Interaction thermodynamics investigation of bovine serum albumin with black phosphorus quantum dots via spectroscopic and molecular simulation techniques

In this paper, the binding interaction thermodynamics of black phosphorus quantum dots (BPQDs) with bovine serum albumin (BSA) was explored systematically and comprehensively to interpret the influence of BPQDs on both the conformational structure and the biological function of BSA. The results of a variety of spectroscopic strategies and molecular simulation technique revealed that the endogenous fluorescence of BSA was quenched by BPQDs spontaneously via the static quenching mechanism based on the main binding forces of van der Waals interaction and hydrogen bonds formation. BPQDs interacted strongly with the Sudlow's site I of BSA via stoichiometric ratio of 1:1 to construct the novel stable ground-state complex. The results of three-dimensional fluorescence spectrometry and circular dichroism spectroscopy showed that BPQDs reduced the prominent α-helix structure content and the thermal stability of BSA through concentration-dependent manner. These results not only disclose the binding interaction mechanism of BPQDs with BSA comprehensively but also illustrate the variation of the secondary structure of BSA after its association with BPQDs carefully. Such research paves the way for the targeted design of black phosphorus derivatives with excellent biocompatibility and the safety application of such nanoparticles in the clinic diagnosis and the effective therapy of serious diseases in human beings.