Study X-ray photoelectron spectroscopy determination of interactions between gold nanoparticles and epidermal growth factor for potential use in biomedicine

Abstract

Nowadays, biomedical applications of gold nanoparticles coupled with Epidermal Growth Factor have attracted huge attention because of its theranostic activity, which could be useful for diagnosis and treatment of neurodegenerative diseases. Therefore, there is a great interest to know the nature of the intermolecular interactions between the gold nanoparticles and epidermal growth factor (EGF). A two-step synthesis was performed. In the first step, gold nanoparticles were synthesized by chemical reduction of tetrachloroauric acid using sodium citrate as reducing and capping agent. Secondly, gold nanoparticles were coupled with EGF. The obtained nanoparticles were characterized by ultraviolet-visible spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and zeta-potential before and after being coupled with the EGF. Gold nanoparticles with an average diameter of 8.09 nm were obtained. After coupled with EGF, the particle average diameter increased to 9.14 nm. X-ray photoelectron spectroscopy showed an electrostatic interaction between gold nanoparticles and EGF. Zeta potential corroborated these results. Thus, it was possible for the first time to identify the interactions between these two chemical species. Since gold nanoparticles may act as carriers of EGF, these results illustrate the great potential for the use of this bionanocomposite in neurodegenerative disease treatment.