ReaxFF MD Simulations of Peptide-Grafted Gold Nanoparticles

Abstract

Functionalized gold nanoparticles have critical applications in biodetection with surface-enhanced Raman spectrum and drug delivery. In this study, reactive force field molecular dynamics simulations were performed to study gold nanoparticles, which are modified with different short-chain peptides consisting of amino acid residues of cysteine and glycine in different grafting densities in the aqueous environment. Our study showed slight facet-dependent peptide adsorption on a gold nanoparticle with the 3 nm core diameter. Peptide chains prefer to adsorb on the Au(111) facet compared to those on other facets of Au(100) and Au(110). In addition to the stable thiol interaction with gold nanoparticle surfaces, polarizable oxygen and nitrogen atoms show strong interactions with the gold surface and polarize the gold nanoparticle surfaces with an overall positive charge. Charges of gold atoms vary according to their contacts with peptide atoms and lattice positions. However, at the outmost peptide layer, the whole functionalized Au nanoparticles exhibit overall negative electrostatic potential due to the grafted peptides. Moreover, simulations show that thiol groups can be deprotonated and subsequently protons can be transferred to water molecules and carboxyl groups.

Peptide-Conjugated Nano Delivery Systems for Therapy and Diagnosis of Cancer

“…This method is the simplest approach for functionalizing the surface of NDS with peptides [31,32]. This method has been extensively employed for preparing cysteine (Cys, C)-containing peptides functionalized AuNPs owing to the presence of the thiol group of cycteine, which is capable of forming a strong S-Au covalent bond with the surface of AuNPs [33][34][35][36][37]. Lévy et al demonstrated that the cysteine-alanine-leucine-asparagineasparagine (CALNN) pentapeptide is capable of converting citrate-capped AuNPs to stable and water-soluble AuNPs equipped with chemical features similar to proteins [37].…”

The Peptide Functionalized Inorganic Nanoparticles for Cancer-Related Bioanalytical and Biomedical Applications

“…Generally, the NPs were firstly produced by the hydrothermal or solvothermal approaches [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ]. The as-prepared NPs were then modified with different peptides to achieve different functionalities for further applications.…”

“…The ligand exchange method is the simplest strategy for preparing peptide functionalized NPs, which essentially involves displacement of original ligand on NP surface by a specific peptide ligand and/or a mixture of peptide ligand [ 40 , 41 ]. Cysteine (Cys, C)-containing peptides have been used successfully to synthesize various peptide functionalized AuNPs by ligand exchange method because the thiol group (−HS) of cysteine can form strong S-Au covalent bond with surface Au atoms of AuNPs [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. As early as 2004, Lévy and colleagues demonstrated that the pentapeptide, CALNN, can convert citrate-capped AuNPs into extremely stable, water-soluble AuNPs with some chemical properties analogous to those of proteins [ 42 ].…”

Molecular Dynamics Simulations of a Catalytic Multivalent Peptide–Nanoparticle Complex

“…2021, 22, 3624 2 of 17 gold nanoparticles (NP) by means of atomistic simulations. From simulations, observed experimental evidences have been interpreted as the result of changes in peptide conformation due to the gold nanocluster [22], or to the presence of water molecules and structured sulphur interfacial atoms within the peptide monolayer [23], or the protonation/deprotonation state of peptide-capped gold functional groups [24]. It also has been shown that the self-assembly of bio-functionalized gold NPs [25] can be affected by the flexibility, stability and conjugation dynamics of the peptide functional groups which, in turn, is a function of the peptide length.…”