Decoration of gold nanoparticles with thiolated pH-responsive polymeric (PEG-b-p(2-dimethylamio ethyl methacrylate-co-itaconic acid) shell: A novel platform for targeting of anticancer agent.

The aim of this study was to design and develop a new pH-responsive nano-platform for controlled and targeted delivery of anticancer drugs. Engineering of pH-responsive nanocarriers was prepared via decoration of gold nanoparticles (NPs) by thiolated (methoxy-poly(ethylene glycol)-b-poly((2-dimethylamino) ethyl methacrylate-co-itaconic acid) (mPEG-b-p(DMAEMA-co-IA) copolymer and fully characterized by various techniques and subsequently used for loading and targeted delivery of anticancer agent, methotrexate (MTX). By conjugation of MTX with the amino groups of polymeric shell of gold NPs (with the high loading capacity of 31%), since MTX is also the target ligand of folate receptors, the targeted performance of NPs examined through the cell uptake study. The results indicated that MTX-loaded NPs showed 1.3 times more cell internalization than MTX free NPs. Cell cytotoxicity studies pointed out ~1.5 and 3 times higher cell cytotoxicity after 24h for MTX-loaded nanoparticles than MTX in MTT assay and cell cycle arrest experiments, respectively. Additionally, mPEG was used as the outer shell of NPs which caused the long-term dispersibility of the NPs even under high ionic strength. The in-vitro pH-triggered drug release of MTX showed that MTX released more than three times in simulated cancerous tissue (40°C, pH5.3) than physiologic condition (37°C, pH7.4) during 48h. The results of various experiments determined that the developed smart nanocarrier proposed as a promising nanocarrier for active and passive targeting of anionic anti-cancer agents such as MTX.