UiO-66-NH2 MOF-based ratiometric fluorescent probe for the detection of dopamine and reduced glutathione

Metal-organic framework materials (MOFs) are highly promising materials for biomedical applications owing to high porosity, adjustable pore structure and high loading capacity. In this paper, we herein reported a novel UiO-66-NH2 MOF-based ratiometric fluorescent probe for the high sensitive detection of dopamine and reduced glutathione. Light-emitting metal-organic framework materials UiO-66-NH2 MOF with a fluorescence emission wavelength of 450 nm was synthesized by a simple hydrothermal synthesis. Dopamine could self-oxidize in polyethyleneimine (PEI) solution to form copolymer (PDA-PEI), which can emit yellow-green fluorescence at 530 nm. PDA-PEI can quench the fluorescence of UiO-66-NH2 MOF via FRET and the fluorescence intensity of PDA-PEI at 530 nm is increasing. Due to the reductive properties of glutathione, the formation of PDA-PEI could be blocked and the fluorescence of the UiO-66-NH2 MOF could be restored. Therefore, dopamine and reduced glutathione could be detected simultaneously via monitoring the ratiometric fluorescence intensity (I530/I450). The ratiometric fluorescent method showed good linearity curve with the concentration of dopamine in the range of 4–50 μM and with the concentration of reduced glutathione in the range of 1–70 μM. Furthermore, the ratiometric fluorescent method had a low detection limit for DA (0.68 μM) and GSH (0.57 μM), and was successfully applied for DA and GSH determination in human serum.