The Interaction of Amines with Gold Nanoparticles

Abstract

Understanding the interactions between amines and the surface of gold nanoparticles is important because of their role in the stabilization of the nanosystems, in the formation of the protein corona, and in the preparation of semisynthetic nanozymes. By using fluorescence spectroscopy, electrochemistry, X‐ray photoelectron spectroscopy, high‐resolution transmission electron microscopy, and molecular simulation, a detailed picture of these interactions is obtained. Herein, it is shown that amines interact with surface Au(0) atoms of the nanoparticles with their lone electron pair with a strength linearly correlating with their basicity corrected for steric hindrance. The kinetics of binding depends on the position of the gold atoms (flat surfaces or edges) while the mode of binding involves a single Au(0) with nitrogen sitting on top of it. A small fraction of surface Au(I) atoms, still present, is reduced by the amines yielding a much stronger Au(0)–RN.+ (RN., after the loss of a proton) interaction. In this case, the mode of binding involves two Au(0) atoms with a bridging nitrogen placed between them. Stable Au nanoparticles, as those required for robust semisynthetic nanozymes preparation, are better obtained when the protein is involved (at least in part) in the reduction of the gold ions.

An Unconventional Immunosensor for Biomolecule Detection via Nonspecific Gold Nanoparticle–Antibody Interactions

“…The adsorption of AuNPs on antibody is reported to be caused by their nonspecific interactions, physical and/or chemical . The physical interactions include the electrostatic interaction between negatively charged tannic-acid-capped AuNPs and the positively charged region of the anti-IgG antibody, hydrophobic attraction between the planar aromatic moieties of tannic acid and the antibody chain, and hydrogen bond. − Electrostatic interaction is reported to be the initial driving force of their attachment. , The charge distribution of an antimouse IgG monoclonal antibody has been reported in previous work, and it was found that the binding sites of the antibody are positively charged. , The structure of antimouse IgG monoclonal antibody used in our work remains confidential by the ELISA kit supplier, but it is assumed to share a charge distribution similar to that in the reference above, considering their similarity. Therefore, electrostatic interaction occurs between the anti-IgG antibody and tannic acids on AuNPs, which leads to soft attachment of AuNPs to the antibody.…”

Antimicrobial peptide-conjugated phage-mimicking nanoparticles exhibit potent bactericidal action against Streptococcus pyogenes in murine wound infection models

“…S4†) indicated that PhaNPs(Ag(-)peptide(-)) can bind to bacteria by targeting surface thiols, reducing disulfide bridges to thiols, and bind to amine rich peptide sequences used by the bacteria for forming chain like structures. 73–75…”

A colorimetric sensor with dual-ratio and dual-mode for detection of nicotine in tobacco samples

“…NIC is an organic amine that can interact with the surface of Au(0) atoms of AuNPs through its lone electron pair. 40,41 The molecular form of NIC changes due to its different protonation degree in solution at different pH values. To investigate the existence form of NIC in different pH environments in detail, the p K a of the NIC molecule was simulated by using the quantitative structure–activity relationship (QSAR) model built using MarvinSketch software (Fig.…”