Molecular Electronics Laboratory, Department of Bioelectronics and Biosensors, Science Campus, Alagappa University, Karaikudi 630003, India.
Molecular Electronics Laboratory, Department of Bioelectronics and Biosensors, Science Campus, Alagappa University, Karaikudi 630003, India.
Biosens Bioelectron. 2017 Sep 15;95:168-173. doi: 10.1016/j.bios.2017.04.022. Epub 2017 Apr 20.
Supported binary liposome mixture of cationic liposome N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium propane (DOTAP) and the zwitterionic liposome 1,2-Dioleoyl-sn-Glycero-3-Phosphoethanolamine (DOPE) were tethered on thiol monolayers in the absence and presence of gold nanoparticle to enhance sensor stability and sensitivity for label free DNA and protein sensing for the first time. Cysteamine hydrochloride (Cyst), 3-Mercaptopropionic acid (MPA), 11-Mercaptoundecanoic acid (MUDA) and 11-amino-1-undecane thiol (AUT) monolayers were used as tethers on gold surfaces. Electrochemical studies in the presence of [Fe(CN)] indicate that the presence of both DOPE and AuNP decreases the electrostatic interaction between DOTAP and MPA layer during the formation of DOPE-DOTAP-AuNP (DDA) whereas they enhance the repulsive force on the Cyst and AUT monolayers. In the thiol monolayer supported DDA, the gelation of neutral lipid DOPE by the AuNP is disfavored which inturn promotes stability of vesicle structure. The membrane protein melittin's interaction with the DDA indicates the presence of intact vesicle by showing decreased charge transfer for the MUDA and AUT in the presence of [Fe(CN)]. On the contrary, the presence of the bilayer and semi circled DDA on the MPA and cysteamine layers were confirmed by the increased redox reaction. Atomic Force Microscopic (AFM) and Transmission Electron Microscopic (TEM) images support the presence of an array like semi circled DDA on the MPA and well separated DDA vesicles on the MUDA with variable sizes. Dynamic Light Scattering (DLS) and Fourier Transform Infrared spectroscopy (FTIR) suggest effective coordination between DOPE, DOTAP and AuNP. Label free DNA hybridization sensing in presence of the negatively charged [Fe(CN)] indicates the lowest DNA detection limit of 1×10M with linearity range 1×10 to 1×10M. Similarly, streptavidin sensing shows the lowest detection of 1ngml with a linear range 100ng to 1µg due to the increased reactive sites and distance.
首次将阳离子脂质体 N-[1-(2,3-二油酰基)丙基]-N,N,N-三甲基铵丙烷 (DOTAP) 和两性离子脂质体 1,2-二油酰基-sn-甘油-3-磷酸乙醇胺 (DOPE) 的支持二元脂质体混合物键合到硫醇单层上，在没有和存在金纳米粒子的情况下，提高了传感器的稳定性和灵敏度，用于无标记 DNA 和蛋白质传感。半胱胺盐酸盐 (Cyst)、3-巯基丙酸 (MPA)、11-巯基十一烷酸 (MUDA) 和 11-氨基-1-十一烷硫醇 (AUT) 单层作为金表面上的键合。在 [Fe(CN)] 的存在下进行电化学研究表明，DOPE 和 AuNP 的存在降低了 DOPE-DOTAP-AuNP (DDA) 形成过程中 DOTAP 和 MPA 层之间的静电相互作用，而它们增强了 Cyst 和 AUT 单层上的排斥力。在硫醇单层支持的 DDA 中，AuNP 使中性脂质 DOPE 凝胶化变得不利，从而促进了囊泡结构的稳定性。膜蛋白蜂毒素与 DDA 的相互作用表明存在完整的囊泡，因为在 [Fe(CN)] 的存在下，MUDA 和 AUT 的电荷转移减少。相反，在 MPA 和半胱胺层上存在双层和半圆形 DDA 是通过增加氧化还原反应来证实的。原子力显微镜 (AFM) 和透射电子显微镜 (TEM) 图像支持在 MPA 上存在类似圆形的半圆形 DDA 阵列和在 MUDA 上具有不同尺寸的分离良好的 DDA 囊泡。动态光散射 (DLS) 和傅里叶变换红外光谱 (FTIR) 表明 DOPE、DOTAP 和 AuNP 之间的有效配位。在带负电荷的 [Fe(CN)] 的存在下进行无标记 DNA 杂交传感表明，DNA 的最低检测限为 1×10M，线性范围为 1×10 至 1×10M。同样，由于反应位点和距离的增加，链霉亲和素传感显示出最低的 1ngml 检测下限，线性范围为 100ng 至 1µg。
