Real-time, multiplexed electrochemical DNA detection using an active complementary metal-oxide-semiconductor biosensor array with integrated sensor electronics

Abstract

Optical biosensing based on fluorescence detection has arguably become the standard technique for quantifying extents of hybridization between surface-immobilized probes and fluorophore-labeled analyte targets in DNA microarrays. However, electrochemical detection techniques are emerging which could eliminate the need for physically bulky optical instrumentation, enabling the design of portable devices for point-of-care applications. Unlike fluorescence detection, which can function well using a passive substrate (one without integrated electronics), multiplexed electrochemical detection requires an electronically-active substrate to analyze each array site and benefits from the addition of integrated electronic instrumentation to further reduce platform size and eliminate the electromagnetic interference that can result from bringing non-amplified signals off chip. We report on an active electrochemical biosensor array, constructed with a standard complementary metaloxide-semiconductor (CMOS) technology, to perform quantitative DNA hybridization detection on chip using targets conjugated with ferrocene redox labels. A 4×4 array of gold working electrodes and integrated potentiostat electronics, consisting of control amplifiers and current-input analog-todigital converters, on a custom-designed 5×3 mm 2 CMOS chip drive redox reactions using cyclic voltammetry, sense DNA binding, and transmit digital data off chip for analysis. We demonstrate multiplexed and specific detection of DNA targets as well as real-time monitoring of hybridization, a task that is difficult, if not impossible, with traditional fluorescence-based microarrays.

Disposable Biosensors for Clinical Diagnosis

“…Disposable electrochemical sensors and biosensors have significant applications as diagnostic tools in the point-of-care testing. The use of several disposable biosensors in the point-ofcare assessment of acetylcholinesterase, 127 bacteria, [128][129][130][131] cancer biomarkers, [132][133][134] and DNA targets 135 has been reported in the literature. A portable sensor system comprising sixteen electrodes for DNA detection is illustrated in Figure 9.…”

“…Different strategies have been proposed for the detection of cardiac biomarkers under the concept of point-of-care diagnostics. [129][130][131][132][133][134][135] For example, Jagadeesan et al have designed a low-cost and rapid method for the modification of paper electrodes with conducting polymers for the amperometric detection of troponin 138 for point-of-care diagnosis. Polyaniline was deposited on the patterned screen printed paper electrodes by electrodeposition, followed by immobilization of anti-cardiac troponin-I using 1-Ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride and N -hydroxysuccinimide coupling.…”

Functionalized ensembles of nanoelectrodes as affinity biosensors for DNA hybridization detection

“…Different approaches have been employed to enable electrochemical detection of the hybridization event, many of them requiring the use of electrochemical labels such as redox or enzyme labels (Carpini et al, 2004;Levine et al, 2009;Tang et al, 2009) or intercalating redox probes (Girousi and Kinigopoulou, 2010;Wei et al, 2011), or by enabling the label-free detection (Kerman et al, 2003). Recently, the DNA hybridization event was detected by binding the capture DNA onto the surface of complex 3D-structures, such as carbon nanotubes (Abdullin et al, 2007;Li et al, 2003) or metal nanowires (Lapierre-Devlin et al, 2005).…”

Photonic detection and characterization of DNA using sapphire microspheres

“…22 In addition, real-time hybridization monitoring using confocal microscopy cannot be performed, because it is hard to distinguish between unbound targets in solution and those that have been hybridized to the probe on the surface, as both will fluoresce when imaged. 23 Photonic microcavities such as circular resonators or spherical resonators are promising optical label-free detection setups. 20,24 In a photonic microcavity, the target molecules are sampled hundreds of times because of the recirculation of light within the microcavity by total internal reflection (TIR).…”