Connectivity-Based Biocompatible Force Field for Thiolated Gold Nanoclusters

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• 作者：Matthew J. Guberman-Pfeffer ; James Ulcickas ; Jos茅 A. Gasc贸n
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：December 10, 2015
• 年：2015
• 卷：119
• 期：49
• 页码：27804-27812
• 全文大小：486K
• ISSN：1932-7455

文摘

Thiolated gold nanoclusters (AuNCs), sub-2 nm Au particles capped by Au(I) thiolate complexes, promise to have a myriad of applications in biomedical diagnosis and therapy as well as industrial catalysis, energy production, and monitoring of environmental pollutants. Computational simulations are a valuable tool in elucidating design principles for optimizing application-specific physicochemical properties. However, thiolated AuNCs protected, conjugated, and/or interacting with macromolecules often exceed the limit of computational tractability with present-day quantum chemistry software. To facilitate theoretical studies, a molecular mechanics force field, AuSBio, is presented that reasonably reproduces, and retains, characteristic structural features of perhaps the most intensively studied thiolated AuNC, Au₂₅L₁₈ (L = alkylthiolate), over 2 ns finite temperature molecular dynamics simulations. AuSBio was parametrized within the framework of force fields for (bio)organic simulations to reproduce equilibrium structures and the vibrational density of states for small homoleptic and larger thiolated Au clusters. AuSBio was further validated by the ability to reproduce the experimental structure of Au₃₈L₂₄, as well as bundling of long-chain alkylthiolate ligands, and the nonlinear frequency modulation pattern of a Raman-active vibrational mode, observed experimentally for the Au₂₅ cluster. We envision our AuSBio force field facilitating, in a practical manner, molecular mechanics or hybrid quantum/molecular mechanics simulations on the structure and dynamics of thiolated AuNC bioconjugates and AuNC monolayer-mediated molecular recognition and catalysis events.