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An electrochemical DNA biosensor fabricated from graphene decorated with graphitic nanospheres

Raja Jamaluddin RZA, Tan LL, Chong KF, Heng LY

Nanotechnology, 2020 Nov 27;31(48):485501.
PMID: 32748805 DOI: 10.1088/1361-6528/abab2e

Graphene decorated with graphitic nanospheres functionalized with pyrene butyric acid (PBA) is used for the first time to fabricate a DNA biosensor. The electrode was formed by attaching a DNA probe onto PBA, which had been stacked onto a graphene material decorated with graphene nanospheres (GNSs). The nanomaterial was drop-coated onto a carbon screen-printed electrode (SPE) to create the GNS-PBA modified electrode (GNS-PBA/SPE). A simple method was used to produce GNS by annealing graphene oxide (GO) solution at high temperature. Field emission scanning electron micrographs confirmed the presence of a spherical shape of GNS with a diameter range of 40-80 nm. A stable and uniform PBA-modified GNS (GNS-PBA) was obtained with a facile ultrasonication step. Thus allowing aminated DNA probes of genetically modified (GM) soybean to be attached to the nanomaterials to form the DNA biosensor. The GNS-PBA/SPE exhibited excellent electrical conductivity via cyclic voltammetry (CV) and differential pulse voltammetry (DPV) tests using potassium ferricyanide (K3[Fe(CN)6]) as the electroactive probe. By employing an anthraquinone monosulfonic acid (AQMS) redox intercalator as the DNA hybridization indicator, the biosensor response was evaluated using the DPV electrochemical method. A good linear relationship between AQMS oxidation peak current and target DNA concentrations from 1.0 × 10-16 to 1.0 × 10-8 M with a limit of detection (LOD) of less than 1.0 × 10-16 M was obtained. Selectivity experiments revealed that the voltammetric GM DNA biosensor could discriminate complementary sequences of GM soybean from non-complementary sequences and hence good recoveries were obtained for real GM soybean sample analysis. The main advantage of using GNS is an improvement of the DNA biosensor analytical performance.

Matched MeSH terms: Electrodes
An electrochemical sensor based on gold nanoparticles-functionalized reduced graphene oxide screen printed electrode for the detection of pyocyanin biomarker in Pseudomonas aeruginosa infection

Rashid JIA, Kannan V, Ahmad MH, Mon AA, Taufik S, Miskon A, et al.

Mater Sci Eng C Mater Biol Appl, 2021 Jan;120:111625.
PMID: 33545813 DOI: 10.1016/j.msec.2020.111625

Multidrug resistant Pseudomonas aeruginosa (P. aeruginosa) is known to be a problematic bacterium for being a major cause of opportunistic and nosocomial infections. In this study, reduced graphene oxide decorated with gold nanoparticles (AuNPs/rGO) was utilized as a new sensing material for a fast and direct electrochemical detection of pyocyanin as a biomarker of P. aeruginosa infections. Under optimal condition, the developed electrochemical pyocyanin sensor exhibited a good linear range for the determination of pyocyanin in phosphate-buffered saline (PBS), human saliva and urine at a clinically relevant concentration range of 1-100 μM, achieving a detection limit of 0.27 μM, 1.34 μM, and 2.3 μM, respectively. Our developed sensor demonstrated good selectivity towards pyocyanin in the presence of interfering molecule such as ascorbic acid, uric acid, NADH, glucose, and acetylsalicylic acid, which are commonly found in human fluids. Furthermore, the developed sensor was able to discriminate the signal with and without the presence of pyocyanin directly in P. aeruginosa culture. This proposed technique demonstrates its potential application in monitoring the presence of P. aeruginosa infection in patients.

Matched MeSH terms: Electrodes
Fulltext An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

Naderipour A, Asuhaimi Mohd Zin A, Bin Habibuddin MH, Miveh MR, Guerrero JM

PLoS One, 2017;12(2):e0164856.
PMID: 28192436 DOI: 10.1371/journal.pone.0164856

In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method.

