Lateral Flow Assays - Alex Debreceni: Difference between revisions
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Lateral flow assay is a paper based microfluidic technique used to detect a specific chemical component in a complex mixture. Lateral Flow Assays are used for cheap, easy to use, and rapid portable detection devices, such as pregnancy tests and blood-glucose level indicators. This technology is also widely used in medical fields to test bodily fluids such as urine, blood, sweat, and saliva. | Lateral flow assay is a paper based microfluidic technique used to detect a specific chemical component in a complex mixture. Lateral Flow Assays are used for cheap, easy to use, and rapid portable detection devices, such as pregnancy tests and blood-glucose level indicators. This technology is also widely used in medical fields to test bodily fluids such as urine, blood, sweat, and saliva.[1] | ||
='''Components'''= | ='''Components'''= | ||
Revision as of 21:10, 17 February 2017
Introduction
Lateral flow assay is a paper based microfluidic technique used to detect a specific chemical component in a complex mixture. Lateral Flow Assays are used for cheap, easy to use, and rapid portable detection devices, such as pregnancy tests and blood-glucose level indicators. This technology is also widely used in medical fields to test bodily fluids such as urine, blood, sweat, and saliva.[1]
Components
The first component of most lateral flow assay devices is the sample pad. The sample pad is the spot where the fluid sample is placed. The sample pad treats the sample and modulates any chemical variability. The sample pad is generally made of cotton linter, glass fibre, rayon, and filtration materials. Sample pads are pretreated with a pH buffer, surfactants, and blocking reagents. the next part of a general lateral flow assay is the conjugate pad. The conjugate pad couples the analyte in the sample with the conjugate and releases the pairing. These conjugates are generally antibodies that specifically bind to the target molecule. These antibodies are bound to the pad using nanoparticles, such as gold. The next part of LFA devices is the reaction membrane. This membrane works as a capturing mechanism for the conjugate-analyte pair. This part also forms visible bands when the analyte is present. The final part of the system is the waste reservoir. This component serves as a sink for excess sample and prevents wicking towards the reaction membrane.
Mechanism
A liquid sample, which contains the analyte of interest is placed on the sample pad. Through capillary action, the fluid travels through the various zones of the device. When the fluid reaches the conjugate pad, the analyte will bind to the antibodies specific to the molecule. these antibodies are conjugated to colored or fluorescent particles. The most common conjugate particles are colloidal gold and latex microspheres. The conjugate-analyte pairing travels with the fluid to the reaction membrane This membrane contains antibodies or antigens, immobilized in a nitrocellulose These particles react with the analyte and activates the test line. The control line in the system activates when there is flow through the system. When both lines are present, the analyte is present in the sample. If only the control line is present, there is no analyte in the sample. Once the fluid passes these sections, and absorbing pad at the end of the system collects the excess. This pad also maintains the capillary action throughout the full device.
