To achieve highly effective drug accumulation at the tumor site,conventional nano-sized delivery systems most frequently utilize PEGylation strategy and active targeting ligands,allowing nanomedicine to achieve passive tumor accumulation by EPR effect as well as specific and efficient tumor cell recognition and uptake.It is known that PEGylation capable of realizing long circulation is facing a dilemma of reduced tumor cellular uptake in design of drug delivery vehicle [1].Previous studies suggest that smart removal of PEG at tumor site provides a feasible solution to this issue.The concomitant incorporation of different functional moieties in a single system is,however,technically challenging due to a limited site for chemical modification [2].It would be desirable to develop a smart drug delivery system that can not only be readily functionalized,but can also camouflage the targeting ligands in the blood circulation while instantaneously expose tumor-targeting ligands through PEG detachment in response to tumor extracellular environment.