Binding of uranyl ion by a DNA aptamer attached to a solid support

A UO22+-specific DNA aptamer was attached to aminopolystyrene (aminoPS) using sulfo-SMCC as a cross-linking agent in view of high affinity of DNA for uranyl ion. Capacity of the aptamer-conjugated aminoPS resins for uranyl uptake was measured, revealing that about 0.63 mu g of uranium can be complexed to 1 g of the resins, which clearly demonstrates that most of DNA aptamers introduced to the resins can strongly bind to uranyl ion. In the presence of 21 mM bicarbonate ion at pH 8.01, apparent dissociation constant (K-d(app)) of about 84.6 pM and log formation constant (K-f) of about 22.9 were obtained. Results of the present study strongly suggest that modification of the aptamer-containing resins can improve uranyl-binding ability, probably leading to economical recovery of uranium from seawater. (C) 2011 Elsevier Ltd. All rights reserved.