Electrically Guided DNA Immobilization and Multiplexed DNA Detection with Nanoporous Gold Electrodes

Abstract

Molecular diagnostics have significantly advanced the early detection of diseases, where the electrochemical sensing of biomarkers (e.g., DNA, RNA, proteins) using multiple electrode arrays (MEAs) has shown considerable promise. Nanostructuring the electrode surface results in higher surface coverage of capture probes and more favorable orientation, as well as transport phenomena unique to nanoscale, ultimately leading to enhanced sensor performance. The central goal of this study is to investigate the influence of electrode nanostructure on electrically-guided immobilization of DNA probes for nucleic acid detection in a multiplexed format. To that end, we used nanoporous gold (np-Au) electrodes that reduced the limit of detection (LOD) for DNA targets by two orders of magnitude compared to their planar counterparts, where the LOD was further improved by an additional order of magnitude after reducing the electrode diameter. The reduced electrode diameter also made it possible to create a np-Au MEA encapsulated in a microfluidic channel. The electro-grafting reduced the necessary incubation time to immobilize DNA probes into the porous electrodes down to 10 min (25-fold reduction compared to passive immobilization) and allowed for grafting a different DNA probe sequence onto each electrode in the array. The resulting platform was successfully used for the multiplexed detection of three different biomarker genes relevant to breast cancer diagnosis.

Biosensors-on-Chip: An Up-to-Date Review

“…Veselinovic et al further demonstrated that nanostructuring the surface of electrodes leads to higher surface coverage and consequently enhanced sensor performance. Specifically, they integrated nanoporous gold multielectrode arrays within microchannels for facilitating the multiplexed detection of DNA biomarkers for cancer, namely the BRCA1, BRCA2, and p53 breast cancer-related genes, through electrophoretic guidance [ 83 ]. Similarly, Wu et al developed an amplification-free, SERS microfluidic approach for the detection of KRAS gene, commonly known for its mutations in cancer cells [ 84 ].…”

Nanostructured Architectures for Biomolecular Detection inside and outside the Cell

“…For example, in the development of a multiplexed sensor for breast cancer genes. [130] Nanoporous noble metals have been employed in many other biomedical fields. Nanoporous materials with a platinum-gold alloy have been used for glucose sensing.…”

New Disposable Electrochemical Paper‐based Microfluidic Device with Multiplexed Electrodes for Biomarkers Determination in Urine Sample

“… developed a rapid and sensitive assay in a microfluidic device based on a multivalent aptasensor array chip and silver aggregated amplification for detection of proteins platelet‐derived growth factor‐BB and vascular endothelial growth factor‐165 by fluorescence. The multiplexed detection of three different biomarker genes relevant to a breast cancer diagnosis was performed by Veselinovic and co‐workers through square wave voltammetry. They used electrically guided immobilization of DNA probes for nucleic acid in a multiplexed format.…”