We demonstrate for the first time rapid construction-deconstruction of high-density PEG brushes on nanosphere surfaces at 40 degrees C for 5 min by thermally induced shrinkage of disulfide PEG. These reaction conditions can avoid thermal instability of PEG chains generally occurring during PEG brush construction at higher temperature for longer incubation. This method will be an important strategy for fabrication of bioinert nanocarriers, because control of surface characteristics on the surface of nanocarriers is significant in biomedical applications.