Shenzhen Key Laboratory of Flexible Printed Electronics Technology, School of Science, Harbin Institute of Technology (Shenzhen), University Town, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Shenzhen 518055, Guangdong, Harbin 150001, Heilongjiang, China.
Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structure Materials of Guangdong Province, Shantou University, Shantou 515063, Guangdong, China.
Soft Matter. 2022 Jun 8;18(22):4305-4314. doi: 10.1039/d2sm00167e.
A clear physical picture of the dynamic behavior of molecules on the surface of the lipid membrane is highly desired and has attracted great attention from researchers. In this study, a step forward in this direction based on previous studies was presented with second harmonic generation (SHG) and molecular dynamic (MD) simulation. Specifically, details on the orientation flipping and cross-membrane transport of two charged molecules, 4-(4-diethylaminostyry)-1-methyl-pyridinium iodide (D289) and malachite green (MG), on the surface of 2-dioleoyl--3-phospho--(1-glycerol) sodium salt (DOPG) lipids were presented. Firstly, the orientation flipping of the two molecules on the surface of lipids before their cross-membrane transport was confirmed by the MD simulation. Then, the concentration dependent rate of the cross membrane transport for MG/D289 was analyzed. It was found that a simplified model could satisfactorily interpret the faster cross-membrane transport of MG under higher bulk concentrations. A different concentration dependent dynamics was observed with D289 and the reason behind it was also discussed. With this investigation, the surface structures and dynamics of D289 and MG on the DOPG lipid surface were clearly presented.
人们非常希望能够清晰地了解脂质膜表面分子的动态行为，并对此展开了深入研究。在之前研究的基础上，本研究基于二次谐波产生（SHG）和分子动力学（MD）模拟方法取得了进一步的进展。具体来说，本研究详细介绍了两种带电分子（4-（4-二乙氨基苯乙烯基）-1-甲基吡啶𬭩碘化物（D289）和孔雀绿（MG））在 2-二油酰基-3-磷酸甘油（DOPG）脂质表面的翻转和跨膜转运过程。首先，通过 MD 模拟确认了这两种分子在跨膜转运之前在脂质表面的翻转。然后，分析了 MG/D289 跨膜转运的浓度依赖性速率。结果表明，一个简化的模型可以很好地解释在较高的体相浓度下 MG 更快的跨膜转运。同时还观察到了 D289 具有不同的浓度依赖性动力学，并且讨论了其背后的原因。通过这项研究，清晰地呈现了 D289 和 MG 在 DOPG 脂质表面的表面结构和动力学。
