Miniaturized Capacitive Devices for the Detection of Circulating Biomarkers, Enabling Real-Time Kinetic Measurements, Integrable with Microfluidic Systems

3/13/2019 16:20 - 16:55

A label-free device has been developed, based on differential double-layer capacitance readout at micro-fabricated gold electrodes, to detect biomarkers in serum or other bio-sample volumes. By means of electrochemical impedance spectroscopy (EIS) measurements in a three electrodes set-up, the device functionalized with self-assembled monolayers of DNA has been calibrated, by measuring in real time the differential capacitance changes at variable concentrations of DNA in a saline buffer, obtaining a dynamic range extended over few orders of magnitude. Micro-RNAs has then been quantified in human plasma of patients with heart disease, demonstrating a limit of detection (LOD) of 1 pM and the possibility to detect single base mismatch in the target sequence. The same platform was successfully used to detect Her2 in serum, by means of a Her2 directed nanobodies (single domain antibodies) conjugated with the DNA strand complementary to that immobilized on the microelectrode. A further device development towards multiplexing read-out, integrated with a paper-based microfluidic set-up is in progress