Screen-printed Electrodes Research Articles

Enzymatic bimetallic Cu-Ni micromotor sensor for xanthine detection

Enzymatic bimetallic Cu-Ni micromotors modified screen-printed electrodes were designed for the determination of xanthine. The bimetallic Cu-Ni micromotors were prepared by electrochemical template deposition. Morphological and structural characterization revealed that the smaller size and active mobility of the particles contribute to a larger specific surface area. The increase in surface area enhances electro-catalytic activities and sensitivity. These improved properties enable the newly created xanthine oxidase-modified Cu-Ni micromotors to function effectively as a high-performance sensor. Designed specifically for detecting xanthine, this sensor boasts high sensitivity, a broad measurement range, low detection limits, and excellent reproducibility and stability. The enzymatic bimetallic micromotor-based sensor was also successfully employed to measure xanthine levels. The limits of detection were determined to be 15.7 nM and 21.53 μM for xanthine concentration ranges of 0.1 μM–1 μM and 10 μM–300 μM, respectively, based on electrochemical signals under a magnetic field. Besides, the detection limit was calculated as 9.02 μM for xanthine concentrations ranging from 0.3 μM to 20 μM, based on the speed of the micromotors under a magnetic field (S/N = 3). The impressive results highlight the significant potential of bimetallic Cu-Ni micromotors as sensors, suggesting their promising applications in monitoring food freshness and enhancing security technology.

Molecular displacement approach for the electrochemical detection of protein-bound propofol

Propofol is one of the principal drugs used for the sedation of patients undergoing mechanical ventilation in intensive care units. The correct dosage of such sedative drugs is highly important, but current methods of determining infusion rates are limited and there is a lack of suitable methods for directly determining patient blood propofol concentrations. A significant challenge for the development of propofol sensors is that propofol demonstrates very high protein binding, leading to a low free fraction in blood. Here we present a method for improving the efficacy of an electrochemical propofol sensor by increasing the free fraction via a molecular displacement approach. When used in conjunction with a carbon nanotube/graphene oxide/iron oxide nanoparticle functionalised screen-printed electrode, it was found that this approach dramatically improved the sensor's sensitivity towards propofol. Ibuprofen was found to be the most effective displacement agent, with an optimal concentration of 30 mM. The resultant sensitivity was 2.82 nA/μg/ml/mm2 with a coefficient of variation of 0.07, and the limit of detection was 0.2 μg/ml. This approach demonstrates high specificity towards drugs commonly administered to intensive care patients.

A flexible electrochemical sensor based on AuBi bimetal for detection of Cd ions in packaged drinking water

Heavy metal ion Cd, as a toxic pollutant, can accumulate in human body through the bioaccumulation effect of food chain and poses a threat to human health. Packaged drinking water is one of the main water sources for many people, making it crucial to detect their cadmium ion levels. In this work, an AuBi bimetal film was electrodeposited onto a flexible screen-printed electrode to construct highly sensitive cadmium ion sensors. The prepared sensor could enrich trace cadmium ions in the target electrolyte, followed by sensitive detection of cadmium ions using stripping wave voltammetry. The electrochemical results demonstrated that the developed sensor based on AuBi bimetal exhibited a significant linear response to cadmium ions in the range of 50 μg/L to 800 μg/L, with a low detection limit of 11.68 μg/L (S/N=3), and it also showed good repeatability. The prepared flexible electrochemical sensor was employed to detect the cadmium ion level in five common types of packaged drinking water available on the market, and the relative standard deviation (RSD) and recovery were within normal ranges, indicating that it could achieve rapid and sensitive detection of cadmium ion level in drinking water and other foodstuffs.

Screen-Printed Nanohybrid Palladium-Based Electrodes for Fast and Simple Determination of Estradiol in Livestock

Screen-Printed Nanohybrid Palladium-Based Electrodes for Fast and Simple Determination of Estradiol in Livestock

Predicting the risk of chronic kidney disease based on uric acid concentration in stones using biosensors integrated with a deep learning-based ANN system

Elevated levels of uric acid (UA) in the body may not only lead to the formation of stones but also increase the risk of developing chronic kidney disease (CKD). This study presents a biosensor for detecting UA concentration in stones and a deep learning-based artificial neural network (ANN) system for analyzing CKD risk. The biosensor is a screen-printed electrode (SPE) chip, whose surface was modified using oxygen plasma, enabling the detection of UA concentration via cyclic voltammetry. Experimental results show a good linear relationship between UA concentration and anodic peak current within the range of 0.15–5 mM. The surface modification method for this biosensor is simple and cost-effective. The ANN system took age and creatinine values as inputs, utilizing the Chronic_Kidney_Disease dataset and supplementary data from literatures for training. After detecting the UA concentration in stones using the biosensor, the result was converted into serum uric acid concentration, allowing the estimation of creatinine level, which was then used by the ANN to assess the risk of developing CKD. This system can assist urologists in determining whether patients should seek consultation with nephrologists for early diagnosis and treatment.

