Electrical Impedance Cell Counting

Provided an electric circuit model of a cell between a pair of electrodes in a channel fig.

Electrical impedance cell counting.

Principle of laser flow cytometry blood cells of a diluted measurement suspension are injected into a capillary and hydrodynamically focussed by a sheath flow to finally enter the flow channel 250 µm x 250 µm of a quartz cell. This is specifically done on body cavity fluids that are poorly cellular 1000 cells ul because most automated analyzers impedance or laser based are insensitive to such low values. The coulter principle and the coulter counter that is based on it is the commercial term for the technique known as resistive pulse sensing or electrical zone sensing. Whole blood is passed between two electrodes through an aperture so narrow that only one cell can pass through at a time.

Cell counting is any of various methods for the counting or similar quantification of cells in the life sciences including medical diagnosis and treatment it is an important subset of cytometry with applications in research and clinical practice. A coulter counter is an apparatus for counting and sizing particles suspended in electrolytes it is used for cells bacteria prokaryotic cells and virus particles. 3a the impedance dependent on medium resistance r m cell cytoplasm resistance r i cell membrane capacitance c mem electrical double layer and capacitance c dl and all value of these parameters contributing to total impedance are dependent on frequency ω. It is used in almost every hematology analyzer.

The traditional method for counting cells is electrical impedance also known as the coulter principle. The impedance changes as a cell passes through. Microfluidic electrical impedance flow cytometry is now a well known and established method for single cell analysis. Electrical impedance method the coulter principle 8.

In 2007 morgan et al. Two detection techniques are routinely applied in flow cytometry laser flow cytometry and impedance counting. Given the richness of the information provided by impedance measurements this non invasive and label free approach can be used in a wide field of applications ranging from simple cell counting to disease diagnostics. For example the complete blood count can help a physician to determine why a patient feels unwell and what to do to help.

The automated complete blood cell count is performed using a number of different physical principles such as electrical impedance light scatter and fluorescence. A typical coulter counter has one or more microchannels that. Manual cell counts rbc nucleated cells or platelets are performed using a hemocytometer. This chapter reviews the basic principles that form the basis of modern hematology blood cell counting instruments as well as flow cytometry instruments.