BIOSENSORS & BIOELECTRONICS
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2015
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IF 6.409
Hong Guo Chen,Wang Ren,Jing Jia,Ji Feng,Zhong Feng Gao,Nian Bing Li,Hong Qun Luo
We describe here a fluorometric assay for sensitive detection of oligonucleotides , based on a target recycling amplification strategy driven by toehold-mediated strand displacement reaction and on exonuclease III (Exo Ш)-assisted fluorescence background suppression strategy. The network consists of a pair of partially complementary DNA hairpins (HP 1 and HP 2 ) with 3′ overhang ends, between which the spontaneous hybridization is kinetically hindered by the stems. The target DNA is repeatedly used to trigger a recycling progress between the hairpins, generating numerous HP 1 –HP 2 duplex complexes. Exo III was then employed to digest the double strand parts of the residual hairpins and the intermediate products. The fluorescent dye , SYBR Green I , binds to the double-strand DNA products and emits strong fluorescence to achieve sensitive detection of the target DNA with the detection limit of 5.34 pM. Moreover, this proposed strategy showed high discrimination efficiency towards target DNA against mismatched DNA and was successfully applied in the analysis of human serum sample.
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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产品关联
DOI
PubMed
高影响因子
TALANTA
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2022
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IF 6.556
Li Peng,Jian Zhu,Bin Yang,Huimin Hao,Shuyan Lou
Carbaryl is a widely-used carbamate pesticide and the detection of its residues in environmental, food and clinical samples is of great importance. In this sturdy, we developed a green photocatalytic-biosensor based on double strand DNA-SYBR green I complex for sensitively colorimetric detection of carbaryl. This green photocatalytic-biosensor can oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) into blue ox-TMB. Meanwhile thiocholine is catalytically produced by acetylcholinesterase (AChE) to directly reduce blue ox-TMB into colorless TMB. But the activity of AChE will be suppressed by carbaryl, thus generating less thiocholine and resulting in more ox-TMB for colorimetric analysis . After the careful optimization of sensing conditions (2 μM for DNA concentration, 50 × concentration for SYBR Green I, 10 min for illumination time), the lowest detectable concentration for carbaryl is 0.008 ng/mL with a linear response in the range of 0.01–0.25 ng/mL. In addition, this photocatalytic-biosensor has good selectivity over non-target chemicals (acetamiprid, atrazine , carbendazim , melamine , bisphenol A , estradiol). It also allows detection of pesticides in real samples verified by a standard HPLC method.
研究领域:
环境科学
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分析化学
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生物化学
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农业科学
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产品关联
DOI
PubMed
高影响因子
Food Bioscience
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2025
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IF 5.9
Shanglin Li,Bingkun Yang,Mei Liu,Liaoliao Xie,Yonghong Meng
Sensitive and reliable detection of aflatoxin B1 (AFB1) is critical for food safety monitoring. Herein, we developed an innovative amplification free, dual-mode microsensor integrated with smartphone imaging for visual quantitative detection of AFB1. We used a bivalent fluorescence-enhancing (BFE) aptamer and SYBR Green I (SG I) for a ratiometric fluorescence system. The rationally designed BFE aptamer featured two confined binding pockets that simultaneously achieved high-affinity recognition and intrinsic fluorescence amplification for AFB1. This unique design eliminated the need for complex probe labeling while significantly improving detection stability and sensitivity. SG I further complemented the system by generating a green emission upon binding to the BFE aptamer-AFB1 complex, enabling dual-color visualization and robust ratiometric quantification. To further expand the detection versatility, we constructed a smartphone-based digital platform, allowing on-site testing with favorable accuracy. The optimized method achieved wide detection ranges of 1–200 ng/mL (ratiometric fluorescence mode) and 1−100 ng/mL (visual mode), with detection limit of 0.69 ng/mL and 0.94 ng/mL, high selectivity and satisfied recoveries (94.0 %–108.3 %) in food sample analysis. The integration of target signal self-amplification with smartphone readout represents an advancement in portable food safety control, offering a practical approach for mycotoxin monitoring.
研究领域:
食品安全
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分析化学
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生物传感器
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环境监测
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毒理学
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产品关联
DOI
高影响因子
Arabian Journal of Chemistry
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2021
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IF 5.165
Jiankang Deng,Jing Hu,Juanjuan Zhao,Zhiqiang Zhang,Qinghua Wang,Rongrong Wu
Patulin (PAT) contamination in fruit and fruit products is a significant public health concern. Here, we developed a ratiometric fluorescent aptasensor for PAT detection based on aptamer-recognition and Exonuclease III amplification. Two structure selective dyes, SYBR Green I (SGI) and N-methyl mesoporphyrin IX (NMM), were used as fluorescent probes. In the developed biosensing system, the binding of PAT to aptamer triggered the liberation of cDNA. Subsequently, amplification was mediated by Exonuclease III. S1 was released from the S1-S2 duplex by enzymatic hydrolyzation and incorporated into a stable G-quadruplex. As a result, the fluorescence of SGI decreased, whereas that of NMM increased. There was a strong linear correlation between the relative fluorescence intensity and PAT concentrations (20 to 500 ng·L −1 range) (R 2 = 0.99). The biosensing system was highly sensitive, and could detect PAT concentration as low as 4.7 ng·L −1 . The sensor was also highly specific, and could differentiate PAT from several other related mycotoxins. In summary, we developed a new bioassay for the accurate detection of PAT contamination in fruits and fruit products. This research provides a new approach for developing ratiometric bioassays based on structure-selective dyes and enzymatic conversion processes.
