scholarly journals Paper-based aptamer-antibody biosensor for gluten detection in a deep eutectic solvent (DES)

2021 ◽  
Author(s):  
Rossella Svigelj ◽  
Nicolò Dossi ◽  
Cristian Grazioli ◽  
Rosanna Toniolo
Keyword(s):  
Dynamic Range ◽  
Limit Of Detection ◽  
Low Cost ◽  
Deep Eutectic Solvent ◽  
Electrochemical Sensing ◽  
Sensing Platform ◽  
Screen Printed Carbon Electrode ◽  
Highly Sensitive ◽  
Rapid Tests

AbstractPaper has been widely employed as cheap material for the development of a great number of sensors such as pregnancy tests, strips to measure blood sugar, and COVID-19 rapid tests. The need for new low-cost analytical devices is growing, and consequently the use of these platforms will be extended to different assays, both for the final consumer and within laboratories. This work describes a paper-based electrochemical sensing platform that uses a paper disc conveniently modified with recognition molecules and a screen-printed carbon electrode (SPCE) to achieve the detection of gluten in a deep eutectic solvent (DES). This is the first method coupling a paper biosensor based on aptamers and antibodies with the DES ethaline. Ethaline proved to be an excellent extraction medium allowing the determination of very low gluten concentrations. The biosensor is appropriate for the determination of gluten with a limit of detection (LOD) of 0.2 mg L−1 of sample; it can detect gluten extracted in DES with a dynamic range between 0.2 and 20 mg L−1 and an intra-assay coefficient of 10.69%. This approach can be of great interest for highly gluten-sensitive people, who suffer from ingestion of gluten quantities well below the legal limit, which is 20 parts per million in foods labeled gluten-free and for which highly sensitive devices are essential. Graphical abstract

An electrochemical sensing platform amplified with a Au@Ag nanoparticle-decorated three-dimensional N-doped graphene aerogel for ultrasensitive determination of baicalein

2020 ◽  
Vol 44 (37) ◽  
pp. 15975-15982
Author(s):  
Xueliang Niu ◽  
Weili Zhang ◽  
Yan Huang ◽  
Likai Wang ◽  
Zhongfang Li ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Electrochemical Sensing ◽  
Ag Nanoparticle ◽  
Graphene Aerogel ◽  
Sensing Platform ◽  
Highly Sensitive ◽  
Signal Amplifier ◽  
Doped Graphene ◽  
Sensitive Determination

A novel electrochemical method for highly sensitive determination of baicalein was developed with Au@Ag/3DNGA as signal amplifier.

scholarly journals A Highly Sensitive Electrochemical Sensor Based on Electrocatalytic Reduction Effect of Cu2+ on Trace Determination of Malathion in Soil and Other Complex Matrices

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
F. M. Alshareef ◽  
M. I. Orif ◽  
E. A. Al-Harbi ◽  
M. S. El-Shahawi
Keyword(s):  
Environmental Samples ◽  
Dynamic Range ◽  
Superior Performance ◽  
Electrocatalytic Reduction ◽  
Adsorbed Species ◽  
Sensing Platform ◽  
Highly Sensitive ◽  
The Matrix ◽  
Reduction Effect

The current strategy reports a highly sensitive and selective square wave-cathodic stripping voltammetric protocol for malathion determination. The established method was based on the controlled adsorptive accumulation of malathion in the presence of Cu2+ ions in an aqueous solution of pH 2 onto the hanging mercury dropping electrode (HMDE) and measuring the resulting cathodic peak current of the adsorbed species at −0.42 V versus Ag/AgCl electrode. The low limits of detection (LOD) and quantification (LOQ) of malathion of the assay were estimated to be 3.1 × 10−10 and 1.03 × 10−9 M with a linear dynamic range of 1.03×10−9 – 2.0 × 10−7 M, respectively. The method was satisfactorily applied and validated for malathion determination in environmental samples. The experimental Student texp and Fexp values did not exceed the tabulated ttab (2.78) and Ftab (6.39) at 95% (P = 0.05) confidence (n = 5), confirming the precision and independence on the matrix. The developed sensing platform for the detection of malathion shows superior performance to conventional electrochemical methods. The proposed sensor offered simple, economical, reproducible, and applicable approach for the determination of malathion in environmental samples.

A novel and highly sensitive electrochemical sensor based on a high-quality modified graphene electrode for the determination of hydrochlorothiazide in pharmaceutical formulations and human plasma

2015 ◽  
Vol 7 (21) ◽  
pp. 9254-9260 ◽  
Author(s):  
Engin Er ◽  
Hüseyin Çelikkan ◽  
M. Levent Aksu ◽  
Nevin Erk
Keyword(s):  
Electrochemical Sensor ◽  
Human Plasma ◽  
Pharmaceutical Formulations ◽  
Electrochemical Activity ◽  
Electrochemical Sensing ◽  
High Quality ◽  
Sensing Platform ◽  
Highly Sensitive ◽  
Modified Graphene

An electrochemical sensing platform based on high-quality graphene was developed to detect hydrochlorothiazide (HCT) with a highly satisfactory electrochemical activity.

scholarly journals Electrochemical sensing platform for simultaneous detection of 6-mercaptopurine and 6-thioguanine using RGO-Cu2O/Fe2O3 modified screen-printed graphite electrode

