Highly Sensitive Electrochemical Aptasensor for Detecting the VEGF165 Tumor Marker with PANI/CNT Nanocomposites

Sensing targeted tumor markers with high sensitivity provides vital information for the fast diagnosis and treatment of cancer patients. A vascular endothelial growth factor (VEGF165) have recently emerged as a promising biomarker of tumor cells. The electrochemical aptasensor is a promising tool for detecting VEGF165 because of its advantages such as a low cost and quantitative analysis. To produce a sensitive and stable sensor electrode, nanocomposites based on polyaniline (PANI) and carbon nanotube (CNT) have potential, as they provide for easy fabrication, simple synthesis, have a large surface area, and are suitable in biological environments. Here, a label-free electrochemical aptasensor based on nanocomposites of CNT and PANI was prepared for detecting VEGF165 as a tumor marker. The nanocomposite was assembled with immobilized VEGF165 aptamer as a highly sensitive VEGF165 sensor. It exhibited stable and wide linear detection ranges from 0.5 pg/mL to 1 μg/mL, with a limit of detection of 0.4 pg/mL because of the complementary effect of PANI/CNT. The fabricated aptasensor also exhibited good stability in biological conditions, selectivity, and reproducibility after several measurement times after the dissociation process. Thus, it could be applied for the non-invasive determination of VEGF, in biological fluid diagnosis kits, or in an aptamer-based biosensor platform in the near future.

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A highly sensitive electrochemical aptasensor for vascular endothelial growth factor detection based on toehold-mediated strand displacement reaction

Analytical Methods ◽

10.1039/d1ay01263k ◽

2021 ◽

Author(s):

Zhong Gao ◽

Fangling Ren ◽

Guangyi Yang ◽

Guangjun Feng ◽

Lun Wu ◽

...

Keyword(s):

Vascular Endothelial Growth Factor ◽

Growth Factor ◽

High Sensitivity ◽

Vascular Endothelial ◽

Electrochemical Aptasensor ◽

Strand Displacement ◽

Highly Sensitive ◽

Recycling Amplification ◽

Sensitivity Specificity ◽

Endothelial Growth Factor

An electrochemical aptasensor with high sensitivity, specificity and good intra-day reproducibility is reported to meet the detection needs of vascular endothelial growth factor (VEGF). The toehold-mediated strand displacement recycling amplification...

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Optimizing the Limit of Detection of Waveguide-Based Interferometric Biosensor Devices

Sensors ◽

10.3390/s19173671 ◽

2019 ◽

Vol 19 (17) ◽

pp. 3671 ◽

Cited By ~ 8

Author(s):

Jonas Leuermann ◽

Adrián Fernández-Gavela ◽

Antonia Torres-Cubillo ◽

Sergio Postigo ◽

Alejandro Sánchez-Postigo ◽

...

Keyword(s):

Limit Of Detection ◽

Low Cost ◽

High Sensitivity ◽

Label Free ◽

Noise Optimization ◽

Compact Size ◽

Order Of Magnitude ◽

Index Changes ◽

Photonic Sensors ◽

Monitoring Devices

Waveguide-based photonic sensors provide a unique combination of high sensitivity, compact size and label-free, multiplexed operation. Interferometric configurations furthermore enable a simple, fixed-wavelength read-out making them particularly suitable for low-cost diagnostic and monitoring devices. Their limit of detection, i.e., the lowest analyte concentration that can be reliably observed, mainly depends on the sensors response to small refractive index changes, and the noise in the read-out system. While enhancements in the sensors response have been extensively studied, noise optimization has received much less attention. Here we show that order-of-magnitude enhancements in the limit of detection can be achieved through systematic noise reduction, and demonstrate a limit of detection of ∼ 10 - 8 RIU with a silicon nitride sensor operating at telecom wavelengths.

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A Label-Free Fluorescent AND Logic Gate Aptasensor for Sensitive ATP Detection

Sensors ◽

10.3390/s18103281 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3281 ◽

Cited By ~ 1

Author(s):

Jingjing Zhang ◽

Chunzheng Yang ◽

Chaoqun Niu ◽

Chen Liu ◽

Xuepin Cai ◽

...

