A cobalt(III) complex as a dual-modal probe for the detection of sodium dithionite via MRI and fluorescence

Abstract

A fluorescence/magnetic resonance (MR) dual-mode molecular probe H1 based on cobalt(III) complexes was designed and synthesized in this work, which can be used to detect sodium dithionite (Na2S2O4) and for real-time biological imaging in vivo. The probe combines highly sensitive fluorescence imaging technology and high-resolution magnetic resonance imaging (MRI) technology, which can address the limitations of each individual modality. Probe H1 used Co3+ as the MRI unit and 3-acetylacetone-7-diethylamino-coumarin as the fluorescence unit. The diamagnetic Co3+ is reduced to paramagnetic Co2+ through the strong reductivity of Na2S2O4, and the MR signal as well as the fluorescence signal can be activated simultaneously due to the change in magnetic properties of the cobalt ion and the paramagnetic quenching effect of Co2+. Probe H1 demonstrates excellent detection performance in monitoring Na2S2O4, including excellent selectivity, high sensitivity (LOD = 9 μM), and anti-interference. Furthermore, probe H1 was successfully applied to the detection of exogenous Na2S2O4 in vivo through magnetic resonance/fluorescence dual-mode imaging, which can potentially be used in pathological hypoxic microenvironments fields in the future.