Lateral Flow Devices

An area of significant growth for Lateral Flow Device (LFD) use is for ‘point-of-care’ diagnostic tests in healthcare. Aptamers show numerous advantages over antibodies, which may present issues when trying to develop a rapid assay kit. The aspects where aptamers are superior include:

  1. Temperature control requirements: High stability of aptamers at high temperatures and ability to refold allow application in low resource settings.
  2. Restrictions to conditions: Aptamers show more resistance to different chemical buffers such as large ranges of pH, ion strength, and organic reagents.
  3. Batch-to-batch variations: Aptamers can be replicated by simple chemical synthesis with very high fidelity once the sequence of the aptamer is known.
  4. High Cost: Aptamers show cost advantages over antibodies as aptamers are produced entirely synthetically.
  5. Reagent immobilisation: Aptamers are much smaller than antibodies therefore more can be immobilized on the same GNP or NC membrane surface.
  6. Target Limitation: Nearly any target can be used including low molecular weight substances for aptamer selection in unlimited conditions.

Example of in house developed LFD.

The project concentrated on gold nanoparticle labelled Aptamer detection of a protein target to demonstrate the aptamer gold complex works in the context of a traditional LFD. The project was carried out to demonstrate that the aptamer gold complex works in the context of a prototype LFD.

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Due to the quality of the prototypes, success was determined by the positive staining of a target relative to a non-target protein in the context of a dot blot type assay.

Through work with LFD partners we have successfully demonstrated that aptamers, for a range of targets, outperform in-house antibody equivalents. Further development is underway with a focus on optimising a variety of assay formats and a review of aptamer binding to various membranes and colloidal particles, both critical to LFD production.