Label-free identification of single dielectric nanoparticles and viruses with ultraweak polarization forces
Label-free identification of single dielectric nanoparticles and viruses with ultraweak polarization forces
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DOI：
10.1038/nmat3369
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发表时间：
2012-09-01
期刊：
影响因子：
41.2
通讯作者：
Gomila, Gabriel
中科院分区：
文献类型：
--
作者：
Fumagalli, Laura;Esteban-Ferrer, Daniel;Gomila, Gabriel
纳米颗粒的材料组成的无标记检测可以通过量化纳米颗粒对施加的电场的固有介电响应来实现。然而，介电纳米级物体对几何和非局部效应的敏感性使得介电响应极其微弱。在这里，我们表明，静电力显微镜与亚微微牛顿分辨率可以解决单个介电纳米粒子的介电常数，而不需要任何参考材料，以及区分具有相同的表面，但不同的内部组成的纳米粒子。我们明确地确定了未标记的类似于10 nm的纳米粒子的相似的形态，但不同的低极化材料，并区分空含DNA的病毒衣壳。我们的方法应该使原位表征纳米级生物和生物大分子成为可能。
Label-free detection of the material composition of nanoparticles could be enabled by the quantification of the nanoparticles' inherent dielectric response to an applied electric field. However, the sensitivity of dielectric nanoscale objects to geometric and non-local effects makes the dielectric response extremely weak. Here we show that electrostatic force microscopy with sub-piconewton resolution can resolve the dielectric constants of single dielectric nanoparticles without the need for any reference material, as well as distinguish nanoparticles that have an identical surface but different inner composition. We unambiguously identified unlabelled similar to 10 nm nanoparticles of similar morphology but different low-polarizable materials, and discriminated empty from DNA-containing virus capsids. Our approach should make the in situ characterization of nanoscale dielectrics and biological macromolecules possible.