scholarly journals An Electrochemical Sensor Based on Gold-Nanocluster-Modified Graphene Screen-Printed Electrodes for the Detection of β-Lactoglobulin in Milk

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3956
Author(s):  
Jingyi Hong ◽  
Yuxian Wang ◽  
Liying Zhu ◽  
Ling Jiang
Keyword(s):  
Electrochemical Sensor ◽  
Electrochemical Sensors ◽  
Limit Of Detection ◽  
Gold Nanoclusters ◽  
Enzyme Linked Immunosorbent Assay ◽  
Gold Nanocluster ◽  
Detection Range ◽  
Screen Printed Electrodes ◽  
Β Lactoglobulin ◽  
Screen Printed

A simple and low-cost electrochemical sensor based on multimodified screen-printed electrodes (SPEs) was successfully synthesized for the sensitive detection of β-lactoglobulin (β-Lg). The surface treatment of SPEs was accomplished by a simple drip coating method using polyethyleneimine (PEI), reduced graphene oxide (rGO), and gold nanoclusters (AuNCs), and the treated SPEs showed excellent electrical conductivity. The modified SPEs were then characterized with UV-Vis, SEM, TEM, and FTIR to analyze the morphology and composition of the AuNCs and the rGO. An anti-β-Lg antibody was then immobilized on the composite material obtained by modifying rGO with PEI and AuNCs (PEI-rGO-AuNCs), leading to the remarkable reduction in conductivity of the SPEs due to the reaction between antigen and antibody. The sensor obtained using this novel approach enabled a limit of detection (LOD) of 0.08 ng/mL and a detection range from 0.01 to 100 ng/mL for β-Lg. Furthermore, pure milk samples from four milk brands were measured using electrochemical sensors, and the results were in excellent agreement with those from commercial enzyme-linked immunosorbent assay (ELISA) methods.

scholarly journals Streptavidin-conjugated gold nanoclusters as ultrasensitive fluorescent sensors for early diagnosis of HIV infection

2018 ◽  
Vol 4 (11) ◽  
pp. eaar6280 ◽  
Author(s):  
Aditya Dileep Kurdekar ◽  
L. A. Avinash Chunduri ◽  
C. Sai Manohar ◽  
Mohan Kumar Haleyurgirisetty ◽  
Indira K. Hewlett ◽  
...  
Keyword(s):  
Hiv Infection ◽  
Limit Of Detection ◽  
Gold Nanoclusters ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Metal Nanoclusters ◽  
Detection Range ◽  
In Silico Studies ◽  
P24 Antigen ◽  
Hiv 1

We have engineered streptavidin-labeled fluorescent gold nanoclusters to develop a gold nanocluster immunoassay (GNCIA) for the early and sensitive detection of HIV infection. We performed computational simulations on the mechanism of interaction between the nanoclusters and the streptavidin protein via in silico studies and showed that gold nanoclusters enhance the binding to the protein, by enhancing interaction between the Au atoms and the specific active site residues, compared to other metal nanoclusters. We also evaluated the role of glutathione conjugation in binding to gold nanoclusters with streptavidin. As proof of concept, GNCIA achieved a sensitivity limit of detection of HIV-1 p24 antigen in clinical specimens of 5 pg/ml, with a detection range up to1000 pg/ml in a linear dose-dependent manner. GNCIA demonstrated a threefold higher sensitivity and specificity compared to enzyme-linked immunosorbent assay for the detection of HIV p24 antigen. The specificity of the immunoassay was 100% when tested with plasma samples negative for HIV-1 p24 antigen and positive for viruses such as hepatitis B virus, hepatitis C virus, and dengue. GNCIA could be developed into a universal labeling technology using the relevant capture and detector antibodies for the specific detection of antigens of various pathogens in the future.

scholarly journals Disposable Carbon Dots Modified Screen Printed Carbon Electrode Electrochemical Sensor Strip for Selective Detection of Ferric Ions

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Shao Chien Tan ◽  
Suk Fun Chin ◽  
Suh Cem Pang
Keyword(s):  
Electrochemical Sensor ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Carbon Nanodots ◽  
Selective Detection ◽  
Carbon Electrode ◽  
Ferric Ions ◽  
Detection Range ◽  
Screen Printed Carbon Electrode ◽  
Screen Printed

