细胞计数板的使用.doc

For microbiology, cell culture, and many applications that require use of suspensions of cells it is necessary to determine cell concentration. One can often determine cell density ofa suspension spectrophotometrically, however that form of determination does not allow an assessment of cell viability, nor can one distinguish cell types. A device used for determining the number of cells per unit volume ofa suspension is called a counting chamber. The most widely used type of chamber is called a hemocytometer, since it was originally designed for performing blood cell counts. To prepare the counting chamber the mirror-like polished surface is carefully cleaned with lens paper. The coverslip is also cleaned. Coverslips for counting chambers are specially made and are thicker than those for conventional microscopy, since they must be heavy enough to e the surface tension ofa drop of liquid. The coverslip is placed over the counting surface prior to putting on the cell suspension. The suspension is introduced into one of the V-shaped wells with a pasteur or other type of pipet. The area under the coverslip fills by capillary action. Enough liquid should be introduced so that the mirrored surface is just covered. The charged counting chamber is then placed on the microscope stage and the counting grid is brought into focus at low power. It is essential to be extremely careful with hi