Matched MeSH terms: Electrodes
An in silico assessment on the potential of using saline infusion to overcome non-confluent coagulation zone during two-probe, no-touch bipolar radiofrequency ablation of liver cancer

Yip WP, Kho ASK, Ooi EH, Ooi ET

Med Eng Phys, 2023 Feb;112:103950.
PMID: 36842773 DOI: 10.1016/j.medengphy.2023.103950

No-touch bipolar radiofrequency ablation (bRFA) is known to produce incomplete tumour ablation with a 'butterfly-shaped' coagulation zone when the interelectrode distance exceeds a certain threshold. Although non-confluent coagulation zone can be avoided by not implementing the no-touch mode, doing so exposes the patient to the risk of tumour track seeding. The present study investigates if prior infusion of saline into the tissue can overcome the issues of non-confluent or butterfly-shaped coagulation. A computational modelling approach based on the finite element method was carried out. A two-compartment model comprising the tumour that is surrounded by healthy liver tissue was developed. Three cases were considered; i) saline infusion into the tumour centre; ii) one-sided saline infusion outside the tumour; and iii) two-sided saline infusion outside the tumour. For each case, three different saline volumes were considered, i.e. 6, 14 and 22 ml. Saline concentration was set to 15% w/v. Numerical results showed that saline infusion into the tumour centre can overcome the butterfly-shaped coagulation only if the infusion volume is sufficient. On the other hand, one-sided infusion outside the tumour did not overcome this. Two-sided infusion outside the tumour produced confluent coagulation zone with the largest volume. Results obtained from the present study suggest that saline infusion, when carried out correctly, can be used to effectively eradicate liver cancer. This presents a practical solution to address non-confluent coagulation zone typical of that during two-probe bRFA treatment.

Matched MeSH terms: Electrodes
Fulltext Analysis and Testing of a Suitable Compatible Electrode's Material for Continuous Measurement of Glucose Concentration

Slaninova N, Fiedorova K, Selamat A, Danisova K, Kubicek J, Tkacz E, et al.

Sensors (Basel), 2020 Jun 30;20(13).
PMID: 32629993 DOI: 10.3390/s20133666

The subject of the submitted work is the proposal of electrodes for the continual measurement of the glucose concentration for the purpose of specifying further hemodynamic parameters. The proposal includes the design of the electronic measuring system, the construction of the electrodes themselves and the functionality of the entire system, verified experimentally using various electrode materials. The proposed circuit works on the basis of micro-ammeter measuring the size of the flowing electric current and the electrochemical measurement method is used for specifying the glucose concentration. The electrode system is comprised of two electrodes embedded in a silicon tube. The solution consists of the measurement with three types of materials, which are verified by using three solutions with a precisely given concentration of glucose in the form of a mixed solution and enzyme glucose oxidase. For the testing of the proposed circuit and the selection of a suitable material, the testing did not take place on measurements in whole blood. For the construction of the electrodes, the three most frequently used materials for the construction of electrodes used in clinical practice for sensing biopotentials, specifically the materials Ag/AgCl, Cu and Au, were used. The performed experiments showed that the material Ag/AgCl, which had the greatest sensitivity for the measurement even without the enzyme, was the most suitable material for the electrode. This conclusion is supported by the performed statistical analysis. On the basis of the testing, we can come to the conclusion that even if the Ag/AgCl electrode appears to be the most suitable, showing high stability, gold-plated electrodes showed stability throughout the measurement similarly to Ag/AgCl electrodes, but did not achieve the same qualities in sensitivity and readability of the measured results.

