First fluorescent sensor for lutein in aqueous media based on thiosemicarbazide-bridged bis-tetraphenylethylene

This work designed and synthesized the first organic fluorescent sensor for lutein in aqueous solutions based on blue to yellow fluorescence change of thiosemicarbazide-bridged bis-tetraphenylene (Bis-TPE). By condensing monohydroxy tetraphenylene derivatives with p-phenylene di-isothiocyanate, Bis-TPE was produced. A fluorescence spectrophotometer was used to scan the fluorescence emission spectra from 380 to 700 nm with 360 nm as the excitation wavelength. The fluorescence spectra showed that Bis-TPE exhibited high selective sensing ability for lutein in aqueous medium, and the fluorescence showed red-shift phenomenon with a limit of detection as low as 0.26 μM for lutein. The sensing mechanism was confirmed by mass spectrometry, infrared, and fluorescence Job's plots based on the 1:1 stoichiometric ratio of double hydrogen bonding. The successful application of Bis-TPE in sensing test strips means that Bis-TPE can achieve efficient detection of lutein in complex environments. As a result, an aggregation-induced luminescence-based lutein fluorescence sensor was constructed, which exhibited highly selective and sensitive sensing of lutein, and provided a new research idea for the object detection of such structures.