Near-infrared light-activatable siRNA delivery by microcapsules for combined tumour therapy.

A polyelectrolyte microcapsule-based layer-by-layer (LbL) technique has been widely used as a multifunctional vehicle for combined tumor therapy. Meanwhile, with the rapid development of combined tumour therapy, the challenge for designing multifunctional drug delivery system has attracted much more attention. Herein, we developed a new type of microcapsule (MC) system called MPA@siRNA@DOX@MC, which conjugated with siRNA and DOX as well as ICG-Der-02 (MPA) by electrostatic absorption. MPA as indocyanine green (ICG) fluorescence dye, exhibiting high fluorescence emission and photothermal conversion ability under NIR laser irradiation, was uploaded onto this drug system for realizing the controllable drug release and cancer theranostics. In addition, the results revealed that MPA@siRNA@DOX@MC possessed several ideal properties including high drug-loading capacity, excellent siRNA transfection efficiency, siRNA sequence protection and remarkably improved tumour-targeting capacity. Moreover, the combined therapy based on this drug system displayed improved therapeutic efficacy and negligible side effects both in vivo and in vitro experiment. Ultimately, MPA@siRNA@DOX@MC drug delivery system successfully combined the photothermal therapy and chemotherapy with controlled siRNA sequence silencing may have a promising potential in combined tumor therapy.