Multiresponsive Nanoprobes For Turn-On Fluorescence/F-19 Mri Dual-Modal Imaging

Multiresponsive nanoprobes are highly desirable for low background and highly sensitive imaging in biomedical applications. Herein, we design a glutathione (GSH)/pH dual-responsive nanoprobe capable of both fluorescence imaging in cells and F-19 magnetic resonance imaging (F-19 MRI) in deep tissue, by encapsulating manganese oleate (Mn(OA)(2)) on the surface of fluorinated fluorescent quantum dots (F-ZnS:Mn2+). In this approach, Mn(OA)(2) serves as an efficient quencher of both fluorescence and F-19 MRI signal. Both the fluorescence and F-19 MRI signal can be turned on by introducing glutathione (GSH) that breaks up the Mn-O bonds within Mn(OA)(2) under weak acidity conditions (e.g., pH 6.0). The imaging results in cells and mice suggest that this novel strategy can offer a promising nanoprobe for turn-on fluorescence/F-19 MRI dual-modal tumor imaging.