Formation and Colloidal Stability of DMPC Supported Lipid Bilayers on SiO2 Nanobeads

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• 作者：Sushma Savarala ; Selver Ahmed ; Marc A. Ilies ; Stephanie L. Wunder
• 刊名：Langmuir
• 出版年：2010
• 出版时间：July 20, 2010
• 年：2010
• 卷：26
• 期：14
• 页码：12081-12088
• 全文大小：893K
• 年卷期：v.26,no.14(July 20, 2010)
• ISSN：1520-5827

文摘

Supported lipid bilayers (SLBs) of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) were formed on 20−100 nm silica (SiO₂) nanobeads, and the formation was accompanied by an 8 nm increase in diameter of the SiO₂, consistent with single nanobeads surrounded by a DMPC bilayer. Complete SLBs were formed when the nominal surface areas of the DMPC matched that of the silica, SA_DMPC/SA_SiO2 = 1, and required increasing ionic strength and time to form on smaller size nanobeads, as shown by a combination of nano-differential scanning calorimetry (nano-DSC), dynamic light scattering (DLS), and zeta potential (ζ) measurements. For 5 nm SiO₂, where the nanoparticle and DMPC dimensions were comparable, DMPC fused and formed SLBs on the nanobeads, but it did not form single bilayers around them. Instead, stable agglomerates of 150−1000 nm were formed over a wide surface ratio range (0.25 ≤ SA_DMPC/SA_SiO2 < 2) in 0.75 mM NaCl. At ionic strengths > 1 mM NaCl, charge shielding, as measured by zeta potential measurements (ζ → 0), resulted in precipitation of the SLBs.