New Strategy for Ultrasensitive Aptasensor Fabrication: D–A–D Constitution as a Charge Transfer Platform and Recognition Element

Over the past decade, various sensing systems based on aptamers have attracted a great deal of studies directed at designing highly selective biosensors. In this paper, we described a new-style electrochemical aptamer sensor (aptasensor) via a donor–acceptor link substrate, which was characterized by electrochemical methods and other helpful characterization instruments. Molecules with D–A–D configuration always undergo an intrinsic signal amplification due to the elongation of the π-electron conjugation. Triphenylamine, a peripheral electron donor, has excellent hole-transport property and is able to assemble on the surface of glassy carbon electrode by π–π stacking interaction. To further improve the performance of the adenosine triphosphate (ATP) sensor, we chose diphenylfumaronitrile-containing electron-withdrawing group as the central core to promote charge transfer, which can also efficiently combine with aptamers by multihydrogen bond function. Surprisingly, the sensing platform showed a wide liner range from 0.1 pM to 100 nM, with a detection limit of 0.018 pM. We examined the ATP in human serum sample, indicating that the novel aptasensor based on D–A–D conjugated polymer holds great possibility for practical detection of ATP. Moreover, it is foreseeable that the conjugated polymers of the D–A structure will have promising application in the preparation of biosensors.