Update information. We have constructed nanoparticles that can in-situ label the protein microenvironment in living cells. When the nanoparticles were exposed to cellular vesicles, hydrogen peroxide was used to initiate the labeling reaction for 1 minute. The nanoparticles could activate the biotin tag around them, and the activated biotin tag molecules would bind to the proteins around the nanoparticles, so as to obtain the protein microenvironment of the nanoparticles in the living cellular vesicles.