Virus counter
The virus counter is an instrument for rapid quantification of viruses in liquid samples. It is a specialized flow cytometer that uses high-sensitivity fluorescence detection to give a direct measurement of the concentration of virus particles in a fraction of the time required for traditional plaque assays. Early development The virus counter was developed in 2001 at University of Colorado Boulder. The Single Nanometric Particle Enumerator (SNaPE) instrument was based on the principle of fluorescence detection from single stained nucleic acids aggregates by evaluating respiratory viruses. Quantification results from the instrument correlated with expected virus concentration and the values would be significantly higher than those obtained by standard plaque titer methods typically used for virus quantification. The measured concentrations were similar in magnitude to quantitative PCR results, both being substantially higher than plaque titer values. In 2004 the virus counter’s added a second detection channel to the SNaPE instrument which improved data analysis substantially to increase specificity. The principle of detection was based on staining proteins and nucleic acids with fluorescent dyes within a liquid sample. As stained particles passed through the probe region and interacted with a laser, emissions were detected and recorded for analysis. This dual channel system