A disposable electrochemical sensor strip based on carbon nanodots (C-Dots) modified screen printed carbon electrode (SPCE) was fabricated for selective detection of ferric ions (Fe3+) in aqueous solution. C-Dots of mean diameters within the range of 1–7 nm were synthesized electrochemically from spent battery carbon rods. The analytical performance of this electrochemical sensor strip was characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The deposition of C-Dots had enhanced the electron-transfer kinetics and current intensity of the SPCE remarkably by 734% as compared to that of unmodified SPCE. Under optimized conditions, the electrochemical sensor strip exhibited a linear detection range of 0.5 to 25.0 ppm Fe3+ with a limit of detection (LOD) of 0.44±0.04 ppm (at S/N ratio = 3). Validation of results by the electrochemical sensor strip was done by comparing analysis results obtained using an Atomic Absorption Spectrometer (AAS).

scholarly journals Electrochemical Properties of Screen-Printed Carbon Nano-Onion Electrodes

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3884
Author(s):  
Loanda R. Cumba ◽  
Adalberto Camisasca ◽  
Silvia Giordani ◽  
Robert J. Forster
Keyword(s):  
High Performance ◽  
Electrode Materials ◽  
Limit Of Detection ◽  
Low Cost ◽  
Analytical Sensitivity ◽  
High Performing ◽  
Carbon Particles ◽  
Screen Printed Electrodes ◽  
Ink Formulation ◽  
Screen Printed

The properties of carbon nano-onions (CNOs) make them attractive electrode materials/additives for the development of low-cost, simple to use and highly sensitive Screen Printed Electrodes (SPEs). Here, we report the development of the first CNO-based ink for the fabrication of low-cost and disposable electrodes, leading to high-performance sensors. Achieving a true dispersion of CNOs is intrinsically challenging and a key aspect of the ink formulation. The screen-printing ink formulation is achieved by carefully selecting and optimising the conductive materials (graphite (GRT) and CNOs), the polymer binder, the organic solvent and the plasticiser. Our CNO/GRT-based screen-printed electrodes consist of an interconnected network of conducting carbon particles with a uniform distribution. Electrochemical studies show a heterogeneous electron transfer rate constant of 1.3 ± 0.7 × 10−3 cm·s−1 and a higher current density than the ferrocene/ferrocenium coupled to a commercial graphite SPEs. In addition, the CNO/GRT SPE can detect dopamine in the concentration range of 10.0–99.9 µM with a limit of detection of 0.92 µM (N = 3). They exhibit a higher analytical sensitivity than the commercial graphite-based SPE, with a 4-fold improvement observed. These results open up the possibility of using high-performing CNO-based SPEs for electrochemical applications including sensors, battery electrodes and electrocatalysis.

scholarly journals Screen-printed electrodes modified with HRP-zirconium alcoxide film for the development of a biosensor for acetaminophen detection

2010 ◽  
Vol 8 (5) ◽  
pp. 1034-1040 ◽  
Author(s):  
Veronica Sima ◽  
Cecilia Cristea ◽  
Ede Bodoki ◽  
Gabriela Duţu ◽  
Robert Sāndulescu
Keyword(s):  
Electrode Materials ◽  
Limit Of Detection ◽  
Operation Mode ◽  
Pharmaceutical Products ◽  
Hydration Properties ◽  
Zirconium Alkoxide ◽  
Screen Printed Electrodes ◽  
Gel Film ◽  
Protective Environment ◽  
Screen Printed

AbstractThe development of a biosensor based on the immobilization of horseradish peroxidase (HRP) within a zirconium alkoxide-polyetilenimine film onto screen-printed electrodes (SPE) for acetaminophen detection and acetaminophen quantification in pharmaceutical products is described. The biosensor operation mode is based on monitoring the amperometric signal produced by the electrochemical reduction of the enzymatically generated electroactive oxidized species of acetaminophen in the presence of hydrogen peroxide. The enzyme immobilization is performed by retention in a polyethylenimine-zirconium alcoxide porous gel film, a technique that offers good entrapping and a protective environment for the biocomponent due to the hydration properties of the immobilization layer. SPEs have the advantage of being easily mass-produced at low costs with superior characteristics in comparison with classical electrode materials. In this configuration, zirconium alkoxide demonstrates its electrocatalytic activity. The biosensor allows the quantification of acetaminophen with a limit of detection of 6.21×10−8 M and a linear range between 4.35×10−7 M and 4.98×10−6 M. Finally, the biosensor is applied to the quantitative analysis of acetaminophen in Perdolan® tablets.

