Nanozymes for Biomedical Sensing Applications: From In Vitro to Living Systems

Abstract Nanozymes are the functional nanomaterials with enzyme-like characteristics. After discussing the advantages of nanozymes compared with natural enzymes and conventional artificial enzymes in the introduction section, various nanozyme-based biosensing strategies for in vitro and in living systems were discussed. Four subsections were devoted to in vitro sensing with nanozymes. First, nanozymes with peroxidase-mimicking activities for colorimetric sensing of H 2 O 2 and other important targets were discussed. Second, nanozymes with oxidase-mimicking activities for colorimetric sensing of dopamine, acetylcholinesterase, etc., were discussed. Third, the colorimetric detection of oxidase substrates was achieved by combining natural oxidases and nanozymes with peroxidase-mimicking activities. For example, glucose, choline, d -alanine, uric acid, and xanthine have been successfully detected with this strategy. Fourth, other detection strategies based on fluorescence, chemiluminescence, and electrochemistry using nanozymes were discussed. Then, the recent progress in nanozymes for in vivo sensing of important biotargets was discussed. For instance, the monitoring glucose dynamic changes in living rats were achieved with newly fabricated integrative nanozymes. Finally, the remaining challenges and future directions in nanozymes research are speculated to inspire researchers for further studies.