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 UiO66-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 (I-530/I-450). The ratio metric fluorescent method showed good linearity curve with the concentration of dopamine in the range of 4-50 mu M and with the concentration of reduced glutathione in the range of 1-70 mu M. Furthermore, the ratiometric fluorescent method had a low detection limit for DA (0.68 mu M) and GSH (0.57 mu M), and was successfully applied for DA and GSH determination in human serum.