AIE-based fluorescence probes with different torsional configurations for monitoring human serum albumin

Human serum albumin (HSA) levels can reflect a variety of health issues in the human body, and quantitative examination of HSA is of great significance for disease diagnosis. Herein, we rationally designed and developed two novel AIE small molecule fluorescent probes, AE-BP and AE-AQ. Two probes have various torsion configurations and can be applied to the detection of exogenous HSA. They have high signal-to-noise ratio and selectivity and can enter the HSA cavity smoothly. Both probes can combine with the IB site, successfully avoiding most drug interference and having different detection effects on HSA. Meanwhile, the rational mechanism of AE-BP and AE-AQ to perform target detection was investigated using density functional theory. Furthermore, the scientific problems associated with the high signal-to-noise ratio and low aggregation of fluorescent probes were explained by investigating the effects of different torsional configurations on the detection effect. The main factors to be concerned in designing HSA fluorescent probes were proposed. This work provides methods and concepts for designing fluorescent probes for HSA based on the AIE strategy, as well as an effective manner for fluorescent probes to detect HSA. We anticipate that AE-BP and AE-AQ will be employed as new tools for detecting HSA at the preclinical stage.