Keyword(s):

Deoxyribonucleic Acid ◽

Limit Of Detection ◽

Low Cost ◽

Logic Gate ◽

Label Free ◽

Detection Range ◽

Sensitivity Range ◽

Highly Sensitive ◽

Input Signals ◽

Atp Detection

In this study, a label-free fluorescent, enzyme-free, simple, highly sensitive AND logic gate aptasensor was developed for the detection of adenosine triphosphate (ATP). Double-stranded deoxyribonucleic acid (DNA) with cohesive ends was attached to graphene oxide (GO) to form an aptasensor probe. ATP and single-stranded DNA were used as input signals. Fluorescence intensity of PicoGreen dye was used as an output signal. The biosensor-related performances, including the logic gate construction, reaction time, linearity, sensitivity, and specificity, were investigated and the results showed that an AND logic gate was successfully constructed. The ATP detection range was found to be 20 to 400 nM (R2 = 0.9943) with limit of detection (LOD) of 142.6 pM, and the sensitivity range was 1.846 × 106 to 2.988 × 106 M−1. This method for the detection of ATP has the characteristics of being simple, low cost, and highly sensitive.

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Detection of Mercury Ion with High Sensitivity and Selectivity Using a DNA/Graphene Oxide Hybrid Immobilized on Glass Slides

Biosensors ◽

10.3390/bios11090300 ◽

2021 ◽

Vol 11 (9) ◽

pp. 300

Author(s):

Li Gao ◽

Qiuxiang Lv ◽

Ni Xia ◽

Yuanwei Lin ◽

Feng Lin ◽

...

Keyword(s):

Graphene Oxide ◽

High Selectivity ◽

Limit Of Detection ◽

Low Cost ◽

High Sensitivity ◽

Mercury Ions ◽

Research Areas ◽

Glass Slides ◽

Highly Sensitive ◽

Sensitivity And Selectivity

Excessive mercury ions (Hg2+) cause great pollution to soil/water and pose a major threat to human health. The high sensitivity and high selectivity in the Hg2+ detection demonstrated herein are significant for the research areas of analytical chemistry, chemical biology, physical chemistry, drug discovery, and clinical diagnosis. In this study, a series of simple, low-cost, and highly sensitive biochips based on a graphene oxide (GO)/DNA hybrid was developed. Hg2+ is detected with high sensitivity and selectivity by GO/DNA hybrid biochips immobilized on glass slides. The performance of the biosensors can be improved by introducing more phosphorothioate sites and complementary bases. The best limit of detection of the biochips is 0.38 nM with selectivity of over 10:1. This sensor was also used for Hg2+ detection in Dendrobium. The results show this biochip is promising for Hg2+ detection.

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A rapid, accurate, scalable, and portable testing system for COVID-19 diagnosis

Nature Communications ◽

10.1038/s41467-021-23185-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Guanhua Xun ◽

Stephan Thomas Lane ◽

Vassily Andrew Petrov ◽

Brandon Elliott Pepa ◽

Huimin Zhao

Keyword(s):

Limit Of Detection ◽

Low Cost ◽

High Volume ◽

N Gene ◽

Testing System ◽

Target Sequence ◽

One Pot ◽

Sequence Detection ◽

Highly Sensitive ◽

Speed Accuracy

AbstractThe need for rapid, accurate, and scalable testing systems for COVID-19 diagnosis is clear and urgent. Here, we report a rapid Scalable and Portable Testing (SPOT) system consisting of a rapid, highly sensitive, and accurate assay and a battery-powered portable device for COVID-19 diagnosis. The SPOT assay comprises a one-pot reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) followed by PfAgo-based target sequence detection. It is capable of detecting the N gene and E gene in a multiplexed reaction with the limit of detection (LoD) of 0.44 copies/μL and 1.09 copies/μL, respectively, in SARS-CoV-2 virus-spiked saliva samples within 30 min. Moreover, the SPOT system is used to analyze 104 clinical saliva samples and identified 28/30 (93.3% sensitivity) SARS-CoV-2 positive samples (100% sensitivity if LoD is considered) and 73/74 (98.6% specificity) SARS-CoV-2 negative samples. This combination of speed, accuracy, sensitivity, and portability will enable high-volume, low-cost access to areas in need of urgent COVID-19 testing capabilities.

