Optical detection of single nanoparticles and viruses
Optical detection of single nanoparticles and viruses
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DOI：
10.1109/jstqe.2006.885086
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发表时间：
2006-11-01
影响因子：
4.9
通讯作者：
Novotny, Lukas
中科院分区：
文献类型：
--
作者：
Ignatovich, Filipp V.;Topham, David;Novotny, Lukas
我们已经开发了两种不同的光学技术用于检测纳米级颗粒。其中一种方法是基于测量施加在纳米颗粒上的光学梯度力，因为它通过一个封闭的光场，和其他方法使用无背景干涉计划来检测从激光照射的粒子的散射场振幅。在这两种情况下，测量的信号取决于颗粒尺寸的三次幂（R-3），而不是传统的基于散射的检测方法固有的R-6依赖性。在我们的计划中，较弱的尺寸依赖性导致更好的信噪比（SNR）的小颗粒。与质谱法类似，第一种检测方法在粒子通过紧密聚焦的激光束时影响粒子的轨迹。另一方面，第二种检测方法结合了干涉仪和分裂检测器，在没有粒子的情况下不产生信号。对于这两个系统，我们演示了实时（1毫秒）检测单个纳米粒子在一个微流体系统，并讨论了每种检测方法的限制。
We have developed two different optical techniques for the detection of nanoscale particles. One of the methods is based on measuring the optical gradient force exerted on a nanoparticle as it passes through a confined optical field, and the other method uses a background-free interferometric scheme to detect the scattered field amplitude from a laser-irradiated particle. In both cases, the measured signal depends on the third power of the particle size (R-3) as opposed to the R-6 dependence inherent to traditional scattering-based detection methods. The weaker size dependence in our schemes leads to a better signal-to-noise ratio (SNR) for small particles. Similar to mass spectrometry, the first detection method influences the trajectory of a particle as it passes through a tightly focused laser beam. On the other hand, the second detection method combines an interferometer with a split detector that yields no signal in the absence of a particle. For both systems, we demonstrate real-time (1 ms) detection of single nanoparticles in a Imcrofluidic system and discuss the limits of each detection approach.