Nanostructure and Corresponding Quenching Efficiency of Fluorescent DNA Probes.

Wenjuan Guo,Guangping Chen,Zhao Dai,Yanhong Wei,Yuanyuan Chu,Yifei Zhao

doi:10.3390/ma11020272

Abstract

Based on the fluorescence resonance energy transfer (FRET) mechanism, fluorescent DNA probes were prepared with a novel DNA hairpin template method, with SiO2 coated CdTe (CdTe/SiO2) core/shell nanoparticles used as the fluorescence energy donors and gold (Au) nanoparticles (AuNPs) as the energy acceptors. The nanostructure and energy donor/acceptor ratio in a probe were controlled with this method. The relationship between the nanostructure of the probes and FRET efficiency (quenching efficiency) were investigated. The results indicated that when the donor/acceptor ratios were 2:1, 1:1, and 1:2; the corresponding FRET efficiencies were about 33.6%, 57.5%, and 74.2%, respectively. The detection results indicated that the fluorescent recovery efficiency of the detecting system was linear when the concentration of the target DNA was about 0.0446–2.230 nmol/L. Moreover, the probes showed good sensitivity and stability in different buffer conditions with a low detection limit of about 0.106 nmol/L.

Highlights

Fluorescent DNA probes [1] are a kind of optical DNA biosensor [2] based on the fluorescence resonance energy transfer (FRET) mechanism [3]
FRET occurs when the electronic excitation energy of a donor chromophore is transferred to a nearby acceptor molecule via a through-space dipole–dipole interaction between the donor-acceptor pair within 1–10 nm distances
The results indicated that the FRET recovery efficiency (Fr) of the detection system reached a maximum when indicated that the FRET recovery efficiency (Fr) of the detection system reached a maximum when the pH value was 8 and the ssDNA10 concentration was 1.115 nmol/L (Figure 9a)

Summary

Introduction

Fluorescent DNA probes [1] are a kind of optical DNA biosensor [2] based on the fluorescence resonance energy transfer (FRET) mechanism [3]. The field of fluorescent DNA probes improved considerably with the introduction of inorganic nanoparticles, such as quantum dots (QDs) [4,5] and gold (Au) nanoparticles (AuNPs) [6,7,8] as energy donors and acceptors [9], respectively. As a new kind of luminescent inorganic fluorophores, QDs are being widely used in chemical sensors [10], DNA detection [11], cell labeling [12], and imaging [13] because they have a broad and continuous excitation spectrum, a narrow size-tunable symmetric emission spectrum, and a high fluorescence quantum yield. In the field of fluorescent DNA biosensors, AuNPs are commonly used as energy acceptors because of their high extinction coefficient and wide absorption spectra

Methods

Discussion

Conclusion