Au nanoparticles have been used for biomedical application since 1970s. However, the toxicity of them has become a rising issue, leading to an urgent need to understand the molecular mechanisms of the interaction between gold nanopartilcles and biological system, such as proteins. Self-assembled monolayers (SAMs) of organic thiols on Au surface are excellent model systems to study the interactions of Au nanoparticle and proteins. In this paper, molecular dynamics simulation of an all-atom model has been used to study the structural properties of self-assembled alkanethiol monolayers with different chain lengths chemisorbed on the Au (111), (110), and (100) surfaces . The interaction between Au-S was modeled using Morse potential, while for the Au-Au interactions, an embedded-atom (EAM) method was used. The adsorption of protein on SAMs with different chain lengths and terminals has also been investigated. We show that the arrangement of alkanethiol chains on Au largely relies on the atomic packing of Au surface. In particular, it is found that the SAM layer of alkanethiol chains forms a well-ordered (√3x√3) <i>R</i>30° triangular lattice on Au (111) surface at 300K, which is consistent with the experimental results. Furthermore, the adsorption of protein varies with the composition and the length of the monolayer, e.g., the carboxyl group-terminated SAMs are more effective to absorb protein compared with the methyl-terminated SAMs.

Interaction of gold nanoparticles with protein studied by atomistic simulations

251st National Meeting (2016)

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