Homogeneous DNA Detection Based on Fluorescence Quenching by Nanoparticles in Single-step Format :Target-Induced Configu

A new strategy for homogeneous detection of DNA hybridization in single-step format was developed based on fluorescence quenching by gold nanoparticles.The gold nanoparticle is functionalized with 5'-thiolated 48-base oligonucleotide(probe sequence),whose 3'-terminus is labeled with fluorescein(FAM),a negatively charged fluo-rescencc dye.The oligonucleotide adopts all extended configuration due to the electrostatic repulsion between nega-tively charged gold nanoparticle and the FAM-attached probe sequence.After addition of the complementary target sequence,specific DNA hybridization induces a conformation change of the probe from an extended stmcture to an arch.1ike configuration,which brings the fluorophore and the gold nanoparticle in close proximity.The fluorescence is efficiently quenched by gold nanoparticles.The fluorescence quenching efficiency is related to the target concen.tration,which allows the quantitative detection for target sequence in a sample.A linear detection range from 1.6 to 209.4 nmoI/L Was obtained under the optimized experimental conditions with a detection limit of 0.1 nmol,L.In the assay system,the gold nanoparticles act as both nanoscaffolds and nanoquenchers.Furthermore,the proposed strategy.in which only two DNA sequences arc involved,is not only different from the traditional molecular bea-cons or reverse molecular beacons but also different from the commonly used sandwich hybridization methods.In addition,the DNA hybridization detection was achieved in homogenous solution in a single-step format,which al-lows real.time detection and quantification with other advantages such as easy operation and elimination of washing steps.

作 者： ZHANG,Songbai WU,Zaisheng XIE,Ming SHEN,Guoli YU,Ruqin   作者單位： State Key Laboratory for Chemol Biosensing and Chemometrics,College of Chemistry and Chemical Engineering,Hunan University.Changsha,Hunan 410082,China  刊 名： 中國化學（英文版）  SCI 英文刊名： CHINESE JOURNAL OF CHEMISTRY  年，卷(期)： 2009 27(3)  分類號： O6  關鍵詞： DNA hybridization   fluorescence quenching   gold nanoparticle   fluorescence resonance energy transfer   configuration transform  

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