Lateral Flow Devices

Lateral Flow Assays

The Lateral Flow Device (LFD) rapid assay format is routinely used in ‘point-of-care’ diagnostic tests in healthcare; or field-based diagnostic for environmental monitoring etc. In this assay format, aptamers have several key advantages over antibodies, which include:

  • More robust assaysAptamers selections often include the end matrix to limit assay interference from non-target components e.g. milk proteins etc.
  • Lower production cost – Aptamers are chemical entities, which means the synthesis of these macromolecules is straightforward and very cost effective compared to protein based affinity ligands (antibodies, affinity proteins etc) which rely on cell or bacterial culture based production methods.
  • Low batch-to-batch variability –As aptamers are chemically synthesised, batch-to-batch variation is significantly reduced.
  • Higher reagent immobilisation – Aptamers are much smaller and are less prone to aggregation than antibodies; so more capture reagent can be immobilised on the same membrane surface area.
  • Greater temperature stability – aptamers are much more stable at higher temperatures, eliminating the requirement for temperature controlled storage and shipping.
The example shows an prototype LFD in a ‘traditional LFD format ‘using aptamers labelled with gold nanoparticles for specific detection of a protein target.

Novel ‘gain of signal’ approach for small molecule detection

Our specially designed displacement approach allows us to select aptamers which can directly be used in Lateral Flow Devices, ELISA-like assays etc., for the detection of small molecules. We developed also developed a particular method that allows for ‘Gain of Signal’ sensing from a single reagent (no need for sandwich-pairs) in these formats.

1.Aptamers are displaced by a specific target binding.
2.Displaced aptamers are carried along the LFD pad in the samples matrix
3.Displaced aptamers are re-captured by re-capture molecule at the end of the LFD

‘Gain of signal’ approach for simplified LFD development is functional in different matrices and shows linear concentration dependent responses

Data show  linear concentration dependent binding of an aptamer to its antibiotic target (top) as well as re-capturing of the aptamer-target complex (bottom) in different matrices.