A supramolecular ratiometric fluorescent probe for the detection of human serum albumin

In this study, an amphiphilic organic fluorescent molecule (denoted by BCPB) was employed as a ratiometric fluorescent probe for the detection of human serum albumin (HSA). In an aqueous solution, the micellar assemblies of BCPB showed a strong excimer emission at 660 nm. The presence of HSA can induce the disassembly of BCPB aggregates and reassemble with HSA to form BCPB-HSA complexes, resulting in a ratio change in the fluorescence emission of BCPB at 540 nm (monomer) and 660 nm (aggregate). Accordingly, the fluorescence color also undergoes a visually recognizable change from red to green. As a ratiometric fluorescence probe of HSA, BCPB has a fast response (<5 s), low limit of detection (8.3 nmol L−1, S/N = 3), good selectivity, and strong anti-interference ability. Finally, BCPB was loaded into the hydrogel to prepare a portable hydrogel kit, which successfully realized the in situ visual detection of HSA in an aqueous solution and human serum.