The affinity change upon incorporation of LNA and 2′-amino-LNA monomers into an avidin binding DNA aptamer is described. The kinetic profile of selected modified-aptamer was obtained by surface plasmon resonance experiments and compared with the profile of the parent unmodified DNA aptamer. We report significant improvement of avidin binding affinity by the incorporation of single LNA modifications into the aptamer, and successful incorporation of 2′-amino LNA as a novel monomer in aptamers with potential function as carrier unit for additional molecular entities. © 2009 Elsevier Ltd. All rights reserved.