Probing the interaction of flower-like CdSe nanostructure particles targeted to bovine serum albumin using spectroscopic techniques

The interaction between flower-like CdSe nanostructure particles (CdSe NP) and bovine serum albumin (BSA) was investigated from a spectroscopic angle under simulative physiological conditions. Under pH 7.4, CdSe NP could effectively quench the intrinsic fluorescence of BSA via static quenching. The binding constant (KA) was 6.38, 3.27, and 1.90×104 M−1 at 298, 304, and 310 K, respectively and the number of binding sites was 1.20. According to the Vanʹt Hoff equation, the thermodynamic parameters (ΔH°=−77.48 kJ mol−1, ΔS°=−168.17 J mol−1 K−1) indicated that hydrogen bonds and van der Waals forces played a major role in stabilizing the BSA−CdSe complex. Besides, UV–vis and circular dichroism (CD) results showed that the addition of CdSe NP changed the secondary structure of BSA and led to a decrease in α-helix. These results suggested that BSA underwent substantial conformational changes induced by flower-like CdSe nanostructure particles.