Selected DNA aptamers as hydroxyapatite affinity reagents

DNA aptamers were selected for their ability to bind specifically and quickly to crystalline hydroxyapatite (Ca-10(PO4)(6)(OH)(2); HAP), the primary mineral component of enamel and bone. Aptamers were found to have an enhanced percent of G-nucleotides and a propensity for forming a G-quadruplex secondary structure. One aptamer was studied in comparison to control sequences and was found to bind with high affinity and at high loading capacity, with enhanced binding kinetics, and with specificity for crystalline HAP material over amorphous calcium phosphate (ACP) and beta-tricalcium phosphate (TCP). The fluorescently-functionalized aptamer was demonstrated to specifically label HAP in a surface binding experiment and suggests the usefulness of this selected aptamer in biomedical or biotechnology fields where the labeling of specific calcium phosphate materials is required. (C) 2020 Elsevier B.V. All rights reserved.