Time-Resolved Lateral Flow Immunoassay-TR-LFIA
Lateral flow assays can be aptly sensitive with the right kinetics of antigen:antibody binding and the selection of suitable reagents and optimization of conditions. However, in clinical diagnostics applications, the detection background noise coming from clinical samples (i.e. blood) and autofluorescence/scattering signals from strip materials (i.e. nitrocellulose membranes) is always a big issue and affects diagnostic sensitivity. Time Resolved (TR) is a well-established technique to improve the signal to noise ratio in central lab settings but has previously not been developed for POC use. BioMedomics is the first company to utilize TR technology for a potentially revolutionary approach to LFIA testing.
BioMedomics is developing a unique patented TR detection system with long lifetime probes able to reduce the sample noise described above and increase test sensitivity well beyond the capabilities for current POC testing platforms. In prototype testing, TR-LFIA was able to detect a key CV biomarker, C-Reactive Protein (CRP), at 0.2 picograms/mL – a level only possible with expensive central lab testing equipment. BioMedomics is working with other biomarkers and is utilizing existing OEM manufacturers to develop a commercially viable TR reader.
A highly sensitive time-resolved LFIA platform is a very important tool for future clinical diagnostic applications.
Fig 1. Lateral Flow Immunoassay Principle
The new technologies associated with BioMedomics’ development will open many new and broad business opportunities while still being able to detect results with a simple, fast, reliable, and portable platform.
Clinical standards for detection of acute myocardial infarction (AMI) are moving to so called "high sensitivity standards" for detection of changes in cardiac troponin currently achievable only by central lab equipment. A TR-LFIA troponin test has the potential to allow a POC test to meet this high sensitivity standard and revolutionize the $2 billion CV POC market.
Similarly standards in HIV testing are changing to meet detection needs for a constantly mutating virus. Test sensitivity only available in central lab equipment has been key to early detection when the virus is most virulent. A TR-LFIA HIV test has the potential for similar early detection in an advantageous POC setting. Many POC markets would benefit from similar increases in testing sensitivity.
Time Resolved Bioassays
The time-resolved bioassays separate the fluorescence of interest from the background through lifetime differences. The technique involves exciting a fluorscent label of a long lifetime with a short pulse of light, then waiting a period of time for the background and other unwanted fluorescence to decay to a low level before collecting the remaining long-lived fluorescent signal. The ability to eliminate the background is especially important for biomedical diagnostics. Time-resolved methods have been reported to increase the detection sensitivity by two or more orders of magnitudes over conventional fluorescence detection.