scholarly journals Development of a Magnetic Nanoparticles-Based Screen-Printed Electrodes (MNPs-SPEs) Biosensor for the Quantification of Ochratoxin A in Cereal and Feed Samples

Toxins ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 317 ◽  
Author(s):  
Xian Zhang ◽  
Zuohuan Wang ◽  
Hui Xie ◽  
Renjie Sun ◽  
Tong Cao ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Ochratoxin A ◽  
Limit Of Detection ◽  
Screen Printed Electrodes ◽  
Combined Use ◽  
Highly Sensitive ◽  
Relative Standard ◽  
Liquid Chromatography Tandem Mass ◽  
Feed Samples ◽  
Screen Printed

A rapid and sensitive electrochemical biosensor based on magnetic nanoparticles and screen-printed electrodes (MNPs-SPEs sensor) was developed for the detection of ochratoxin A (OTA) in cereal and feed samples. Different types of magnetic nanoparticles-based ELISA (MNPs-ELISA) were optimized, and the signal detection, as well as sensitivity, was enhanced by the combined use of screen-printed electrodes (SPEs). Under the optimized conditions, the calibration curve of the MNPs-SPEs sensor was y = 0.3372x + 0.8324 (R2 = 0.9805). The linear range of detection and the detection limit were 0.01–0.82 ng/mL and 0.007 ng/mL, respectively. In addition, 50% inhibition (IC50) was detectable at 0.10 ng/mL. The limit of detection (LOD) of this MNPs-SPEs sensor in cereal and feed samples was 0.28 μg/kg. The recovery rates in spiked samples were between 78.7% and 113.5%, and the relative standard deviations (RSDs) were 3.6–9.8%, with the coefficient of variation lower than 15%. Parallel analysis of commercial samples (corn, wheat, and feedstuff) showed a good correlation between MNPs-SPEs sensor and liquid chromatography tandem mass spectrometry (LC/MS-MS). This new method provides a rapid, highly sensitive, and less time-consuming method to determine levels of ochratoxin A in cereal and feedstuff samples.

scholarly journals Adaptation of ELISA Detection of Plasmodium Falciparum and Plasmodium Vivax Circumsporozoite Proteins in Mosquitoes to a Multiplex Bead-Based Immunoassay

2021 ◽  
Author(s):  
Alice Sutcliffe ◽  
Seth R. Irish ◽  
Eric Rogier ◽  
Micaela Finney ◽  
Sarah Zohdy ◽  
...  
Keyword(s):  
Lower Limit ◽  
Limit Of Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Limits Of Detection ◽  
Detection Range ◽  
Cutoff Value ◽  
Sporozoite Rate ◽  
The Impact ◽  
Lower Limits ◽  
Multiplex Bead

