Using fluorescently-labeled magnetic nanocomposites as a dual contrast agent for optical and magnetic resonance imaging

Abstract

Dual-modality imaging probes synergistically combine magnetic resonance (MR) and fluorescence into a single nanocomposite. This promising technique affords a new level of flexibility for molecular imaging uses in biomedical research. In this study, we report a new strategy for the synthesis of a novel attapulgite nanorod-based atta@Fe₃O₄@[Ru(bpy)₂(fmp)]Cl₂ nanocomposite (atta@Fe₃O₄@Ru NC). Our synthesized NC has both photoluminescent and magnetic properties, bright fluorescence, as well as significant magnetic resonance. Transmission electron microscopy, energy dispersive spectroscopy, fluorescence spectrometry, and magnetization measurements were all used to validate its properties. In vitro studies showed that our functionalized NC had high cellular biocompatibility and was successfully used to label living cells through endocytosis of cells. Moreover, a CCK8 assay showed that even high concentrations of the atta@Fe₃O₄@Ru NC had low toxicity. Finally, the intravenous administration of the atta@Fe₃O₄@Ru NC to a rabbit model of hepatic carcinoma resulted in a marked and negatively enhanced T₂-weighted MRI in both normal liver and tumor, which can further enhance the visibility of the liver cancer tissue and normal liver tissue. Collectively, these results suggest that the atta@Fe₃O₄@Ru NC can be used for tumor discovery and diagnosis.