Effect of natural electric field on bioconjugation, secondary structure and the crystallization mechanism of peptide composite with gold nanoparticles on mica surface (R2)

Abstract

Establishing the mechanism of the influence of the electric field on the bioconjugation and crystallization of peptide (PT) composites with gold nanoparticles (NPs) on solid surfaces is of great scientific and practical importance. In aqueous solutions, leaching of the mica surface leads to the formation of an adsorption layer of K⁺ and Si⁺ ions and the emergence of an internal natural electric field with fixed polarity. This field changes the character of PT conjugation with gold NPs. Unlike gold substrate, this electric field changes the mechanism of crystallization and growth of the solid layers of the PT composites. As a result, the carboxyl functional groups of PT molecules are replaced by the amine groups. Thus, the structure of the crown around the gold NPs changes significantly, and on the mica surface, the initially neutral surface of the gold NPs becomes negatively charged. The electric field also affects the secondary structure of PT molecules and reduces the number of allowed conformations. In addition to the deamination of the amino group of lysine with the formation of CH₃, the leaching of the mica surface leads to the formation of new compounds, namely, KOH and Si₃N₄. The obtained results have important scientific significance in establishing the mechanism of the formation of the protein corona around NPs. They can be used especially in pharmacology and medicine for the development of new nanomedical platforms and for the study of their therapeutic functionality in vivo. This may also increase the pharmacological efficacy of both existing and developing drugs.