Affinity related to the strength of interaction that may exist between an aptamer and it's target. Usually aptamers that have slow-off rates show strong interactions with their target. These high affinity aptamers can bind low amounts of target making them sensitive reagents. Also in the development of any diagnostic tests, it is important that aptamer would recognize only the desired target and would not cross-react with any other non-target molecule presented in the sample mixture. This selective binding of aptamers to the chosen target molecule and no other in the entire sample mixture is defined as the specificity. We could provide you information about aptamers with most affinity and specifity to your target.

Fluorescence polarization assay could be used to estimate an interaction between aptamers and small molecule target such as peptides, proteins. This approach is based on the induced-fit binding mechanism of nucleic acid aptamers which was used to transform the small target binding event into a detectable fluorescence anisotropy signal.

Laser scanning microscopy data could be used for visual illustration of aptamer binding with its target.

Flow cytometry facilitates quantitative, multi-parameter analysis of target cell populations (protein, virus, etc) based on the binding of target with the ligand. This method is used to get information about aptamer specifity and affinity.