Department of Chemistry, Imperial College London, London SW7 2AY, United Kingdom.
J Chem Phys. 2018 May 21;148(19):194704. doi: 10.1063/1.5028557.
The free energy of adhesion per unit area (hereafter referred to as the adhesion strength) of lipid arrays on surfaces is a key parameter that determines the nature of the interaction between materials and biological systems. Here we report classical molecular simulations of water and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers at model silica surfaces with a range of silanol densities and structures. We employ a novel technique that enables us to estimate the adhesion strength of supported lipid bilayers . We find that silanols on the silica surface form hydrogen bonds with water molecules and that the water immersion enthalpy for all surfaces varies linearly with the surface density of these hydrogen bonds. The adhesion strength of lipid bilayers is a linear function of the surface density of hydrogen bonds formed between silanols and the lipid molecules on crystalline surfaces. Approximately 20% of isolated silanols form such bonds but more than 99% of mutually interacting geminal silanols do not engage in hydrogen bonding with water. On amorphous silica, the bilayer displays much stronger adhesion than expected from the crystalline surface data. We discuss the implications of these results for nanoparticle toxicity.
单位面积的粘附自由能（以下简称粘附强度）是决定材料与生物系统之间相互作用性质的关键参数。在此，我们报告了在一系列具有不同硅醇密度和结构的模型二氧化硅表面上进行的水和 1,2-二肉豆蔻酰基-sn-甘油-3-磷酸胆碱（DMPC）脂质双层的经典分子模拟。我们采用了一种新的技术，可以估计支撑脂质双层的粘附强度。我们发现，二氧化硅表面上的硅醇与水分子形成氢键，并且所有表面的水浸焓与这些氢键的表面密度呈线性关系。脂质双层的粘附强度是硅醇与晶体表面上的脂质分子之间形成的氢键表面密度的线性函数。大约 20%的孤立硅醇形成这种键，但超过 99%的相互作用的偕二硅醇不与水形成氢键。在无定形二氧化硅上，双层的粘附强度比从晶体表面数据预期的要强得多。我们讨论了这些结果对纳米颗粒毒性的影响。
