Interactions and characterization of Zein-BSA nanoparticles: Multi-spectral analysis and molecular simulations

Zein-bovine serum albumin (BSA) nanoparticles (NPs) with varying mass ratios were prepared via anti-solvent precipitation method at pH 4.0. Zein-BSA NPs at high Zein mass ratios exhibited superior particle characteristics and surface morphology. Ultraviolet-visible, fluorescence, and X-ray diffraction analyses demonstrated the formation and conformational transition during the binding of Zein and BSA, while ANS hydrophobic binding, fourier transform infrared spectra, and circular dichroism confirmed the hydrophobic exposure and secondary structure assignment. Molecular dynamic simulations revealed that Zein spontaneously bound to the IIB domain of BSA with a binding free energy of −63.52 ± 6.37 kcal/mol, which was dominated by hydrophobic and electrostatic interactions, supplemented by hydrogen bonds. Dissociation experiments supported the key role of hydrophobic and electrostatic interactions in maintaining the stability of the NPs. These findings provided insights into the formation and stabilization mechanisms of Zein-BSA NPs, and their potential applications as encapsulation carriers for bioactive substances or as novel nanoscale food substrates.