Photonic Sensing: Principles and Applications for Safety and Security Monitoring

Chapter 2

Microchip-Based Flow Cytometry in Photonic Sensing: Principles and Applications for Safety and Security Monitoring

Benjamin R. Watts

McMaster University, Department of Engineering Physics, Hamilton, ON, Canada

Zhiyi Zhang

Institute for Microstructural Sciences, National Research Council of Canada, Ottawa, ON, Canada

Chang-Qing Xu

McMaster University, Department of Engineering Physics, Hamilton, ON, Canada

2.1 Introduction

Flow cytometry is a powerful analysis tool whose power is derived from the speed of analysis and in its multiparameter detection capabilities. The measured characteristics of the sample analyzed by a flow cytometer give a very accurate picture of the sample while simultaneously eliminating the painstaking labor dictated by manual counting [1]. Flow cytometry is accomplished by flowing a population of diversely or similarly sized cells—in single file via hydrodynamic focusing—past a laser beam allowing individual interrogation of each cell in the population measuring properties such as size, shape, cell viability, cell DNA content, cell surface marker characteristics, or even cell life cycle distribution. A conventional cytometer consists of four basic systems integrated together, as shown in the schematic representation in Figure 2.1 [2]. The four components are the flow cell for handling samples, the excitation system to provide a means for detection via scattering and fluorescence, the collection system to analyze the numerous parameters from labeled ...