Disposable Pencil Graphite Electrode Research Articles

Electrochemical investigation of the antimicrobial agent daptomycin utilizing disposable pencil graphite electrode and DNA interaction with green techniques

Electrochemical investigation of the antimicrobial agent daptomycin utilizing disposable pencil graphite electrode and DNA interaction with green techniques

A three-components-based disposable electrochemical sensor for the detection of heavy metal ions in water

The development of an efficient sensor based on a novel three-components nanocomposite is presented for the detection of heavy metal ions (Cd2+ and Pb2+) in water. For the preparation of three-components nanocomposite surface, the polydopamine reduced graphene oxide (PyDA/RGO) composite was initially prepared by a one-step polymerization of dopamine (DA) on RGO followed by surface modification of the prepared composite with cysteine (Cys). The formation of three-components nanocomposite surface (i.e., Cys/PyDA/RGO) was initially confirmed through physical characterization techniques, including X-ray diffraction and infrared spectroscopy, whereas scanning electron microscopy revealed the surface morphology after each step of sensor fabrication. The electrochemical properties of the sensing platform were evaluated through electrochemical techniques, including cyclic voltammetry and electrochemical impedance spectroscopy with an external ferri‐−/ferrocyanide redox probe. The prepared three-components nanocomposite on disposable pencil graphite electrode (Cys/PyDA/RGO/PGE) showed an improved charge transfer rate as compared to PyDA/RGO/PGE and bare PGE electrode. Targeted heavy metal ions were detected on the sensor surface using differential pulse voltammetry with greater sensitivity, showing detection limits of 0.77 and 1.13 ppb for Cd+2 and Pb+2 ions in citrate buffer solution, respectively. The sensor demonstrated comparable performance in the tap water samples.

Development of graphene oxide-based biosensing platforms for label-free bioelectronic detection of pathogenic microorganisms.

A novel electrochemical nanogenosensor devoted to clinical analysis is reported for label-free detection of pathogenic microorganisms in the present work. The designed biosensor is composed of graphene oxide-modified disposable pencil graphite electrodes as a sensing platform. Escherichia coli is used as a model case. A 5'-aminohexyl-linked 22-base sequence probe representing the E. coli amplicon is immobilized onto sensor surfaces via carbodiimide chemistry. Hybridization is performed with denatured PCR amplicons of the bacteria. Detection is realized by transduction with the electrochemical impedance spectrometry technique. The selectivity of the designed genosensor is measured using Mycobacterium tuberculosis and Klebsiella pneumoniae sequences. Outstanding sensitivity is achieved with this genosensor array platform with a detection limit of 102 nM. This platform offers promise for rapid, simple, and cost-effective detection of various pathogenic microorganisms.

Optimized aptamer-based next generation biosensor for the ultra-sensitive determination of SARS-CoV-2 S1 protein in saliva samples

COVID-19 is an infectious disease caused by the SARS-CoV-2 virus, which rapidly spread worldwide and resulted in a pandemic. Efficient and sensitive detection techniques have been devised since the onset of the epidemic and continue to be improved at present. Due to the crucial role of the SARS-CoV-2 S1 protein in facilitating the virus's entry into cells, efforts in detection and treatment have primarily centered upon this protein. In this study, a rapid, ultrasensitive, disposable, easy-to-use, cost-effective next generation biosensor based on optimized aptamer (Optimer, OPT) was developed by using a disposable pencil graphite electrode (PGE) and applied for the impedimetric determination of SARS-CoV-2 S1 protein. The S1 protein interacted with the OPT in the solution phase and then immobilized onto the PGE surface. Subsequently, measurements using electrochemical impedance spectroscopy (EIS) were conducted in a solution containing a redox probe of 1 mM [Fe(CN)6]3−/4−. Under optimum conditions, the limit of detection (LOD) for the S1 protein in buffer medium at concentrations ranging from 101 to 106 ag/mL was calculated as 8.80 ag/mL (0.11 aM). The selectivity of the developed biosensor was studied against MERS-CoV-S1 protein (MERS) and Influenza Hemagglutinin antigen (HA). Furthermore, the application of the biosensor in artificial saliva medium is demonstrated. The LOD was also calculated in artificial saliva medium in the concentration range of 101–105 ag/mL and calculated as 2.01 ag/mL (0.025 aM). This medium was also used to assess the selectivity of optimized-aptamer based biosensor.

