A microfluidic-based electrochemical biochip for label-free diffusion-restricted DNA hybridization analysis.

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TitleA microfluidic-based electrochemical biochip for label-free diffusion-restricted DNA hybridization analysis.
Publication TypeJournal Article
Year of Publication2012
AuthorsBen-Yoav, H, Dykstra, PH, Bentley, WE, Ghodssi, R
JournalBiosens Bioelectron
Volume38
Issue1
Pagination114-20
Date Published2012 Oct-Dec
ISSN1873-4235
KeywordsBiosensing Techniques, Diffusion, DNA, Single-Stranded, Electrochemical Techniques, Limit of Detection, Microfluidic Analytical Techniques, Oligonucleotide Array Sequence Analysis
Abstract

DNA hybridization detection in microfluidic devices can reduce sample volumes, processing times, and can be integrated with other measurements. However, as device footprints decrease and their complexity increase, the signal-to-noise ratio in these systems also decreases and the sensitivity is thereby compromised. Device miniaturization produces distinct properties and phenomena with greater influence at the micro-scale than at the macro-scale. Here, a diffusion-restriction model was applied to a miniaturized biochip nanovolume reactor to accurately characterize DNA hybridization events that contribute to shifts in both charge transfer resistance and diffusional resistance. These effects are shown to play a significant role in electrochemical impedance spectroscopy (EIS) analyses at these length scales. Our highly functional microfluidic biosensor enables the detection of ssDNA targets selectively, with a calculated detection limit of 3.8 nM, and cross-reactivity of 13% following 20 min incubation with the target. This new biosensing approach can be further modeled and tested elucidating diffusion behavior in miniaturized devices and improving the performance of biosensors.

DOI10.1016/j.bios.2012.05.009
Alternate JournalBiosens Bioelectron
PubMed ID22651970