Elucidating the binding mechanism between bovine serum albumin and TiO2 nanoparticles with diverse properties: Insights from spectroscopic methods and molecular docking simulation

The interaction mechanism between bovine serum albumin (BSA) and titanium dioxide (TiO 2 ) nanoparticles with different shapes, surface charge and hydrophobic properties was studied using multiple spectral methods and molecular docking simulation. UV–vis spectra showed that when BSA interacted with the four TiO 2 NPs, the TiO 2 nanoparticles and BSA formed a stable ground state complex. Fluorescence spectra showed that the binding capacities of four different types of TiO 2 nanoparticles with BSA are as follows: spherical TiO 2 (s-TiO 2 ) > rod-shaped TiO 2 (r-TiO 2 ) > positively charged TiO 2 (c-TiO 2 ) > hydrophobic TiO 2 (h-TiO 2 ). The results of synchronous fluorescence, circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy revealed that s-TiO 2 , r-TiO 2 , and c-TiO 2 have a weak effect on the conformation of BSA, whereas h-TiO 2 has a greater effect. Molecular docking and MD simulations results show that the content of hydroxyl groups plays a key role in the binding capacity.