23rd July 2019

Aptamer based ‘gain of signal’ assay for small molecule detection

Detecting small molecules represents a challenge for In vitro diagnostics (IVD) due to sensitivity and specificity limits of many detection methods. Our specially designed displacement approach allows us to select aptamers that can readily be used in various IVD and point of care (POC) assays for the detection of small molecules. As the aptamers undergo a conformational change upon small molecule binding, gives a ‘signal amplification’ effect also termed as ‘gain of signal’ which can be used as a basis for small molecule detection. This allows simplified downstream assay development and makes them useful as alternatives in ELISA-like assays, Lateral Flow Devices (LFD’s), Molecular Beacons, Biosensors, etc.

At Aptamer Group we have performed similar ‘Gain of signal’ displacement assays that are compatible with various analysis methods. These include ELISA–like assays using simple fluorescence measurements and qPCR for enhanced sensitivity (figure 1) and Lateral flow based assays (figure 2).

Figure 1. Displacement ELISA–like assay with gain of signal measurements for small molecule detection using: A) fluorescence for easy detection B) qPCR for enhanced sensitivity.

Figure 2. Displacement assay data (left) shows concentration dependent binding of an aptamer to its antibiotic target, and re-capturing of the aptamer-target complex (right) in different matrices.

Overall, the data suggests that our aptamers can be incorporated into existing ELISA and LFD platforms showing target specific responses even in crude sample matrices. The re-capture approach is compatible with different matrices and shows linear concentration dependent responses. The aptamers can be used in a rapid, gain of signal assay that can be used to discover, deduce and quantify sample compounds. In turn this can reduce the heavy reliance on antibodies and mass spec for small molecule analysis. If you want more information on how our aptamers can be readily used in your research, please contact using the form below.