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Standard Test Method for Automated Analyses of Cells—the Electrical Sensing Zone Method of Enumerating and Sizing Single Cell Suspensions
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NORM herausgegeben am 15.1.2016
Bezeichnung normen: ASTM F2149-16
Anmerkung: UNGÜLTIG
Ausgabedatum normen: 15.1.2016
SKU: NS-638485
Zahl der Seiten: 4
Gewicht ca.: 12 g (0.03 Pfund)
Land: Amerikanische technische Norm
Kategorie: Technische Normen ASTM
Keywords:
automated cell counting, electrical sensing zone, size distribution,, ICS Number Code 07.100.01 (Microbiology in general)
Significance and Use |
3.1 The electrical sensing zone method for cell counting is used in tissue culture, government research, and hospital, biomedical, and pharmaceutical laboratories for counting and sizing cells. The method may be applicable to a wide range of cells sizes and cell types, with appropriate validation 3.2 The electrical sensing zone methodology was introduced in the mid-1950s (9). Since this time, there have been substantial improvements which have enhanced the operator's ease of use. Among these are the elimination of the mercury manometer, reduced size, greater automation, and availability of comprehensive statistical computer programs. 3.3 This instrumentation offers a rapid result as contrasted to the manual counting of cells using the hemocytometer standard counting chamber. The counting chamber is known to have an error of 10 to 30 %, as well as being time-consuming 1.1 This test method, provided the limitations are understood, covers a procedure for both the enumeration and measurement of size distribution of most all cell types. The instrumentation allows for user-selectable cell size settings and is applicable to a wide range of cell types. The method works best for spherical cells, and may be less accurate if cells are not spherical, such as for discoid cells or budding yeast. The method is appropriate for suspension as well as adherent cell cultures 1.2 Cells commonly used in tissue-engineered medical products 1.3 Electrical sensing zone instrumentation (commonly referred to as a Coulter counter) is manufactured by a variety of companies and is based upon electrical impedance. This test method, for cell counting and sizing, is based on the detection and measurement of changes in electrical resistance produced by a cell, suspended in a conductive liquid, traversing through a small aperture (see Fig. 11.4 Limitations are discussed as follows: 1.4.1 Coincidence—Occasionally, more than a single cell transverses the aperture simultaneously. Only a single larger pulse, as opposed to two individual pulses, is generated. The result is a lower cell count and higher cell volume measurement. The frequency of coincidence is a statistically predictable function of cell concentration that is corrected by the instrument. This is called coincidence correction (8). This phenomenon may be reduced by using lower cell concentrations. 1.4.2 Viability—Electrical sensing zone cell counting enumerates both viable and nonviable cells and cannot determine percent viable cells. A separate test, such as Trypan blue, is required to determine percent viable cells. 1.4.3 Cell Diameter—This is a function of the size range capability of the aperture size selected. Measurements may be made in the cell diameter range of 0.6 μm to 1200 μm. Setting the counting size range on the instrument can affect the test results, especially if the cell size has a large distribution, and should be carefully controlled to help achieve repeatability. 1.4.4 Size Range of the Aperture—The size range for a single aperture is proportional to its diameter. The response has been found to depend linearly on diameter over a range from 2 % to 80 % of the diameter. However, the aperture tube may become prone to blockage at levels greater than 60 % of diameter. Therefore, the practical operating range of the aperture is considered to be 2 % to 60 % of the diameter. 1.4.5 Humidity—10 % to 85 %. 1.4.6 Temperature—10 °C to 35 °C. 1.4.7 Electrolyte Solution—The diluent for cell suspension shall provide conductivity and have minimal effect on cell size. The electrolyte of choice is commonly phosphate-buffered saline. |
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