Title: Detection of interleukin-8 mRNA using a gold nanowire-based biosensor with a stem-loop probe

Authors: Cao Huu Tien; Tran Van Man; Ha Van Linh; Pham Xuan Thanh Tung; Do Thi Thanh Thuy; Le Van Hieu

Addresses: University of Science, Vietnam National University-Ho Chi Minh City, 227 Nguyen Van Cu Street, District 5, Ho Chi Minh City, Vietnam ' University of Science, Vietnam National University-Ho Chi Minh City, 227 Nguyen Van Cu Street, District 5, Ho Chi Minh City, Vietnam ' University of Science, Vietnam National University-Ho Chi Minh City, 227 Nguyen Van Cu Street, District 5, Ho Chi Minh City, Vietnam ' Laboratory for Nanotechnology, Vietnam National University-Ho Chi Minh City, Community 6, Linh Trung Ward, Thu Duc District, Ho Chi Minh City, Vietnam ' Center for Molecular Biomedicine, The University of Medicine and Pharmacy at Ho Chi Minh City, 217 An Duong Vuong, District 5, Ho Chi Minh City, Vietnam ' University of Science, Vietnam National University-Ho Chi Minh City, 227 Nguyen Van Cu Street, District 5, Ho Chi Minh City, Vietnam

Abstract: We report a signal-off, electrochemical DNA (E-DNA) sensor for detection of salivary mRNA employing a stem-loop probe. One end of a stem-loop DNA is immobilised onto a gold electrode via a terminal thiol modification (forming a self assembled monolayer) with the other end bearing a redox-reporting methylene blue to create an E-DNA sensor. In the absence of target, the stem structure of the probe DNA holds the redox tag in proximity to the electrode, producing a large faradaic current. Hybridisation to a complementary oligonucleotide removes the redox tag from the electrode, significantly decreasing this current and supporting the ready detection of specific DNA sequences. The observed signal gain is sufficient to achieve a demonstrated detection limit of 200 pM, which is among the best reported for signal-off electrochemical DNA detection. This suggests that E-DNA signalling arises from binding-linked changes.

Keywords: electrochemical sensors; E-DNA signalling; stem-loop probes; biosensors; interleukin-8 mRNA; gold nanowires; nanotechnology; DNA sensors; salivary mRNA; self assembled monolayers; DNA sequences; electrochemical DNA detection.

DOI: 10.1504/IJNT.2015.067893

International Journal of Nanotechnology, 2015 Vol.12 No.5/6/7, pp.347 - 357

Available online: 25 Feb 2015 *

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