Quantum Dot-Mediated Separation-Free Assay for Point Mutation Detection

Keywords:
quantum dots, single nucleotide polymorphisms, coincidence detection

Abstract:
We describe a novel semiconductor quantum dot (QD)-based biosensing assay for single nucleotide polymorphism (SNP) detection. By integrating a QD-mediated dual-color fluorescence coincidence detection method with oligonucleotide ligation assay (OLA), we have achieved rapid SNP detection in a homogenous separation-free format. Detection of target signal is carried out on a single quantum dot basis using ultrasensitive confocal fluorescence spectroscopy. Comparing with other separation-free SNP detection schemes such as molecular beacon and microparticle-based flow cytometry, our assay shows advantages in much enhanced sensitivity and speed. Moreover, we have demonstrated that this QD-based assay allowed SNP detection with nearly infinite specificity. Our developed QD-based SNP assay requires no need for immobilization and wash after duplex denaturation, no need for complicated probe design, and no need for temperature control during measurement, rendering this a simple, fast, cost effective, and potentially an on-line monitoring assay for point mutation detection.

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Nanotech 2005 Conference Program Abstract