Unexpected enrichment of DNA aptamers for Zn2+ ions from an insulin selection.

ABSTRACT

We serendipitously discovered Zn2+-binding DNA aptamers when selecting insulin aptamers. The Zn-1 aptamer binds to Zn2+ with a dissociation constant (Kd) of ∼1 µM, and has 450-fold higher selectivity for Zn2+ over Cd2+. A strand-displacement based fluorescent sensor achieved a limit of detection of 0.2 µM Zn2+.