2021 ◽  
Author(s):  
Fatemeh Irannezhad ◽  
Jamileh Seyed-Yazdi ◽  
Seyedeh Hoda Hekmatara
Keyword(s):  
Dynamic Range ◽  
Graphite Electrode ◽  
Limit Of Detection ◽  
Simultaneous Detection ◽  
Differential Pulse ◽  
Electrochemical Sensing ◽  
X Ray Diffraction ◽  
Sensing Platform ◽  
Facile Fabrication ◽  
Screen Printed

A sensitive electrochemical sensor was developed using reduced graphene oxide RGO-Cu2O/Fe2O3 nanocomposite for 6-mercaptopurine detection based on a facile fabrication method. The surface morphology and structural composition of this nanocomposite was evaluated by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared (FT-IR) spectroscopy. The screen-printed graphite electrode (SPGE) modified with RGO-Cu2O/Fe2O3 nanocomposite (RGO-Cu2O/Fe2O3/SPGE) indicated excellent electrochemical properties to detect 6-mercaptopurine. The linear dynamic range was estimated between 0.05 and 400.0 μM for 6-mercaptopurine detection, with a limit of detection of 0.03 μM. Also, RGO-Cu2O/Fe2O3/SPGE sensor showed good activity for simultaneous detection of 6-mercaptopurine and 6-thioguanine. In the coexistence system of 6-mercaptopurine and 6-thioguanine, two clear and well-isolated voltammetric peaks were obtained by differential pulse voltammetry (DPV). Additionally, the proposed sensor was examined for applicability by determining 6-mercaptopurine and 6-thioguanine in real samples, and the recovery in the range of 97.5-103.0 % was obtained.

scholarly journals Photo-Electrochemical Sensing of Dopamine by a Novel Porous TiO2 Array-Modified Screen-Printed Ti Electrode

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3566 ◽  
Author(s):  
Francesco Tavella ◽  
Claudio Ampelli ◽  
Salvatore Leonardi ◽  
Giovanni Neri
Keyword(s):  
Modified Electrode ◽  
Limit Of Detection ◽  
Low Cost ◽  
Electrochemical Sensing ◽  
Porous Tio2 ◽  
Response Range ◽  
Potential Applications ◽  
Visible Reflectance ◽  
Screen Printed

In this paper, the development of a nanoporous TiO2 array-modified Ti electrode for photo-electrochemical (PEC) sensing of dopamine (DA) is reported. A porous TiO2 array-modified electrode was fabricated from the controlled anodic oxidation of a Ti working electrode of commercial screen-printed electrodes (SPE). The anodization process and the related morphological and microstructural transformation of the bare Ti electrode into a TiO2/Ti electrode was followed by scanning electron microscopy (SEM) and UV-visible reflectance spectroscopy (DR-UV-Vis). The modified electrode was irradiated with a low-power (120 mW) UV-Vis LED lamp (λ = 400 nm) and showed good performance for the detection of DA with a large linear response range, a sensitivity of 462 nA mM−1 cm−2, and a limit of detection of 20 µM. Moreover, it showed higher photocurrents in the presence of DA in comparison to some foreign species such as ascorbic acid, uric acid, glucose, K+, Na+, and Cl−. Thus, this proposed low-cost photo-electrochemical sensor, with the advantage of very simple fabrication, demonstrates potential applications for the determination of dopamine in real samples.

scholarly journals Electrochemical Sensor Based on Nanodiamonds and Manioc Starch for Detection of Tetracycline

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Wilson Silva Fernandes-Junior ◽  
Leticia Fernanda Zaccarin ◽  
Geiser Gabriel Oliveira ◽  
Paulo Roberto de Oliveira ◽  
Cristiane Kalinke ◽  
...  
Keyword(s):  
Electrochemical Sensor ◽  
Electrochemical Sensors ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Low Cost ◽  
Polymeric Materials ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
High Repeatability

The use of nanostructured materials is already well-known as a powerful tool in the development of electrochemical sensors. Among several immobilization strategies of nanomaterials in the development of electrochemical sensors, the use of low-cost and environmentally friendly polymeric materials is highlighted. In this context, a new nanostructured biocomposite electrode is proposed as an electrochemical sensor for the analysis and determination of tetracycline. The composite electrode consists of a modified glassy carbon electrode (GCE) with a nanodiamond-based (ND) and manioc starch biofilm (MS), called ND-MS/GCE. The proposed sensor showed better electrochemical performance in the presence of tetracycline in comparison to the unmodified electrode, which was attributed to the increase in the electroactive surface area due to the presence of nanodiamonds. A linear dynamic range from 5.0 × 10 − 6 to 1.8 × 10 − 4  mol L−1 and a limit of detection of 2.0 × 10 − 6  mol L−1 were obtained for the proposed sensor. ND-MS/GCE exhibited high repeatability and reproducibility for successive measurements with a relative standard deviation (RSD) of 6.3% and 1.5%, respectively. The proposed electrode was successfully applied for the detection of tetracycline in different kinds of water samples, presenting recoveries ranging from 86 to 112%.

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

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.

scholarly journals Immobilization of Pseudomonas aeruginosa static biomass on eggshell powder for on-line preconcentration and determination of Cr (VI)

2020 ◽  
Vol 18 (1) ◽  
pp. 303-313 ◽  
Author(s):  
Aamir Rasheed ◽  
Tahseen Ghous ◽  
Sumaira Mumtaz ◽  
Muhammad Nadeem Zafar ◽  
Kalsoom Akhter ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Time Flow ◽  
Highly Sensitive ◽  
Glass Column ◽  
On Line ◽  
Preconcentration Time ◽  
Ultra Trace

AbstractIn the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) using Pseudomonas aeruginosa static biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1 and a detection limit of 6.25 μg L-1 for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.

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