Matched MeSH terms: Electrodes*
Fulltext Analysis of machining pit by using electrical discharge machine die sinking

Md Razak Daud, Wan Nor Shela Ezwane Wan Jusoh, Syahrullail Samion

Journal of Engineering and Science Research, 2018;2(6):63-67.
MyJurnal

This study investigates metal removal rate (MRR) of the biomaterial by using discharge machine Neuar CNC A50 Electrical Discharge Machine Die Sinking (EDM DS). The purpose of this study is to compare machining curvature cup for material SKD 11 and stainless steel with shape curvature cup acetabular. The result showed that electrode wear is higher when high current is applied. For each applied current 0.5A and 3.0A could result electrode wear of 0.236 mm, 0.246 mm and 0.269 mm respectively. Mean time of complete discharged for each pit with 0.3mm depth with supply 0. 5A is 6.51 minutes; 1. 5A is 3.54 minutes and 3A is 1.52 minutes. The biggest mean parameter of the pit is 0.356 mm, with 3A of current is applied. From this study, it can be concluded that low current set may give lower electrode copper wear. The experiment will help a researcher to discharge biomaterial types of metal with small size of copper electrode use of EDM DS Neuar for discharge multi hole or micro pit.

Matched MeSH terms: Electrodes
Fulltext Anomalous metal segregation in lithium-rich material provides design rules for stable cathode in lithium-ion battery

Lin R, Hu E, Liu M, Wang Y, Cheng H, Wu J, et al.

Nat Commun, 2019 04 09;10(1):1650.
PMID: 30967531 DOI: 10.1038/s41467-019-09248-0

Despite the importance of studying the instability of delithiated cathode materials, it remains difficult to underpin the degradation mechanism of lithium-rich cathode materials due to the complication of combined chemical and structural evolutions. Herein, we use state-of-the-art electron microscopy tools, in conjunction with synchrotron X-ray techniques and first-principle calculations to study a 4d-element-containing compound, Li2Ru0.5Mn0.5O3. We find surprisingly, after cycling, ruthenium segregates out as metallic nanoclusters on the reconstructed surface. Our calculations show that the unexpected ruthenium metal segregation is due to its thermodynamic insolubility in the oxygen deprived surface. This insolubility can disrupt the reconstructed surface, which explains the formation of a porous structure in this material. This work reveals the importance of studying the thermodynamic stability of the reconstructed film on the cathode materials and offers a theoretical guidance for choosing manganese substituting elements in lithium-rich as well as stoichiometric layer-layer compounds for stabilizing the cathode surface.

Matched MeSH terms: Electrodes
Application of interface material and effects of oxygen gradient on the performance of single-chamber sediment microbial fuel cells (SSMFCs)

Wang CT, Sangeetha T, Yan WM, Chong WT, Saw LH, Zhao F, et al.

J Environ Sci (China), 2019 Jan;75:163-168.
PMID: 30473281 DOI: 10.1016/j.jes.2018.03.013

Single-chamber sediment microbial fuel cells (SSMFCs) have received considerable attention nowadays because of their unique dual-functionality of power generation and enhancement of wastewater treatment performance. Thus, scaling up or upgrading SSMFCs for enhanced and efficient performance is a highly crucial task. Therefore, in order to achieve this goal, an innovative physical technique of using interface layers with four different pore sizes embedded in the middle of SSMFCs was utilized in this study. Experimental results showed that the performance of SSMFCs employing an interface layer was improved regardless of the pore size of the interface material, compared to those without such layers. The use of an interface layer resulted in a positive and significant effect on the performance of SSMFCs because of the effective prevention of oxygen diffusion from the cathode to the anode. Nevertheless, when a smaller pore size interface was utilized, better power performance and COD degradation were observed. A maximum power density of 0.032mW/m2 and COD degradation of 47.3% were obtained in the case of an interface pore size of 0.28μm. The findings in this study are of significance to promote the future practical application of SSMFCs in wastewater treatment plants.

Matched MeSH terms: Electrodes
Fulltext Application of nanomaterials in the development of biosensors for food safety and quality control

Farah, A.A., Sukor, R., Fatimah, A.B., Jinap, S.

