pH-Responsive polymeric Janus containers for controlled drug delivery

In this study, we develop a novel approach to fabricate pH-responsive polymeric Janus hollow spheres (JHSs) with bi-layered structures by two-step polymerization with silica particles as templates. The inner layer is the biodegradable poly(ε-caprolactone) (PCL) brush and the outer layer is cross-linked pH-responsive poly(diethylaminoethylmethacrylate) (PDEAEMA). So, these as-synthesized JHSs can selectively load oil-soluble materials into the cavities and controllably release them by changing the pH. Doxorubicin (DOX) is selected as a model drug which is loaded into the cavity of the JHSs and showed faster release at acidic pH than at physiological pH. It was revealed that the intracellular uptake of JHSs at the pH of tumorous tissues was significantly larger than that under the same conditions at the pH of the normal physiological environment.