Comparison of electrical properties of viruses studied by AC capacitance scanning probe microscopy
Comparison of electrical properties of viruses studied by AC capacitance scanning probe microscopy
复制标题
DOI：
10.1021/ja075244z
复制
发表时间：
2008-01-23
影响因子：
15
通讯作者：
Matsui, Hiroshi
中科院分区：
文献类型：
--
作者：
MacCuspie, Robert I.;Nuraje, Nurxat;Matsui, Hiroshi
用交流电容扫描探针显微镜比较了5型腺病毒(AV5)、1型单纯疱疹病毒(HSV1)、猴病毒40(SV40)、痘苗病毒(MVA)和豌豆花叶病毒(CPMV)5种病毒的电容。这项技术利用涂铂的原子力显微镜针尖作为电极，探测针尖和底部电极之间的材料电容，已被应用于以纳米空间分辨率研究半导体和聚合物的表面结构，但这种技术还没有探索到纳米尺度的生物样品。因为大多数生物细胞是劣导体，所以这种通过电容探测细胞电学性质的方法是合乎逻辑的。这种扫描探针技术表明，每种病毒都有可区分的和特有的电容。利用突变病毒进行了一系列的对照实验，以验证不同病毒的特征电容响应的来源。HSV1衣壳上带有绿色荧光蛋白的突变使电容从9×10~(-6)增加到1×10~(-5)F/cm(2)，频率为104赫兹。单纯疱疹病毒2型(HSV2)的包膜和糖蛋白被化学提取后，其电容降低。这些对照实验表明，衣壳蛋白和包膜糖蛋白的介电性质显著影响病毒的整体介电常数。由于这些衣壳蛋白和糖蛋白是病毒株的特征，该技术可以应用于单个病毒水平的检测和鉴定，使用其不同的电容谱作为指纹而无需标记。
Capacitances of five types of viruses, adenovirus type 5 (AV5), herpes simplex virus type 1 (HSV1), simian virus 40 (SV40), vaccinia (MVA), and cowpea mosaic virus (CPMV), were compared by AC capacitance scanning probe microscopy. This technique, using a Pt-coated AFM tip as an electrode to probe capacitance of materials between the tip and a bottom electrode, has been applied to study surface structures of semiconductors and polymers with nanometer spatial resolution; however, biological samples at the nanoscale have not been explored by this technique yet. Because most biological cells are poor conductors, this approach to probe electric properties of cells by capacitance is logical. This scanning probe technique showed that each virus has distinguishable and characteristic capacitance. A series of control experiments were carried out using mutant viruses to validate the origin of the characteristic capacitance responses for different viruses. A mutation on the capsid in HSV1 with green fluorescence proteins increased capacitance from 9 x 10(-6) to 1 x 10(-5) F/cm(2) at the frequency of 104 Hz. Herpes simplex virus type 2 (HSV2) decreased capacitance when its envelope and glycoproteins were chemically extracted. These control experiments indicate that dielectric properties of capsid proteins and envelope glycoproteins significantly influence overall dielectric constants of viruses. Because those capsid proteins and glycoproteins are characteristic of the virus strain, this technique could be applied to detect and identify viruses at the single viron level using their distinct capacitance spectra as fingerprints without labeling.