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A quantum dot-aptamer beacon using a DNA intercalating dye as the FRET reporter: Application to label-free thrombin detection
- Source :
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Biosensors & Bioelectronics . Mar2011, Vol. 26 Issue 7, p3346-3352. 7p. - Publication Year :
- 2011
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Abstract
- Abstract: A new quantum dot (QD)-aptamer (apt) beacon that acts by folding-induced dissociation of a DNA intercalating dye, BOBO-3(B), is demonstrated with label-free thrombin detection. The beacon, denoted as QD-apt:B, is constructed by (1) coupling of a single-stranded thrombin aptamer to Qdot 565 via EDC/Sulfo-NHS chemistry and (2) staining the duplex regions of the aptamer on QD with excess BOBO-3 before thrombin binding. When mixing a thrombin sample with QD-apt:B, BOBO-3 is competed away from the beacon due to target-induced aptamer folding, which then causes a decrease in QD fluorescence resonance energy transfer (FRET)-mediated BOBO-3 emission and achieves thrombin quantitation. In this work, the effects of Mg2+, coupling time, and aptamer type on the beacon''s performances are investigated and discussed thoroughly with various methods, including transmission electron microscopy (TEM), dynamic light scattering (DLS), and two-color differential gel electrophoresis. Using the best aptamer beacon (HTQ37), we attain highly specific and wide-range detection (from nM to μM) of thrombin in buffer, and the beacon can sense nM-range thrombin in 15% diluted serum. Compared to the reported QD aptamer assays, our method is advantageous from the aspect of using a simple sensory unit design without losing the detection sensitivity. Therefore, we consider the QD-apt:B beacon a potential alternative to immuno-reagents and an effective tool to study nucleic acid folding on QD as well. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 09565663
- Volume :
- 26
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- Biosensors & Bioelectronics
- Publication Type :
- Academic Journal
- Accession number :
- 58539534
- Full Text :
- https://doi.org/10.1016/j.bios.2011.01.015