scholarly journals Direct immunosensing of avian influenza A virus in whole blood using hybrid nanocomposites

2018 ◽  
Author(s):  
John Buozis ◽  
Syed Rahin Ahmed ◽  
Rohit Chand ◽  
Éva Nagy ◽  
Suresh Neethirajan
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Hybrid Nanocomposites ◽  
Buffer Solution ◽  
Solution Ph ◽  
Detection Range ◽  
Viral Antibodies ◽  
Elisa Testing

AbstractA sandwich-based electrochemical immunosensor was designed for detection of avian influenza virus (AIV) strains H5N1 and H4N6. This sensor was developed using gold-graphene nanocomposites, immobilized viral antibodies, and CdTe quantum dot electrochemical tagging. The nanocomposites were formed by the simultaneous reduction of a gold salt and graphene using hydroquinone as the reducing agent, thus producing non-spherical gold nanoparticles on graphene sheets. Viral antibodies were immobilized on nanocomposites and CdTe quantum dots through N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide and N-hydroxysuccinimide chemistry. Cyclic voltammetry studies were used to validate the detection of H5N1 surface protein and H4N6 inactivated virus. The immunosensor detected H5 protein in phosphate buffer solution (pH 7.4) with a limit of detection (LOD) of 10 fg/mL and a linear detection range was established for 10 ng/mL to 10 pg/mL. The biosensor detected H4N6 in three parts diluted whole chicken blood with a LOD of 1.28×10−7 hemagglutinating units (HAU). Commercial ELISA testing for H5N1 and H4N6 showed limits of detection of 10 ng/mL and 0.128 HAU, respectively. The sensor showed 106-fold increased detection of H4N6 virus in blood in comparison to its commercial ELISA kit counterpart. The developed immunosensor effectively change the way avian influenza is detected, monitored, and controlled; transforming time-consuming reactive methods, into rapid predictive technology.

scholarly journals Ta2O5/rGO Nanocomposite Modified Electrodes for Detection of Tryptophan through Electrochemical Route

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 811 ◽  
Author(s):  
Shun Zhou ◽  
Zefeng Deng ◽  
Zhongkang Wu ◽  
Mei Xie ◽  
Yaling Tian ◽  
...  
Keyword(s):  
Human Serum ◽  
Limit Of Detection ◽  
Human Life ◽  
Phosphate Buffer Solution ◽  
Modified Electrodes ◽  
Essential Amino Acids ◽  
Buffer Solution ◽  
Solution Ph ◽  
Catalytic Systems ◽  
Detection Range

l-tryptophan is one of the eight kinds of essential amino acids for sustainable human life activity. It is common to detect the concentration of tryptophan in human serum for diagnosing and preventing brain related diseases. Herein, in this study, GCE (glassy carbon electrode) modified by Ta2O5-reduced graphene oxide (-rGO) composite (Ta2O5-rGO-GCE) is synthesized by the hydrothermal synthesis-calcination methods, which is used for detecting the concentration of tryptophan in human serum under the as-obtained optimal detection conditions. As a result, the obtained Ta2O5-rGO-GCE shows larger electrochemical activity area than other bare GCE and rGO-GCE due to the synergistic effect of Ta2O5 NPs and rGO. Meanwhile, Ta2O5-rGO-GCE shows an excellent response to tryptophan during the oxidation process in 0.1 M phosphate buffer solution (pH = 6). Moreover, three wide linear detection range (1.0–8.0 μM, 8.0–80 μM and 80–800 μM) and a low limit of detection (LOD) of 0.84 μM (S/N = 3) in the detection of tryptophan are also presented, showing the larger linear ranges and lower detection limit by employing Ta2O5-rGO-GCE. Finally, the as-proposed Ta2O5-rGO-GCE with satisfactory recoveries (101~106%) is successfully realized for the detection of tryptophan in human serum. The synthesis of Ta2O5-rGO-GCE in this article could provide a slight view for the synthesis of other electrochemical catalytic systems in detection of trace substance in human serum.

scholarly journals Electro-Polymerized Titan Yellow Modified Carbon Paste Electrode for the Analysis of Curcumin

Surfaces ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 191-204
Author(s):  
Edwin S. D’Souza ◽  
Jamballi G. Manjunatha ◽  
Chenthattil Raril ◽  
Girish Tigari ◽  
Huligerepura J. Arpitha ◽  
...  
Keyword(s):  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Modified Carbon Paste Electrode ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Solution Ph ◽  
Real Sample Analysis ◽  
Titan Yellow ◽  
Paste Electrode