A BDD-Au/SPCE-based electrochemical DNA aptasensor for selective and sensitive detection of theophylline

The proposed aptasensor using a DNA aptamer for the detection of theophylline (THEO) is being reported for the first time, as previous methods predominantly employed RNA aptamers. DNA aptamers have attracted significant attention due to their advantages over antibodies, including greater stability and cost-effectiveness, making them ideal for various diagnostic applications as biosensors. THEO, a drug commonly used in the treatment of respiratory diseases such as asthma, requires precise monitoring in the bloodstream due to its narrow therapeutic index. In this paper, we present the first optimization of THEO detection using a DNA aptamer-based sensor (aptasensor), utilizing a composite boron-doped diamond/Gold (BDD-Au) on screen-printed carbon electrodes. Thiolated DNA aptamers were immobilized on the BDD-Au surface, where they selectively targeted THEO in biological samples. Optimization of the aptasensor was achieved using a Box-Behnken design, determining optimal conditions of 3.0 μM for aptamer concentration, 90 min for aptamer immobilization time, and 1.0 mM for tris(2-carboxyethyl)phosphine concentration. The resulting DNA aptasensor demonstrated excellent selectivity for THEO, with a linear detection range from 1 to 1.0 mM and a detection limit of 52 nM. The sensor maintained stability for up to four weeks and exhibited high recovery rates when tested in blood serum, highlighting its potential for clinical monitoring of THEO levels.

A Novel Methylene Blue Indicator-Based Aptasensor for Rapid Detection of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a significant opportunistic pathogen highly prevalent in the environment, requiring early detection methods to prevent infections in vulnerable individuals. The most specific aptamer for P. aeruginosa, F23, has been used for the development of various assays and sensors for early diagnosis and monitoring. In this study, a novel F23-based electrochemical aptasensor was designed using disposal gold screen-printed electrodes (Au-SPEs) with high reproducibility. Methylene blue (MB) was used as an exogenous indicator, which significantly amplified the electrochemical signal and improved the sensitivity of detection. The aptasensor explored a limit of detection (LOD) of 8 CFU·mL-1 and high selectivity for P. aeruginosa over other interfering bacteria. Furthermore, it showed potential to detect P. aeruginosa in tap water samples, offering a point-of-care tool for rapidly controlling the growth of this bacterium in various applications.

An Ultrasensitive Electrochemical DNA‐Nano Biosensor for Monitoring Tirapazamine as Anticancer Drug Using Zno/Co3O4 Nanocomposite

AbstractIn this study, we used a screen‐printed electrode (SPE) modified with polypyrrole (PP), ZnO/Co3O4 nanocomposite, and ds‐DNA as an extremely sensitive DNA biosensor to monitor tirapazamine (TPZ) real samples. To build the ds‐DNA/PP/ZnO/Co3O4 NC/SPE biosensor, the layer‐by‐layer manufacturing process was used. The proper alteration of the SPE surface as well as the effective fabrication of the ZnO/Co3O4 nanocomposite were both validated by the physicochemical characterization techniques. As a result of improving its conductivity of electricity along with allowing charged particles to move more easily, the modified SPE demonstrated much decreased the resistance of charge transfer based on the results of electrochemical impedance spectroscopy. With the 0.43 nM LOD value, the suggested biosensor effectively measured TPZ throughout a broad concentration between 0.001 and 120 µM. Additionally, the molecular docking investigation among the TPZ molecule as well as the DNA was conducted to anticipate the TPZ contact sites with DNA and verified the experimental results. By combining the benefits of ZnO/Co3O4 nanocomposite with vital information from the molecular docking investigation, the current research lays the door for the creation of very sensitive DNA biosensors, which can be utilized to track and measure TPZ of real samples.

