PEGylated hollow pH-responsive polymeric nanocapsules for controlled drug delivery

Novel pH-responsive PEGylated hollow nanocapsules (HNCaps) were fabricated through a combination of distillation-precipitation copolymerization and surface thiol-ene 'click' grafting reaction. For this purpose, SiO2 nanoparticles were synthesized using the Stober approach, and then modified using 3-(trimethoxysilyl)propyl methacrylate (MPS). Afterward, a mixture of triethyleneglycol dimethacrylate (as crosslinker), acrylic acid (AA; as pH-responsive monomer) and MPS-modified SiO2 nanoparticles (as sacrificial template) was copolymerized using the distillation-precipitation approach to afford SiO2@PAA core-shell nanoparticles. The SiO2 core was etched from SiO2@PAA using HF solution, and the obtained PAA HNCaps were grafted with a thiol-end-capped poly(ethylene glycol) (PEG) through a thiol-ene 'click' reaction to produce PAA-g-PEG HNCaps. The fabricated HNCaps were loaded with doxorubicin hydrochloride (DOX) as a model anticancer drug, and their drug loading and encapsulation efficiencies as well as pH-dependent drug release behavior were investigated. The anticancer activity of the drug-loaded HNCaps was extensively evaluated using MTT assay against human breast cancer cells (MCF7). The cytotoxicity assay results as well as superior physicochemical and biological features of the fabricated HNCaps mean that the developed DOX-loaded HNCaps have excellent potential for cancer chemotherapy. (c) 2020 Society of Chemical Industry