A modest, efficient, and sensitive chemically modified electrode was fabricated for sensing curcumin (CRC) through an electrochemically polymerized titan yellow (TY) modified carbon paste electrode (PTYMCPE) in phosphate buffer solution (pH 7.0). Cyclic voltammetry (CV) linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) approaches were used for CRC detection. PTYMCPE interaction with CRC suggests that the electrode exhibits admirable electrochemical response as compared to bare carbon paste electrode (BCPE). Under the optimized circumstances, a linear response of the electrode was observed for CRC in the concentration range 2 × 10−6 M to 10 × 10−6 M with a limit of detection (LOD) of 10.94 × 10−7 M. Moreover, the effort explains that the PTYMCPE electrode has a hopeful approach for the electrochemical resolution of biologically significant compounds. Additionally, the proposed electrode has demonstrated many advantages such as easy preparation, elevated sensitivity, stability, and enhanced catalytic activity, and can be successfully applied in real sample analysis.

scholarly journals Electrochemical Polymerised Graphene Paste Electrode and Application to Catechol Sensing

2019 ◽  
Vol 13 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Jamballi G. Manjunatha
Keyword(s):  
Modified Electrode ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Sample Pretreatment ◽  
Differential Pulse ◽  
Buffer Solution ◽  
Solution Ph ◽  
Graphene Paste Electrode ◽  
Paste Electrode

Objective: To build up an advantageous strategy for sensitive determination of catechol (CC), a poly (proline) modified graphene paste electrode (PPMGPE) was fabricated and used as a voltammetric sensor for the determination of CC. Methods: The performance of the modified electrode was studied using cyclic voltammetric (CV) and differential pulse voltammetric method (DPV). The modified electrode was characterized by CV and DPV. The surface of the modified electrode was examined by FESEM. The electrochemical behavior of CC in phosphate buffer solution (pH 7.5) was inspected using bare graphene paste electrode (BGPE) and PPMGPE. Results & Conclusion: The PPMGPE shows a lower limit of detection, calculated to be 8.7×10–7mol L−1 (S/N=3). This modified electrode was applied successfully for the determination of CC in water samples without applying any sample pretreatment.

scholarly journals Dendrites Nanostructures of Co3O4 for the Selective Determination of Uric Acid

2021 ◽  
Author(s):  
Ramesh Lal ◽  
Bhajan Lal Bhattia ◽  
Ali M. Alsalme ◽  
Asma A. Al-Othman ◽  
Ayman Nafady ◽  
...  
Keyword(s):  
Composite Material ◽  
Uric Acid ◽  
Limit Of Detection ◽  
Low Cost ◽  
Phosphate Buffer Solution ◽  
Clinical Samples ◽  
Buffer Solution ◽  
Solution Ph ◽  
Dendrite Morphology ◽  
Selective Determination

Abstract The gout is mainly found due to accumulation of uric acid crystals into the joints which produces the inflammatory symptoms. Thus, it is highly demanded to detect uric acid from our body. Herein, we used wet chemical method for the preparation of composite material of cobalt oxide (Co3O4) with hydroxide functionalized multi-walled carbon nanotubes (MWCNTs). The analytical techniques such as scanning electron microscopy (SEM), powder X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Infra-red spectroscopy (FTIR) were used to characterize the composite material. The Co3O4 exhibits a dendrite morphology and very well chemically coupled with MWCNTs. The elemental analysis confirmed the presence of Co, O and C as main constituent of the composite material. The Co3O4 exhibits a cubic unit cell crystallography in the composite system. The FTIR study has revealed the characteristic bands of Co-O bands in the composite material. The cyclic voltammetry was used to study the electrochemical properties of prepared materials. The composite sample with highest percentage of MWCNTs showed an excellent electrochemical activity towards the oxidation of uric acid in phosphate buffer solution pH 7.3. The enzyme free uric acid sensor possessed a linear range of 0.1 mM to 3 mM with a quantified limit of detection of 0.005 mM. The modified electrode is stable, selective, and very sensitive towards uric acid, therefore it may be used for the monitoring of uric acid from clinical samples. The proposed composite material is low cost, and earth abundant, thus it can be of great interest for energy and biomedical fields.

scholarly journals Voltammetric Approach for Pharmaceutical Samples Analysis; Simultaneous Quantitative Determination of Resorcinol and Hydroquinone

2021 ◽  
Author(s):  
Ebrahim Nabatian ◽  
Mahdi Mousavi ◽  
Mostafa Pournamdari ◽  
Saeid Ahmadzadeh
Keyword(s):  
Simultaneous Determination ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Regression Equations ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Solution Ph ◽  
Pharmaceutical Samples

