Functional Bioelectronic Materials for Long-Term Biocompatibility and Functionality

Wearable and implantable bioelectronics have received a great deal of interest since the need for personalized healthcare systems has arisen. Bioelectronics are designed to detect biological signals and apply medical treatments, thereby enabling patients to monitor and manage their health conditions. However, current bioelectronics lack long-term stability, biocompatibility, and functionality after implantation into the human body. In particular, the intrinsically different natures of the devices and human tissue result in low device–tissue compatibility. The obstacles for this can be defined as (1) physical, (2) biological, and (3) interfacial. The mechanical mismatch between rigid device materials and soft tissue results in physical incompatibility, which causes user discomfort and scar tissue formation. In addition, devices can show poor biocompatibility since the device materials are recognized as foreign bodies by the immune system. Accordingly, the applied devices can be toxic and/or induce an undesirable immune response and inflammation. Last, tissue environments are moist, irregular, and dynamic, which causes poor interfacial compatibility between the device and the human body. Herein, we describe various recent strategies to overcome limitations in the physical, biological, and interfacial compatibility of bioelectronics for long-term functionality in vivo. Moreover, in the last part of the review, we mention current limitations and future perspectives of bioelectronics for commercialization.