Fabrication of Hybrid Nanostructures Based on Fe(3)O(4) Nanoclusters as Theranostic Agents for Magnetic Resonance Imaging and Drug Delivery

Combining anticancer drugs with inorganic nanocrystals to construct multifunctional hybrid nanostructures has become a powerful tool for cancer treatment and tumor suppression. However, it remains a critical challenge to synthesize compact, multifunctional nanostructures with improved functionality and reproducibility. In this study, we report the fabrication of magnetite hybrid nanostructures employing Fe(3)O(4) nanoparticles (NPs) to form multifunctional magnetite nanoclusters (NCs) by combining an oil-in-water microemulsion assembly and a layer-by-layer (LBL) method. The Fe(3)O(4) NCs were firstly prepared via a microemulsion self-assembly technique. Then, polyelectrolyte layers composed of poly(allylamine hydrochloride) (PAH) and poly(sodium 4-styrenesulfonate) (PSS) and doxorubicin hydrochloride (DOX) were capped on Fe(3)O(4) NCs to construct the Fe(3)O(4) NC/PAH/PSS/DOX hybrid nanostructures via LBL method. The as-prepared hybrid nanostructures loaded with DOX demonstrated the pH-responsive drug release and higher cytotoxicity towards human lung cancer (A549) cells in vitro and can serve as T(2)-weighted magnetic resonance imaging (MRI) contrast agents, which can significantly improve T(2) relaxivity and lead to a better cellular MRI contrast effect. The loaded DOX emitting red signals under excitation with 490 nm are suitable for bioimaging applications. This work provides a novel strategy to build a Fe(3)O(4)-based multifunctional theranostic nanoplatform with T(2)-weighted MRI, fluorescence imaging, and drug delivery. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s11671-019-3026-7) contains supplementary material, which is available to authorized users.