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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

Strategy for the magnetically assisted DNA sensor with CP amplification. In the presence of target DNA, the capturing probe and the signaling probe form the ‘sandwich’ complex with the target and anchor at the MMP surfaces. After the stringent washing step and magnetic separation, the cationic luminescent polymer meets the signaling probe to form a FRET pair and emit amplified fluorescence from the fluorescein, which reflects the quantity of target DNA.
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sch1: Strategy for the magnetically assisted DNA sensor with CP amplification. In the presence of target DNA, the capturing probe and the signaling probe form the ‘sandwich’ complex with the target and anchor at the MMP surfaces. After the stringent washing step and magnetic separation, the cationic luminescent polymer meets the signaling probe to form a FRET pair and emit amplified fluorescence from the fluorescein, which reflects the quantity of target DNA.

Mentions: In our design, the DNA sensor is composed of three components: a cationic CP (PF, the light-harvesting polymer that serves as the signal amplification factor), a fluorescein-tagged DNA probe (signaling probe) and a streptavidin-coated MMP labeled with biotinylated DNA probes (capturing probe). Both the signaling probe and the capturing probe are designed to be complementary to different parts of the DNA target sequence, which forms the basis of ‘sandwich-type’ detection. The detection strategy is described in Scheme 1. In the presence of target DNA, the capturing probe brings the target DNA, along with the signaling probe, proximal to the MMP. In contrast, in the absence of target DNA, the ‘sandwich’ complex cannot be formed, and thus the signaling probe is not attached to the MMP during the magnetic separation step. As a result, only in the presence of target DNA can the cationic luminescent polymer meet the signaling probe to form a FRET pair and emit amplified fluorescence from the fluorescein that reflects the quantity of target DNA.


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)

Strategy for the magnetically assisted DNA sensor with CP amplification. In the presence of target DNA, the capturing probe and the signaling probe form the ‘sandwich’ complex with the target and anchor at the MMP surfaces. After the stringent washing step and magnetic separation, the cationic luminescent polymer meets the signaling probe to form a FRET pair and emit amplified fluorescence from the fluorescein, which reflects the quantity of target DNA.
© Copyright Policy
Related In: Results  -  Collection

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

sch1: Strategy for the magnetically assisted DNA sensor with CP amplification. In the presence of target DNA, the capturing probe and the signaling probe form the ‘sandwich’ complex with the target and anchor at the MMP surfaces. After the stringent washing step and magnetic separation, the cationic luminescent polymer meets the signaling probe to form a FRET pair and emit amplified fluorescence from the fluorescein, which reflects the quantity of target DNA.
Mentions: In our design, the DNA sensor is composed of three components: a cationic CP (PF, the light-harvesting polymer that serves as the signal amplification factor), a fluorescein-tagged DNA probe (signaling probe) and a streptavidin-coated MMP labeled with biotinylated DNA probes (capturing probe). Both the signaling probe and the capturing probe are designed to be complementary to different parts of the DNA target sequence, which forms the basis of ‘sandwich-type’ detection. The detection strategy is described in Scheme 1. In the presence of target DNA, the capturing probe brings the target DNA, along with the signaling probe, proximal to the MMP. In contrast, in the absence of target DNA, the ‘sandwich’ complex cannot be formed, and thus the signaling probe is not attached to the MMP during the magnetic separation step. As a result, only in the presence of target DNA can the cationic luminescent polymer meet the signaling probe to form a FRET pair and emit amplified fluorescence from the fluorescein that reflects the quantity of target DNA.

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