Flow Cytometry
Introduction
Cytometry is a combination of two greek words: cyto- cell, and metry - measurement. So cyto-metry is about making cell measurements. To elaborate, flow cytometry is a technique for analysing particles (cells in this case) which are suspended in a fluid stream by flowing the cells past an interrogation point. A light source is directed on to a hydrodynamically focused stream to create a zone for interrogation. As cells flow through this interrogation zone they scatter the light, at this point any fluorescent compounds that are inside or attached to the cell can be excited by the light source and emit light themselves, at a longer wavelength to the excitation source. Multiparametric information about the physical and chemical characteristics of a cell can be determined from the detection and analysis of both the scattered and fluorescent light.
Fluidics
There are 3 key components in a flow cytometer, which include Fluidics, Optics and Electronics. The fluidics deals with delivering the sample to the interrogation point one cell at a time. The sheath fluid and the sample are pressurised and used to deliver the sample to the interrogation point. One of the basic principles of flow cytometry is the ability to analyze individual particles, or cells. The main purpose of the fluidics system is to deliver the sample to the interrogation zone one cell at a time. When a sample is taken into a flow cytometer the particles are randomly dispersed throughout the suspending medium, the fluidics system is able to align this randomly dispersed sample to a precise, single cell stream. Central to the fluidics system is the flow chamber, there are two types of flow chambers; jet-in-air and in cuvette. The flow chamber consists of a core channel through which the sample is injected under pressure. Surrounding this core channel is an outer chamber with flowing sheath fluid which, due to the narrowing dimensions of the flow chamber flows faster than the injected sample.
Cytometry is a combination of two greek words: cyto- cell, and metry - measurement. So cyto-metry is about making cell measurements. To elaborate, flow cytometry is a technique for analysing particles (cells in this case) which are suspended in a fluid stream by flowing the cells past an interrogation point. A light source is directed on to a hydrodynamically focused stream to create a zone for interrogation. As cells flow through this interrogation zone they scatter the light, at this point any fluorescent compounds that are inside or attached to the cell can be excited by the light source and emit light themselves, at a longer wavelength to the excitation source. Multiparametric information about the physical and chemical characteristics of a cell can be determined from the detection and analysis of both the scattered and fluorescent light.
Fluidics
There are 3 key components in a flow cytometer, which include Fluidics, Optics and Electronics. The fluidics deals with delivering the sample to the interrogation point one cell at a time. The sheath fluid and the sample are pressurised and used to deliver the sample to the interrogation point. One of the basic principles of flow cytometry is the ability to analyze individual particles, or cells. The main purpose of the fluidics system is to deliver the sample to the interrogation zone one cell at a time. When a sample is taken into a flow cytometer the particles are randomly dispersed throughout the suspending medium, the fluidics system is able to align this randomly dispersed sample to a precise, single cell stream. Central to the fluidics system is the flow chamber, there are two types of flow chambers; jet-in-air and in cuvette. The flow chamber consists of a core channel through which the sample is injected under pressure. Surrounding this core channel is an outer chamber with flowing sheath fluid which, due to the narrowing dimensions of the flow chamber flows faster than the injected sample.