Analytical Methods
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2018
·Vol. 10
·期 34
·4183-4188
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IF 2.073
Renjun Wang,Xiaolu Yan,Jing Sun,Xiao Wang,Xian-En Zhao,Wei Liu,Shuyun Zhu
In this contribution, DNA-templated silver nanoclusters (DNA-AgNCs) were successfully utilized as novel fluorescent probes for the detection of quinolones for the first time. The as-prepared DNA-AgNCs exhibited strong emission at 596 nm, which could be quenched by Cu2+ ions. The addition of quinolones caused restoration of fluorescence intensity of the DNA-AgNCs–Cu2+ system. This detection protocol exhibited excellent sensitivities for four kinds of quinolones. For instance, the linear ranges were from 20 to 100 nM for nalidixic acid with the limit of detection (LOD) 2.0 nM, from 5 to 120 nM for cinoxacin with the LOD 1.2 nM, from 5 to 100 nM for ciprofloxacin with the LOD 1.0 nM, and from 1 to 60 nM for moxifloxacin with the LOD 96 pM, respectively. Benefiting from high sensitivity, satisfactory recoveries were obtained for trace detection of quinolones in real samples, such as tablets and human urine.
研究领域:
分析化学
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纳米技术
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生物医学工程
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NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 40
·17296-17301
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IF 3.288
Tao Lei,Ting Huang,Tianze Wang,Peng Yu,Taiping Qing,Beixi Nie
Thiocyanate (SCN−) is a metabolite of cyanide detoxification, which is considered to be a biomarker of environmental tobacco smoke exposure. Herein, a simple, fast and label-free fluorescent sensor was developed to determine SCN− based on the in situ formation of DNA-templated fluorescent copper nanoclusters (CuNCs). Without SCN−, the Cu(II) ions in buffer were reduced by ascorbic acid and then accumulated on the DNA template, showing a high fluorescence. However, in the presence of SCN−, the Cu(II) ions reacted with thiocyanate and then the remaining unreacted Cu(II) ions were reduced by ascorbic acid, producing a small amount of the CuNCs and a weak fluorescence. Several important parameters such as the concentrations of DNA, Cu(II) ions and ascorbic acid were optimized. Under the optimized conditions, the linear range was 10–100 μM and the limit of detection (LOD) was 4.94 μM for thiocyanate assay. Due to the strong chelation between SCN− and the Cu(II) ions, high selectivity was achieved for SCN− detection by this sensor, with practical applications in real water and artificial saliva. The operation process is simple and the signal response of this method to thiocyanate is fast, within a few minutes. Therefore, the developed assay has great potential to determine thiocyanate for the assessment of water safety and human health.
研究领域:
分析化学
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生物医学工程
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环境科学
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TALANTA
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2017
·
IF 4.162
Dan Han,Chunying Wei
In this work, we develop a fluorescent molecular beacon based on the DNA-templated silver nanoclusters (DNA-Ag NCs). The skillfully designed molecular beacon can be conveniently used for detection of diverse virulence genes as long as the corresponding recognition sequences are embedded. Importantly, the constructed detection system allows simultaneous detection of multiple nucleic acids , which is attributed to non-overlapping emission spectra of the as-synthesized silver nanoclusters. Based on the target-induced fluorescence enhancement, three infectious disease-related genes HIV, H1N1, and H5N1 are detected, and the corresponding detection limits are 3.53, 0.12 and 3.95 nM, respectively. This design allows specific, versatile and simultaneous detection of diverse targets with easy operation and low cost.
研究领域:
生物化学
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分子生物学
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医学诊断
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PubMed
高影响因子
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 8
·1-8
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IF 5.479
Mao Anqi,Wei Chunying
DNA-templated silver nanoclusters (DNA-Ag NCs) with cytosine (C)-rich sequences (four or more segments of consecutive (2–5) C-bases) were synthesized. They display green and/or orange/red emissions under different excitation wavelengths. There is indication that more consecutive C-bases lead to longer emission wavelengths. The ratio of the red and green emissions of the DNA-Ag NCs depends on whether the NCs were synthesized under acidic or basic conditions. We also prepared the DNA copper/silver nanoclusters (DNA-Cu/Ag NCs) which can be synthesized in shorter time and display higher stability. The DNA-Cu/Ag NCs, under 470 nm photoexcitation, always display green emission, with a peak at 550 nm, irrespective of whether being prepared under acidic or basic conditions. The fluorescence of the Cu/Ag NCs is selectively quenched by Hg(II) ions which can be quantified by this nanoprobe with a detection limit as low as 2.4 nM. The quenching mechanism was studied by Stern-Volmer plots and lifetime studies which revealed that both static and dynamic quenching are operative.
