Fluoroalbumin, an engineered vehicle for drug analysis

Traditional fluorescent proteins, based on genetic encoding and expression, have introduced biocompatible fluorescent labeling analysis methods at the cellular and organismal levels, becoming an essential research tool in life sciences. In contrast, organic small-molecule fluorescent dyes offer greater flexibility in modification and tunability of wavelengths. The integration of the advantages of fluorescent proteins and organic dyes is a key focus for further enriching fluorescence analysis technologies in the understanding of life. In this work, we utilized the spontaneous and covalent modification of fluorescent dyes with human serum albumin to construct a series of complexes with different fluorescent activities, which we named fluoroalbumin (FLA). FLAs exhibit high fluorescence brightness, excellent photostability, and biocompatibility. Interestingly, the natural drug-binding sites of albumin are preserved, and through allosteric effects, they regulate the fluorescence signals of FLAs, thereby enabling the fluorescence analysis of clinical drugs such as ibuprofen.