Spectral characters of Rhodamine B as a multi-information fluorescence probe for bovine serum albumins

The mechanisms of interaction between bovine serum albumin (BSA) with Rhodamine B (RB) have been investigated using fluorescence spectroscopy. The quenching of fluorescence from BSA takes place when increasing the RB concentration. Similar fluorescence quenching from RB also takes place when increasing the BSA concentration. Dual quenching is attributed to the binding of RB to BSA and the energy transfer between BSA and RB. In this interaction, BSA as well as RB acts as both donor and acceptor. Furthermore, increasing the concentration of RB also leads to BSA fluorescence peak splitting at 345 nm. Therefore, not only the intensity, but also shape and peak position of the fluorescence spectrum from BSA are controllable by the concentration of RB. This multi-information fluorescence probe method indicates potential applications in bio-optical sensor.