Schematic presentation of fluorescent DNA-Ag nanoclusters (NCs) exhibiting red and green emission under different pH values, and green emissive DNA-Cu/Ag NCs for sensitive and rapid detection of Hg 2+ .
研究领域:
生物化学
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分析化学
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纳米科学
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PubMed
高影响因子
RSC Advances
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2017
·Vol. 7
·期 40
·24628-24632
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IF 3.108
Jiaona Xu,Chunying Wei
A novel, label-free fluorescence detection method was proposed for the formation of the G-quadruplex DNAs based on placing two DNA-Ag NCs together to light-up fluorescence. Herein, we designed two tailored DNA sequences noted as target DNA (abbreviated as T-DNA) and complementary DNA (abbreviated as C-DNA), respectively. T-DNA contains two cytosine-rich sequences at the 3′- and 5′-end responsible for Ag NCs synthesis, together with the guanine-rich (G-rich) DNA sequence in the middle segment. C-DNA was designed completely complementary to the G-rich segment of the T-DNA. Provided that the middle G-rich oligonucleotide of T-DNA folds into G-quadruplex in the presence of monovalent cations, the located at 3′ and 5′ terminuses two darkish DNA-Ag NCs approximate, leading to the enhanced fluorescence signal readout. Upon addition of the C-DNA, the G-quadruplex structure is unfolded and the two DNA-Ag NCs are separated, then the fluorescence signal is quenched. On the contrary, when the G-rich oligonucleotide with mutational bases failed to form the G-quadruplex, the fluorescence signal decreased clearly. This design allowed specific and general detection of the formation of diverse G-quadruplexes with easy operation and low cost. We believed that the proposed approach laid a foundation for the researchers in bioimaging, pharmacology, diagnostics, and other fields.
研究领域:
生物化学
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分子生物学
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分析化学
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BIOSENSORS & BIOELECTRONICS
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2014
·
IF 6.451
Xuyue Zheng,Tianming Yao,Ying Zhu,Shuo Shi
In the present study, a new strategy based on Cu 2+ mediated DNA-templated silver nanoclusters (DNA-Ag NCs) was developed, as a label-free, on–off–on fluorescent probe for the detection of l -histidine. Eight synthesized DNA oligonucleotides (D1–D8) were experimentally tested, and D5-Ag NCs was finally selected for l -histidine detection due to its best fluorescent properties. The fluorescence emission of D5-Ag NCs could be quenched by Cu 2+ via electron or energy transfer. Upon addition of l -histidine, the chelation between Cu 2+ and the imidazole group of l -histidine leads to Cu 2+ liberation from D5-Ag NCs, and subsequently results in a dramatic fluorescence enhancement of the probe. The method displayed a good selectivity toward l -histidine over all the other amino acids , with a linear relationship in the range of 0.20–80 μM, and a limit of detection (LOD) of 4.3 nM. The strategy was also successfully applied to detect l -histidine in diluted human urine, exhibiting great opportunities for practical application in biological system.
