scholarly journals Amperometric Formaldehyde Sensor Based on a Pd Nanocrystal Modified C/Co2P Electrode

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Huan Wang ◽  
Yaodan Chi ◽  
Xiaohong Gao ◽  
Sa Lv ◽  
Xuefeng Chu ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Linear Response ◽  
Chemical Reduction ◽  
Reduction Process ◽  
High Sensitivity ◽  
Cost Effective ◽  
Effective Electron ◽  
Cobalt Phosphide ◽  
Permeable Electrode ◽  
Sensing Performance

Ultrafine Pd nanocrystals were grown on the cobalt phosphide (Co2P) decorated Vulcan XC-72 carbon (C/Co2P), which is realized by first implementing the corresponding metal precursor and then the further chemical reduction process. The as-synthesized C/Co2P/Pd composite was further constructed to form a gas permeable electrode. This electrode can be applied for formaldehyde (HCHO) detection. The results demonstrate that the Co2P nanocrystal can significantly improve the sensing performance of the C/Co2P/Pd electrode for catalytic oxidation of HCHO, which is considered to be attributed to the effective electron transfer from Co2P to Pd in the C/Co2P/Pd composites. Furthermore, the assembled C/Co2P/Pd sensor exhibits high sensitivity of 617 nA/ppm and good selectivity toward various interfering gases such as NO2, NO, SO2, CO2, and CO. It also shows the excellent linear response that the correlation coefficient is 0.994 in the concentration range of 1–10 ppm. Therefore, the proposed cost-effective C/Co2P/Pd nanocomposite, which owns advantages such as high activity and good stability, has the potential to be applied as an effective electrocatalyst for amperometric HCHO detection.

scholarly journals Protocol optimization for a fast, simple and economical chemical reduction synthesis of antimicrobial silver nanoparticles in non-specialized facilities

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Roberto Vazquez-Muñoz ◽  
M. Josefina Arellano-Jimenez ◽  
Fernando D. Lopez ◽  
Jose L. Lopez-Ribot
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Chemical Reduction ◽  
Nitrate Solution ◽  
Synthesis Method ◽  
Reduction Process ◽  
Cost Effective ◽  
Silver Nitrate Solution ◽  
Synthesis Time ◽  
Average Size

Abstract Objective Silver nanoparticles (AgNPs) can be difficult or expensive to obtain or synthesize for laboratories in resource-limited facilities. The purpose of this work was to optimize a synthesis method for a fast, facile, and cost-effective synthesis of AgNPs with antimicrobial activity, which can be readily implemented in non-specialized facilities and laboratories. Results The optimized method uses a rather simple and rapid chemical reduction process that involves the addition of a polyvinylpyrrolidone solution to a warmed silver nitrate solution under constant vigorous stirring, immediately followed by the addition of sodium borohydride. The total synthesis time is less than 15 min. The obtained AgNPs exhibit an aspect ratio close to 1, with an average size of 6.18 ± 5 nm. AgNPs displayed potent antimicrobial activity, with Minimal Inhibitory Concentration values of ≤ 4 µg mL−1 for Staphylococcus aureus and ≤ 2 µg mL−1 for Candida albicans. The resulting method is robust and highly reproducible, as demonstrated by the characterization of AgNPs from different rounds of syntheses and their antimicrobial activity.

scholarly journals A fast and simple protocol for synthesizing effective antimicrobial silver nanoparticles in non-specialized facilities

2019 ◽  
Author(s):  
Roberto Vazquez-Munoz ◽  
M. Josefina Arellano-Jimenez ◽  
Jose L. Lopez-Ribot
Keyword(s):  
Silver Nanoparticles ◽  
Metallic Nanoparticles ◽  
Chemical Reduction ◽  
Nitrate Solution ◽  
Synthesis Method ◽  
Antimicrobial Properties ◽  
Reduction Process ◽  
Cost Effective ◽  
Silver Nitrate Solution ◽  
Average Size