International Food Research Journal, 2016;23(5):1849-1856.
MyJurnal

Nanotechnology contribute to significant impacts in every way in our daily life. Recently,
the application of nanotechnology in biosensors has been a trend in developing a highly
sensitive, selective, quick response, inexpensive, high volume production, great reliability
and miniaturized sensors. High demands on the production of rapid sensors for food safety
and quality control purposes are increasingly become the interest for researchers all over the
world. This is because, in food sector, the quality of a certain product is based on their periodic
chemical and microbilogical analysis. The uses of nanomaterials in biosensors are very
promising because they mediate current flow. Surface modification of the electrode based on
various nanomaterials including nanoparticle, nanofiber, nanowire and nanotube significantly
increase the performance of the biosensor. Ultimately, this implementation will enhance the
sensor’s sensitivity and stability. This review explores the previous research and development
work on nanomaterials-based sensors for food applications.

Matched MeSH terms: Electrodes
Application of rotten rice as a substrate for bacterial species to generate energy and the removal of toxic metals from wastewater through microbial fuel cells

Daud NNM, Ahmad A, Yaqoob AA, Ibrahim MNM

Environ Sci Pollut Res Int, 2021 Nov;28(44):62816-62827.
PMID: 34215989 DOI: 10.1007/s11356-021-15104-w

Microbial fuel cells (MFCs) are the efficient and sustainable approach for the removal of toxic metals and generate energy concurrently. This article highlighted the effective use of rotten rice as an organic source for bacterial species to generate electricity and decrease the metal concentrations from wastewater. The obtained results were corresponding to the unique MFCs operation where the 510 mV voltage was produced within 14-day operation with 1000 Ω external resistance. The maximum power density and current density were found to be 2.9 mW/m2 and 168.42 mA/m2 with 363.6 Ω internal resistance. Similarly, the maximum metal removal efficiency was found to be 82.2% (Cd), 95.71% (Pb), 96.13% (Cr), 89.50% (Ni), 89.82 (Co), 99.50% (Ag), and 99.88% (Cu). In the biological test, it was found that Lysinibacillus strains, Chryseobacterium strains, Escherichia strains, Bacillus strains are responsible for energy generation and metal removal. Furthermore, a multiparameter optimization revealed that MFCs are the best approach for a natural environment with no special requirements. Lastly, the working mechanism of MFCs and future recommendations are enclosed.

Matched MeSH terms: Electrodes
Application of the central composite design for condition optimization for semi-aerobic landfill leachate treatment using electrochemical oxidation

Mohajeri S, Aziz HA, Isa MH, Zahed MA, Bashir MJ, Adlan MN

Water Sci Technol, 2010;61(5):1257-66.
PMID: 20220248 DOI: 10.2166/wst.2010.018

In the present study, Electrochemical Oxidation was used to remove COD and color from semi-aerobic landfill leachate collected from Pulau Burung Landfill Site (PBLS), Penang, Malaysia. Experiments were conducted in a batch laboratory-scale system in the presence of NaCl as electrolyte and aluminum electrodes. Central composite design (CCD) under Response surface methodology (RSM) was applied to optimize the electrochemical oxidation process conditions using chemical oxygen demand (COD) and color removals as responses, and the electrolyte concentrations, current density and reaction time as control factors. Analysis of variance (ANOVA) showed good coefficient of determination (R(2)) values of >0.98, thus ensuring satisfactory fitting of the second-order regression model with the experimental data. In un-optimized condition, maximum removals for COD (48.77%) and color (58.21%) were achieved at current density 80 mA/cm(2), electrolyte concentration 3,000 mg/L and reaction time 240 min. While after optimization at current density 75 mA/cm(2), electrolyte concentration 2,000 mg/L and reaction time 218 min a maximum of 49.33 and 59.24% removals were observed for COD and color respectively.

