Automated Disposable Enzyme-Linked Immunosorbent Assay For At Home Detection
At A Glance
Researchers at Colorado State University have developed a hybrid disposable ELISA device to sequentially add and wash reagents from a test zone with only two, easy to perform end-user steps. The device operates using hydrophilic channels and paper for passive, pump-free flow to enable detection of target analytes in at-home settings by untrained users that were previously undetectable outside a centralized laboratory. Immediate application for the device includes COVID-19 detection.
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Enzyme linked immunosorbent assays (ELISAs) are used to detect a wide range of analytes with tremendous sensitivity and specificity. These analytes include whole cells, proteins, antibodies, and small molecules. High sensitivity is enabled by using an enzyme label to amplify a signal, while the high specificity is enabled using a “sandwich” immunoassay that captures an analyte between two highly specific probe. The analyte can be a protein (including an antibody), peptide, small molecule, or intact virus or bacterial particle as examples. Both enzymatic detection and the sandwich assay format require multiple washing steps and sequential delivery of reagents. These washing and reagent addition steps yield robust analytical performance from ELISAs, but they are complicated to perform and relegate the assay to a centralized laboratory with expensive equipment and trained technicians. In many testing situations the time and financial resources needed for ELISAs are not available. There are more affordable point-of-care alternatives, but they often lack the analytical performance needed.
One of the most common alternatives to an ELISA is the lateral flow immunoassay (LFIA). Lateral flow strips are inexpensive and easy to use in comparison to the ELISA. They require only a sample addition step from the end user and the results are easy to interpret in most settings. The pregnancy test is the most common example of a lateral flow device, which has an estimated global market of $1.3 billion/yr, but there are also LFIAs for seasonal influenza and a number of sexually transmitted diseases. Although they are easy to use, lateral flow strips perform poorly compared to ELISAs, with well documented reports of high false positive and negative rates and unreliable quantification. Substandard sensitivity and specificity in LFIAs stem from the inability to use enzymes as labels and sequentially wash and add reagents, which limits the scope of possible target analytes (e.g. disease biomarkers, antibodies, whole cells).
- At-home sensor is easy to operate
- Only two steps are required to perform the assay
- Results are clear to interpret
- Detects various biomolecules at low concentrations
- Higher sensitivity
- Replacement for many lateral flow assay devices
- Immediate application for COVID-19 sensing
- At home detection/diagnostics
Last updated: September 2020