论文标题
中性多磷胆碱改性脂质体作为边界级别的脂质体
Neutral polyphosphocholine-modified liposomes as boundary superlubricants
论文作者
论文摘要
边界润滑与两个滑动的分子润滑膜包被表面有关，其中能量耗散发生在润滑膜之间的滑动平面上。水合润滑范式在水性培养基中说明了超低摩擦，已扩展到各种系统，磷脂酰胆碱（PC）脂质由于其高水化水平而被认为是极有效的润滑元件。在这项工作中，我们扩展了先前的研究（Lin等，Langmuir 35（2019）6048-6054），在其中制备了带电的脂质 - 脂质 - 磷酸磷酸胆碱）（PMPC）（PMPC）共轭物，为中性的Lipid-Pmpc conjugate提供了不同的情况。这种中性分子通过将高水溶性PMPC连接到脂质体的表面，并在脂质双层中掺入其脂质部分，从而稳定脂质体。这种中性的多磷胆碱脂质体提供了表面润滑性，该表润滑性很好地填充了（摩擦系数= CA. 10-3甚至更低）。相比之下，带负电荷的脂质/多磷胆碱偶联物改性脂质体无法吸附为带负荷的（云母）表面。我们的方法提供稳定的脂质体，可以吸附在带负电荷的表面并提供超润滑性的情况下。
Boundary lubrication is associated with two sliding molecularly thin lubricated film-coated surfaces, where the energy dissipation occurs at the slip-plane between lubricated films. The hydration lubrication paradigm, which accounts for ultralow friction in aqueous media, has been extended to various systems, with phosphatidylcholine (PC) lipids recognized as extremely efficient lubrication elements due to their high hydration level. In this work, we extend a previous study (Lin et al., Langmuir 35 (2019) 6048-6054), where a charged lipid-poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) conjugate was prepared, to the very different case of a neutral lipid-PMPC) conjugate. This neutral molecule stabilizes the liposomes by attaching highly water-soluble PMPC to the surface of liposomes with its lipid moieties incorporated in the lipid bilayers. Such neutral polyphosphocholinated liposomes provide a surface lubricity which is well within the superlubrication regime (coefficient of friction = ca. 10-3 or even lower). In contrast, negatively charged lipid/polyphosphocholine conjugates modified liposomes were unable to adsorb on negatively-charged (mica) surfaces. Our method provides stable liposomes that can adsorb on negatively charged surfaces and provide superlubricity.
