Quantitative regularities of protein immobilization on the surfaces of gold nanoparticles

Abstract

Nanodispersed particles with receptor protein molecules immobilized on their surfaces are actively used as a means of isolation, concentration, and detection of various compounds. In this case, immobilization can be carried out under various conditions; accordingly, it is possible to obtain products that differ significantly in composition and reactivity. To date, the question of the relationship of these characteristics remains open. In the present work, using the example of protein adsorption on the surfaces of spherical gold nanoparticles, a quantitative characteristic of the laws of immobilization processes is carried out. The equilibrium constants of the protein-nanoparticle interaction and the composition of the resulting conjugates were determined, and the structure of the formed protein layer on the surfaces of the nanoparticles was characterized. The results obtained are summarized in the form of a theoretical model describing the formation of nanoparticle-protein complexes. By analyzing the proposed model, the conditions for the formation of mono- and multilayer coverage of nanoparticles by protein molecules were established and verified experimentally.