Silver nanoparticles-enhanced time-resolved fluorescence sensor for VEGF(165) based on Mn-doped ZnS quantum dots.
A silver nanoparticles (AgNPs)-enhanced time-resolved fluorescence (TR-FL) sensor based on long-lived fluorescent Mn-doped ZnS quantum dots (QDs) is developed for the sensitive detection of vascular endothelial growth factor-165 (VEGF165), a predominant cancer biomarker in cancer angiogenesis. The aptamers bond with the Mn-doped ZnS QDs and the BHQ-2 quencher-labelling strands hybridized in duplex are coupled with streptavidin (SA)-functionalized AgNPs to form the AgNPs-enhanced TR-FL sensor, showing lower fluorescence intensity in the duplex state due to the fluorescence resonance energy transfer (FRET) between the Mn-doped ZnS QDs and quenchers. Upon the addition of VEGF165, the BHQ-2 quencher-labelling strands of the duplex are displaced, leading to the disruption of the FRET. As a result, the fluorescence of the Mn-doped QDs within the proximity of the AgNPs is recovered. The FL signal can be measured free of the interference of short-lived background by setting appropriate delay time and gate time, which offers a signal with high signal-to-noise ratio in photoluminescent biodetection. Compared with the bare TR-FL sensor, the AgNPs-based TR-FL sensor showed a huge improvement in fluorescence based on metal-enhanced fluorescence (MEF) effect, and the sensitivity increased 11-fold with the detection limit of 0.08 nM. In addition, the sensor provided a wide range of linear detection from 0.1 nM to 16 nM.
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China. Electronic address: dongzhunjutcm@hotmail.com.
Dong
D
Zhu
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China. Electronic address: liwaii@126.com.
Wei
W
Li
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China.
Hong-Mei
HM
Wen
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China.
Sheng
S
Yu
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China.
Zhao-Yi
ZY
Miao
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China.
An
A
Kang
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, PR China.
Aihua
A
Zhang
D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000235:genetics; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008274:Magnesium / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis*; D017967:Zinc Compounds / Q000737:chemistry*
D052157:Aptamers, Nucleotide; D018036:Selenium Compounds; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D017967:Zinc Compounds; D012834:Silver; D008274:Magnesium; C044696:zinc selenide
Fluorescence resonance energy transfer; Metal-enhanced fluorescence; Mn-doped ZnS quantum dots; Time-resolved