SENSORS AND ACTUATORS B-CHEMICAL
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2017
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IF 5.401
Yanli Zhang,Haiyan Li,Meng Chen,Xiang Fang,Pengfei Pang,Hongbin Wang,Zhan Wu,Wenrong Yang
Silver ion (Ag + ) is a highly toxic heavy metal ion to aquatic organisms and accumulates in the human body via the food chain. Therefore, fast and accurate detection of Ag + in water and food resources has become a critical issue within the scope of human health. Herein, we developed an ultrasensitive electrochemical biosensor for detection of Ag + based on magnetic Fe 3 O 4 @gold core-shell nanoparticles (Fe 3 O 4 @Au NPs) labeling with hybridization chain reaction (HCR) amplification strategy. In this sensing strategy, the magnetic Fe 3 O 4 @Au NPs were selected for labeling with HCR product and enrichment on the surface of magnetic gold electrode. Thiolated-oligonucleotide (S1) was firstly immobilized on the surface of Fe 3 O 4 @Au NPs through Au–S chemical bond. In the presence of Ag + , cytosine-rich DNA oligonucleotide S2 hybridized with S1 to form an intramolecular duplex, in which Ag + can selectively bind to cytosine–cytosine mismatches forming C–Ag + –C complex. The exposed stem of the C–Ag + –C complex opened two alternating ferrocene-labeled DNA hairpins (H 1 and H 2 ) in turn and triggered HCR to form a supersandwich DNA structure on the surface of Fe 3 O 4 @Au NPs. The HCR products modified Fe 3 O 4 @Au NPs were brought to the surface of magnetic gold electrode for direct electrochemical measurements. The proposed strategy led to a low detection limit of 0.5 fM and a wide dynamic range of 1 fM–100 pM for target Ag + . The developed biosensor was highly selective and its practical applicability in tap water and lake water samples was also investigated with a satisfactory result.
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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产品关联
DOI
高影响因子
Catalysts
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2020
·Vol. 10
·期 6
·600
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IF 3.52
Zui Tao,You Zhou,Nuo Duan,Zhouping Wang
Lead (II) is regarded as one of the most hazardous heavy metals, and lead contamination has a serious impact on food chains, human health, and the environment. Herein, a colorimetric aptasensor based on the graphene/Fe3O4-AuNPs composites with enhanced peroxidase-like activity has been developed to monitor lead ions (Pb2+). In short, graphene/Fe3O4-AuNPs were fabricated and acted as an enzyme mimetic, so the color change could be observed by chromogenic reaction. The aptamer of Pb2+was decorated on the surface of the amine magnetic beads by streptavidin–biotin interaction, and the complementary strands of the aptamer and target Pb2+competed for the binding Pb2+aptamer. In the presence of Pb2+, aptamers bonded the metal ions and were removed from the system by magnetic separation; the free cDNA was adsorbed onto the surface of the graphene/Fe3O4-AuNPs composites, thus inhibiting the catalytic activity and the color reaction. The absorbance of the reaction solution at 652 nm had a clear linear correlation with the Pb2+concentration in the range of 1–300 ng/mL, and the limit of detection was 0.63 ng/mL. This assay is simple and convenient in operation, has good selectivity, and has been used to test tap water samples, which proves that it is capable for the routine monitoring of Pb2+.Keywords:peroxidase;aptamer;graphene;enzyme mimetic;colorimetric method;food safety;rapid detection
研究领域:
环境科学
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分析化学
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材料科学
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生物技术
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公共卫生
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DOI
高影响因子
ELECTROANALYSIS
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2017
·Vol. 29
·期 9
·2098-2105
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IF 2.851
Fang Shang,Yuan Liu,Sui Wang,Yufang Hu,Zhiyong Guo
An ultrasensitive electrochemiluminescence (ECL) immunosensor for the detection of tetrodotoxin (TTX) is proposed, which are composed of the branched poly-(ethylenimine) (BPEI) functionalized graphene (BGNs)/Fe 3 O 4 -Au magnetic capture probes and luminol-capped gold nanocomposites (luminol-AuNPs) as the signal tag. Herein, a typical sandwich immunecomplex was constructed on the glassy carbon electrode. The BGNs/Fe 3 O 4 -Au hybrids could efficiently conjugate primary antibody via the Au−S chemical bonds or Au−N chemical bonds and rapidly separate under external magnetic field. The introduction of BPEI to GO could enhance the luminol-ECL intensity. Meanwhile, the multifunctional nanocomposites have been proved with good water-solubility, excellent electron transfer, outstanding stability, etc. The luminescent luminol-AuNPs, a high efficient electrochemiluminescence marker, can be assembled on the second antibody, which can produce the ECL signal to achieve the determination of TTX. This proposed ECL immunosensor with a linear range from 0.01–100 ng/mL can be applied in the detection of TTX in real samples with satisfactory results.