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Demonstration of a Label-Free and Low-Cost Optical Cavity-Based Biosensor Using Streptavidin and C-Reactive Protein

Biosensors ◽

10.3390/bios11010004 ◽

2020 ◽

Vol 11 (1) ◽

pp. 4

Author(s):

Donggee Rho ◽

Seunghyun Kim

Keyword(s):

Limit Of Detection ◽

Point Of Care ◽

Low Cost ◽

Optical Cavity ◽

Sample Volume ◽

Small Sample ◽

Label Free ◽

C Reactive Protein ◽

Reactive Protein ◽

Cavity Structure

An optical cavity-based biosensor (OCB) has been developed for point-of-care (POC) applications. This label-free biosensor employs low-cost components and simple fabrication processes to lower the overall cost while achieving high sensitivity using a differential detection method. To experimentally demonstrate its limit of detection (LOD), we conducted biosensing experiments with streptavidin and C-reactive protein (CRP). The optical cavity structure was optimized further for better sensitivity and easier fluid control. We utilized the polymer swelling property to fine-tune the optical cavity width, which significantly improved the success rate to produce measurable samples. Four different concentrations of streptavidin were tested in triplicate, and the LOD of the OCB was determined to be 1.35 nM. The OCB also successfully detected three different concentrations of human CRP using biotinylated CRP antibody. The LOD for CRP detection was 377 pM. All measurements were done using a small sample volume of 15 µL within 30 min. By reducing the sensing area, improving the functionalization and passivation processes, and increasing the sample volume, the LOD of the OCB are estimated to be reduced further to the femto-molar range. Overall, the demonstrated capability of the OCB in the present work shows great potential to be used as a promising POC biosensor.

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Integrating high-performing electrochemical transducers in lateral flow assay

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-021-03301-y ◽

2021 ◽

Author(s):

Antonia Perju ◽

Nongnoot Wongkaew

Keyword(s):

High Performance ◽

Point Of Care ◽

Low Cost ◽

High Sensitivity ◽

Lateral Flow ◽

Analytical Performance ◽

Label Free ◽

High Performing ◽

Lateral Flow Assays ◽

Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

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Low-cost flexible plasmonic nanobump metasurfaces for label-free sensing of serum tumor marker

Biosensors and Bioelectronics ◽

10.1016/j.bios.2019.111905 ◽

2020 ◽

Vol 150 ◽

pp. 111905 ◽

Cited By ~ 8

Author(s):

Jinfeng Zhu ◽

Zhengying Wang ◽

Shaowei Lin ◽

Shan Jiang ◽

Xueying Liu ◽

...

Keyword(s):

Tumor Marker ◽

Low Cost ◽

Label Free ◽

Serum Tumor Marker

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Highly sensitive detection of Cr(vi) in groundwater by bimetallic NiFe nanoparticles

Analytical Methods ◽

10.1039/c6ay03089k ◽

2017 ◽

Vol 9 (6) ◽

pp. 1031-1037 ◽

Cited By ~ 3

Author(s):

Jingtao Liu ◽

Yu Ding ◽

Lifei Ji ◽

Xin Zhang ◽

Fengchun Yang ◽

...

Keyword(s):

Heavy Metal ◽

Hexavalent Chromium ◽

Low Cost ◽

High Sensitivity ◽

Sensitive Detection ◽

Toxic Heavy Metal ◽

Metal Pollutants ◽

Highly Sensitive ◽

Highly Sensitive Detection ◽

Heavy Metal Pollutants

Hexavalent chromium (Cr(vi)) is one of the most toxic heavy metal pollutants in groundwater, and thus the detection of Cr(vi) with high sensitivity, accuracy, and simplicity and low cost is of great importance.

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