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Magnetically assisted DNA assays: high selectivity using conjugated polymers for amplified fluorescent transduction.

Xu H, Wu H, Huang F, Song S, Li W, Cao Y, Fan C - Nucleic Acids Res. (2005)

Bottom Line: We demonstrate that the use of magnetic microparticles significantly improves the selectivity of this class of DNA sensors.Compared with previously reported DNA sensors with CP amplification, this novel sensing strategy displays excellent discrimination against non-cognate DNA in the presence of a protein mixture or even human serum.We also demonstrate that the magnetically assisted DNA sensor can conveniently identify even a single-nucleotide mismatch in the target sequence.

View Article: PubMed Central - PubMed

Affiliation: Division of Nanobiology and Nanomedicine, Shanghai Institute of Applied Physics, Chinese Academy of Sciences Shanghai 201800, China.

ABSTRACT
We report a strategy for conjugated polymer (CP)-based optical DNA detection with improved selectivity. The high sensitivity of CP-based biosensors arises from light harvesting by the CP and the related amplified fluorescent signal transduction. We demonstrate that the use of magnetic microparticles significantly improves the selectivity of this class of DNA sensors. Compared with previously reported DNA sensors with CP amplification, this novel sensing strategy displays excellent discrimination against non-cognate DNA in the presence of a protein mixture or even human serum. We also demonstrate that the magnetically assisted DNA sensor can conveniently identify even a single-nucleotide mismatch in the target sequence.

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Related in: MedlinePlus

Left panel: normalized fluorescence spectra for DNA sensing based on PF-amplified FRET signals ([PF] = 5.4 × 10−7 M). The concentrations of target DNA are 0, 1.0, 3.0, 5.0, 7.0, 9.0 and 10.0 nM, respectively, from bottom to top. Right panel: dependence of FRET signals on target DNA concentrations. Error bars were estimated from at least three independent measurements.
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fig2: Left panel: normalized fluorescence spectra for DNA sensing based on PF-amplified FRET signals ([PF] = 5.4 × 10−7 M). The concentrations of target DNA are 0, 1.0, 3.0, 5.0, 7.0, 9.0 and 10.0 nM, respectively, from bottom to top. Right panel: dependence of FRET signals on target DNA concentrations. Error bars were estimated from at least three independent measurements.

Mentions: Previous spectroscopic studies have proven that the emission of PF has sufficient spectral overlap with the fluorescein absorption that they form an excellent FRET pair (38). Consistent with this, we observed well-defined FRET signals upon addition of PF to the test solution containing probe 2 (Figures 1 and 2). The light-harvesting PF sensitized the emission of the fluorescein (the energy-transfer acceptor), leading to fluorescent signal amplification. In fact, we could still observe well-defined PF-sensitized fluorescein emission at probe 2 concentrations that were sufficiently dilute (100 pM) that fluorescence emission was negligible by direct excitation of fluorescein (Figure 1). These results verify that light-harvesting polymers do provide optical signal amplification and improve the detection sensitivity.


Magnetically assisted DNA assays: high selectivity using conjugated polymers for amplified fluorescent transduction.

Xu H, Wu H, Huang F, Song S, Li W, Cao Y, Fan C - Nucleic Acids Res. (2005)

Left panel: normalized fluorescence spectra for DNA sensing based on PF-amplified FRET signals ([PF] = 5.4 × 10−7 M). The concentrations of target DNA are 0, 1.0, 3.0, 5.0, 7.0, 9.0 and 10.0 nM, respectively, from bottom to top. Right panel: dependence of FRET signals on target DNA concentrations. Error bars were estimated from at least three independent measurements.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1131937&req=5

fig2: Left panel: normalized fluorescence spectra for DNA sensing based on PF-amplified FRET signals ([PF] = 5.4 × 10−7 M). The concentrations of target DNA are 0, 1.0, 3.0, 5.0, 7.0, 9.0 and 10.0 nM, respectively, from bottom to top. Right panel: dependence of FRET signals on target DNA concentrations. Error bars were estimated from at least three independent measurements.
Mentions: Previous spectroscopic studies have proven that the emission of PF has sufficient spectral overlap with the fluorescein absorption that they form an excellent FRET pair (38). Consistent with this, we observed well-defined FRET signals upon addition of PF to the test solution containing probe 2 (Figures 1 and 2). The light-harvesting PF sensitized the emission of the fluorescein (the energy-transfer acceptor), leading to fluorescent signal amplification. In fact, we could still observe well-defined PF-sensitized fluorescein emission at probe 2 concentrations that were sufficiently dilute (100 pM) that fluorescence emission was negligible by direct excitation of fluorescein (Figure 1). These results verify that light-harvesting polymers do provide optical signal amplification and improve the detection sensitivity.

Bottom Line: We demonstrate that the use of magnetic microparticles significantly improves the selectivity of this class of DNA sensors.Compared with previously reported DNA sensors with CP amplification, this novel sensing strategy displays excellent discrimination against non-cognate DNA in the presence of a protein mixture or even human serum.We also demonstrate that the magnetically assisted DNA sensor can conveniently identify even a single-nucleotide mismatch in the target sequence.

View Article: PubMed Central - PubMed

Affiliation: Division of Nanobiology and Nanomedicine, Shanghai Institute of Applied Physics, Chinese Academy of Sciences Shanghai 201800, China.

ABSTRACT
We report a strategy for conjugated polymer (CP)-based optical DNA detection with improved selectivity. The high sensitivity of CP-based biosensors arises from light harvesting by the CP and the related amplified fluorescent signal transduction. We demonstrate that the use of magnetic microparticles significantly improves the selectivity of this class of DNA sensors. Compared with previously reported DNA sensors with CP amplification, this novel sensing strategy displays excellent discrimination against non-cognate DNA in the presence of a protein mixture or even human serum. We also demonstrate that the magnetically assisted DNA sensor can conveniently identify even a single-nucleotide mismatch in the target sequence.

Show MeSH
Related in: MedlinePlus