Spectroscopic and Isothermal Titration Calorimetry Studies of Binding Interactions Between Carbon Nanodots and Serum Albumins

Carbon nanodots (C-dots) have attracted great attention as a new class of luminescent nanomaterials. In order to better understand the basic behavior of C-dots in biological systems, the binding characteristics of C-dots with bovine serum albumin (BSA) and human serum albumin (HSA) were investigated using spectroscopic approaches and isothermal titration calorimetry at pH 7.4. We found that the intrinsic fluorescence of BSA and HSA was quenched by the C-dots with a dynamic quenching mode. It was proved that the C-dots had little influence on the conformation of BSA and HSA by their UV–vis and circular dichroism spectra. Some important thermodynamic parameters were calculated, and the positive values of ΔH° and ΔS° indicate that the binding process was endothermic, and that the interaction was driven by favorable entropy and unfavorable enthalpy. It also showed that the hydrophobic force played a major role in the binding process.