Cell quantization

BY: MAIRA SULTAN

MOHAMMAD ALI JINNAH UNIVERSITY

ISLAMABAD

Introduction

Numerous procedures in biology and medicine

require the counting of cells.

In medicine RBCs and WBCs

concentration of pathogens in Body fluids can

reveal information about the progress of an

infectious disease

Methods

Different mehod of cell count are available:

– Hemocytometers

– Automated Cell Counters

– Flow Cytometers

– Spectrophotometry

– Image Analysis

Hemocytometers

gridded chamber on a glass slide

1 mm x 1 mm chambers

subdivided into 0.05 mm x 0.05 mm

sample of cell suspension

cell suspension counting chamber by capillary action.

microscope is focused

1 mm2, 100 nl area of counting chamber

Repeated

results are averaged

Flow cytometer

most frequently used

fluorescence detection technologies

detect labelled intracellular components

cells flow in a narrow stream

front of a laser beam

Spectrophotometry

not a reliable method

cell density

measure absorbance of light

culture is placed in a transparent cuvette

OD is proportional to the biomass in the cell suspension

Plating and CFU counting

slowest method

gives an accurate estimate

cells can be simply plated on a petri dish

each cell will give rise to a single colony or Colony

Forming Unit (CFU)

volume of culture concentration can be

calculated

Image Analysis

high-quality microscopy images

statistical classification algorithm

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