PDF(Pubmed)
Abstract：
Hybrid lipid bilayers (HLBs) are rugged biomimetic cell membrane interfaces that can form on inorganic surfaces and be designed to contain biologically important components like cholesterol. In general, HLBs are formed by depositing phospholipids on top of a hydrophobic self-assembled monolayer (SAM) composed of one-tail amphiphiles, while recent findings have shown that two-tail amphiphiles such as inverse phosphocholine (CP) lipids can have advantageous properties to promote zwitterionic HLB formation. Herein, we explored the feasibility of fabricating cholesterol-enriched HLBs on CP SAM-functionalized TiO2 surfaces with the solvent exchange and vesicle fusion methods. All stages of the HLB fabrication process were tracked by quartz crystal microbalance-dissipation (QCM-D) measurements and revealed important differences in fabrication outcome depending on the chosen method. With the solvent exchange method, it was possible to fabricate HLBs with well-controlled cholesterol fractions up to ~65 mol% in the upper leaflet as confirmed by a methyl-β-cyclodextrin (MβCD) extraction assay. In marked contrast, the vesicle fusion method was only effective at forming HLBs from precursor vesicles containing up to ~35 mol% cholesterol, but this performance was still superior to past results on hydrophilic SiO2. We discuss the contributing factors to the different efficiencies of the two methods as well as the general utility of two-tail CP SAMs as favorable interfaces to incorporate cholesterol into HLBs. Accordingly, our findings support that the solvent exchange method is a versatile tool to fabricate cholesterol-enriched HLBs on CP SAM-functionalized TiO2 surfaces.
摘要：
杂化脂质双层(HLBs)是粗糙的仿生细胞膜界面,其可以在无机表面上形成并且被设计成包含生物学上重要的组分如胆固醇。总的来说,HLBs是通过将磷脂沉积在由单尾两亲物组成的疏水自组装单层（SAM）的顶部而形成的，而最近的发现已经表明双尾两亲物如反磷酸胆碱(CP)脂质可以具有促进两性离子HLB形成的有利性质。在这里，我们探索了用溶剂交换和囊泡融合方法在CPSAM功能化的TiO2表面上制造富含胆固醇的HLBs的可行性。通过石英晶体微平衡耗散（QCM-D）测量来跟踪HLB制造过程的所有阶段，并根据所选方法揭示了制造结果的重要差异。用溶剂交换法,通过甲基-β-环糊精（MβCD）提取试验证实，可以在上部小叶中制造出胆固醇含量控制良好的HLBs，最高可达65mol％。与此形成鲜明对比的是,囊泡融合方法仅在从含有高达35摩尔%胆固醇的前体囊泡形成HLBs时有效，但这种性能仍然优于过去的亲水性SiO2的结果。我们讨论了两种方法不同效率的影响因素，以及双尾CPSAM作为将胆固醇掺入HLB中的有利界面的普遍实用性。因此，我们的发现支持溶剂交换方法是在CPSAM功能化的TiO2表面上制造富含胆固醇的HLBs的通用工具。
