Aptamer-based affinity separations
The specific binding between an aptamer and its target can be exploited for the purification of the target molecule. Therefore, the aptamer is immobilized on a solid support and then contacted with the sample containing the target molecule. The target can be eluted from the affinity matrix e.g. by unfolding of the aptamer. This method is not only applicable for the purification of proteins from complex samples; moreover a depletion of small molecular contaminants like Ochratoxin A is possible.
Here, aptamers are used for the detection of proteins as well as for the sensing of small molecules or larger structures like bacteria. For this purpose different platforms are used: Microarrays allow for multiplexed detection and low sample consumption. In cooperation with Prof. Ester Segal (Technion Israel Institute for Technology) porous silicon is decorated with aptamers to develop label-free aptamer-based biosensors for various targets.
Aptamers for specific cellular targeting
Aptamers can be selected to specifically bind to structures present on cellular surfaces. In case that these target structures are related to a specific disease, aptamers can be applied in diagnostic assays. For example, aptamer-modified quantum dots can be used for specific staining of certain cell populations.