Green Voltammetric Detection of Ophthalmic Drug Nepafenac Using Pencil Graphite Electrode as a Responsive Disposable Electrochemical Sensor

AbstractIn this study, the electrochemical properties of nepafenac, used after eye surgery operations, were investigated on a disposable pencil graphite electrode. Cyclic and square wave voltammetry techniques were used to investigate the electrochemical properties of nepafenac. Two peaks at potentials of approximately +0.33 V and +1.03 V in the anodic direction and two peaks at potentials of approximately +0.29 V and +0.08 V in the cathodic direction were observed on the surface of the disposable pencil electrode in acetate (pH 4.8) medium with the cyclic voltammetry technique. The analytical performance of the developed voltammetric technique had good linearity in the concentration range of 0.30 µM to 3.5 µM at pH 4.8. The LOD value of this voltammetric method in acetate (pH 4.8) medium was calculated as 0.035 µM (8.90 ng mL−1). For reproducibility, the relative standard deviation (RSD) values for Ia and IIa anodic peak current/potential were found to be 1.45%/0.43% and 1.28%/0.25%, respectively. The voltammetric method was successfully applied to urine and pharmaceutical preparations and the results were compared with the spectrophotometric method.

A Self-Powered Enzymatic Glucose Sensor Utilizing Bimetallic Nanoparticle Composites Modified Pencil Graphite Electrodes as Cathode.

Enzymatic biofuel cells (EBFC) are promising sources of green energy owing to the benefits of using renewable biofuels, eco-friendly biocatalysts, and moderate operating conditions. In this study, a simple and effective EBFC was presented using an enzymatic composite material-based anode and a nonenzymatic bimetallic nanoparticle-based cathode respectively. The anode was constructed from a glassy carbon electrode (GCE) modified with a multi-walled carbon nanotube (MWCNT) and ferrocene (Fc) as a conductive layer coupled with the enzyme glucose oxidase (GOx) as a sensitive detection layer for glucose. A chitosan layer was also applied to the electrode as a protective layer to complete the composite anode. Chronoamperometry (CA) results show that the MWCNT-Fc-GOx/GCE electrode has a linear relationship between current and glucose concentration, which varied from 1 to 10mM. The LOD and LOQ were calculated for anode as 0.26mM and 0.87mM glucose, respectively. Also the sensitivity of the proposed sensor was calculated as 25.71 A/mM. Moreover, the studies of some potential interferants show that there is no significant interference for anode in the determination of glucose except ascorbic acid (AA), uric acid (UA), and dopamine (DA). On the other hand, the cathode consisted of a disposable pencil graphite electrode (PGE) modified with platinum-palladium bimetallic nanoparticles (Nps) which exhibit excellent conductivity and electron transfer rate for the oxygen reduction reaction (ORR). The constructed EBFC was optimized and characterized using various electroanalytical techniques. The EBFC consisting of MWCNT-Fc-GOx/GCE anode and Pt-PdNps/PGE cathode exhibits an open circuit potential of 285.0mV and a maximum power density of 32.25µWcm-2 under optimized conditions. The results show that the proposed EBFC consisting of an enzymatic composite-based anode and bimetallic nanozyme-based cathode is a unique design and a promising candidate for detecting glucose while harvesting power from glucose-containing natural or artificial fluids.