Abstract Objective Silver nanoparticles (AgNPs) can be difficult or expensive to obtain or synthesize for laboratories in resource-limited facilities. The purpose of this work was to create a fast, facile, and cost-effective method for synthesizing AgNPs with potent antimicrobial properties, that can be readily implemented in non-specialized laboratories.Results Our developed method uses a rather simple and rapid chemical reduction process that involves the addition of a polyvinylpyrrolidone solution to a warmed silver nitrate solution under constant vigorous stirring, immediately followed by the addition of sodium borohydride with constant stirring for an additional 15 minutes. AgNPs had an aspect ratio close to 1, with an average size of 6.18 ± 5 nm. AgNPs displayed potent antimicrobial activity, with Minimal Inhibitory Concentration values of 3 µg mL-1 and 1.5 µg mL-1 for Staphylococcus aureus and Candida albicans respectively.Keywords : Silver nanoparticles, nanoantibiotics, synthesis method, AgNPs, metallic nanoparticles

Computationally Assisted Design of High Signal-to-Noise Photoinduced Electron Transfer-Based Voltage-Sensitive Dyes

2020 ◽  
Author(s):  
Rishikesh Kulkarni ◽  
Anneliese Gest ◽  
Chun Kei Lam ◽  
Benjamin Raliski ◽  
Feroz James ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dft Calculations ◽  
Photoinduced Electron Transfer ◽  
Density Functional ◽  
Embryonic Stem ◽  
High Sensitivity ◽  
Md Simulations ◽  
High Signal ◽  
Signal To Noise ◽  
Green Fluorescent

<p>High signal-to-noise optical voltage indicators will enable simultaneous interrogation of membrane potential in large ensembles of neurons. However, design principles for voltage sensors with high sensitivity and brightness remain elusive, limiting the applicability of voltage imaging. In this paper, we use molecular dynamics (MD) simulations and density functional theory (DFT) calculations to guide the design of a bright and sensitive green-fluorescent voltage-sensitive fluorophore, or VoltageFluor (VF dye), that uses photoinduced electron transfer (PeT) as a voltage-sensing mechanism. MD simulations predict an 11% increase in sensitivity due to membrane orientation, while DFT calculations predict an increase in fluorescence quantum yield, but a decrease in sensitivity due to a decrease in rate of PeT. We confirm these predictions by synthesizing a new VF dye and demonstrating that it displays the expected improvements by doubling the brightness and retaining similar sensitivity to prior VF dyes. Combining theoretical predictions and experimental validation has resulted in the synthesis of the highest signal-to-noise green VF dye to date. We use this new voltage indicator to monitor the electrophysiological maturation of human embryonic stem cell-derived medium spiny neurons. </p>

Pollution, Toxicity and Carcinogenicity of Organic Dyes and their Catalytic Bio-Remediation

2019 ◽  
Vol 25 (34) ◽  
pp. 3645-3663 ◽  
Author(s):  
Muhammad Ismail ◽  
Kalsoom Akhtar ◽  
M.I. Khan ◽  
Tahseen Kamal ◽  
Murad A. Khan ◽  
...  
Keyword(s):  
Water Pollution ◽  
Textile Industry ◽  
Pathogenic Bacteria ◽  
Diarrheal Disease ◽  
Organic Dyes ◽  
Chemical Reduction ◽  
Cost Effective ◽  
Agricultural Runoff ◽  
E Coli ◽  
Sanitation Services

: Water pollution due to waste effluents of the textile industry is seriously causing various health problems in humans. Water pollution with pathogenic bacteria, especially Escherichia coli (E. coli) and other microbes is due to the mixing of fecal material with drinking water, industrial and domestic sewage, pasture and agricultural runoff. Among the chemical pollutants, organic dyes due to toxic nature, are one of the major contaminants of industrial wastewater. Adequate sanitation services and drinking quality water would eliminate 200 million cases of diarrhea, which results in 2.1 million less deaths caused by diarrheal disease due to E. coli each year. Nanotechnology is an excellent platform as compared to conventional treatment methods of water treatment and remediation from microorganisms and organic dyes. In the current study, toxicity and carcinogenicity of the organic dyes have been studied as well as the remediation/inactivation of dyes and microorganism has been discussed. Remediation by biological, physical and chemical methods has been reviewed critically. A physical process like adsorption is cost-effective, but can’t degrade dyes. Biological methods were considered to be ecofriendly and cost-effective. Microbiological degradation of dyes is cost-effective, eco-friendly and alternative to the chemical reduction. Besides, certain enzymes especially horseradish peroxidase are used as versatile catalysts in a number of industrial processes. Moreover, this document has been prepared by gathering recent research works related to the dyes and microbial pollution elimination from water sources by using heterogeneous photocatalysts, metal nanoparticles catalysts, metal oxides and enzymes.

