Dual-Transducer Malaria Aptasensor Combining Electrochemical Impedance and Surface Plasmon Polariton Detection on Gold Nanohole Arrays

Two transducer principles are combined in one aptamer biosensor (aptasensor) by simultaneously performing electrochemical impedance spectroscopy (EIS) and surface plasmon polariton (SPP) detection of a malaria biomarker. A thin gold film perforated with nanohole arrays is modified with small and highly charged aptamer receptors and utilized for the detection of Plasmodium falciparum lactate dehydrogenase (PfLDH), the main biomarker of malaria. Monitoring the same analyte binding events by two independent transduction principles not only corroborates the in situ detection, but also covers a concentration range of six orders of magnitude (1 pM-1 mu M). The EIS method is highly sensitive to low concentrations of PfLDH (1 pM-100 nM), whereas SPP is sensitive to higher concentrations of the target (10 nM-1 mu M), owing to either high interfacial or more bulk sensitivity, respectively. Thus, we propose the dual-transducer aptasensor based on gold nanohole arrays as a platform for a broad dynamic concentration range and reliable detection.