Abstract A simple and precise analytical approach developed for single and simultaneous determination of resorcinol (RC) and hydroquinone (HQ) in pharmaceutical samples using carbon paste electrode (CPE) modified with 1-Ethyl-3-methylimidazolium tetrafluoroborate as ionic liquid and ZnFe2O4 nanoparticle. A significant enhancement in the peak current and sensitivity of the proposed sensor observed by using modifiers in the composition of working electrode compared to bare CPE which is in accordance with the results obtained from electrochemical impedance spectroscopy investigations. Electrochemical investigations revealed a well-defined irreversible oxidation peak for RC over a wide concentration range from 3.0 µM to 500 µM in 0.1 M phosphate buffer solution (pH 6.0) with the linear regression equations of Ip (µA) = 0.0276 CRC (µM) + 0.5508 (R2 = 0.997). The limit of detection and quantification for RC analysis were found to be 1.46 µM and 4.88 µM, respectively. However, the obtained SW voltammograms for simultaneous determination of RC and HQ exhibited a desirable peak separation of about 360 mV potential difference and a satisfactory linear response over the range of 50-700 µM and 5-350 µM with the favorable correlation coefficient of 0.991 and 0.995, respectively. The diffusion coefficient (D) of RC and the electron transfer coefficient (α) at the surface of ZnFe2O4/NPs/IL/CPE estimated to be 2.83×10−4 cm s−1 and 0.76. The proposed sensor as a promising and low-cost method successfully applied for determination of RC in commercial pharmaceutical formulations such as the resorcinol cream of 2% O/W emulsion available on the market with the recovery of 98.47±0.04.

Detection of Hepatitis a Virus in Drinking Water by Enzyme -Immunoassay Using Ultracentrifugation for Virus Concentration

1985 ◽  
Vol 17 (10) ◽  
pp. 39-41 ◽  
Author(s):  
A. Schnattinger
Keyword(s):  
Membrane Filtration ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Phosphate Buffer Solution ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Concentration ◽  
Buffer Solution ◽  
Solution Ph ◽  
Two Stage

Ten litres of tapwater were seeded with 200 µl (8×108 HAV particles) of a commercial (Organon Teknika) suspension of hepatitis A virus. Following WALTER and RÜDIGER (1981), the contaminated tapwater was treated with a two-stage technique for concentration of viruses from solutions with low virus titers. The two-stage technique consists of aluminium hydroxideflocculation (200 mg/l Al2(SO4)3. 18 H2O, pH 5,4-5,6) as first stage, the second stage of a lysis of aluminium hydroxidegel with citric acid/sodium citrate-buffer (pH 4,7; 1 ml/l sample), separation of viruses from the lysate by ultracentrifugation and suspension in 1 ml phosphate buffer solution (pH 7,2). A commercial solid phase enzyme-linked immunosorbent assay (ELISA) was used for the detection of HAV. HAV was detecterl in the 10.000:1 concentrates, but not in the seeded 101 samples. Approximately 4×108 of the inoculated 8×108 HAV particles were found in the 1 ml concentrates. The efficiency of detection is about 50%, the virus concentration 5000-fold. Although the percentage loss of HAV in comparison with concentration by means of membrane filtration is similar, the ultracentrifugation method yields a larger sample/concentrate ratio, so that smaller amounts of HAV can be detected more efficiently because of the smaller end-volume.

Non-enzymatic determination of purine nucleotides using a carbon dot modified glassy carbon electrode

2019 ◽  
Vol 11 (30) ◽  
pp. 3866-3873 ◽  
Author(s):  
R. Karthikeyan ◽  
D. James Nelson ◽  
S. Abraham John
Keyword(s):  
Glassy Carbon ◽  
Low Cost ◽  
Phosphate Buffer Solution ◽  
Purine Nucleotides ◽  
Buffer Solution ◽  
Solution Ph ◽  
Carbon Dot ◽  
Enzymatic Determination ◽  
Sensitive Determination

Selective and sensitive determination of one of the purine nucleotides, inosine (INO) using a low cost carbon dot (CD) modified glassy carbon (GC) electrode in 0.2 M phosphate buffer solution (pH 7.2) was demonstrated in this paper.