Matched MeSH terms: Electrodes
Fulltext Aptamer-Antibody Complementation On Multiwalled Carbon Nanotube-Gold Transduced Dielectrode Surfaces To Detect Pandemic Swine Influenza Virus

Wang F, Gopinath SC, Lakshmipriya T

Int J Nanomedicine, 2019;14:8469-8481.
PMID: 31695375 DOI: 10.2147/IJN.S219976

BACKGROUND: A pandemic influenza viral strain, influenza A/California/07/2009 (pdmH1N1), has been considered to be a potential issue that needs to be controlled to avoid the seasonal emergence of mutated strains.
MATERIALS AND METHODS: In this study, aptamer-antibody complementation was implemented on a multiwalled carbon nanotube-gold conjugated sensing surface with a dielectrode to detect pandemic pdmH1N1. Preliminary biomolecular and dielectrode surface analyses were performed by molecular and microscopic methods. A stable anti-pdmH1N1 aptamer sequence interacted with hemagglutinin (HA) and was compared with the antibody interaction. Both aptamer and antibody attachments on the surface as the basic molecule attained the saturation at nanomolar levels.
RESULTS: Aptamers were found to have higher affinity and electric response than antibodies against HA of pdmH1N1. Linear regression with aptamer-HA interaction displays sensitivity in the range of 10 fM, whereas antibody-HA interaction shows a 100-fold lower level (1 pM). When sandwich-based detection of aptamer-HA-antibody and antibody-HA-aptamer was performed, a higher response of current was observed in both cases. Moreover, the detection strategy with aptamer clearly discriminated the closely related HA of influenza B/Tokyo/53/99 and influenza A/Panama/2007/1999 (H3N2).
CONCLUSION: The high performance of the abovementioned detection methods was supported by the apparent specificity and reproducibility by the demonstrated sensing system.

Matched MeSH terms: Electrodes
Fulltext Aptasensing nucleocapsid protein on nanodiamond assembled gold interdigitated electrodes for impedimetric SARS-CoV-2 infectious disease assessment

Ramanathan S, Gopinath SCB, Ismail ZH, Md Arshad MK, Poopalan P

Biosens Bioelectron, 2022 Feb 01;197:113735.
PMID: 34736114 DOI: 10.1016/j.bios.2021.113735

In an aim of developing portable biosensor for SARS-CoV-2 pandemic, which facilitates the point-of-care aptasensing, a strategy using 10 μm gap-sized gold interdigitated electrode (AuIDE) is presented. The silane-modified AuIDE surface was deposited with ∼20 nm diamond and enhanced the detection of SARS-CoV-2 nucleocapsid protein (NCP). The characteristics of chemically modified diamond were evidenced by structural analyses, revealing the cubic crystalline nature at (220) and (111) planes as observed by XRD. XPS analysis denotes a strong interaction of carbon element, composed ∼95% as seen in EDS analysis. The C-C, CC, CO, CN functional groups were well-refuted from XPS spectra of carbon and oxygen elements in diamond. The interrelation between elements through FTIR analysis indicates major intrinsic bondings at 2687-2031 cm-1. The aptasensing was evaluated through electrochemical impedance spectroscopy measurements, using NCP spiked human serum. With a good selectivity the lower detection limit was evidenced as 0.389 fM, at a linear detection range from 1 fM to 100 pM. The stability, and reusability of the aptasensor were demonstrated, showing ∼30% and ∼33% loss of active state, respectively, after ∼11 days. The detection of NCP was evaluated by comparing anti-NCP aptamer and antibody as the bioprobes. The determination coefficients of R2 = 0.9759 and R2 = 0.9772 were obtained for aptamer- and antibody-based sensing, respectively. Moreover, the genuine interaction of NCP aptamer and protein was validated by enzyme linked apta-sorbent assay. The aptasensing strategy proposed with AuIDE/diamond enhanced sensing platform is highly recommended for early diagnosis of SARS-CoV-2 infection.

Matched MeSH terms: Electrodes
Aromatic biomass (torch ginger) leaf-derived three-dimensional honeycomb-like carbon to enhance gravimetric supercapacitor

Taer E, Yanti N, Padang E, Apriwandi A, Zulkarnain Z, Haryanti NH, et al.

