An Immunocompatible Conductive Polymer for Long-Term Bioelectronic Implants
Xianchi Zhou, Zihao Zhu, Wenbin Dai, Wenzhong Cao, Zuolong Liu, Kexin Chen, Yan Yu, Fan Zhang, Shaomin Zhang, Fan Jia, Youxiang Wang, Jian Ji, Peng Zhang
Abstract
Tissue-electronic interfaces are vital for neural implants, health monitoring devices, and augmented reality applications; however, the host immune reaction against the electrodes profoundly impacts their durability, precision, and overall fidelity. Building a highly immunocompatible yet conductive interface for implantable electrodes remains a significant challenge. Here, by screening PEDOT derivatives functionalized with diverse immunoregulatory moieties, we identified PEDOT-TMO as a candidate combining superior immunocompatibility with robust conductivity for long-term bioelectronic implants. PEDOT-TMO/PSS coatings exhibit substantially mitigated acute inflammation and chronic fibrotic response following subcutaneous implantation in mice compared to conventional PEDOT/PSS, while preserving its original electrochemical properties. During extended in vivo brain implantation trials in freely moving rat models, we observed that the immunocompatible conductive polymer-coated silicon electrode can reliably record electrophysiological signals for at least 8 weeks, demonstrating significantly better performance compared to PEDOT/PSS-coated and bare electrodes. Notably, the PEDOT-TMO/PSS interface substantially reduced the expression of S100A9 in surrounding brain tissue. Pharmacological inhibition of S100A9 similarly attenuated tissue responses to brain implants, suggesting a target for neuroinflammation inhibition. The new type of immunocompatible conductive polymer reported here holds promise in enhancing and extending the long-term function in a range of bioelectronic devices by attenuating local immune responses to functional bioelectrodes.