Investigations to reveal the nature of interactions between bovine hemoglobin and semiconductor zinc oxide nanoparticles by using various optical techniques

The interaction between bovine hemoglobin (BHb) and zinc oxide (ZnO) nanoparticle is investigated by UV–vis absorption, fluorescence, synchronous fluorescence, time-resolved fluorescence, FT-IR and circular dichroism techniques under physiological pH 7.4. The static mode of fluorescence quenching of BHb by ZnO nanoparticle indicates formation of BHb–ZnO complex in the ground state. The process of binding of ZnO nanoparticles on BHb is a spontaneous molecular interaction procedure in which electrostatic interaction plays a major role. The CD spectra reveal that α helicity of BHb is reduced by increasing ZnO nanoparticle concentration although the structure of BHb preserves its α-helical structure.