Investigation of the interaction between colloidal TiO2 and bovine hemoglobin using spectral methods

The interaction between bovine hemoglobin (BHb) and TiO2 colloid was investigated by UV/vis absorption, UV/vis diffuse reflectance spectrum, IR, fluorescence, synchronous fluorescence, and three-dimensional fluorescence spectra techniques under physiological pH 7.40. TiO2 effectively quenched the intrinsic fluorescence of BHb via static quenching. The process of binding TiO2 on BHb was a spontaneous molecular interaction procedure. The thermodynamic parameters, ΔH° and ΔS° were estimated to be −78.07 kJ mol−1, −110.93 J mol−1 K−1 according to the van’ Hoff equation. This indicates that the van der Waals and hydrogen bonds interactions played a major role in stabilizing the TiO2–BHb complex. The effect of TiO2 on the conformation of BHb was analyzed using synchronous fluorescence spectroscopy.