Implantable flexible neuroelectrodes: advances in material innovation, structural design, and performance optimization

In recent years, implantable neuroelectrodes have been widely applied in various fields, including deep brain electrical stimulation, neuroprosthesis, and recording neuronal electrical activity in neuroscience research. However, with the rapid advancement of neuroscience and brain–computer interface technology, the limitations of traditional rigid neuroelectrodes have become increasingly evident. Flexible neuroelectrodes constructed from soft materials are emerging as a key research focus in the neural interface field. This review presents a systematic classification of the material selection, structural design, and key performance of implantable flexible neuroelectrodes and analyzes the optimization of achieving electrode flexibility in avoiding tissue damage and immune response. Furthermore, we summarized the contemporary challenges in performance optimization and material innovation, proposing potential solutions. By integrating and reviewing existing innovative approaches to flexible implantable neuroelectrodes, this review aims to provide an important theoretical foundation and technical guidance for the development of high-performance implantable neuroelectrodes.