Thermodynamic Parameters and Fluorescence Responses of Supramolecular Complexation of BODIPY-R6G with Serum Albumins of Blood

The paper presents the results of an integrated spectral and computational study of the supramolecular complexation of 3-(4,4-difluoro-5-phenyl-3a,4a-diaza-4-bora-s-indacen-3-yl)propionic acid (BODIPY-R6G, where R6G is rhodamine 6G, the name of the dye comes from the similarity of its spectral properties to those of rhodamine 6G.) with bovine serum albumin (BSA) and human serum albumin (HSA). Using steady-state and time-resolved fluorescence spectroscopy approaches, the mechanism of BODIPY-R6G fluorescence quenching in the presence of serum albumins (SA) was rationalized and the thermodynamic parameters of the interaction of BODIPY-R6G with BSA and HSA were determined. The BODIPY-R6G location and energy characteristics upon binding to BSA and HSA were determined using molecular docking. The obtained results, together with the determined detection limits of BSA (12.4 μg/mL) and HSA (7.7 μg/mL) for BODIPY-R6G, indicate the potential of using BODIPY for the purposes of labeling and fluorescence sensorics of the serum albumins studied in the work.