Fluorescent amphiphilic copolymer-based tumor theranostics for facile DOX-loading and tumor microenvironment-triggered release

Novel reduction/pH dual-stimuli responsive fluorescent amphiphilic copolymer PEG-Cys-P(DEAEMA-co-Rh6GEAm) with detachable poly(ethylene glycol) (PEG) corona through bio-reducible disulfide linkage and pendent cationic groups was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization for tumor theranostic application. The doxorubicin (DOX)-loaded micelles could be easily fabricated via facile micellization in the presence of DOX in water, with a high drug-loading capacity (DLC) of 39.2%. They exhibited fast release ratio with the synergetic effect of reductive agent and pH in the simulated tumor micro-environment, while the leakage can be efficiently avoided in the physiological media. Furthermore, the fluorescence intensity of the copolymer possessed a reversibly transformation in different pH media, indicating the potential application for intracellular fluorescence imaging of tumors.