Direct self-assembly of AIE-active tetraphenylethene derivative with cucurbit[7]uril as a fluorescence probe for metformin detection

A fast, simple, sensitive and stable “turn-on” fluorescent probe method by the self-assembly of aggregation-induced emission luminogen 1,1,2,2-tetra(biphenyl-4-yl)ethene and cucurbit[7]uril was developed for selective determination of metformin. Simultaneously the host–guest complex can improve the poor water solubility of traditional aggregation-induced emission material. The response mechanism of the supramolecular probe to metformin was studied by UV–visible absorption spectroscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, dynamic light scattering technology, scanning electron microscope. The proposed method showed good sensitivity and accuracy for the detection of metformin. The relative fluorescence intensity was linearly correlated with the concentration of metformin in the range of 5 to 100 µM, with a detection limit of 1.5 µM. In addition, the aggregation-induced emission probe was successfully utilized to determine the metformin concentration in serum samples, and the recovery ranged from 90.80% to 104.0% with satisfactory results. Therefore, the established fluorescence assay provides a promising pathway for metformin analysis in biomedicine.