J Sci Food Agric, 2023 Dec;103(15):7411-7423.
PMID: 37431642 DOI: 10.1002/jsfa.12846

BACKGROUND: Porous carbon electrode (PCE) is identified as a highly suitable electrode material for commercial application due to its production process, which is characterized by simplicity, cost-effectiveness and environmental friendliness. PCE was synthesized using torch ginger (Etlingera elatior (Jack) R.M. Smith) leaves as the base material. The leaves were treated with different concentrations of ZnCl2 , resulting in a supercapacitor cell electrode with unique honeycomb-like three-dimensional (3D) morphological pore structure. This PCE comprises nanofibers from lignin content and volatile compounds from aromatic biomass waste.
RESULTS: From the characterization of physical properties, PCE-0.3 had an impressive amorphous porosity, wettability and 3D honeycomb-like structural morphology with a pore framework consisting of micropores and mesopores. According to the structural advantages of 3D hierarchical pores such as interconnected honeycombs, PCE-0.3 as supercapacitor electrode had a high specific capacitance of up to 285.89 F g-1 at 1 A. Furthermore, the supercapacitor exhibited high energy and power density of 21.54 Wh kg-1 and 161.13 W kg-1 , respectively, with a low internal resistance of 0.059 Ω.
CONCLUSION: The results indicated that 3D porous carbon materials such as interconnected honeycombs derived from the aromatic biomass of torch ginger leaves have significant potential for the development of sustainable energy storage devices. © 2023 Society of Chemical Industry.

Matched MeSH terms: Electrodes
Aryl diazonium modification for improved graphite fiber brush in microbial fuel cell

Siti Farah Nadiah Rusli, Mimi Hani Abu Bakar, Loh Kee Shyuan, Mohd Shahbudin Mastar, Seratul Jemiah Abdul Rani, Mohd Shahbudin Mastar

Sains Malaysiana, 2018;47:3017-3023.

Aryl diazonium salts are coupling agents that assist in molecules attachment to interfaces for sensing purposes. Despite
not being fully explored and not yet widely applicable for cell-based sensors, the high stability of aryl diazonium salt
formed sensing system is highly favorable in biological applications. Carbon-based electrodes are the most commonly
used in aryl diazonium modification due to its post grafting stable C-C bond formation. Here, salt bridge based microbial
fuel cells (MFCs) were used to study on the effect of aryl diazonium modification on the anode graphite fibre brush. Aryl
diazonium salts were in situ generated by the diazonation of p-phenylenediamine with NaNO2 in HCl solution. The
electrochemical performance of the aryl diazonium modified graphite brush MFC was measured and compared with the
unmodified graphite brush MFC. The power output of the modified graphite brush bioanode was higher (8.33 W/m3
)
than the unmodified graphite brush (7.60 W/m3
) after 20 days of operation with ferricyanide as the catholyte. After 70
days of operation using phosphate buffer solution as the catholyte, the Pmax of modified brush was three times higher
(0.06 W/m3
) than of the unmodified brush (0.02 W/m3
), which indicates an enhanced binding towards the substrate that
facilitates a better electron transfer between the microbial and electrode surface.

Matched MeSH terms: Electrodes
Fulltext Assessment of a 16-Channel Ambulatory Dry Electrode EEG for Remote Monitoring

