scholarly journals ARGINASE-BASED AMPEROMETRIC BIOSENSOR FOR MANGANESE IONS ANALYSIS

2016 ◽  
Vol 1 ◽  
pp. 22-28 ◽  
Author(s):  
Nataliya Stasyuk ◽  
Mariya Synenka ◽  
Galina Gayda ◽  
Oleh Smutok ◽  
Mykhailo Gonchar
Keyword(s):  
Environmental Control ◽  
Limit Of Detection ◽  
Hansenula Polymorpha ◽  
High Sensitivity ◽  
Methylotrophic Yeast ◽  
Cost Effective ◽  
Metallic Ions ◽  
Actual Problem ◽  
Enzyme Biosensor ◽  
Manganese Compounds

The development of simple cost-effective sensitive enzymatic methods for analysis of toxic metallic ions is an actual problem. Promising tools for elaboration of such methods are Mn2+-dependent enzymes. A novel manganese(II)-sensitive amperometric bi-enzyme biosensor based on of recombinant human arginase I (arginase) isolated from the gene-engineered strain of methylotrophic yeast Hansenula polymorpha and commercial urease is described. The biosensing layer with urease and apo-enzyme of arginase was placed onto a polyaniline-Nafion composite platinum electrode. The developed sensor revealed a high sensitivity to Mn2+-ions – 9200±20 A/(M∙m2)with the apparent Michaelis-Menten constant derived from Mn2+-ions calibration curve of 11.5±1.0 µM. A linear concentration range was observed from 1 µM to 6,5 µM MnCl2, a limit of detection being of 0.15 µM and a response time – 2.5 min. The proposed biosensor may be useful to monitor manganese compounds in laboratories of medicine, food industry and environmental control service.

scholarly journals Coupling multiplex pre-amplification and droplet digital PCR for longitudinal monitoring ofESR1andPIK3CAmutations from plasma cell-free DNA

2019 ◽  
Author(s):  
Huilan Yao ◽  
Grant Wu ◽  
Subhasree Das ◽  
Crystal MacKenzie ◽  
Hua Gao ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Hot Spot ◽  
Metastatic Breast ◽  
High Sensitivity ◽  
Cost Effective ◽  
Digital Pcr ◽  
Cost Effective Method ◽  
High Prevalence ◽  
High Concordance ◽  
Hotspot Mutations

AbstractHere we report on the development of a sensitive and cost-effective method to longitudinally trackESR1andPIK3CAmutations from cfDNA in patients with metastatic breast cancer (MBC) using a streamlined and de-centralized workflow. Hotspot mutations inESR1have been shown to cause resistance to aromatase inhibitor–based and anti-estrogenic therapies, whilePIK3CAmutations have high prevalence in MBC. As a result, their utility as circulating biomarkers to predict or monitor response in the clinical development of investigational compounds has been the focus of many studies. Six regions inESR1andPIK3CAgenes containing 20 hotspot mutations were pre-amplified, followed by optimized singleplex ddPCR assays to detect allele frequencies of individual mutations. Without pre-amplification, the limit of detection (LOD) and limit of linearity (LOL) of individual ddPCR assays were at 0.05-0.1% and 0.25% level, respectively. With pre-amplification, the LOD and LOL were slightly elevated at 0.1-0.25% and 0.25-0.5% levels, respectively. High concordance was achieved to the BEAMing assay (Sysmex Inostics) for mutation positive assays (r=0.98, P<0.0001). In conclusion, coupling pre-amplification and ddPCR assays allowed us for the detection of up to 20 hot spot mutations inESR1andPIK3CAwith high sensitivity and reproducibility.

scholarly journals Diagnostic performance of rapid antigen tests (RATs) for SARS-CoV-2 and their efficacy in monitoring the infectiousness of COVID-19 patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
John G. Routsias ◽  
Maria Mavrouli ◽  
Panagiota Tsoplou ◽  
Kyriaki Dioikitopoulou ◽  
Athanasios Tsakris
Keyword(s):  
Diagnostic Performance ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Cost Effective ◽  
Clinical Samples ◽  
True Positive ◽  
Antigen Tests ◽  
The Cost ◽  
Very High ◽  
Test Result

