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Molecular Beacon Lighting up on Graphene Oxide

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Liu_Juewen(9)(1)-s.pdf (879.95 KB)

Date

2012-05-01

Authors

Huang, Po-Jung Jimmy
Liu, Juewen

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Journal ISSN

Volume Title

Publisher

American Chemical Society

Abstract

A molecular beacon (MB) is comprised of a fluorophore and a quencher linked by a DNA hairpin. MBs have been widely used for homogeneous DNA detection. In addition to molecular quenchers, many nanomaterials such as graphene oxide (GO) also possess excellent quenching efficiency. Most reported fluorescent sensors relied on DNA probes physisorbed by GO, which may suffer from nonspecific probe displacement and false positive signal. In this work, we report the preparation and characterization of a MB using graphene oxide (GO) as quencher, where an amino and FAM (6-carboxyfluorescein) dual labeled DNA was covalently attached to GO via an amide linkage. A major challenge was to remove noncovalently attached probes due to strong DNA adsorption by GO. While DNA desorption was favored at low salt, high pH, high temperature, and by using organic solvents, the cDNA was required to achieve complete desorption of noncovalently linked DNA probes. The DNA adsorption energy was measured using isothermal titration calorimetry, revealing the heterogeneous nature of GO. The covalent probe has a detection limit of 2.2 nM using a sample volume of 0.05 mL. With a 2 mL sample, the detection limit can reach 150 pM. The covalent probe is highly resistant to nonspecific probe displacement and will find applications in serum and cellular samples where high probe stability is demanded.

Description

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry copyright © American Chemical Society after peer review and technical editing by publisher. To access the final edited and published work see Huang, P.-J. J., & Liu, J. (2012). Molecular Beacon Lighting up on Graphene Oxide. Analytical Chemistry, 84(9), 4192–4198. https://doi.org/10.1021/ac300778s

Keywords

DNA, graphene oxide, molecular beacon

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Citation

URI

http://dx.doi.org/10.1021/ac300778s
 http://hdl.handle.net/10012/11395

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Waterloo Research
Chemistry
Waterloo Institute for Nanotechnology