Unlocking Pb Sensing Potential in a DNA G-Quadruplex via Loop Modification with Fluorescent Chalcone Surrogates.

The ability of guanine (G)-rich DNA to bind toxic lead (Pb) ions within a G-quadruplex (GQ) motif is a leading DNA biosensor strategy. A major analytical hurdle for GQ detection of Pb is competitive GQ templating by potassium (K) ions. We employ the on-strand DNA synthesis of internal fluorescent chalcone surrogates within the 15-mer thrombin binding aptamer (TBA15) to address this challenge.