Enhanced Electrochemical and Photochemical Sensors for In Vivo Biological Monitoring Based on Carbon Nanomaterials

Abstract In vivo monitoring of biological compounds and xenobiotic substances is essential to deeply understand their mechanisms and functions within living subjects. However, there are many challenges impeding the development of these technologies, typically including the complexity of the biological environment, the detection limit of the substance, and the stability of the short‐ and long‐term sensing. Recently, carbon nanomaterials have been synthesized, investigated, and applied in electrochemical and optical sensors to assist in this endeavor. This review provides up‐to‐date information about the major carbon nanomaterials (e.g., graphene, graphene oxide/reduced graphene oxide, carbon nanotubes, carbon fibers, and CDs) used in in vivo electrochemical and photochemical sensing. First, the properties and synthesis methods of carbon nanomaterials are briefly discussed. Then, based on these nanomaterials, the fabrication and applications of in vivo electrochemical sensors (e.g., microdialysis, microelectrodes, and microneedles) and photochemical sensors (fluorescence, visualization, and bioimaging) are discussed in detail. Finally, the challenges and perspectives are discussed to further advance the application of carbon nanocomposites and to provide a reference source for future research on developing biocompatible electrochemical and photochemical sensors in vivo, leading to the creation of more efficient and reliable high‐throughput biological monitoring.