AbstractThe most widely used test for the diagnosis of SARS-CoV-2 infection is a PCR test. PCR has very high sensitivity and is able to detect very low amounts of RNA. However, many individuals receiving a positive test result in a context of a PCR-based surveillance might be infected with SARS-CoV-2, but they are not contagious at the time of the test. The question arises regards if the cost effective, portable rapid antigen tests (RATs) have a better performance than PCR in identification of infectious individuals. In this direction, we examined the diagnostic performance of RATs from 14 different manufacturers in 400 clinical samples with known rRT-PCR cycles threshold (cT) and 50 control samples. Substantial variability was observed in the limit of detection (LOD) of different RATs (cT = 26.8–34.7). The fluorescence-based RAT exhibited a LOD of cT = 34.7. The use of the most effective RATs leads to true positive rates (sensitivities) of 99.1% and 90.9% for samples with cT ≤ 30 and cT ≤ 33, respectively, percentages that can guarantee a sensitivity high enough to identify contagious patients. RAT testing may also substantially reduce the quarantine period for infected individuals without compromising personal or public safety.

scholarly journals PfHRP2 detection using plasmonic optrodes: performance analysis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Médéric Loyez ◽  
Mathilde Wells ◽  
Stéphanie Hambÿe ◽  
François Hubinon ◽  
Bertrand Blankert ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Limit Of Detection ◽  
Fiber Surface ◽  
Malaria Diagnosis ◽  
High Sensitivity ◽  
Cost Effective ◽  
Label Free ◽  
Multiple Receptors ◽  
Label Free Detection

Abstract Background Early malaria diagnosis and its profiling require the development of new sensing platforms enabling rapid and early analysis of parasites in blood or saliva, aside the widespread rapid diagnostic tests (RDTs). Methods This study shows the performance of a cost-effective optical fiber-based solution to target the presence of Plasmodium falciparum histidine-rich protein 2 (PfHRP2). Unclad multimode optical fiber probes are coated with a thin gold film to excite Surface Plasmon Resonance (SPR) yielding high sensitivity to bio-interactions between targets and bioreceptors grafted on the metal surface. Results Their performances are presented in laboratory conditions using PBS spiked with growing concentrations of purified target proteins and within in vitro cultures. Two probe configurations are studied through label-free detection and amplification using secondary antibodies to show the possibility to lower the intrisic limit of detection. Conclusions As malaria hits millions of people worldwide, the improvement and multiplexing of this optical fiber technique can be of great interest, especially for a future purpose of using multiple receptors on the fiber surface or several coated-nanoparticles as amplifiers.

scholarly journals DEVELOPMENT OF ARGININE DEIMINASE BASED CONDUCTOMETRIC BIOSENSOR FOR ARGININE DETERMINATION

2021 ◽  
Vol 18 (2) ◽  
pp. 4-13
Author(s):  
O. O. Soldatkin ◽  
I. S. Kucherenko ◽  
O. Ya. Sayapina ◽  
D. Yu. Kucherenko ◽  
S. V. Marchenko ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Buffer Capacity ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Arginine Deiminase ◽  
Real Samples ◽  
Covalent Crosslinking ◽  
Enzyme Biosensor ◽  
First Time ◽  
Conductometric Biosensor

For the first time, a conductometric enzyme biosensor was developed to determine arginine concentrations. The bioselective membrane of the biosensor was formed by immobilization of arginine deiminase on the surface of gold planar transducer using covalent crosslinking of glutaraldehyde with bovine serum albumin. An effect of the solution characteristics (ionic strength, buffer capacity) on the biosensor functioning was studied. The proposed monoenzyme biosensor was shown to have high sensitivity to arginine (minimum limit of detection - 5 μM) and good selectivity towards possible interferents. The linear range of determination was from 10 to 800 μM. The biosensor sensitivity to arginine is 72 μS /μM. The developed biosensor was demonstrated to be promising for the arginine analysis in real samples.

scholarly journals Electrochemical nano-roughening of gold microstructured electrodes for the enhanced detection of copper and glucose

2021 ◽  
Author(s):  
Eduardo Gonzalez Martinez ◽  
Sokunthearath (Kevin) Saem ◽  
Nadine Beganovic ◽  
Jose Moran-Mirabal
Keyword(s):  
Surface Area ◽  
Limit Of Detection ◽  
Film Surface ◽  
High Sensitivity ◽  
Cost Effective ◽  
Progressive Increase ◽  
Gold Electrodes ◽  
Limit Of Quantification ◽  
Thin Film Surface ◽  
Electroactive Surface Area

