Flow cytometry

A Vocabulary. Match the words on the left with suitable words on the right.

1 physical                                           a) light

2 a beam                                            b) light into signals

3 internal                                            c) signals

4 scatter                                             d) particles to detectors

5 fluorescence                                 e) of light

6 transport                                        f) characteristics

7 convert                                            g) intensity

8 produce                                          h) complexity


B Text

Flow cytometry is a technology that measures and then analyses multiple physical characteristics of
single particles, usually cells, as they flow in a fluid stream through a beam of light. The
properties measured include a particles’ relative size, relative granularity or internal
complexity, and relative fluorescence intensity. An optical-to-electronic coupling system records
how the cell or particle scatters laser light and emits fluorescence.

A flow cytometer is made up of three main systems: fluidics, optics and electronics.

The fluidics system transports particles in a stream to the laser beam for interrogation.

The optics system consists of lasers to illuminate the particles in the sample stream and optical
filters to direct the resulting light signals to the appropriate detectors.

The electronics system converts the detected light signals into electronic signals. These signals
can then be processed by the computer.

In the flow cytometer, particles are carried to the laser intercept in a fluid stream. Any
suspended particle or cell from 0.2-150 micrometers in size is suitable for analysis. The portion
of the fluid stream where particles are located is called the sample core. Particles pass through
the laser intercept and they scatter laser light. Any fluorescent molecules present on the particle
fluoresce. The scattered and fluorescent light is collected by lenses. The scattered and
fluorescent light then enters the appropriate detectors. The detectors produce electronic signals.
These signals correspond with the optical signals which strike the detectors.


C Questions. Find answers to the following questions:

1 What properties of a cell or particle can you measure by a flow cytometer?

2 What light source is used in most flow cytometer?

3 What are the three main systems in a flow cytometer?

4 What is the name of the portion of the fluid stream where the cells are located?

5 When cells pass through the focused laser beam, what two types of light signals do you get?

6 Which part of the flow cytometer collects light emitted by a particle?

Vocabulary warm-up

1 Particles                           příslušný

2 Fluid                                  vydávat, vyzařovat

3 Beam                                čočky

4 Granularity                     přeměnit

5 Complexity                     zpracovat

6 Fluorescence                 granularita

7 Emit                                   částice

8 Scatter                             paprsek

9 Illuminate                       komplexnost

10 Appropriate                 kapalina

11 Convert                         fluorescence

12 Process                          osvítit, ozářit

13 Lenses                           rozptýlit


Grammar point

Past perfect (předminulý čas)