First voltammetric studies, spectrophotometric and molecular docking investigations of the interaction of an anticancer drug ribociclib-DNA and analytical applications of disposable pencil graphite sensor

Ribociclib (RIB) is a cyclin-dependent kinase inhibitor used in the treatment of breast cancer. In this study, for the first time, the electrochemical behavior, quantification and interaction of RIB with DNA were carried out using voltammetric, spectrophotometric and molecular docking techniques. An environmentally-friendly disposable pencil graphite electrode (PGE) sensor was used as the working electrode. Utilizing the cyclic voltammetry technique, RIB produced an irreversible anodic wave around +0.837 V and reversible signals around +0.278 V/+0.209 V on the PGE surface. Using the PGE sensor, the RIB compound gave a very distinct anodic signal at a potential of +0.77 V in PBS (pH 3.0). For this analytical signal, the limit of detection and limit of quantitation values of RIB in the concentration range of 0.0139 3 M–0.0973 3 M in PBS (pH 3.0) were determined as 2.84 nM and 9.46 nM, respectively. The interaction of RIB with DNA was studied by voltammetric, spectrophotometric and molecular docking techniques. In the evaluation of the results obtained with all three techniques, the interaction of the RIB molecule with DNA was determined to occur through minor groove binding.

Development of a chitosan-gold nanocomposite based disposable pencil graphite electrode for the selective detection of thiram in peach juice

ABSTRACT Hazardous chemicals that are mostly employed in modern agriculture for pest management have caused long-term environmental accumulation as well as major issues with food safety and human health. So, there is an urgent demand for efficient detection methods for environmental monitoring. To do this, the most contemporary electrochemical sensor technology is suggested. In this study, a new electrochemical sensor has been developed to detect thiram (Th) fungicide, utilising a modified activated pencil graphite electrode (a-PGE) made from chitosan-gold nanoparticle polymer (Ch-AuNPs) for the first time. The Ch-AuNPs/a-PGE surface has been characterised using cyclic voltammetry (CV), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Following adjustments to experimental parameters, the proposed electrochemical sensor demonstrated a linear calibration curve within the range of 4.90–140 μM, displaying a rapid response to thiram with a detection limit of 1.15 μM. The sensor exhibited notable selectivity, stability, and reproducibility. To assess its practical utility, the sensor was applied to analyse thiram in peach juice, and the recovery process indicated its effectiveness as a practical, swift, and efficient tool in pesticide residue monitoring.

First electrochemical investigation and determination of non-steroidal anti-inflammatory drug etofenamate using disposable pencil graphite electrode with voltammetric techniques

In this study, the electrochemical properties of etofenamate, an active ingredient belonging to the non-steroidal anti-inflammatory drug group, were investigated using cyclic voltammetry (CV) and square wave voltammetry (SW) techniques on a disposable pencil graphite electrode (PGE). With the CV technique, reversible voltammetric waves of around +0.470 V and irreversible voltammetric waves of around +1.02 V were produced on the PGE. An environmentally friendly, selective and highly sensitive SW voltammetric method was developed using disposable PGE. This voltammetric method gave very good analytical working range on PGE in PBS (pH = 3.0) medium at concentrations ranging from 0.017 μM to 0.306 μM. The LOD value of this analytical method in PBS (pH = 3.0) medium was calculated as 0.0011 μM (0.406 μg L−1). The developed voltammetric method was successfully applied to urine and drug samples. The results of the voltammetric method were compared with the results of the spectrophotometric method. The results were found to be compatible with each other.

Application of eco‐friendly disposable pencil graphite sensor for electrochemical evaluation and determination of podophyllotoxin using in cancer treatment

AbstractA sensitive, simple and selective voltammetric method was developed for the quantification of plant‐derived podophyllotoxin, which is included in antineoplastic drugs, using a disposable pencil graphite electrode. Using the square‐wave voltammetry technique, podophyllotoxin gave a very good voltammetric response at +1.24 V (vs. Ag/AgCl) potential (at 0.0 V and after 60 s pre‐concentration) in Britton Robinson (pH 4.0) media. This procedure was used to detection the compound in the concentration range of 12.4–299.5 nM with a limit of detection to 2.62 nM (1.08 μg L−1). The proposed method has been successfully applied to human urine samples.