Abstract Background: Plasmodium spp. sporozoite rates in mosquitoes are used to better understand malaria transmission intensity, the relative importance of vector species and the impact of interventions. These rates are typically estimated using an enzyme-linked immunosorbent assay (ELISA) utilizing antibodies against the circumsporozoite protein of P. falciparum (Pf), P. vivax VK210 (Pv210) or P. vivax VK247 (Pv247), employing assays that were developed over three decades ago. The ELISA method requires a separate assay plate for each analyte tested and can be time consuming as well as requiring sample volumes not always available. The bead-based multiplex platform allows simultaneous measurement of multiple analytes and may improve the lower limit of detection for sporozoites.Methods: Recombinant positive controls for Pf, Pv210 and Pv247 and previously developed circumsporozoite (cs) ELISA antibodies were used to optimize conditions for the circumsporozoite multiplex bead assay (csMBA) and to determine the detection range of the csMBA. After optimizing assay conditions, known amounts of sporozoites were used to determine the lower limit of detection for the csELISA and csMBA and alternate cutoff measures were applied to demonstrate how cutoff criteria can impact lower limits of detection. Sporozoite rates from 1275 mosquitoes collected in Madagascar and 255 mosquitoes collected in Guinea were estimated and compared using the established csELISA and newly optimized csMBA. All mosquitoes were tested (initial test), and those that were positive were retested (retest). When sufficient sample volume remained, an aliquot of homogenate was boiled and retested (boiled retest), to denature any heat-unstable cross-reactive proteins. Results: Following optimization of the csMBA, the lower limit of detection was 25 sporozoites per mosquito equivalent for Pf, Pv and Pv247 whereas the lower limits of detection for csELISA were found to be 1400 sporozoites for Pf, 425 for Pv210 and 1650 for Pv247. Combined sporozoite rates after re-testing of samples that initially tested positive for Madagascar mosquitoes by csELISA and csMBA were 1.4% and 10.3%, respectively, and for Guinea mosquitoes 2% by both assays. Boiling of samples followed by csMBA resulted in a decreased in the Madagascar sporozoite rate to 2.8-4.4% while the Guinea csMBA sporozoite rate remained at 2.0%. Using an alternative csMBA cutoff value of median fluorescence intensity (MFI) of 100 yielded a sporozoite rate after confirmational testing of 3.7% for Madagascar samples and 2.0% for Guinea samples. Whether using csMBA or csELISA, the following steps may help minimize false positives: specimens are appropriately stored and bisected anterior to the thorax-abdomen junction, aliquots of homogenate are boiled and retested following initial testing, and an appropriate cutoff value is determined.Conclusions: The csMBA is a cost-comparable and time saving alternative to the csELISA and may help eliminate false negatives due to a lower limit of detection, thus increasing sensitivity over the csELISA. The csMBA expands the potential analyses that can be done with a small volume of sample by allowing multiplex testing where analytes in addition to Pf, Pv210 and Pv247 can be added following optimization.

scholarly journals Electrochemical Sensors Based on Screen-Printed Electrodes: The Use of Phthalocyanine Derivatives for Application in VFA Detection

Biosensors ◽  
2016 ◽  
Vol 6 (3) ◽  
pp. 46 ◽  
Author(s):  
Amadou Ndiaye ◽  
Sébastien Delile ◽  
Jérôme Brunet ◽  
Christelle Varenne ◽  
Alain Pauly
Keyword(s):  
Electrochemical Sensors ◽  
Screen Printed Electrodes ◽  
Screen Printed

scholarly journals Development of a Direct Competitive ELISA Kit for Detecting Deoxynivalenol Contamination in Wheat

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 50
Author(s):  
Li Han ◽  
Yue-Tao Li ◽  
Jin-Qing Jiang ◽  
Ren-Feng Li ◽  
Guo-Ying Fan ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
High Performance ◽  
Limit Of Detection ◽  
High Specificity ◽  
Hplc Method ◽  
Rapid Screening ◽  
Enzyme Linked Immunosorbent Assay ◽  
Detection Range ◽  
Technical Requirements ◽  
Relative Standard

This study was conducted to develop a self-assembled direct competitive enzyme-linked immunosorbent assay (dcELISA) kit for the detection of deoxynivalenol (DON) in food and feed grains. Based on the preparation of anti-DON monoclonal antibodies, we established a standard curve with dcELISA and optimized the detection conditions. The performance of the kit was evaluated by comparison with high-performance liquid chromatography (HPLC). The minimum detection limit of DON with the kit was 0.62 ng/mL, the linear range was from 1.0 to 113.24 ng/mL and the half-maximal inhibition concentration (IC50) was 6.61 ng/mL in the working buffer; there was a limit of detection (LOD) of 62 ng/g, and the detection range was from 100 to 11324 ng/g in authentic agricultural samples. We examined four samples of wheat bran, wheat flour, corn flour and corn for DON recovery. The average recovery was in the range of 77.1% to 107.0%, and the relative standard deviation (RSD) ranged from 4.2% to 11.9%. In addition, the kit has the advantages of high specificity, good stability, a long effective life and negligible sample matrix interference. Finally, wheat samples from farms in the six provinces of Henan, Anhui, Hebei, Shandong, Jiangsu and Gansu in China were analyzed by the kit. A total of 30 samples were randomly checked (five samples in each province), and the results were in good agreement with the standardized HPLC method. These tests showed that the dcELISA kit had good performance and met relevant technical requirements, and it had the characteristics of accuracy, reliability, convenience and high-throughput screening for DON detection. Therefore, the developed kit is suitable for rapid screening of DON in marketed products.

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