Influence of Single-Stranded DNA Coatings on the Interaction between Graphene Nanoflakes and Lipid Bilayers
Influence of Single-Stranded DNA Coatings on the Interaction between Graphene Nanoflakes and Lipid Bilayers
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DOI：
10.1021/acs.jpcb.9b04042
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发表时间：
2019-09-12
影响因子：
3.3
通讯作者：
McCabe, Clare
中科院分区：
文献类型：
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作者：
Moore, Timothy C.;Yan, Alexander H.;McCabe, Clare
使用分子动力学模拟，它表明，单链DNA（ssDNA）的部分涂层减少了渗透深度的石墨烯纳米片（GNF）到磷脂双层通过衰减驱动渗透的疏水力。当GNF穿透双层时，ssDNA保持吸附在双层外部的GNF上，在那里它保护石墨烯免受周围水的影响。渗透深度被发现是控制的ssDNA涂层的GNF的量，与稀疏的涂层导致更深的渗透，因为ssDNA屏蔽较少的GNF表面。随着包被密度的增加，GNF进入双层的可能性降低，而GNF倾向于平放在双层表面上，ssDNA的糖磷酸骨架与亲水性脂质头部基团相互作用。虽然部分插入的ssDNA包被的GNF没有观察到双层破坏，但发现更大的、裸露的、部分插入的GNF优先从双层中提取磷脂，这进一步证明脂质提取是GNF的主要细胞毒性机制。因此，ssDNA的涂层可以通过屏蔽不利的石墨烯-水相互作用来降低GNF的细胞毒性，从而防止石墨烯渗透和脂质提取。
Using molecular dynamics simulations, it is demonstrated that a partial coating of single-stranded DNA (ssDNA) reduces the penetration depth of a graphene nanoflake (GNF) into a phospholipid bilayer by attenuating the hydrophobic force that drives the penetration. As the GNF penetrates the bilayer, the ssDNA remains adsorbed to the GNF outside of the bilayer where it shields the graphene from the surrounding water. The penetration depth is found to be controlled by the amount of ssDNA coating the GNF, with a sparser coating resulting in a deeper penetration since the ssDNA shields less of the GNF surface. As the coating density is increased, the likelihood of the GNF entering the bilayer is reduced where it instead tends to lie flat on the bilayer surface with the sugar phosphate backbone of ssDNA interacting with the hydrophilic lipid head groups. While no bilayer disruption is observed for a partially inserted ssDNA-coated GNF, a larger, bare, partially inserted GNF is found to preferentially extract phospholipids from the bilayer, offering further evidence of lipid extraction as a main cytotoxicity mechanism of GNFs. Therefore, a coating of ssDNA may reduce the cytotoxicity of GNFs by shielding the unfavorable graphene-water interaction, thus preventing graphene penetration and lipid extraction.