Dual functional AuNRs@MnMEIOs nanoclusters for magnetic resonance imaging and photothermal therapy

Abstract

A novel dual functional theranosis platform is developed based on manganese magnetism-engineered iron oxide (MnMEIO) and gold nanorods (AuNRs) to combine magnetic resonance (MR) imaging and photothermal therapy in one nanocluster. The platform showed improved T-2-weighted MR imaging and exhibited a near-infrared (NIR) induced temperature elevation due to the unique characteristics of AuNRs@MnMEIOs nanoclusters. The obtained dual functional spherical-shaped nanoclusters showed low cytotoxicity, and high cellular uptake efficiency. The AuNRs@MnMEIOs nanoclusters also demonstrated a 1.9 and 2.2 folds r(2) relaxivity value higher than those of monodispersed MnMEIO and Resovist. In addition, in vivo MR imaging study found that the contrast enhancements were -70.4 +/- 4.3% versus 7.5 +/- 3.0% in Her-2/neu overexpression tumors as compared to the control tumors. More importantly, NIR laser irradiation to the tumor site resulted in outstanding photothermal therapeutic efficacy and without damage to the surrounding tissue. In additional, the prepared dual functional AuNRs@MnMEIOs display high stability and furthermore disperse even in the presence of external magnet, showing that AuNRs@MnMEIOs nanoclusters can be manipulated by an external magnetic field. Therefore, such nanoclusters combined MR imaging and photothermal therapeutic functionality can be developed as a promising nanosystem for effective cancer diagnosis and therapy. (C) 2014 Elsevier Ltd. All rights reserved.