Figure 1.

Chemical structure of mPEG-S-PBLG copolymer and schematic diagram of the resulting self-assembled pH-responsive micelles for efficient delivery of DOX in targeted cancer therapy. (A) The amphiphilic polymer is able to efficiently encapsulate chemotherapeutic drugs (such as DOX) to form micellar formulation. (B) After intravenous injection (a), DOX-loaded micelles could accumulate at tumor sites through the EPR effect (b) and responsively release drugs in the mild acidic extracellular environment (pH 6.5, c) or the acidic intracellular compartment (endosome/lysosome, pH 5.5, d) upon the internalization into cancer cells (e), resulting in cancer cell death (f).