Cost‐Effective Cholesterol Monitoring by Enzyme‐Based Electrochemical Assay

AbstractHerein we present a practical, disposable, enzyme‐based electrochemical biosensor to revolutionize a rapid and precise measurement of cholesterol level in saliva. To create a biosensor that can measure cholesterol levels, cholesterol oxidase (ChOx) was immobilized on disposable pencil graphite electrode (PGE) via EDC/NHS chemistry. This ChOx‐PGE biosensor has been characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS). Various critical experimental parameters, including nafion concentration, enzyme concentration, enzyme‐cholesterol interaction time, were optimized ensuring consistency and precision in our results and maintained constant throughout the experiments. Under optimum conditions, the detection limit was found to be 62 μM and the sensitivity of the sensor was calculated as 1112.8 Ohm mM−1 cm−2. The potential interferences such as glucose, ascorbic acid, uric acid, cysteine was selected to test the selectivity and no significant response was observed. Finally, the proposed biosensor was effectively employed to measure cholesterol level in saliva. This biosensor boasts a rapid response time of just 20 minutes and achieves a remarkable detection limit of 95 μM for salivary cholesterol, surpassing existing techniques. Our assay not only offers an innovative solution for cholesterol monitoring but also opens new horizons in point‐of‐care diagnostics with its disposable and practical design.

Novel Determination of the Influence of Idarubicin upon DNA Chain Structure Using an Electrochemical DNA Biosensor by Voltammetry

Two sequences of DNA (single-strand DNA (ssDNA) and double-strand DNA (dsDNA)) modified disposable electrodes were designed to investigate the effect of antitumor agent drug idarubicine (IDA) on the DNA chain structure. The effect of IDA on DNA structure was analyzed by square wave voltammetry (SWV) depending on not only the guanine signal but also IDA oxidation response. The present study included the electrochemical investigation of IDA and the investigation of the biomolecular interaction between IDA and DNA. IDA was detected in buffer and urine using disposable pencil graphite electrodes (PGE) with SWV and cyclic voltammetry (CV)). The detection limit (LOD) of IDA in urine samples was 0.089 µg mL−1 with SWV under optimum conditions. For the biomolecular interaction of IDA and DNA, all electrochemical conditions, such as the concentration of DNA, concentration of IDA, interaction phase (at electrode surface/in solution phase), the interaction pH, and the interaction time were optimized. IDA interacted biomolecularly with DNA at the electrode surface and in solution phase using two methods. There is no previous electrochemical study performed on the interaction of IDA with ssDNA. Hence, the effect of IDA on both ssDNA and dsDNA was presented for the first time.

Sol-gel derived ceramic nanocomposite CNFs anchored with a nanostructured CeO2 modified graphite electrode for monitoring the interaction of a selective tyrosine kinase inhibitor capmatinib with dsDNA.

In the current study, the potential interaction mechanisms between capmatinib (CAP), a selective tyrosine kinase inhibitor, and calf thymus double-stranded DNA (ds-DNA) were evaluated. In this research, we construct an amplified electrochemical platform based on a disposable pencil graphite electrode (PGE) modified with nanostructured CeO2 decorated carbon nanofiber ceramic film (CeNPs@CNF-CF) for monitoring CAP-dsDNA interaction at physiological pH. The morphology and structure of the obtained CeNPs@CNF nanocomposite were characterized. The CeNPs@CNF-CF/PGE was characterized by scanning electron microscopy (SEM). The CAP-dsDNA interaction was examined using cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. Voltammetric experiments were conducted using CeNPs@CNF-CF/PGE. The interaction of CAP with dsDNA was investigated after applying different incubation times. The addition of dsDNA to the CAP solution decreased the peak currents of the latter and led to a negative shift in peak potentials, suggesting that the electrostatic type of interaction is the most likely to occur. SWV was employed to quantify dsDNA, demonstrating excellent sensitivity (LOD = 5 × 10-8 M). The binding constant (K b) of CAP and dsDNA was calculated to be 4.54 ± 0.18 × 104 M-1 using SW voltammetric data.

