Aptamers are readily incorporated into existing ELISA platforms. The resulting assays benefit from advantages of aptamers over antibodies, which often present issues when trying to develop a rapid assay kit.
Aptamer benefits include:
- Increased specificity– incorporation of counter-selection steps during aptamer selection means that aptamers can be isolated which do not recognise closely-related compounds.
- Wider range of outputs– aptamers can be conjugated to multiple reporter molecules including fluorophores, biotin, enzymes (e.g. strep-HRP) and quencher molecules.
- Virtually no target limitation– nearly any target can be used for aptamer selection; including low molecular weight targets in almost any buffer conditions or matrix.
- No temperature control requirements-high stability of aptamers at various temperatures and their ability to refold, eliminates the need for cold-chain shipping and storage.
- Robust Assays– aptamers show more resistance to different chemical buffers such as large ranges of pH, ionic strength etc.
- Works in crude sample matrices – aptamers can be selected to function in a range of matrices e.g. plasma, milk, urine etc.
- Low batch-to-batch variability – aptamers are prepared by simple chemical synthesis with very high fidelity once the sequence of the aptamers is known.
- Cost effective – aptamers show cost advantages over antibodies as aptamers are produced synthetically.
- Works with existing technology– can be used by all existing plate reader models and aptamers can be designed to work in tandem with high-quality monoclonal antibodies.
Aptamers can be easily incorporated into existing ELISA platforms
The example shows an prototype ELONA (Enzyme Linked OligoNucleotide Assay) in a ‘traditional ELISA-like format. The proteins were fixed at the microtiterplate surface; biotinylated aptamers Target binding aptamers could directly measured ; aptamers ‘using aptamers labelled with gold nanoparticles for specific detection of a protein target.
ELISA-like Assays for small molecule detection
Our small molecule targeting aptamers are designed in such way that they can be used in a range of ‘ELISA-like’ formats. They can be labelled with fluorophores to allow direct reading or with traditional moieties (such as biotin) to facilitate more sensitive assays. The readout of the assays are in a ‘gain of signal’ format and no ‘sandwich pair’ is required. We have developed a number of ELISA-like assays for targeting small molecules and show specific and linear responses even in crude sample matrices.