One of the main challenges for electrochemical sensor miniaturization is the fabrication of electrodes with a smaller footprint, while maintaining, or even increasing, their sensitivity for the targeted application. Our research group has previously demonstrated the enhancement of the electroactive surface area of gold electrodes up to 6-fold, relative to planar gold electrodes with the same footprint, through the generation of a wrinkled thin film surface via thermal shrinking. In this work, the electroactive surface area of wrinkled gold electrodes was further enhanced up to 5-fold (30-fold over flat electrodes) using a chronoamperometric pulsing technique. Scanning electron microscopy images showed progressive increase of surface roughness in response to an increasing number of applied pulses. The resulting nanoroughened electrodes present several advantages in addition to the enhanced electroactive surface area. These electrodes offer superior fouling resistance compared to that of wrinkled and flat electrodes when submerged in a solution containing bovine serum albumin at high concentrations. Cyclic voltammetry data also revealed greater sensitivity of nanoroughened electrodes toward anodic copper stripping, where the limit of quantification of copper by the nano-roughened electrodes was 0.3 ppm. Nano-roughened electrodes also allowed the highly sensitive enzyme-free detection of glucose through chronoamperometry, with a limit of detection of 0.5 mM, whereas planar electrodes did not demonstrate any ability to oxidize glucose. We foresee that this methodology to fabricate nanostructured electrodes will accelerate the development of simple, cost-effective and high sensitivity electrochemical platforms.

Recent Developments in Electrochemical Determination of Sulfonamides

2020 ◽  
Vol 17 ◽  
Author(s):  
Li Fu ◽  
Xinyi Zhang ◽  
Su Ding ◽  
Fei Chen ◽  
Yanfei Lv ◽  
...  
Keyword(s):  
Human Health ◽  
Limit Of Detection ◽  
Low Cost ◽  
High Sensitivity ◽  
Cost Effective ◽  
Electrochemical Determination ◽  
Veterinary Antibiotics ◽  
Drug Residues ◽  
Detection Range

Background: Sulfonamides are the anti-bacterial and anti-inflammatory drugs synthesized, which are widely used as medical and veterinary antibiotics. However, the excess dosage of sulfonamides can harm human health. The drug residues in the animal products also can harm human health through the food chain. The long-term consumption of animal food containing drug residues will cause some toxic and side effects on human body functions, which will seriously threaten human health. Methods: Electroanalytical methods are attracting much attention because of their advantage over conventional methods, as they are quick, low-cost, high sensitivity, and portable. This review examines the progress made in the selective electrochemical determination of sulfonamides in the last 20 years. Results: In this review, we describe the development of electrochemical methods for sulfonamides determination. Then, we pay special attention to the detection of sulfonamides using molecular imprinting technology. The linear detection range with the limit of detection has been listed for comparison. Conclusion: Electrochemical determination of sulfonamides is a fast, simple, sensitive, and cost-effective approach. The surface modification of commercial electrodes can significantly improve the sensing performance.

scholarly journals Cost-Effective Electrochemical Activation of Graphitic Carbon Nitride on the Glassy Carbon Electrode Surface for Selective Determination of Serotonin

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6083
Author(s):  
Vijayaraj Kathiresan ◽  
Thenmozhi Rajarathinam ◽  
Seulah Lee ◽  
Suhkmann Kim ◽  
Jaewon Lee ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Cost Effective ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Electrochemical Activation ◽  
Selective Determination ◽  
Electrocatalytic Effect

A simple one-step electrochemical deposition/activation of graphitic carbon nitride (g-C3N4) is highly desired for sensor configurations and remains a great challenge. Herein, we attempt an electrochemical route to exfoliate the g-C3N4 nanosheets in an aqueous solution of pH 7.0 for constructing a sensor, which is highly sensitive for the detection of serotonin (5-HT). The significance of our design is to exfoliate the g-C3N4 nanosheets, a strong electrocatalyst for 5-HT detection. Investigations regarding the effect of neutral pH (pH 7.0) on the bulk g-C3N4 and g-C3N4 nanosheets, physical characterization, and electrochemical studies were extensively carried out. We demonstrate that the g-C3N4 nanosheets have a significant electrocatalytic effect for the 5-HT detection in a dynamic linear range from 500 pM to 1000 nM (R2 = 0.999). The limit of detection and sensitivity of the designed 5-HT sensor was calculated to be 150 pM and 1.03 µA µM−1 cm−2, respectively. The proposed sensor has great advantages such as high sensitivity, good selectivity, reproducibility, and stability. The constructed g-C3N4 nanosheets-based sensor platform opens new feasibilities for the determination of 5-HT even at the picomolar/nanomolar concentration range.

