Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China.
School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China.
J Colloid Interface Sci. 2023 May;637:112-122. doi: 10.1016/j.jcis.2023.01.080. Epub 2023 Jan 18.
Two-dimensional (2D) nanomaterials, such as graphene nanosheets (GNs) and graphene oxide nanosheets (GOs), could adhere onto or insert into a biological membrane, leading to a change in membrane properties and biological activities. Consequently, GN and GO become potential candidates for mediating interleaflet phospholipid transfer. In this work, molecular dynamics (MD) simulations were employed to investigate the effects of GN and GO on lipid flip-flop behavior and the underlying molecular mechanisms. Of great interest is that GN and GO work in opposite directions. The inserted GN can induce the formation of an ordered nanodomain, which dramatically elevates the free energy barrier of flipping phospholipids from one leaflet to the other, thus leading to a decreased lipid flip-flop rate. In contrast, the embedded GO can catalyze the transport of phospholipids between membrane leaflets by facilitating the formation of water pores. These results suggest that GN may work as an inhibitor of the interleaflet lipid translocation, while GO may play the role of scramblases. These findings are expected to expand promising biomedical applications of 2D nanomaterials.
二维（2D）纳米材料，如石墨烯纳米片（GNs）和氧化石墨烯纳米片（GOs），可以附着或插入生物膜中，导致膜性质和生物活性发生变化。因此，GN 和 GO 成为介导双层磷脂转移的潜在候选物。在这项工作中，采用分子动力学（MD）模拟研究了 GN 和 GO 对脂质翻转行为的影响及其潜在的分子机制。有趣的是，GN 和 GO 的作用方向相反。插入的 GN 可以诱导形成有序的纳米域，极大地提高了磷脂从一层翻转到另一层的自由能垒，从而降低了脂质翻转率。相比之下，嵌入的 GO 可以通过促进水孔的形成来促进磷脂在膜双层之间的转运。这些结果表明，GN 可能作为双层间脂质转运的抑制剂，而 GO 可能发挥着翻转酶的作用。这些发现有望扩大 2D 纳米材料在生物医学中的应用前景。