scholarly journals Low Surface Roughness Graphene Oxide Film Reduced with Aluminum Film Deposited by Magnetron Sputtering

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1428
Author(s):  
Xiaowei Fan ◽  
Xuguo Huai ◽  
Jie Wang ◽  
Li-Chao Jing ◽  
Tao Wang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Electron Transfer ◽  
Graphene Oxide ◽  
Magnetron Sputtering ◽  
Chemical Reduction ◽  
Graphene Film ◽  
Conductivity Measurement ◽  
Electrical Conductivity Measurement ◽  
Vis Spectroscopy ◽  
Hcl Solution

Graphene film has wide applications in optoelectronic and photovoltaic devices. A novel and facile method was reported for the reduction of graphene oxide (GO) film by electron transfer and nascent hydrogen produced between aluminum (Al) film deposited by magnetron sputtering and hydrochloric acid (HCl) solution for only 5 min, significantly shorter than by other chemical reduction methods. The thickness of Al film was controlled utilizing a metal detection sensor. The effect of the thickness of Al film and the concentration of HCl solution during the reduction was explored. The optimal thickness of Al film was obtained by UV-Vis spectroscopy and electrical conductivity measurement of reduced GO film. Atomic force microscope images could show the continuous film clearly, which resulted from the overlap of GO flakes, the film had a relatively flat surface morphology, and the surface roughness reduced from 7.68 to 3.13 nm after the Al reduction. The film sheet resistance can be obviously reduced, and it reached 9.38 kΩ/sq with a high transmittance of 80% (at 550 nm). The mechanism of the GO film reduction by electron transfer and nascent hydrogen during the procedure was also proposed and analyzed.

scholarly journals Facile Synthesis of Carboxymethyl Cellulose Coated Core/Shell SiO2@Cu Nanoparticles and Their Antifungal Activity against Phytophthora capsici

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 888
Author(s):  
Nguyen Thi Thanh Hai ◽  
Nguyen Duc Cuong ◽  
Nguyen Tran Quyen ◽  
Nguyen Quoc Hien ◽  
Tran Thi Dieu Hien ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Carboxymethyl Cellulose ◽  
Chemical Reduction ◽  
Low Cost ◽  
Phytophthora Capsici ◽  
Reduction Process ◽  
Spherical Shape ◽  
Core Shell ◽  
Cu Nanoparticles ◽  
Average Size

Cu nanoparticles are a potential material for creating novel alternative antimicrobial products due to their unique antibacterial/antifungal properties, stability, dispersion, low cost and abundance as well as being economical and ecofriendly. In this work, carboxymethyl cellulose coated core/shell SiO2@Cu nanoparticles (NPs) were synthesized by a simple and effective chemical reduction process. The initial SiO2 NPs, which were prepared from rice husk ash, were coated by a copper ultrathin film using hydrazine and carboxymethyl cellulose (CMC) as reducing agent and stable agent, respectively. The core/shell SiO2@Cu nanoparticles with an average size of ~19 nm were surrounded by CMC. The results indicated that the SiO2@Cu@CMC suspension was a homogenous morphology with a spherical shape, regular dispersion and good stability. Furthermore, the multicomponent SiO2@Cu@CMC NPs showed good antifungal activity against Phytophthora capsici (P. capsici). The novel Cu NPs-based multicomponent suspension is a key compound in the development of new fungicides for the control of the Phytophthora disease.