Amine-Functionalized Pencil Graphite Electrode for Simultaneous Determination of Dopamine and Uric Acid

In this study, an electrochemical transducer based on an Amine-functionalized cheap and disposable pencil graphite electrode (NPGE) is proposed for the simultaneous monitoring of Dopamine (DA) and Uric Acid (UA) in biological samples such as serum and urine. The prepared NPGE was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that the incorporation of amine groups significantly improved catalytic activity than the bare pencil graphite electrode (BPGE). Moreover, the electrode modification parameters and effects of different analytical variables such as sweep rate, pH of the supporting electrolyte solution, and possible interfering ions or molecules in quantification were optimized using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimized conditions, DA and UA oxidation currents showed linear responses over the concentration range of 1.06-160 µM for DA and 30.06-150 µM for UA. The limit of detection (LOD) for DA and UA were estimated to be 0.94 and 1.26 µM, respectively. In addition, the transducer’s sensitivity of 5.47 µA.µM-1cm-2 for DA and 1.70 µA.µM-1cm-2 for UA were calculated. Aiming to reuse the transducer, a regeneration solution is proposed which could successfully remove the adsorbed oxidized products from the surface. Finally, the developed transducer’s performance was compared with the established clinical method. Figure 1

Disposable Pencil Lead as an Electrochemical Transducer for Monitoring Catechol in River and Tap Water

A cheap and disposable pencil graphite electrode (PGE) was developed by the incorporation of amine groups (Am-PGE-1). A further improvement in the performance was observed when the aminated electrode (Am-PGE-1) was activated by applying a negative potential scan (Am-PGE-2). The electrochemical transport properties were evaluated through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The Nyquist plot showed a reduced charge transfer resistance value of 24.3 Ω for Am-PGE-2, while it was 95.1 Ω for bare PGE. Thus, Am-PGE-2 was used as a sensing platform for the detection of catechol. It was found that the electrochemical response of catechol oxidation at Am-PGE-2 was twice than the current obtained for bare PGE. Additionally, the effect of pH of the supporting electrolyte and reaction kinetic were studied. The heterogeneous electron transfer rate constant was calculated to be 0.01 s−1. Moreover, CV study revealed that the redox reaction of catechol was a quasi-reversible and diffusion-controlled process. The square wave voltammetry (SWV) technique was applied for the quantitative determination of catechol. The peak current showed a linear dependency on the concentration of catechol from 3 to 150 µM. Furthermore, the analyte could be detected as low as 3.86 µM. Likewise, the sensor demonstrates a good selectivity towards the target analyte than the other possible interfering molecules or ions. Aiming to examine practical applicability, real samples, such as river and household tap water, were tested by using the proposed transducer, and the satisfactory recoveries demonstrate the effectiveness of Am-PGE-2 in real life applications.

Development of a Disposable Aptasensor Using Carboxymethyl Cellulose and Hydroxyapatite Nanoparticles for Voltammetric Detection of Glyphosate

The development of monitoring tools for the detection of glyphosate is an attractive topic since its consumption is one of the debated worldwide issue. Herein, a bionanocomposite modified disposable electrochemical biosensor platform was developed for sensitive and selective detection of glyphosate. For this purpose, carboxymethyl cellulose (CMC) and hydroxyapatite nanoparticles (HaNP) were modified at the surface of disposable pencil graphite electrodes (PGEs). After the fabrication of CMC/HaNP-PGEs, glyphosate specific DNA aptamer that had G-quadruplex structure was immobilized at the surface of CMC/HaNP-PGEs. The specific interaction between DNA aptamer and glyphosate was performed at the electrode surface. Before/after each modification/immobilization/interaction step, anodic current value obtained by cyclic voltammetry measurements performed in 2.00 mM K3[Fe(CN)6]/K4[Fe(CN)6] (1:1) and 0.10 M KCl was recorded, and the changes at the average anodic current values were evaluated in terms of the optimization of experimental parameters. The limit of detection and limit of quantification values were calculated as 0.04 and 0.13 μg ml−1, respectively. The selectivity of the developed aptasensor was tested against 2,4-dichlorophenoxyacetic acid, glufosinate, and (aminomethyl) phosphonic acid. The applicability of the aptasensor was shown using water samples. This novel aptasensor platform is a prototype for future hand-held devices developed for GLY monitoring.

