A deep-red fluorescent probe based on naphthalimide for discrimination of HSA from BSA and tracking HSA by bioimaging

The tertiary structures of HSA and BSA show a 76 % similarity, and the abnormal levels of HSA in body fluids can cause many diseases. Therefore, accurate quantification of HSA and effectively distinguishing HSA from BSA have significant application value in various fields. In this paper, a deep-red fluorescent probe, NITH, based on 1,8-naphthalimide, is demonstrated as a potential tool for accurately quantifying HSA and distinguishing HSA from BSA. The probe not only exhibits large stokes shift (100 nm) and low detection limit (4.61 μg/L, 0.0692 nM), but also effectively detects HSA by entering its hydrophobic cavity and emitting red fluorescence. Furthermore, NITH is capable of tracking the distribution levels of HSA within the cells through endogenous and exogenous cellular imaging. The application of NITH spans various environments such as cells, zebrafish, urine, and test strips, solidifying it as an effective tool for HSA detection.