研究领域:
分析化学
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纳米技术
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毒理学
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环境科学
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产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2020
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IF 7.1
Xiaoou Wei,Yue Sun,Chao Liu,Zhihua Li,Xiaobo Zou,Di Zhang,Wen Zhang,Jiyong Shi,Xiaowei Huang,Yanxiao Li
A novel aptasensor based on the combination of surface-enhanced Raman scattering (SERS) and magnetic separation is presented for sensitive and selective determination of atrazine. 4-(Mercaptomethyl) benzonitrile (MMBN), providing a prominent peak (2227 cm −1 ) in the Raman-silent spectral window (1800–2800 cm −1 ), is selected as Raman tag to eliminate optical interference from biomolecules in sensing system. The MMBN and atrazine-binding aptamer are assembled on silver nanoparticles (AgNPs) to serve as Raman probe (MMBN-AgNPs-aptamer). Meanwhile, Fe 3 O 4 @Au core/shell nanoparticles conjugated with the complementary DNA (Fe 3 O 4 @Au-cDNA) are prepared as Raman substrate to extract the Raman probe with magnetic separation. Atrazine specifically binds to aptamer, and hinders the formation of Fe 3 O 4 @Au-cDNA-aptamer-AgNPs-MMBN (expressed as “Fe 3 O 4 @Au-AgNPs”) complex. Therefore, the Raman intensity of MMBN on substrate decreases with the increment of atrazine concentration. Under optimal SERS conditions, the proposed aptasensor is used to detect atrazine in the laboratory and real samples. The as-prepared atrazine sensor demonstrates a broad dynamic range of 1–50 nM, as well as a low detection limit of 0.67 nM (S/N = 3). For real sample test, the recovery rate ranges from 98.7%–106.6%. The fabricated aptasensor shows superior interference-free performance for atrazine determination in the presence of analogs at high levels.
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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农业化学
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DOI
高影响因子
MICROCHIMICA ACTA
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2020
·Vol. 187
·期 9
·1-8
·
IF 6.232
Li Xiaoyun,Weng Chenyuan,Wang Jing,Yang Wei,Lu Qiaoyun,Yan Xiaoqiang,Sakran Marwan Ahmad,Hong Junli,Zhu Wanying,Zhou Xuemin
A novel label-free and exonuclease III (Exo III)–assisted signal amplification electrochemical aptasensor was constructed for the determination of carcinoembryonic antigen (CEA) via magnetic field–induced self-assembly of magnetic biocomposites (Fe 3 O 4 @Au NPs-S1-S2-S3). The magnetic biocomposites were acquired by modifying double-stranded DNA (S1-S2-S3) on the surface of Fe 3 O 4 @Au nanoparticles (Fe 3 O 4 @Au NPs). Among them, Fe 3 O 4 @Au NPs were used as carriers for magnetic separation, thiolated single-stranded DNA (S1) provided signal sequence, CEA aptamer (S2) worked as a recognition element, and complementary strand (S3) was used to form double strands. In the presence of CEA, S2 bonded with CEA competitively; the exposed S1 could not be cleaved since Exo III was inactive against ssDNA. The G-quadruplex/hemin complexes finally formed with the existence of K + , and the high electrochemical signal of G-quadruplex/hemin complexes was recorded by differential pulse voltammetry (DPV) at − 0.6 V. Conversely, in the absence of CEA, dsDNA was cleaved from the 3′ blunt end by Exo III; the disappearance of G-rich sequence blocked the generation of the signal. This method exhibited good selectivity and sensitivity for the determination of CEA; the linear range was from 0.1 to 200 ng mL −1 and the limit of detection was 0.4 pg mL −1 .
Graphical abstract
研究领域:
生物化学
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分析化学
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生物传感器
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癌症诊断
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）