Electrochemical evaluation and determination of vindesine used in cancer chemotherapy at disposable pencil graphite electrode by voltammetric method

Electrochemical evaluation and determination of vindesine used in cancer chemotherapy at disposable pencil graphite electrode by voltammetric method

Electrochemical sensor based on bio-inspired molecularly imprinted polymer for sofosbuvir detection.

The electropolymerized molecularly imprinted polymers (MIP) have enabled the utilization of various functional monomers with superior selective recognition of the target analyte template. Methyldopa is an attractive synthetic dopamine analogue which has phenolic, carboxylic, and aminic functional groups. In this research, methyldopa was exploited to fabricate selective MIPs, for the detection of sofosbuvir (SFB), by a simple electropolymerization step onto a disposable pencil graphite electrode (PGE) substrate. The interaction between methyldopa, as a functional monomer, and a template has been investigated experimentally by UV spectroscopy. A polymethyldopa (PMD) polymer was electrografted onto PGE in the presence of SFB as a template. X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (ESI), and cyclic voltammetry (CV) were used for the characterization of the fabricated sensor. Differential pulse voltammetry (DPV) of a ferrocyanide/ferricyanide redox probe was employed to indirectly detect the SFB binding to the MIP cavities. The sensor shows a reproducible and linear response over a dynamic linear range from 1.0 × 10-11 M to 1.0 × 10-13 M of SFB with a limit of detection of 3.1 × 10-14 M. The sensor showed high selectivity for the target drug over structurally similar and co-administered interfering drugs, and this enabled its application to detect SFB in its pharmaceutical dosage form and in spiked human plasma samples.

Voltammetric Determination of Favipiravir Used as an Antiviral Drug for the Treatment of Covid-19 at Pencil Graphite Electrode.

This work describes the sensitive voltammetric determination of favipiravir (FAV) based on its reduction for the first time with a low-cost and disposable pencil graphite electrode (PGE). In addition, the determination of FAV was also performed based on its oxidation. Differential pulse (DP) voltammograms recorded in 0.5 M H2SO4 for the reduction of FAV show that peak currents increase linearly in the range of 1.0 to 600.0 μM with a limit of detection of 0.35 μM. The acceptable recovery values (98.9-106.0 %) obtained from a pharmaceutical tablet, real human urine, and artificial blood serum samples spiked with FAV confirm the high accuracy of the proposed method.

Fast, Cheap and Reliable Monitoring of Microalgae-Based Paracetamol Removal from Aquatic Environment Using Electrochemical Sensor Technology

Paracetamol (PRL) is an analgesic and antipyretic drug, and its consumption has increased all across the world during the COVID-19 pandemic era. However, its excessive consumption makes it an endocrine-disrupting factor, and it is toxic for the liver. It easily contaminates water resources due to its high solubility, and has substantial potential to access both aquatic life and humans. Therefore, its removal by sustainable methods is a highlighted issue for today’s world that has experienced increasing scarcity of water. Herein, microalgae-based PRL removal and its electrochemical monitoring were performed. The removal performed with Scenedesmus sp. was monitored by disposable pencil graphite electrodes and cyclic voltammetry. The removal was achieved without the requirement of complex procedures, and the monitoring of this removal finished in less than 1 min. Application of the system in real life was tested in the presence of tap water. The biosorption kinetics, isoterms, and changes in chlorophyll content of the microalgae were calculated, and the microscopic characterizations of the biosorption were performed. The selectivity of the system was studied against other water contaminants. This is the first study about the removal of PRL using Scenedesmus sp. and the monitoring of the removal using disposable electrochemical sensor technology.