Shivaraja TR, Remli R, Kamal N, Wan Zaidi WA, Chellappan K

Sensors (Basel), 2023 Mar 31;23(7).
PMID: 37050713 DOI: 10.3390/s23073654

Ambulatory EEGs began emerging in the healthcare industry over the years, setting a new norm for long-term monitoring services. The present devices in the market are neither meant for remote monitoring due to their technical complexity nor for meeting clinical setting needs in epilepsy patient monitoring. In this paper, we propose an ambulatory EEG device, OptiEEG, that has low setup complexity, for the remote EEG monitoring of epilepsy patients. OptiEEG's signal quality was compared with a gold standard clinical device, Natus. The experiment between OptiEEG and Natus included three different tests: eye open/close (EOC); hyperventilation (HV); and photic stimulation (PS). Statistical and wavelet analysis of retrieved data were presented when evaluating the performance of OptiEEG. The SNR and PSNR of OptiEEG were slightly lower than Natus, but within an acceptable bound. The standard deviations of MSE for both devices were almost in a similar range for the three tests. The frequency band energy analysis is consistent between the two devices. A rhythmic slowdown of theta and delta was observed in HV, whereas photic driving was observed during PS in both devices. The results validated the performance of OptiEEG as an acceptable EEG device for remote monitoring away from clinical environments.

Matched MeSH terms: Electrodes
Fulltext Asymmetric supercapacitor of functionalised electrospun carbon fibers/poly(3,4-ethylenedioxythiophene)/manganese oxide//activated carbon with superior electrochemical performance

Mohd Abdah MAA, Azman NHN, Kulandaivalu S, Sulaiman Y

Sci Rep, 2019 Nov 14;9(1):16782.
PMID: 31728061 DOI: 10.1038/s41598-019-53421-w

Asymmetric supercapacitors (ASC) have shown a great potential candidate for high-performance supercapacitor due to their wide operating potential which can remarkably enhance the capacitive behaviour. In present work, a novel positive electrode derived from functionalised carbon nanofibers/poly(3,4-ethylenedioxythiophene)/manganese oxide (f-CNFs/PEDOT/MnO2) was prepared using a multi-step route and activated carbon (AC) was fabricated as a negative electrode for ASC. A uniform distribution of PEDOT and MnO2 on f-CNFs as well as porous granular of AC are well-observed in FESEM. The assembled f-CNFs/PEDOT/MnO2//AC with an operating potential of 1.6 V can achieve a maximum specific capacitance of 537 F/g at a scan rate of 5 mV/s and good cycling stability (81.06% after cycling 8000 times). Furthermore, the as-prepared ASC exhibited reasonably high specific energy of 49.4 Wh/kg and low charge transfer resistance (Rct) of 2.27 Ω, thus, confirming f-CNFs/PEDOT/MnO2//AC as a promising electrode material for the future energy storage system.

Matched MeSH terms: Electrodes
Au/Pd@rGO nanocomposite decorated with poly (L-Cysteine) as a probe for simultaneous sensitive electrochemical determination of anticancer drugs, Ifosfamide and Etoposide

Hatamluyi B, Lorestani F, Es'haghi Z

Biosens Bioelectron, 2018 Nov 30;120:22-29.
PMID: 30144642 DOI: 10.1016/j.bios.2018.08.008

The simultaneous measurement of the concentration of anticancer drugs with a fast, sensitive and accurate method in biological samples is a challenge for better monitoring of drug therapy and better determine the pharmacokinetics. An electrochemical sensor was developed for the simultaneous determination of anticancer drugs, Ifosfamide (IFO) and Etoposide (ETO) based on pencil graphite electrode modified with Au/Pd@rGO nanocomposite decorated with poly (L-Cysteine). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were utilized to study the properties of the modified electrode. The electrochemical behavior of IFO and ETO on the Au/Pd@rGO@p(L-Cys) modified electrode was investigated by cyclic voltammetry and differential pulse voltammetry (DPV) techniques and the obtained results confirmed its efficiency for the individual and simultaneous sensing of IFO and ETO. After optimization of electrochemical parameters, the fabricated sensor presented excellent performance in simultaneous determination of IFO and ETO with a wide linear range from 0.10 to 90.0 μM and 0.01 to 40.0 μM and low detection limits (3 Sb/m) of 9.210 nM and 0.718 nM, respectively. In addition, this study proved that the constructed sensor could be useful to simultaneous analysis of IFO and ETO in biological samples and pharmaceutical compounds.

