Quantibody® is an array-based multiplex ELISA system for simultaneous quantitative measurement of multiple cytokines, growth factors, proteases, soluble receptors, and other proteins in a wide variety of sample types. Quantibody® combines the high specificity and sensitivity of ELISA with the high throughput of the glass chip-based array.
With this platform, only 50 µl of sample is needed for quantification of up to 40 proteins in quadruplicate, making this array 80 times more efficient than traditional ELISA.
Each 75mm x 25mm glass slide is spotted with 16 identical antibody arrays (also called “subarrays”). Within each subarray, the capture antibodies along with controls are spotted in quadruplicate. The slide comes with a 16-well removable gasket and chamber assembly that allows for simultaneous processing of up to 14 samples per slide. To achieve even higher throughput, 4 slides can be nested into a tray which matches a standard microplate, allowing for automated processing of 64 arrays simultaneously. The latest automated liquid handling work stations can accommodate several trays at once, allowing hundreds of samples to be processed per day.
Like a traditional sandwich-based ELISA, Quantibody uses a matched pair of antibodies for target protein detection. A panel of capture antibodies is printed in multiple identical arrays on a standard slide. After a blocking step, samples are incubated with the arrays. Nonspecific proteins are then washed off, and the arrays are incubated with a cocktail of biotinylated detection antibodies, followed by a streptavidin-conjugated fluor. Signals are then visualized using a fluorescence laser scanner.
To quantify target protein concentrations, the array-specific protein standards, whose concentrations have been predetermined, are provided to generate an 8-point standard curve of each target protein. By comparing signals from unknown samples to the standard curve, the unknown cytokine concentration in the samples will be determined.