Size and surface coverage density are major factors in determining thiol modified gold nanoparticles characteristics

Gold nanoparticles (GNPs) have prominent advantages due to their ultrasmall size and high surface-area-to volume ratio, with multiple and broad applications in medical, agricultural and pharmaceutical industries. GNPs can be functionalized by various molecules including polysaccharides, proteins, peptides, fatty acids, plasmids, or oligonucleotides. GNP surface represents one of the most easily functionalized platforms, the complex level of surface decoration being used to obtain efficacy and to limit off-target toxicity. In the present study, molecular dynamics simulations of thiol modified GNPs were performed to provide insights at the molecular level for the design of conjugated nanoparticles. Our study shows that due to the significant enhancement in the conformational order and packing of the thiol chains, both nanoparticle size and thiol coverage density can be used to modify the structural properties of thiol-modified GNPs (e.g. end-to-end distance, shape factor, tilt angle of thiol chains). This strategy has a lot of potential in designing any (thiol-modified gold) nanoparticlebased carriers (such as those that are used to find and modify the genes that are associated with diseases).