Department of Physics, School of Natural Sciences, Shiv Nadar University, NH-91, Tehsil Dadri, G.B. Nagar, Uttar Pradesh 201314, India.
Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität Zu Kiel, 24098 Kiel, Germany.
ACS Appl Mater Interfaces. 2021 Dec 8;13(48):57023-57035. doi: 10.1021/acsami.1c19004. Epub 2021 Nov 24.
The graphene family, especially graphene oxide (GO), has captured increasing prospects in the biomedical field due to its excellent physicochemical properties. Understanding the health and environmental impact of GO is of great importance for guiding future applications. Although their interactions with living organisms are omnipresent, the exact molecular mechanism is yet to be established. The cellular membrane is the first barrier for a foreign molecule to interact before entering into the cell. In the present study, a model system consisting of a lipid monolayer at the air-water interface represents one of the leaflets of this membrane. Surface pressure-area isotherms and advanced synchrotron X-ray scattering techniques have been employed to comprehend the interaction by varying the electrostatics of the membrane. The results depict a strong GO interaction with positively charged phospholipids, weak interaction with zwitterionic lipids, and interestingly negligible interaction with negatively charged lipids. GO flakes induce significant changes in the out-of-plane organization of a positively charged lipid monolayer with a minor influence on in-plane assembly of lipid chains. This interaction is packing-specific, and the influence of GO is much stronger at lower surface pressure. Even though for zwitterionic phospholipids, the GO flakes may partly insert into the lipid chains, the X-ray scattering results indicate that the flakes preferentially lie horizontally underneath the positively charged lipid monolayer. This in-depth structural description may pave new perspectives for the scientific community for the development of GO-based biosensors and biomedical materials.
石墨烯家族，尤其是氧化石墨烯（GO），由于其优异的物理化学性质，在生物医学领域引起了越来越多的关注。了解 GO 的健康和环境影响对于指导未来的应用至关重要。尽管它们与生物体的相互作用无处不在，但确切的分子机制尚未建立。细胞膜是外来分子进入细胞之前与之相互作用的第一道屏障。在本研究中，由气-液界面处的单层脂质组成的模型系统代表了该膜的一个小叶。通过改变膜的静电特性，我们使用表面压力-面积等温线和先进的同步加速器 X 射线散射技术来理解相互作用。结果表明，GO 与带正电荷的磷脂强烈相互作用，与两性离子脂质弱相互作用，与带负电荷的脂质几乎没有相互作用。GO 薄片会引起带正电荷的脂质单层的面外组织发生显著变化，而对脂质链的面内组装几乎没有影响。这种相互作用是特定于堆积的，并且在较低的表面压力下，GO 的影响要强得多。即使对于两性离子磷脂，GO 薄片可能部分插入脂质链中，X 射线散射结果表明薄片优先水平地位于带正电荷的脂质单层下方。这种深入的结构描述可能为基于 GO 的生物传感器和生物医学材料的开发为科学界开辟新的视角。
