DNA aptamers bind specifically and selectively to (1-->3)-beta-D-glucans.

(1-->3)-Beta-D-Glucans are structural cell wall components of fungi, plants, and some bacteria and have been linked with human respiratory symptoms following aerosol exposure. A clear interpretation of the health impact of (1-->3)-beta-D-glucans is limited by the high cost and uncertainties associated with current glucan quantitation methods. The objective of this research is to develop DNA aptamers for the measurement of (1-->3)-beta-D-glucans. Aptamers are synthetic DNA functional binding molecules that fold into unique conformations, allowing them to bind specifically to their target. Through the in vitro selection process SELEX, we have produced aptamers that are able to bind with sub-micromolar affinity to curdlan, a linear unbranched form of (1-->3)-beta-D-glucans. These aptamers display high selectivity to curdlan and do not bind to non-(1-->3)-beta-D-polysaccharides, suggesting specificity for the beta-(1-->3)-glycosidic linkage. The aptamers produced here will enable the production of more cost-effective, less ambiguous assays for the environmental measurement of (1-->3)-beta-D-glucans.