4th May 2018

Development of biosensors for the detection of small molecules is notoriously difficult due to the lack of suitable antibodies and the relatively small signals, which result upon small molecule binding to them. At Aptamer Group we select aptamers that bind to small molecules with high specificity and undergo a substantial conformational change that gives a readily measurable readout in a number of biosensor platforms.

During aptamer selection, we include counter-selection targets, usually closely related molecules (such as drug metabolites), to drive selectivity to the small molecule target of interest. We also perform the selection in the relevant target matrix (e.g. plasma, milk, river water etc) during the aptamer isolation process, to ensure that the resulting aptamers are functional in the appropriate medium.

In this study, we developed a highly specific aptamer, which binds to the chemotherapeutic target, but not to its metabolite. We immobilised this aptamer onto a biosensor surface and used this sensor to demonstrate specificity of the aptamer.

An aptamer-based biosensor was used to demonstrate concentration dependent detection of the chemotherapeutic target, around the clinically relevant range and a Direct Assay where the target of interest is immobilised on the assay surface and consequently detected by the specific labelled aptamer.

Once the target specificity of the aptamer-based biosensor was established we demonstrated that the aptamer is able to detect the chemotherapeutic agent at clinically relevant concentrations. We successfully demonstrated concentration dependent binding (between 0.1µM to 10µM target) which spans the therapeutic concentration of ~3µM.

If you would like to discuss aptamer technology with us and see how Aptamer Group can assist with your work, please contact us in the form below.