Interactions of nanoparticles with purple membrane films
Interactions of nanoparticles with purple membrane films
复制标题
DOI：
10.1039/c2jm32467a
复制
发表时间：
2012-01-01
影响因子：
--
通讯作者：
Briscoe, Wuge H.
中科院分区：
文献类型：
--
作者：
Bulpett, Jennifer M.;Collins, Andrew M.;Briscoe, Wuge H.
由盐生盐生杆菌紫色膜自组装而成的层状结构，由于其具有质子泵浦能力，有望成为生物电子器件的构建单元这种装置的功能性和耐用性取决于粉末冶金薄板的结构完整性。利用X射线衍射仪，我们研究了两种纳米颗粒(NPs)对硅基PM多层膜结构的影响：羧甲基葡聚糖包覆的磁铁矿(核尺寸为2.4 nm)和柠檬酸盐稳定的金(核尺寸为5 nm)。我们尝试通过两种不同的途径将纳米颗粒渗透到PM多层膜中：简单渗透(FP)和溶液混合共组装(CS)。我们发现，尽管NPs的存在影响了PM膜的自组装过程，但在所有条件下，NPs并没有破坏PM膜的整体片层结构，也没有进入片层间隙。这导致了膜结构中的无序性增加，如通过多层堆叠中的层数随着NP浓度的增加而减少来评估的。尽管如此，UV-Vis光谱测量表明，蛋白质中视网膜残基的构象是完整的，因此在所有添加了NPs的样品中，PM多层膜的质子泵功能都将保持不变。我们的结果表明，纳米粒子对膜结构和功能的影响是微妙和复杂的，我们将从与流体脂双层相比的高弯曲模数的角度来讨论抗NP渗透的脂质-蛋白质复合膜的结构完整性。
Lamellar structures self-assembled from purple membranes (PM) of Halobacterium salinarum are promising building units for bio-electronic devices, due to proton pumping ability of the PM. The functionality and durability of such devices are hinged on the structural integrity of PM lamellae. Using X-ray diffraction, we examined the structure of PM multilayers on silicon when challenged with two types of nanoparticles (NPs): carboxymethyl-dextran coated magnetite (2.4 nm core size) and citrate-stabilised gold (5 nm core size). We tried to infiltrate the PM multilayers with the NPs using two alternative routes: facile penetration (FP) and co-assembly (CS) by solution mixing. We found that under all conditions the NPs did not disrupt the overall lamellar structure of the PM films or enter the inter-lamellar space, although the presence of NPs affected the self-assembly process of the PM films. This caused an increase in the disorder in the film structure, as assessed by the decreasing number of layers in the multilayer stack as the NP concentration increased. Despite this, UV-Vis spectroscopic measurements showed that the conformation of the retinal residue within the protein was intact so the proton pumping functionality of PM multilayers would be retained in all samples with added NPs. Our results show that the effects of NPs on the PM structure and functionality are subtle and complex, and we will discuss the structural integrity of lipid-protein composite PM films against NP infiltration in terms of their high bending modulus as compared with that of fluid lipid bilayers.