Formation of Lipid Sheaths around Nanoparticle-Supported Lipid Bilayers
Formation of Lipid Sheaths around Nanoparticle-Supported Lipid Bilayers
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DOI：
10.1002/smll.201101833
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发表时间：
2012-06-11
期刊：
影响因子：
13.3
通讯作者：
Wunder, Stephanie L.
中科院分区：
文献类型：
--
作者：
Ahmed, Selver;Savarala, Sushma;Wunder, Stephanie L.
高表面积的纳米颗粒经常聚集，对其细胞吸收和环境影响的影响未知。在囊泡或细胞膜的存在下，脂质吸附可以发生在纳米颗粒上，导致形成支持的脂质双层（SLB），其倾向于抵抗细胞摄取。当可用的脂质的量与形成单SLB所需的量相比过量时，示出形成由紧密贴合的脂质双层鞘包围的SLB的大聚集体。该过程的拟议机制是其中小单层囊泡（SUV）吸附到刚好高于脂质的凝胶-液相转变温度Tm的SLB聚集体（如通过动态光散射观察到的），然后在冷却到Tm以下时彼此融合（而不是与下面的SLB融合）。所形成的SLB纳米颗粒袋被连续的紧密配合的脂质鞘包封，并且由于减少的水合排斥和不存在附着于固体支持物的脂质的波动/突出力而在Tm以下沉淀。单SLB可以在高于Tm时释放，其中这些力通过游离脂质囊泡恢复。这种机制可能对药物/DNA的包封/释放有用，并且对纳米颗粒的毒性作用有影响，这可以通过脂质螯合来减轻。
High-surface-area nanoparticles often cluster, with unknown effects on their cellular uptake and environmental impact. In the presence of vesicles or cell membranes, lipid adsorption can occur on the nanoparticles, resulting in the formation of supported lipid bilayers (SLBs), which tend to resist cellular uptake. When the amount of lipid available is in excess compared with that required to form a single-SLB, large aggregates of SLBs enclosed by a close-fitting lipid bilayer sheath are shown to form. The proposed mechanism for this process is one where small unilamellar vesicles (SUVs) adsorb to aggregates of SLBs just above the gel-to-liquid phase transition temperature, Tm, of the lipids (as observed by dynamic light scattering), and then fuse with each other (rather than to the underlying SLBs) upon cooling below Tm. The sacks of SLB nanoparticles that are formed are encapsulated by the contiguous close-fitting lipid sheath, and precipitate below Tm, due to reduced hydration repulsion and the absence of undulation/protrusion forces for the lipids attached to the solid support. The single-SLBs can be released above Tm, where these forces are restored by the free lipid vesicles. This mechanism may be useful for encapsulation/release of drugs/DNA, and has implications for the toxic effects of nanoparticles, which may be mitigated by lipid sequestration.