By combining an appropriate DNA aptamer with a cationic polythiophene optical transducer, human thrombin can be specifically detected on microarrays in the attomole range in less than one hour without any tagging of the target. The system can be modified and utilized as a probe for the detection of various proteins or other biomolecules. This work opens new interesting possibilities for simple and rapid multiparametric analysis in genomics and proteomics.

The cover image depicts biochips based on responsive nanoaggregates made from stoichiometric complexes between a cationic polythiophene and an appropriate DNA aptamer. These structures undergo a conformational transition from an unfolded to a folded (G‐quadruplex) structure in the presence of a specific target protein that results in a significant increase of the fluorescence intensity, as reported on p. 2703 by Leclerc and co‐workers.