A novel dual-responsive core-crosslinked magnetic-gold nanogel for triggered drug release.

A facial approach was reported to prepare a novel dual-responsive core-crosslinked nanogel and investigated for the triggered methotrexate (MTX) release. Nanogels with core-shell architecture were synthesized by decoration of Au/Fe3O4 core/shell NPs using poly(ethylene glycol)-b-poly((N,N-dimethylamino)ethyl methacrylate-co-2-hydroxyethyl methacrylate)-maleic acid (PEG-b-P(DMAEMA-co-HEMA)-MA) for crosslinking and autoreduction processes. The second block containing amino groups and maleate groups as the inner shell was used for the reduction of HAuCl4 (auric cation) in the presence of Fe3O4 NPs and as a crosslinker agent, respectively. Furthermore, to improve the long-term dispersibility of the nanogels, poly(ethylene glycol) was preferred as outer shell even under high ionic strength. After that, NIPAAm was polymerized from the vinyl double bonds for fabricating the thermo and pH-responsive core-crosslinked nanogels. MTX (an anti-cancer agent) was successfully loaded (the loading capacity of 37%) into the nanogels by both ionic interaction and entrapment in polymeric network in the inner shell. The triggered MTX release ability of the synthesized nanocarriers was proved through the comparison of in-vitro drug release at simulated physiological condition and tumor tissue environment. MTT assay showed that MTX-loaded nanocarriers revealed high antitumor activity in MCF7 cell line after incubation following 24 and 48h. It was concluded that the developed nanogels have many promising qualities as an efficient carrier for the targeted MTX delivery to cancer tissues.