A reversible and highly selective fluorescent sensor for mercury(II) using poly(thiophene)s that contain thymine moietiesa

Abstract

A reversible and highly selective assay method has been developed to detect mereury(II) (Hg2+) ions using a conjugated polymer (CP). The transduction mechanism is based on Hg2+-mediated interpolymer π-stacking aggregation, which results hi the fluorescence self-quenching of the CP. CPs that contain thymine moieties, poly[3-(N-thymin-1-ylacetyl) ethylamine-thiophene] (PTT), have been syntfaesized and characterized. In the absence of Hg2+ ions, the PTT chains remain separated from each other and the CP exhibits strong fluorescence emission. Upon adding Hg2+ ions, the formation of interpolymer π-stacking aggregation induced by specific thymine-Hg-thymine interactions results in the fluorescence quenching of PTT. Distinguishing aspects of this assay include the signal amplification of CPs and the specific binding of Hg2+ ions to thymine-thymine (T-T) base pairs. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.