Molecular simulation insights on the in vacuo adsorption of amino acids on graphene oxide surfaces with varying surface oxygen densities

详细信息    查看全文

• 作者：Farzin Rahmani ; Sasan Nouranian ; Mina Mahdavi…
• 关键词：Amino acid ; Graphene ; Graphene oxide ; Molecular dynamics simulation ; Interfacial interactions ; Adsorption ; Modeling and simulation
• 刊名：Journal of Nanoparticle Research
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：18
• 期：11
• 全文大小：9,847 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Nanotechnology
  Inorganic Chemistry
  Characterization and Evaluation Materials
  Physical Chemistry
  Applied Optics, Optoelectronics and Optical Devices
  
• 出版者：Springer Netherlands
• ISSN：1572-896X
• 卷排序：18

文摘

In this fundamental study, a series of molecular dynamics simulations were performed in vacuo to investigate the energetics and select geometries of 20 standard amino acids (AAs) on pristine graphene (PG) and graphene oxide (GO) surfaces as a function of graphene surface oxygen density. These interactions are of key interest to graphene/biomolecular systems. Our results indicate that aromatic AAs exhibit the strongest total interactions with the PG surfaces due to π-π stacking. Tryptophan (Trp) has the highest aromaticity due to its indole side chain and, hence, has the strongest interaction among all AAs (−16.66 kcal/mol). Aliphatic, polar, and charged AAs show various levels of affinity to the PG sheets depending on the strength of their side chain hydrophobic interactions. For example, arginine (Arg) with its guanidinium side chain exhibits the strongest interaction with the PG sheets (−13.81 kcal/mol) following aromatic AAs. Also, glycine (Gly; a polar AA) has the weakest interaction with the PG sheets (−7.29 kcal/mol). When oxygen-containing functional groups are added to the graphene sheets, the π-π stacking in aromatic AAs becomes disrupted and perfect parallelism of the aromatic rings is lost. Moreover, hydrogen bonding and/or electrostatic interactions become more pronounced. Charged AAs exhibit the strongest interactions with the GO surfaces. In general, the AA-GO interactions increase with increasing surface oxygen density, and the effect is more pronounced at higher O/C ratios. This study provides a quantitative measure of AA-graphene interactions for the design and tuning of biomolecular systems suitable for biosensing, drug delivery, and gene delivery applications.