Many therapeutic anticancer drugs,such as doxombicin (DOX),are limited in their clinical applications due to their serious toxicities.To overcome these obstacles,more and more attention is paid to efficient stimulus-response carriers for improving therapeutic efficacy as well as reducing unwanted side-effects [1].A successful pH-sensitive vehicle should remain stable in the normal human body environment (pH 7.4),while releasing the drug around the cancer cells (pH 5.0-6.8) [2].