研究领域:
分析化学
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生物化学
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纳米技术
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PubMed
高影响因子
BIOSENSORS & BIOELECTRONICS
·
2016
·
IF 7.476
Jiaona Xu,Chunying Wei
Two general and reliable fluorescence sensors were proposed in this work utilizing aptamer DNA-templated silver nanoclusters (Ag NCs). Both DNA-AgNCs could be used for label-free detecting of ATP with the limits of detection of 0.44 and 0.65 mM. One of them was further applied to monitor the activity of adenosine deaminase (ADA). In our effort to elucidate the light-up mechanism, we studied a total of six Ag NCs prepared by different DNA sequences , and found that they showed different sensitivity to ATP. Both BT3T3- and BT3T3(R)-templated Ag NCs were chose to make particular studies by UV–vis, TEM, fluorescence, and TCSPC methods. The results showed that when DNA-Ag NCs was kept for 1.5 h and presented a strong fluorescence, the addition of ATP failed to cause a large change of fluorescence intensity ; on the contrary, after Ag NCs was kept for 24 h and emitted a weak fluorescence, adding ATP was able to result in the large fluorescence enhanced of 43 and 33 times for BT3T3- and BT3T3(R)-templated Ag NCs, respectively. The possible mechanism was also suggested that ATP binding to aptamer segment of template induced the change of the DNA secondary structure , which made the aggregated Ag nanoparticles disperse into Ag NCs with an average diameter of about 2 nm that were responsible for the large fluorescence increase. Moreover, ATP could protect the fluorescence intensity of BT3T3(R)-templated Ag NCs from quenching for at least 9 h.
研究领域:
生物化学
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分子生物学
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PubMed
高影响因子
Biosensors-Basel
·
2023
·Vol. 13
·期 5
·520
·
IF 5.4
Guowen Li,Xiufang Huang,Chifang Peng,Fengxia Sun
It is still challenging to achieve simultaneous and sensitive detection of multiple organophosphorus pesticides (OPs). Herein, we optimized the ssDNA templates for the synthesis of silver nanoclusters (Ag NCs). For the first time, we found that the fluorescence intensity of T base-extended DNA-templated Ag NCs was over three times higher than the original C-riched DNA-templated Ag NCs. Moreover, a “turn-off” fluorescence sensor based on the brightest DNA-Ag NCs was constructed for the sensitive detection of dimethoate, ethion and phorate. Under strong alkaline conditions, the P-S bonds in three pesticides were broken, and the corresponding hydrolysates were obtained. The sulfhydryl groups in the hydrolyzed products formed Ag-S bonds with the silver atoms on the surface of Ag NCs, which resulted in the aggregation of Ag NCs, following the fluorescence quenching. The fluorescence sensor showed that the linear ranges were 0.1–4 ng/mL for dimethoate with a limit of detection (LOD) of 0.05 ng/mL, 0.3–2 µg/mL for ethion with a LOD of 30 ng/mL, and 0.03–0.25 µg/mL for phorate with a LOD of 3 ng/mL. Moreover, the developed method was successfully applied to the detection of dimethoate, ethion and phorate in lake water samples, indicating a potential application in OP detection.Keywords:fluorescence sensor;DNA-templated silver nanoclusters;organophosphorus pesticides;fluorescence quenching
研究领域:
分析化学
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环境科学
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纳米技术
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PubMed
高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2020
·
IF 3.306
Qian Qiu,Ru-Ru Gao,Aming Xie,Yingzhi Jiao,Wei Dong
Content of adenosine triphosphate (ATP) is an essential index in the development of various diseases and even some malignant tumors. Biosensing for ATP with high sensitivity and accuracy is of fundamental importance in both biological research and medical diagnostics. Here we report a ratiometric fluorescent sensor for ATP based on multi-color silver nanoclusters (Ag NCs). This nanosystem contains two core components: a hairpin DNA integrated with an ATP aptamer, an anchor sequence and a special template segment for synthesis of green-emitting Ag NCs; a single-stranded DNA (ssDNA) which is incompletely complementary with the anchor sequence to be a duplex scaffold for red-emitting Ag NCs. Once exposed to the target, formation of the ATP/aptamer complexes opens the hairpin structure and releases the anchor sequence to hybridize with the ssDNA, accompanied by the “turn-off” of the green fluorescence and “turn-on” of the red fluorescence. By measuring the fluorescence intensity ratio of the two signals, we successfully establish a ratiometric sensor which exhibits sensitive and accurate assay performance toward ATP, with the limit of detection (LOD) as low as 0.38 μM. Meanwhile, this ratiometric sensor shows stable recovery in real sample assay, indicating their potential promise in practical applications.
