Label free fluorescent aptasensor for potassium ion using structure switching aptamers and berberine.
A simple, rapid and label free fluorescent aptasensor was fabricated for the detection of potassium ion (K( ion) in aqueous solution using K( ion stabilized single stranded DNA (ssDNA) with G rich sequence as the recognition element and a fluorescent dye, berberine, as the fluorescence probe. In the presence of K( ion, the G rich ssDNA is promoted to form the aptamer target complex with a G quadruplex conformation, and berberine binding to the G quadruplex structure results in the enhancement of its fluorescence. The fluorescence intensity of the sensing system displayed a calibration response for K( ion in the range of 0 1600mM with a detection limit of 31nM (S/N=3) and a relative standard deviation (RSD) of 0.45% This label free fluorescence aptasensor is conveniently and effectively applicable for analysis of K( ion in blood serum samples with the recovery range of 81.7 105.3% The assay for detection of potassium ion is easy, economical, robust, and stable in rough conditions.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy