ImageStream combines high-resolution microscopy and flow cytometry in a single instrument, giving researchers the power to conduct quantitative analyses of individual cells and cell populations at the same time, in the same experiment. Incorporating the extended depth of field developed during the SBIR project, ImageStream is designed to provide multispectral images of rapidly moving objects (in flow) with very high sensitivity, producing up to 6 different microscopic images of each cell flowing through the instrument, at a rate of 15,000 cells per minute. It captures the images at high speeds with a built-in, charge coupled device camera that electronically tracks the motion of cells. A sophisticated auto-focus system continually optimizes image quality.
Getting a whole cell into focus is vital for many different types of cellular analyses, especially for a technique known as fluorescence in situ hybridization (FISH). FISH involves the binding of engineered genetic probes to specific genes or other DNA sequences within cells. The genetic probes consist of a short piece of DNA attached to a fluorescent molecule. The DNA part finds and binds to its complementary DNA sequence(s) within the cell's genome and the fluorescent molecule signals that the binding has taken place, producing a small spot of light within the cell. By detecting and counting these "FISH" spots, a clinician or a researcher conducting an analysis can tell, for instance, if a patient has extra copies of a gene or a chromosome, whether there is damage to their genes, or whether they have lost genetic material—all of which are very useful for detecting cancer and birth defects.
FISH analysis is primarily a manual process. Clinicians and researchers have to stare through microscopes, adjusting the focus knob until they find all the FISH spots within a given cell. When they do find the spots, they have to manually count them (for about 50 cells per diagnostic test, on average). According to Amnis, this methodology has several problems: the test is slow and expensive, the counting is subjective and prone to error, and, unless a genetic abnormality is present in at least 10 percent of the cells analyzed, researchers will not likely catch it. Automated microscopy systems have been applied to the problem, but they are forced to take multiple images of each cell at different focus settings to ensure that all FISH spots are detected, slowing the test and reducing the economic advantage of automation, according to Amnis.
Prior to the incorporation of the extended depth-offield technology into the ImageStream system, it was common for one or more FISH spots within a cell to be out of focus as the cell passed through the system By enhancing the depth of field, Amnis has upgraded ImageStream to accurately detect and count FISH spots through an automated process that eliminates the subjectivity associated with manual counting and can be performed on thousands of cells per minute. This helps drive down the cost of testing by eliminating manual labor, reducing the time needed to perform the test, and increasing accuracy to eliminate retests and false results. Amnis recently announced the availability of this new, high-throughput process.
ImageStream is also built for many other applications, including cell signaling and pathway analysis; classification and characterization of peripheral blood mononuclear cell populations; quantitative morphology; apoptosis (cell death) assays; gene expression analysis; analysis of cell conjugates; molecular distribution; and receptor mapping and distribution. These applications are practical for advanced research in the fields of hematology, immunology, and oncology.
As an add-on option, ImageStream users can pair the instrument with Amnis' statistical image-analysis software package, IDEAS. This statistical analysis tool is extremely robust, as it provides more than 200 features for every cell analyzed. These features can be used by clinicians and researchers to generate histograms and scatter plots for graphical identification and representation of cells and cell populations based on characteristics like fluorescence intensity, size, shape, texture, probe distribution heterogeneity, and co-localization of multiple probes.