Institute of Biomedical Engineering, Ji Nan University, Guang Zhou, China.
Biosens Bioelectron. 2011 Dec 15;30(1):216-22. doi: 10.1016/j.bios.2011.09.015. Epub 2011 Sep 22.
We describe an innovative method which can accurately determine the refractive index (RI) of individual microspheres by immersing the microspheres in a medium and analyzing their phase-contrast microscopic images. Compared with the current techniques for microsphere RI measurement, the method has several advantages: it is simple and easy and it cannot only measure the RI of each individual microsphere but also perform measurement simultaneously on all the microspheres in the same field of view. In measurement, microspheres are not required to be suspended in a specific liquid but in any medium with known RI which is appropriate for the microspheres or even just in atmosphere. By using microspheres with known RI as sensors, the method can also be used for rapid in situ measurement of the local RI of inhomogeneous media. In this paper, we describe the principle of the method and the experiments of using the method to measure the RI of individual microspheres. Its applications for sensing instantaneous RI/concentration/temperature variation in critical situations such as anywhere in mixing flows or living biological specimens are also presented.
我们描述了一种创新的方法，可以通过将微球浸入介质并分析其相差显微镜图像来准确确定单个微球的折射率（RI）。与当前的微球 RI 测量技术相比，该方法具有几个优点：它简单易用，不仅可以测量每个单个微球的 RI，还可以同时对同一视场中的所有微球进行测量。在测量中，微球不需要悬浮在特定的液体中，而可以悬浮在任何具有已知 RI 的介质中，该介质适合于微球甚至只是在大气中。通过使用具有已知 RI 的微球作为传感器，该方法还可以用于快速原位测量不均匀介质的局部 RI。本文介绍了该方法的原理以及使用该方法测量单个微球 RI 的实验。还介绍了其在混合流或活生物样本等任何地方的临界情况下用于感应瞬时 RI/浓度/温度变化的应用。
