Amplified detection of single base mismatches with the competing-strand assay reveals complex kinetic and thermodynamic behavior of strand displacement at the electrode surface
| Authors | |
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| Year of publication | 2018 |
| Type | Article in Periodical |
| Magazine / Source | Electrochimica Acta |
| MU Faculty or unit | |
| Citation | |
| Web | https://www.sciencedirect.com/science/article/pii/S0013468618317067 |
| Doi | http://dx.doi.org/10.1016/j.electacta.2018.07.188 |
| Keywords | Single-base mismatch detection; Osmium tetroxide bipyridine labeling; Melting temperature; Surface-immobilized DNA |
| Description | Detection of single-base mismatches with respect to a probe strand has been a predominant pursuit in electrochemical biosensor efforts, due to links found between single nucleotide polymorphisms (SNPs) and the predisposition to various diseases. We report an osmium tetroxide bipyridine-based, thermally-controlled, competitive-strand electrochemical assay to allow amplified detection of single-base mismatches. Optimally designed competitive-strand displacement and hybridization temperature allows us to distinguish the single-mismatched-target from the fully complementary sequence with unambiguous, highly reproducible, robust signal differences of over 90%. Furthermore, we find a complex interplay between the position of the redox label, variations in strand displacement kinetics due to mismatches incorporated into the competitive strand, and alterations in the melting temperature of DNA duplexes tethered on the gold surface, when probed by square-wave voltammetry. These insights will apply to any surface-tethered DNA-based electrochemical biosensor, and can help with understanding complex phenomena involved in these types of assays. (C) 2018 Elsevier Ltd. All rights reserved. |
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