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lateral flow particles

Lateral Flow Assays

Lateral flow assays (immunochromatographic assays) are simple and well-established diagnostic tests intended for point-of-care and laboratory use. The test detects target molecules (e.g. antigens) by displaying a visual indication (most commonly a colored line) on a test pad.

How is the lateral flow test performed?

The test is performed as follows:

  1. Target molecules within the analyte are bonded to their counterparts (e.g. antibodies) that are conjugated to colored particles (e.g. gold nanoparticles).
  2. Capillary flow transports the particle-bound target molecules along the test pad.
  3. The test pad contains a fixed stripe of molecules (antibodies) which bind to the target molecules within the analyte. As the target molecules flow over the stripe, chemical bonds are made thus immobilizing the target molecules.
  4.  Accumulation of target molecules results in visual contrast which signifies a positive test.   

Control over the size, shape and architecture of the underlying particles is important in lateral flow assays. It determines the coating efficiency of the particles with antibodies, ease of flow through the test pad as well as the color and intensity of the test lines.

Typically, nanoparticle suppliers provide non-uniform or polydisperse (CV values >20%) material with particles varying in size, shape and architecture. This significantly diminishes the performance of the particles.

Benefits of Particle Works nanomaterials

Particle Works offers a range of highly monodisperse (CV values <10%) nanoparticles for applications in lateral flow tests. These high-performance materials bring benefits such as:

  • Experiment reproducibility: greater result reliability
  • High signal-to-noise ratios: greater test sensitivity
  • Reduction in number of false-positive results: due to absence of line blurring and reagent consistency.

Products for lateral flow assay development applications

The following nanoparticles in the Particle Works range are suitable for applications in development of lateral flow assays:

Gold Nanoparticles We recommend  our range of PEG functionalized Gold nanoparticles for development of lateral flow tests
Quantum dots We recommend mercaptosuccinic acid functionalized CdSe for development of lateral flow tests (available on request).
Magnetic nanoparticles We recommend PEG functionalized oxidatively stable cobalt nanoparticles for the development of magnetic-immunoassays