Turn-off near-infrared fluorescent probe for free bilirubin detection constructed by enhanced excimer emission

In this study, an amphiphilic near-infrared fluorescent molecule (denoted BCPB) was employed as a fluorescent probe to detect free bilirubin. In an aqueous solution, the micellar assemblies of BCPB possess a strong excimer emission at 660 nm, which was dramatically quenched upon the addition of bilirubin. It has been proven that fluorescence quenching is mainly attributed to photoinduced electron transfer (PET) from BCPB to bilirubin. As a fluorescent probe of bilirubin, BCPB showed advantages, such as fast response (<1 min), good anti-interference ability, and low limit of detection (0.33 μmol L−1, S/N = 3). BCPB was successfully applied to detect free bilirubin in human serum and urine, and the detection showed very high accuracy.