scholarly journals Electrochemical Response of Glucose Oxidase Adsorbed on Laser-Induced Graphene

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1893
Author(s):  
Sónia O. Pereira ◽  
Nuno F. Santos ◽  
Alexandre F. Carvalho ◽  
António J. S. Fernandes ◽  
Florinda M. Costa
Keyword(s):  
Electron Transfer ◽  
Glucose Oxidase ◽  
Ph Dependence ◽  
High Surface ◽  
High Surface Area ◽  
Cost Effective ◽  
Great Promise ◽  
Glucose Detection ◽  
Half Wave ◽  
Electrochemical Transducers

Carbon-based electrodes have demonstrated great promise as electrochemical transducers in the development of biosensors. More recently, laser-induced graphene (LIG), a graphene derivative, appears as a great candidate due to its superior electron transfer characteristics, high surface area and simplicity in its synthesis. The continuous interest in the development of cost-effective, more stable and reliable biosensors for glucose detection make them the most studied and explored within the academic and industry community. In this work, the electrochemistry of glucose oxidase (GOx) adsorbed on LIG electrodes is studied in detail. In addition to the well-known electroactivity of free flavin adenine dinucleotide (FAD), the cofactor of GOx, at the expected half-wave potential of −0.490 V vs. Ag/AgCl (1 M KCl), a new well-defined redox pair at 0.155 V is observed and shown to be related to LIG/GOx interaction. A systematic study was undertaken in order to understand the origin of this activity, including scan rate and pH dependence, along with glucose detection tests. Two protons and two electrons are involved in this reaction, which is shown to be sensitive to the concentration of glucose, restraining its origin to the electron transfer from FAD in the active site of GOx to the electrode via direct or mediated by quinone derivatives acting as mediators.

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.

scholarly journals A two-stage amplified PZT sensor for monitoring lung and heart sounds in discharged pneumonia patients

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hongbin Chen ◽  
Shuai Yu ◽  
Haiyang Liu ◽  
Jie Liu ◽  
Yongguang Xiao ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Cost Effective ◽  
High Ratio ◽  
Heart Sounds ◽  
Two Stage ◽  
Diagnosis And Prognosis ◽  
Sensor Device ◽  
Cost Effective Alternative ◽  
A Charge ◽  
Highly Sensitive Detection

AbstractAssessment of lung and heart states is of critical importance for patients with pneumonia. In this study, we present a small-sized and ultrasensitive accelerometer for continuous monitoring of lung and heart sounds to evaluate the lung and heart states of patients. Based on two-stage amplification, which consists of an asymmetric gapped cantilever and a charge amplifier, our accelerometer exhibited an extremely high ratio of sensitivity to noise compared with conventional structures. Our sensor achieves a high sensitivity of 9.2 V/g at frequencies less than 1000 Hz, making it suitable to use to monitor weak physiological signals, including heart and lung sounds. For the first time, lung injury, heart injury, and both lung and heart injuries in discharged pneumonia patients were revealed by our sensor device. Our sound sensor also successfully tracked the recovery course of the discharged pneumonia patients. Over time, the lung and heart states of the patients gradually improved after discharge. Our observations were in good agreement with clinical reports. Compared with conventional medical instruments, our sensor device provides rapid and highly sensitive detection of lung and heart sounds, which greatly helps in the evaluation of lung and heart states of pneumonia patients. This sensor provides a cost-effective alternative approach to the diagnosis and prognosis of pneumonia and has the potential for clinical and home-use health monitoring.

Pollen-Shaped Hierarchical Structure for Pressure Sensors with High Sensitivity in an Ultrabroad Linear Response Range

2020 ◽  
Vol 12 (49) ◽  
pp. 55362-55371
Author(s):  
Tingting Zhao ◽  
Li Yuan ◽  
Tongkuai Li ◽  
Longlong Chen ◽  
Xifeng Li ◽  
...  
Keyword(s):  
Hierarchical Structure ◽  
Linear Response ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Response Range ◽  
Linear Response Range
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