title: Homogeneous point mutation detection by quantum dot-mediated two-color fluorescence coincidence analysis.
abstract: This report describes a new genotyping method capable of detecting low-abundant point mutations in a homogeneous, separation-free format. The method is based on integration of oligonucleotide ligation with a semiconductor quantum dot (QD)-mediated two-color fluorescence coincidence detection scheme. Surface-functionalized QDs are used to capture fluorophore-labeled ligation products, forming QD-oligonucleotide nanoassemblies. The presence of such nanoassemblies and thereby the genotype of the sample is determined by detecting the simultaneous emissions of QDs and fluorophores that occurs whenever a single nanoassembly flows through the femtoliter measurement volume of a confocal fluorescence detection system. The ability of this method to detect single events enables analysis of target signals with a multiple-parameter (intensities and count rates of the digitized target signals) approach to enhance assay sensitivity and specificity. We demonstrate that this new method is capable of detecting zeptomoles of targets and achieve an allele discrimination selectivity factor >10(5).
authors.affiliation: Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Hsin-Chih
authors.initials: HC
authors.lastname: Yeh
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Ho
authors.forename: Ie-Ming
authors.initials: IeM
authors.lastname: Shih
authors.forename: Tza-Huei
authors.initials: TH
authors.lastname: Wang
mesh_terms: D045744:Cell Line, Tumor; D003116:Color; D004252:DNA Mutational Analysis / Q000379:methods*; D005260:Female; D005456:Fluorescent Dyes; D011905:Genes, ras; D006801:Humans; D009841:Oligonucleotides / Q000737:chemistry; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence
chemical_list: D005456:Fluorescent Dyes; D009841:Oligonucleotides