Rapid capacitive detection of femtomolar levels of bisphenol A using an aptamer-modified disposable microelectrode array

A label-free and single-step method is reported for rapid and highly sensitive detection of bisphenol A (BPA) in aqueous samples. It utilizes an aptamer acting as a probe molecule immobilized on a commercially available array of interdigitated aluminum microelectrodes. BPA was quantified by measuring the interfacial capacitance change rate caused by the specific binding between bisphenol A and the immobilized aptamer. The AC signal also induces an AC electrokinetic effect to generate microfluidic motion for enhanced binding. The capacitive aptasensor achieves a limit of detection as low as 10 fM(2.8 fg a <...aEuro parts per thousand mL (-aEuro parts per thousand 1)) with a 20 s response time. The method is inexpensive, highly sensitive, rapid and therefore provides a promising technology for on-site detection of BPA in food and water samples. B. The ACEK capacitive aptasensor has a limit of detection as low as 10 fM (2.8 fg amL-(1)) with a 20-s response time.