SPIONs/DOX loaded polymer nanoparticles for MRI detection and efficient cell targeting drug delivery

In this research, reducible polydopamine coated magnetic nanoparticles (SPIONs@PDA) were prepared and doxorubicin (DOX) was encapsulated for both magnetic resonance imaging (MRI) detection and cell targeting drug delivery. The SPIONs@PDA exhibited excellent water-solubility and colloidal stability, because the coating of the magnetic nanoparticle was a crosslinked reducible polydopamine synthesized with N,N-bis(acrylate) cystamine (BACy) as a crosslinker, dopamine methacrylamide (DMA) as an anchor to immobilize SPIONs, and polyethylene glycol (PEG) to provide colloidal stability. The SPIONs@PDA showed reduction-sensitivity due to the reducible disulfide bond in the polymer network. Subsequently, a sustained and high cumulative drug release in glutathione (GSH) was observed, rather than the low drug release in PBS (pH 7.4). Fluorescent imaging studies by confocal laser scanning microscopy indicated that the prepared SPIONs@PDA could specifically target tumor cells. The results of the cytotoxicity assays further demonstrated that the DOX-loaded SPIONs@PDA presented efficient antitumor activity to HeLa cells. These favorable properties suggested SPIONs@PDA as promising targeted magnetic nanoparticles for MRI detection and stimuli-triggered drug delivery in cancer theranostics.