Matched MeSH terms: Electrodes
Augmentation of microbial fuel cell and photocatalytic polishing technique for the treatment of hazardous dimethyl phthalate containing wastewater

Sarmin S, Tarek M, Cheng CK, Roopan SM, Khan MMR

J Hazard Mater, 2021 08 05;415:125587.
PMID: 33721778 DOI: 10.1016/j.jhazmat.2021.125587

In the present paper, the potentiality of integrating microbial fuel cells (MFCs) with a photocatalytic reactor to maximize the wastewater treatment efficiency with concurrent power generation was explored. Dimethyl phthalate (DMP) and acetic acid (AA) were the employed substrate and the co-substrate, respectively, using Pseudomonas aeruginosa as a biocatalyst. MFCs operated by single substrate showed the maximum power generation of 0.75-3.84 W m-3 whereas an addition of AA as the co-substrate yielded 3-12 fold higher power generation. Pseudomonas aeruginosa produced phenazine-1-carboxylic acid in DMP-fed MFC as the metabolite whereas AA along with DMP yielded pyocyanin which reduced the charge transfer resistance. Chemical oxygen demand (COD) removal efficiency in the MFCs was circa 62% after 11 days of operation. Thereafter, it further increased albeit with a drastic reduction in power generation. Subsequently, the MFC anolyte was treated in a photocatalytic reactor under visible light irradiation and catalyzed by CuO-gC3N4. The performance of photocatalytic reactor was evaluated, with COD and total organic carbon (TOC) removal efficiency of 88% and 86% after 200 min of light irradiation. The present work suggests that the MFC can be integrated with photocatalysis as a sustainable wastewater treatment method with concurrent power generation.

Matched MeSH terms: Electrodes
Fulltext Automatic Artifact Removal in EEG of Normal and Demented Individuals Using ICA-WT during Working Memory Tasks

Al-Qazzaz NK, Hamid Bin Mohd Ali S, Ahmad SA, Islam MS, Escudero J

Sensors (Basel), 2017 Jun 08;17(6).
PMID: 28594352 DOI: 10.3390/s17061326

Characterizing dementia is a global challenge in supporting personalized health care. The electroencephalogram (EEG) is a promising tool to support the diagnosis and evaluation of abnormalities in the human brain. The EEG sensors record the brain activity directly with excellent time resolution. In this study, EEG sensor with 19 electrodes were used to test the background activities of the brains of five vascular dementia (VaD), 15 stroke-related patients with mild cognitive impairment (MCI), and 15 healthy subjects during a working memory (WM) task. The objective of this study is twofold. First, it aims to enhance the recorded EEG signals using a novel technique that combines automatic independent component analysis (AICA) and wavelet transform (WT), that is, the AICA-WT technique; second, it aims to extract and investigate the spectral features that characterize the post-stroke dementia patients compared to the control subjects. The proposed AICA-WT technique is a four-stage approach. In the first stage, the independent components (ICs) were estimated. In the second stage, three-step artifact identification metrics were applied to detect the artifactual components. The components identified as artifacts were marked as critical and denoised through DWT in the third stage. In the fourth stage, the corrected ICs were reconstructed to obtain artifact-free EEG signals. The performance of the proposed AICA-WT technique was compared with those of two other techniques based on AICA and WT denoising methods using cross-correlation X C o r r and peak signal to noise ratio ( P S N R ) (ANOVA, p ˂ 0.05). The AICA-WT technique exhibited the best artifact removal performance. The assumption that there would be a deceleration of EEG dominant frequencies in VaD and MCI patients compared with control subjects was assessed with AICA-WT (ANOVA, p ˂ 0.05). Therefore, this study may provide information on post-stroke dementia particularly VaD and stroke-related MCI patients through spectral analysis of EEG background activities that can help to provide useful diagnostic indexes by using EEG signal processing.

Matched MeSH terms: Electrodes

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