and the piezionic effect driven by asymmetric ion migration, allowing PHs to mimic biological mechanotransduction and generate electrical cues under mild mechanical stimulation. This review summarizes the fundamental principles, material components, fabrication routes, and structure–property relationships of PHs, and discusses their evolution from passive transducers to active therapeutic and sensing platforms. Representative advances are highlighted in four major biomedical areas, including wound healing and tissue regeneration, bone and cartilage repair, neural regeneration, and wearable and implantable devices. Across these applications, PHs enable self-powered or remotely triggered electrical stimulation, antibacterial and immunomodulatory effects, and integrated sensing functions. We further discuss the key barriers to clinical translation, including limited output efficiency, long-term stability, biosafety evaluation, and scalable manufacturing. Finally, future perspectives are outlined in terms of multi-scale biomimetic design, closed-loop intelligent systems, and multimodal energy integration, highlighting the potential of PHs for next-generation regenerative medicine and personalized healthcare.