NEW JOURNAL OF CHEMISTRY
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2019
·Vol. 43
·期 26
·10517-10522
·
IF 3.069
Shasha Pang,Xianwen Kan
Developing an accurate and sensitive method for the detection of environmental pollutants is of great significance. However, traditional single signal based electrochemical sensors are usually susceptible to external and internal effects. To overcome these influences, in the present work, ferrocene (Fc) was covalently functionalized on multi-walled carbon nanotubes (MWNTs) to fabricate a facile electrochemical sensor for the detection of o-nitrophenol (o-NP) and p-nitrophenol (p-NP). With an increase in the concentration of both the nitrophenols, the peak currents of nitrophenols increased while the peak current of Fc remained constant. Thus, Fc can be used as an inner reference element to obtain a ratiometric signal by dividing nitrophenol current by Fc current, which endowed the sensor with a built-in correction of environmental effects. Moreover, Fc can effectively separate the reduction peaks of o-NP and p-NP, which made it possible to detect o-NP and p-NP individually and simultaneously. Due to the self-calibration based on the ratiometric strategy and the good conductivity of MWNTs, the prepared sensor showed high accuracy, reliability, and sensitivity for o-NP and p-NP detection with the linear range of 1.0 × 10−7 to 1.0 × 10−4 M. The facile, low cost, and sensitive sensor reported here has promising potential for accurate and reliable detection of other compounds.
研究领域:
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2022
·
IF 8.008
Guojuan Zhang,Yujie Han,Zhiguang Liu,Lifang Fan,Yujing Guo
A triple-amplified and ratiometric electrochemical aptasensor for CA125 was designed based on hemin–graphene/SH-β-cyclodextrin@PdPt nanoflower (H-Gr/SH-β-CD@PdPtNF) composites and an exonuclease I (Exo I)-assisted strategy. In the nanocomposite, hemin acts as an internal reference signal owing to the reversible heminox/heminred pair. PdPtNFs can significantly improve the electron transfer rate. SH-β-CD can efficiently enrich quercetin probes through host–guest recognition and increase the second indicator signal. In the presence of CA125, due to the specific binding between the aptamer and CA125, the conformational change of dsDNA (designed by the CA125 aptamer and its complementary DNA) results in the release of quercetin embedded in dsDNA. Subsequently, the free quercetin and DNA fragments are enriched on the H-Gr/SH-β-CD@PdPtNF-modified electrode. Thus, an enhanced oxidation peak from quercetin (IQ) and a reduced peak from hemin (Ihemin) can indicate the same biological identification event. In addition, the recycling amplification of CA125 by Exo I can effectively assist the increase of the quercetin signal. The value of IQ/Ihemin is linear with the concentration of CA125 in the range from 6.0 × 10–4 to 1.0 × 103 ng/mL, and the limit of detection is 1.4 × 10–4 ng/mL. The recovery of CA125 in human blood serum samples was from 99.2 to 104.4%. The proposed sensor is sensitive and reliable, which provides an avenue for the development of triple amplification and ratiometric signal strategies for detecting tumor markers in clinical diagnostics.
研究领域:
生物医学工程
·
临床诊断
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2025
·
IF 7.7
Yunshan Zhang,Sisi Bu,Fang Yang,Tuo Huang,Hao Dong,Jing Ye,Wenlin Xie,Xianzhong Feng,Diming Zhang
The subtle free energy difference introduced by a single nucleotide mutation results in poor specificity of almost all DNA hybridization probe-based single nucleotide polymorphism (SNP) detection techniques. The development of SNP biosensing strategies with both specificity and sensitivity is a hot and difficult issue in the current field. In this study, we creatively constructed a competitive toehold-mediated strand displacement sensing platform (CTMSD) based on the traditional TMSD reaction, which increased the energy barrier through the intrinsic competition mechanism and expanded the detection window of SNPs. Furthermore, based on the characteristics of the CTMSD platform, the dual-signal detection mode was introduced to change the function model of the detection curve through reporting internal reference ratio signal. The new detection curve model not only compensated for sensitivity, significantly enhanced the discrimination factor, but also greatly expanded the detection window with infinite robustness factor over the detection range. The expansion of the detection window and the improvement of specificity of CTMSD for SNP recognition based on the ratiometric signal output model were verified by computer simulations and experiments. In addition, as a deformation of the strand displacement reaction, the CTMSD was readily adaptable to commonly used signal amplification techniques, such as catalytic hairpin assembly (CHA). Through the CTMSD-CHA performance analysis and real testing of cell genomic samples, the practical application value of CTMSD with the ratiometric signal output model was confirmed. This study provides an important reference for the design and improvement of SNP biosensors and even for all nucleic acid biosensors.
研究领域:
生物化学
·
分子生物学
·
医学诊断
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2022
·
IF 8.008
He Chen,Yuan Ding,Jiao Li,Lianrun Huang,Gualberto González-Sapienza,Bruce D. Hammock,Minghua Wang,Xiude Hua
The self-calibration capability of ratiometric signals has been widely considered to enhance the accuracy, sensitivity, and anti-interference ability of immunoassays. Exploring a new approach to generate ratiometric signals can provide more options for various requirements. Herein, we integrated the negative-readout competitive and positive-readout noncompetitive immunoassays into a single assay by employing different color tracers, labeled peptidomimetic and anti-immunocomplex peptides, to create a new unconstrained ratiometric signal approach. Using an immunochromatographic strip (ICS) and a fungicide benzothiostrobin as the analytical platform and analyte, respectively, we showed that this approach can be extensively applied to fluorescence and colorimetry readouts, which have also been proven for strong anti-interference ability to an external light environment. Moreover, the enormous intuitional color changes of ratiometric fluorescent and colorimetric ICSs (RFICS and RCICS) enabled the formation of the color reference cards (like the pH paper) for visual judgment. After adaptation with a portable smartphone, the quantitative detection limits for RFICS and RCICS were 0.17 and 0.44 ng mL–1, respectively. In addition, the ICSs showed good accuracy for the detection of benzothiostrobin in spiked samples.
研究领域:
分析化学
·
生物化学
·
生物技术
·
环境科学
✓ 已验证
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）