30th May 2017
Exquisite Selectivity Possible with Aptamers
At Aptamer Group we can select aptamers that bind to small molecules. This is a key differentiator from antibodies where the target needs to be immunogenic. During selection it is possible to introduce counter-selection molecules to remove aptamers that will bind to moieties closely related to the target. Counter-selection drives selectivity to the target small molecule of interest.
The following data were generated during a recent project at Aptamer Group. The aptamer library was exposed to the target for round 1 and aptamers binding to the small molecule target of interest were amplified after each of 7 subsequent rounds to drive evolutionary selection and refinement of the binding aptamer population.
From round 7 onwards a counter-selection molecule, the main metabolite of the target, was introduced (cs1). In this instance, the counter-selection molecule lacked only a dipiperidine group present on the target of interest. The population of aptamers binding to the target was initially reduced by the introduction of the counter-selection molecule, but then revives exponentially by round 11.
Rounds 9 to 11 were also performed with an extra condition for counter selection (cs2), human plasma (40%) plus the metabolite. With the introduction of plasma, although the concentration of counter-selection binding aptamers increased, as selection progresses the concentration of target binding aptamers also increases.
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