A typical aptamer selection project will progress through the following phases:

Feasibility Study

The applicability of our selection processes to the identification of aptamers to the target of interest is evaluated.

Aptamer Selection Screen

We screen against our proprietary, or a custom developed, aptamer library to determine if it is possible to select aptamers to the target. This involves a few selection rounds in an appropriate buffer to monitor aptamer enrichment and library diversity.

Polyclonal Aptamer Selection

The binding conditions and enriched library established during the screening phase are used to isolate a population of aptamers with affinity for the target. In early rounds, we focus on isolation of aptamers against the target. In later rounds we can use an appropriate counter-selection substrate or closely related moiety to drive target specificity.

Any modification required for end utility may be included during this phase.

Selectivity Profiling

Affinity and specificity/selectivity for the target of interest in selection buffer/matrix is assessed by a biophysical assay or an appropriate biophysical method.

The selected aptamer population(s) can be manufactured and supplied to the customer for evaluation at this stage in the project

Individual Aptamer Identification

Individual aptamer sequences can be isolated and amplified. Isolated aptamers are ranked based on affinity for their target(s).

A selection of the validated aptamers can be prepared and supplied to the customer for evaluation.

Minimal Fragment Identification

Once individual aptamers with the required characteristics have been isolated, the highest ranked aptamers against the target can be chosen and taken forward. The sequence of each aptamer can be determined and the minimal functional binding domain for each aptamer identified.


Production and supply of the selected and sequenced aptamer(s) can be arranged.