研究领域:
食品科学
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分析化学
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生物技术
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产品关联
DOI
高影响因子
TALANTA
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2021
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IF 6.057
Min-Xi Li,Yao Chen,Zeng-Ping Chen,Ru-Qin Yu
Herein, a label free and sensitive miRNA detection method with enhanced practical applicability was developed based on the locked nucleic acid (LNA) assisted repeated fishing amplification strategy. The working mechanism of the proposed method is as follows: 1) a DNA probe (i.e, L-DNA) with LNA bases is immobilized onto the surface of a gold foil. The L-DNA hybridizes with the 3′ terminus of the first strands of complementary deoxyribonucleic acid (cDNA) of the target miRNA in the test samples; 2) The protruding 5′ terminus of the cDNA serves as a ‘fishhook’ to repeatedly fish the products of a hybridization chain reaction (HCR) out from a ‘reaction tube’; 3) The HCR products can be unloaded from the gold foil into a ‘product tube’ through temperature-controlled dehybridization; 4) The concentration of the target miRNA is determined based on the fluorescence intensity generated by the addition of SYBR-Green I (SG) into the ‘product tube’. The proposed platform was applied to the detection of miRNA-122 in cell lysate samples and obtained quantitative results with accuracy comparable to the quantitative reverse transcription PCR method (qRT-PCR). It is worth pointing out that the proposed platform achieved a limit of detection value of 2.9 fM for miRNA-122 by a simple but effective LNA-assisted repeated fishing amplification strategy instead of complicated enzyme-based amplification techniques. It is reasonable to expect that the proposed method provides a competitive alternative for designing practically applicable, cost-effective and label-free miRNA detection methods.
研究领域:
生物化学
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分子生物学
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纳米技术
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分析化学
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产品关联
DOI
PubMed
高影响因子
BIOSENSORS & BIOELECTRONICS
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2013
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IF 5.437
Shuang Dai,Qingwang Xue,Jing Zhu,Yongshun Ding,Wei Jiang,Lei Wang
An ultrasensitive fluorescence method for determination of protein is developed based on hybridization chain reaction (HCR). In this assay, the streptavidin-magnetic nanobeads were conjugated to biotinylated initiators and biotinylated anti-IgG. In the presence of human IgG, the magnetic nanobeads were fixed on the substrate and the carried initiators propagated the chain reaction of hybridization to form the nicked polymers. Because the nanobead probe carries with a large number of oligonucleotides per protein binding event, there is obvious amplification in the nicked polymers. Then, numerous SYBR Green I molecules were intercalated into the grooves of the long dsDNA polymers, generating a substantially apparent increase in the corresponding fluorescence intensity . With HCR amplification and magenetic nanobead to preamplify the fluorescence signal and reduce the background signal, the detection limit of this assay was 14 aM. Compared with the reported protein detection methods, our method exhibited ultrahigh sensitivity. In addition, the proposed method possessed excellent selectivity and low matrix effect . What is more, the assay was also studied for clinical application in human serum with a satisfactory and reliable result.
研究领域:
分析化学
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生物化学
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分子生物学
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纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TALANTA
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2021
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IF 6.057
Pengfei Ma,Hualin Guo,Nuo Duan,Xiaoyuan Ma,Lin Yue,Qianhui Gu,Zhouping Wang
In this study, the original chloramphenicol aptamer containing 80 bases was truncated to 30 bases with high affinity by the SYBR Green I assay. It was found that the ionic strength and type affect the recognition of aptamers, especially magnesium ion played a vital role in the binding process. Furthermore, the binding performance of aptamer, including binding mode, key binding sites and conformational changes were further investigated by circular dichroism spectroscopy, UV–vis absorption spectrum and molecular docking. Based on these research data, we inferred that chloramphenicol bound to the minor groove region in the aptamer double helix. Finally, the optimized aptamer LLR10 was used to develop a novel label free fluorescence polarization assay to detect chloramphenicol within SYBR Green I as the source of fluorescence polarization signal. Under optimal conditions, the designed method showed a linear detection range of 0.1–10 nM with a detection limit of 0.06 nM. Additionally, the aptasensor exhibited a high accuracy to the detection of chloramphenicol in milk samples with a recovery rate from 93.7% to 98.4%. Therefore, the developed label free fluorescence polarization aptasensor provides a new idea for the rapid, reliable and sensitive detection of chloramphenicol, which can be applied to food safety control.
研究领域:
分析化学
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食品科学
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生物化学
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分子生物学
✓ 已验证
DOI
PubMed
高影响因子
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