( When the count and viability an...)Improving the accuracy and speed of mammalian cell counting

When the count and viability analysis is complete, the NucleoCassette can be simply and safely disposed of; and the next sample can be run without delay, and without the need to clean, re-calibrate or maintain the NucleoCounter.

Comparison using CHO hIR Cells

CHO cells overexpressing the human insulin receptor (CHO hIR) with known cell concentrations were counted manually and compared with readings from identical samples with the NucleoCounter (figure 7). Triple concentration determinations indicate improved precision was attained with the system compared with the standard manual method. As indicated by the error bars, the standard deviations for the microscopic method are indicative of the high variability of the technique, whereas the system readings maintained a greater uniformity over a wider range of cell counts. Furthermore, it was shown that the NucleoCounter readings generated coefficients of variation (CV) of <5% under normal conditions.

Additionally, samples were acquired from T-flasks at figure 6 PI is excluded from viable cells. This is utilized in the NucleoCounter to estimate the concentration of nonviable cells and the concentration of total cells in a suspension. figure 7 Precision comparison of NucleoCounter versus manual counting methods. figure 8 Comparison of growth curves observed using either the NucleoCounter or manual methods. various time points, trypsinized and resuspended in Dulbecco's modified Eagle's medium (DMEM). The cells were lyzed with 2% Triton X-100 (Sigma Chemical Co., Perth, Australia) and counts were obtained using both manual method and the NucleoCounter (figure 8). The comparison of the data indicates almost identical growth patterns with either method. However, the time required to acquire the data using the system was a fraction of that required by the manual method.

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