Controlled Release of Active Substance from Biodegradable Copolymer Matrix

2006 ◽  
Vol 510-511 ◽  
pp. 798-801
Author(s):  
Hyung Suk So ◽  
Hyun Chul Shin ◽  
Beom Suk Kim ◽  
Yeong Seok Yoo
Keyword(s):  
Methylene Blue ◽  
Active Substance ◽  
Phosphate Buffer Solution ◽  
Ultra Violet ◽  
Hydroxyl Groups ◽  
Buffer Solution ◽  
Solution Ph ◽  
Effective Discharge ◽  
Constant Rate ◽  
Long Time

The purpose of this study is to develop a new system to control effective discharge of active substances such as agricultural chemicals. To synthesize a naturally dissolvable polymer; ε-caprolactone and diglycolide were copolymerized with ethylene glycol as an initiator to produce macrodiol. As macrodiol has hydroxyl groups in both ends, they are modified with methacryloyl chloride for photochemical networking. After standard macromonomer produced by this procedure was physically mixed with methylene blue, it was networked with ultra-violet rays to be filmed. This film is naturally dissolvable and hydrolytic. As a result of hydrolytic test with a crosslinked structure of 10 % methylene blue, it decreased by 9 % for seven weeks in 37 °C phosphate buffer solution (pH = 7). Thus, we verified that active substance can be discharged from a crosslinked structure for a long time at a constant rate under room temperature.

Fabrication of an Electrochemical Sensor for Glucose Detection using ZnO Nanorods

MRS Advances ◽  
2016 ◽  
Vol 1 (13) ◽  
pp. 861-867 ◽  
Author(s):  
Sanghamitra Mandal ◽  
Mohammed Marie ◽  
Omar Manasreh
Keyword(s):  
Response Time ◽  
Glass Substrate ◽  
Glucose Sensor ◽  
Limit Of Detection ◽  
Sol Gel ◽  
Zno Nanorods ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Coated Glass Substrate ◽  
Coated Glass

ABSTRACTAn electrochemical glucose sensor based on zinc oxide (ZnO) nanorods is fabricated, characterized and tested. The ZnO nanorods are synthesized on indium titanium oxide (ITO) coated glass substrate, using the hydrothermal sol-gel technique. The working principle of the sensor under investigation is based on the electrochemical reaction taking place between cathode and anode, in the presence of an electrolyte. A platinum plate, used as the cathode and Nafion/Glucose Oxidase/ZnO nanorods/ITO-coated glass substrate used as anode, is immersed in pH 7.0 phosphate buffer solution electrolyte to test for the presence of glucose. Several amperometric tests are performed on the fabricated sensor to determine the response time, sensitivity and limit of detection of the sensor. A fast response time less than 3 s with a high sensitivity of 1.151 mA cm-2mM-1 and low limit of detection of 0.089 mM is reported. The glucose sensor is characterized using the cyclic voltammetry method in the range from -0.8 – 0.8 V with a voltage scan rate of 100 mV/s.

OPTIMISATION AND VALIDATION OF HPLC METHOD FOR SIMULTANEOUS QUANTIFICATION OF RIFAMPICIN, ISONIAZID, PYRAZINAMIDE, AND ETHAMBUTOL HYDROCHLORIDE IN ANTI-TUBERCULOSIS 4-FDC TABLET

2015 ◽  
Vol 77 (1) ◽  
Author(s):  
Sholihul Khoiri ◽  
Sudibyo Martono ◽  
Abdul Rohman
Keyword(s):  
High Performance ◽  
Phosphate Buffer Solution ◽  
Gradient Elution ◽  
Hplc Method ◽  
Fixed Dose ◽  
Buffer Solution ◽  
Solution Ph ◽  
Combination Tablet ◽  
Simultaneous Quantification ◽  
Dose Combination

High-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous quantification of four components, namely rifampicin (RIF), isoniazid (INH), pyrazinamide (PYR), and ethambutol hydrochloride (ETM), contained in anti-tuberculosis drugs in fixed dose combination tablet (4-FDC). In order to increase the sensitivity of EMB, the pre-column derivatization technique with phenethyl isocyanate (PEIC) was carried out. The separation was accomplished using Waters Symmetry C8 (250× 4.6 mm i.d.; 5 μm) at 30oC. The mobile phase used was a mixture of acetonitrile and 20 mM phosphate buffer solution (pH 6.8) containing triethylamine and delivered at 1.5 mL/minute using gradient elution. TheUV detector was set at 210 nm. The method was validated in terms of selectivity, linearity, accuracy, precision, detection limit, quantification limit, and robustness according to International Conference on Harmanization (ICH). The optimized method is succcesfully used for quantitative analysis of RIF, INH, PYR and ETM in 4-FDC tablets. The level of these drugs in 4-FDC tablets were in accordance to that specified in Indonesian pharmacopeia.

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