In this era of a push towards precision medicine, doctors and scientists increasingly rely on protein-based information (biomarkers) to characterize their patients’ disease and therapeutic responses.
The enzyme-linked immunosorbent assay (ELISA) is the gold standard in biomarker measurement in clinical and laboratory settings. ELISA relies on an antibody to the biomarker of interest and a detection mechanism to identify whether and how much of the protein is there, typically using colorimetric, fluorescent, or chemiluminescent readout.
Different types of ELISA use slightly different mechanisms. PHASIQ uses a sandwich ELISA in which capture antibody bound to a polystyrene plate binds a targeted protein biomarker, which in turn binds with a detection antibody prepared for chemiluminescent detection. After the protein sample is applied and before the plate is imaged, the plate is washed, and only bound antibody-protein-antibody sandwish combinations will remain for detection when the plate is imaged by a plate-reader.
Single-plex ELISA tests for the presence of protein biomarkers one-at-a-time. Single-plex ELISA is extremely accurate. Yet testing biomarkers individually can be a lengthy and sample-consuming process.
For many research areas, scientists need to test multiple proteins simultaneously. Simultaneous testing for multiple proteins, or multiplex testing, consumes less sample and requires less labor than several individual tests.
Yet, multiplex ELISA data are muddied by unwanted cross-reactions between antibodies in the assay, as shown in the figure. This cross-reactivity brings false-positive or false-negative signals. As a result, multiplex tests for certain biomarker combinations were unfeasible until now.
PHASIQ’s Micropatterned Phase-Separation Technology (MPS™) prevents unwanted cross-reactivity by separating antibodies in our proprietary microdroplets.