Green Synthesis and Spectroscopic Studies of Ag-rGO Nanocomposites for Highly Selective Mercury (II) Sensing

2018 ◽  
Vol 9 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Shubhangi J. Mane-Gavade ◽  
Sandip R. Sabale ◽  
Xiao-Ying Yu ◽  
Gurunath H. Nikam ◽  
Bhaskar V. Tamhankar
Keyword(s):  
Green Synthesis ◽  
Color Change ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Suitable Condition ◽  
Cost Effective ◽  
Spectroscopic Studies ◽  
Calibration Plot ◽  
First Time

Introduction: Herein we report the green synthesis and characterization of silverreduced graphene oxide nanocomposites (Ag-rGO) using Acacia nilotica gum for the first time. Experimental: We demonstrate the Hg2+ ions sensing ability of the Ag-rGO nanocomposites form aqueous medium. The developed colorimetric sensor method is simple, fast and selective for the detection of Hg2+ ions in aqueous media in presence of other associated ions. A significant color change was noticed with naked eye upon Hg2+ addition. The color change was not observed for cations including Sr2+, Ni2+, Cd2+, Pb2+, Mg2+, Ca2+, Fe2+, Ba2+ and Mn2+indicating that only Hg2+ shows a strong interaction with Ag-rGO nanocomposites. Under the most suitable condition, the calibration plot (A0-A) against concentration of Hg2+ was linear in the range of 0.1-1.0 ppm with a correlation coefficient (R2) value 0.9998. Results & Conclusion The concentration of Hg2+ was quantitatively determined with the Limit of Detection (LOD) of 0.85 ppm. Also, this method shows excellent selectivity towards Hg2+ over nine other cations tested. Moreover, the method offers a new cost effective, rapid and simple approach for the detection of Hg2+ in water samples.

scholarly journals Pitfalls in the Immunochemical Determination of β‑Lactam Antibiotics in Water

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 298
Author(s):  
Alexander Ecke ◽  
Rudolf J. Schneider
Keyword(s):  
Limit Of Detection ◽  
Cost Effective ◽  
Enzyme Linked Immunosorbent Assay ◽  
Degree Of Hydrolysis ◽  
Site Analysis ◽  
Antibody Recognition ◽  
Immunochemical Determination ◽  
Key Factor ◽  
Lactam Ring

Contamination of waters with pharmaceuticals is an alarming problem as it may support the evolution of antimicrobial resistance. Therefore, fast and cost-effective analytical methods for potential on-site analysis are desired in order to control the water quality and assure the safety of its use as a source of drinking water. Antibody-based methods, such as the enzyme-linked immunosorbent assay (ELISA), can be helpful in this regard but can also have certain pitfalls in store, depending on the analyte. As shown here for the class of β-lactam antibiotics, hydrolysis of the β‑lactam ring is a key factor in the immunochemical analysis as it influences antibody recognition. With the antibody used in this study, the limit of detection (LOD) in the immunoassay could be significantly reduced by hydrolysis for the five tested penicillins, with the lowest LOD for carbenicillin (0.2 nmol/L) and the greatest impact on penicillins G and V (reduction by 85%). In addition to enhanced quantification, our strategy also provides access to information about the degree of hydrolysis in water samples as shown for the most abundant penicillin amoxicillin.

scholarly journals Multiplexed detection of SARS-CoV-2 and other respiratory infections in high throughput by SARSeq

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ramesh Yelagandula ◽  
◽  
Aleksandr Bykov ◽  
Alexander Vogt ◽  
Robert Heinen ◽  
...  
Keyword(s):  
Influenza A ◽  
Respiratory Infections ◽  
High Sensitivity ◽  
Cost Effective ◽  
Massively Parallel ◽  
Rt Pcr ◽  
Viral Spread ◽  
Saliva Analysis ◽  
Double Blinded ◽  
Generation Sequencing

AbstractThe COVID-19 pandemic has demonstrated the need for massively-parallel, cost-effective tests monitoring viral spread. Here we present SARSeq, saliva analysis by RNA sequencing, a method to detect SARS-CoV-2 and other respiratory viruses on tens of thousands of samples in parallel. SARSeq relies on next generation sequencing of multiple amplicons generated in a multiplexed RT-PCR reaction. Two-dimensional, unique dual indexing, using four indices per sample, enables unambiguous and scalable assignment of reads to individual samples. We calibrate SARSeq on SARS-CoV-2 synthetic RNA, virions, and hundreds of human samples of various types. Robustness and sensitivity were virtually identical to quantitative RT-PCR. Double-blinded benchmarking to gold standard quantitative-RT-PCR performed by human diagnostics laboratories confirms this high sensitivity. SARSeq can be used to detect Influenza A and B viruses and human rhinovirus in parallel, and can be expanded for detection of other pathogens. Thus, SARSeq is ideally suited for differential diagnostic of infections during a pandemic.

Sign in / Sign up

Export Citation Format

Share Document