研究领域:
生物传感
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医学诊断
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分子生物学
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高影响因子
Journal of Biomedical Nanotechnology
·
2018
·Vol. 14
·期 1
·150-160
·
IF 5.068
Li Taotao,Yi Huan,Liu Yuan,Wang Zunliang,Liu Shiquan,He Nongyue,Liu Hongna,Deng Yan
DNA strands have been used as templates to form different sized silver nanoclusters. Although DNA templated silver nanoclusters (NCs) probes which show outstanding fluorescence properties have been widely applied in chemical sensing and cellular imaging, synthesis of DNA template Au–Ag
bimetallic nanoclusters remains a challenge. A facile one-step synthesis method was thus developed in this study to form Au–Ag NCs using C4-ATAT-C4 as template. C4-ATAT-C4 acted as a stabilizer for preventing aggregation of the Au–Ag NCs. The obtained Au–Ag NCs stabilized
by C4-ATAT-C4 showed bright fluorescence and high stability. A series of experiments showed that temperature, citrate-citric acid buffer, sequence and concentration of DNA played an important role in the synthesis of fluorescent Au–Ag NCs. In addition, a ratiometric fluorescence probe
was designed through combining the nucleotide sequence (C4-ATAT-C4) and hybridization sequence in the presence of the double-strand-chelating dye Super SYBR Green (SG). The combination of prepared Au–Ag NCs, Super SG, and perfectly matched DNA emitted fluorescence at 500 and 590 nm,
respectively, when the composite was excited at 290 nm. A gastric cancer gene was also selectively detected by our developed ratiometric fluorescence probe.
研究领域:
生物化学
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纳米生物学
·
分子诊断
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PubMed
高影响因子
Analytical Methods
·
2020
·Vol. 12
·期 13
·1752-1758
·
IF 2.596
Yanli Zhang,Yanqiong Lai,Xia Teng,Shaofu Pu,Zhi Yang,Pengfei Pang,Hongbin Wang,Chun Yang,Wenrong Yang,Colin J. Barrow
We developed a simple, sensitive, low-cost and label-free method to detect microcystin-leucine-arginine (MC-LR) using double-strand DNA-templated copper nanoclusters (dsDNA-CuNCs) as fluorescent probes. The dsDNA template was designed and fabricated by a MC-LR aptamer strand and its complementary strand, which facilitated CuNCs formation and recognized target MC-LR specifically with strong affinity. The formed fluorescent sensing probe of dsDNA-CuNCs exhibited maximum emission wavelength at 575 nm. Upon addition of target MC-LR into dsDNA-CuNCs, fluorescence was quenched considerably due to the high affinity between MC-LR and the aptamer strand, which indicated a conformational change of the dsDNA-CuNCs probe from the dsDNA structure to single-stranded DNA. Then, the change in fluorescence intensity was used to monitor the MC-LR concentration from 0.01 to 1000 μg L−1 with a limit of detection of 4.8 ng L−1. Compared with previous reports, this method did not require design of a complex DNA sequence, fluorescence dye labels or sophisticated experimental techniques. Moreover, the proposed sensing system could be applicable for detection of target MC-LR in real-water samples.
研究领域:
环境科学
·
分析化学
·
纳米技术
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高影响因子
RSC Advances
·
2022
·Vol. 12
·期 46
·30024-30029
·
IF 4.036
Baozhu Zhang,Ziyao Yang,Yuxia Li,Ling Ma,Fenfang Li,Xiuqing Lv,Guangming Wen
A label-free aptasensor has been fabricated in order to detect adenosine triphosphate (ATP) using turn-on fluorescence DNA-Ag NCs. The fluorescence of the DNA-Ag NCs could increase remarkably with the addition of ATP mainly because ATP specifically interacts with its aptamer to change the microenvironment of the darkish DNA-Ag NCs located at one terminus or two termini due to the conformational alteration of the aptamer structure. The proposed sensor can detect ATP in a linear range of 6–27 mM with a good detection limit of 5.0 μM. Additionally, the proposed method succeeded in detecting ATP in fetal bovine serum.
研究领域:
分析化学
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生物传感器
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纳米技术
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DOI
PubMed
高影响因子
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