Optical Sensors Based on Hybrid Aptamer/Conjugated Polymer Complexes

TLDR

Single‑stranded DNA aptamers can bind potassium ions or human α‑thrombin with high specificity. Binding induces a conformational shift in the aptamer, which is sensed by a cationic polythiophene that converts the complex formation into a colorimetric or fluorometric optical signal without labeling. The method detects human thrombin at femtomole levels and can be extended to other proteins and high‑throughput drug screening.

Abstract

Single-stranded DNA (aptamer) can specifically bind potassium ions or human α-thrombin. When binding takes place, the aptamer undergoes a conformational transition from an unfolded to a folded structure. This conformational change of the negatively charged oligonucleotide can be detected by adding a water-soluble, cationic polythiophene derivative, which transduces the new complex formation into an optical (colorimetric or fluorometric) signal without any labeling of the probe or of the target. This simple and rapid methodology has enabled the detection of human thrombin in the femtomole range. This new biophotonic tool can easily be applied to the detection of various other proteins as well as being useful in the high-throughput screening of new drugs.