Construction of pH-responsive nanoplatform from stable magnetic nanoparticles for targeted drug delivery and intracellular imaging

Currently, developing responsive hydrophobic drug delivery systems centered on magnetic nanoparticles is a promising approach for the efficient delivery of hydrophobic drugs to living cells. Here, an efficacious designed strategy was proposed to construct pH-responsive nanoplatform for targeted hydrophobic drug delivery based on the formation of surface-anchored targeting molecules on the surface of Fe3O4 @C via single electron transfer living radical polymerization (SET-LRP) method. First, we prepared polymer-modified Fe3O4 @C using 4-vinylphenylboronic acid (VB) and polyethylene glycol methyl ether methacrylate (PEGMA) as polymerized monomers and confirmed that Fe3O4 @C-VB-PEGMA had high biocompatibility and low cytotoxicity. Next, we prepared curcumin-containing Fe3O4 @C-VB-PEGMA-Cur nanoplatform with an encapsulation efficiency for Cur as high as 67.7%. Furthermore, the nanoplatform not only displayed pH-responsive release behaviors of Cur under different pH values (pH=7.2, 6.5, 5.4), but also can be effectively targeted into HepG2 cells. More importantly, the nanoplatform also exhibited effectively inhibiting the growth of HepG2 cells and continuously intracellular imaging by the targeted releasing of loaded Cur. It is envisaged that these findings are a step forward in the construction of pH-responsive platform as a tool for clinical hydrophobic drug delivery.