Simple and disposable device based on gold nanoparticles modified screen-printed carbon electrode for detection of ciprofloxacin

Simple and disposable device based on gold nanoparticles modified screen-printed carbon electrode for detection of ciprofloxacin

A Novel PCR-Free Ultrasensitive GQD-Based Label-Free Electrochemical DNA Sensor for Sensitive and Rapid Detection of Francisella tularensis

Biological warfare agents are infectious microorganisms or toxins capable of harming or killing humans. Francisella tularensis is a potential bioterrorism agent that is highly infectious, even at very low doses. Biosensors for biological warfare agents are simple yet reliable point-of-care analytical tools. Developing highly sensitive, reliable, and cost-effective label-free DNA biosensors poses significant challenges, particularly when utilizing traditional techniques such as fluorescence, electrochemical methods, and others. These challenges arise primarily due to the need for labeling, enzymes, or complex modifications, which can complicate the design and implementation of biosensors. In this study, we fabricated Graphene Quantum dot (GQD)-functionalized biosensors for highly sensitive label-free DNA detection. GQDs were immobilized on the surface of screen-printed gold electrodes via mercaptoacetic acid with a thiol group. The single-stranded DNA (ssDNA) probe was also immobilized on GQDs through strong π−π interactions. The ssDNA probe can hybridize with the ssDNA target and form double-stranded DNA, leading to a decrease in the effect of GQD but a positive shift associated with the increase in DNA concentration. The specificity of the developed system was observed with different microorganism target DNAs and up to three-base mismatches in the target DNA, effectively distinguishing the target DNA. The response time for the target DNA molecule is approximately 1010 s (17 min). Experimental steps were monitored using UV/Vis spectroscopy, Atomic Force Microscopy (AFM), and electrochemical techniques to confirm the successful fabrication of the biosensor. The detection limit can reach 0.1 nM, which is two–five orders of magnitude lower than previously reported methods. The biosensor also exhibits a good linear range from 105 to 0.01 nM and has good specificity. The biosensor’s detection limit (LOD) was evaluated as 0.1 nM from the standard calibration curve, with a correlation coefficient of R2 = 0.9712, showing a good linear range and specificity. Here, we demonstrate a cost-effective, GQD-based SPGE/F. tularensis DNA test suitable for portable electrochemical devices. This application provides good perspectives for point-of-care portable electrochemical devices that integrate sample processing and detection into a single cartridge without requiring a PCR before detection. Based on these results, it can be concluded that this is the first enzyme-free electrochemical DNA biosensor developed for the rapid and sensitive detection of F. tularensis, leveraging the nanoenzyme and catalytic properties of GQDs.

Developing Screen-Printing Processes for Silver Electrodes Towards All-Solution Coating Processes for Solar Cells.

In recent years, third-generation solar cells have experienced a remarkable growth in efficiency, making them a highly promising alternative energy solution. Currently, high-efficiency solar cells often use top electrodes fabricated by thermal evaporation, which rely on high-cost and high energy-consumption vacuum equipment, raising significant concerns for mass production. This study develops a method for fabricating silver electrodes using the screen-printing process, aiming to achieve solar cell production through an all-solution coating process. By selecting appropriate blocking-layer materials and optimizing the process, we have achieved device efficiencies for organic photovoltaics (OPVs) with screen-printed silver electrodes comparable to those with silver electrodes fabricated by thermal evaporation. Furthermore, we developed a method to cure the silver ink using near-infrared (NIR) annealing, significantly reducing the curing time from 30 min with hot air annealing to just 5 s. Additionally, by employing sheet-to-sheet (S2S) slot-die coating, we scaled up the device area and completed module development, successfully verifying stability in ambient air. We have also extended the application of screen-printed silver electrodes to perovskite solar cells (PSCs).

Electrochemical Growth of Copper Crystals on SPCE for Electrocatalysis Nitrate Reduction.

Copper is efficient, has a high conductivity (5.8 × 107 S/m), and is cost-effective. The use of copper-based catalysts is promising for the electrocatalytic reduction of nitrates. This work aims to grow and characterize copper micro-crystals on Screen-Printed Electrodes (SPEs) for NO3- reduction in water. Copper micro-crystals were grown by cyclic voltammetry. Different cycles (2, 5, 7, 10, 12, 15) of copper electrodeposition were investigated (potential ranges from -1.0 V to 0.0 V, scan rate of 0.1 V s-1). Electrodeposition generated different morphologies of copper crystals on the electrodes, as a function of the number of cycles, with various performances. The presence of numerous edges and defects in the copper micro-crystal structures creates highly reactive active sites, thus favoring nitrate reduction. The manufactured material can be successfully employed for environmental applications.

Caffeic Acid Based Polyurethane Membrane Modified Screen-Printed Electrodes and Their Application for the Simultaneous Determination of Melatonin and Serotonin

Caffeic acid (CA) based polyurethane (PU) films were synthesized and characterized for the simultaneous determination of melatonin (MT) and serotonin (5-HT). The CA based PUs were synthesized using a polyol mixture of 4,4’-diisocyanodiphenylmethane (MPI), polyethylene glycol-200 (PEG), and CA. The PEG–CA monomer units in the polyol were varied in molar ratios of 99:1, 97:3, 95:5, and 90:10. The synthesized PUs were characterized by FTIR spectroscopy and thermal analysis. These CA based PU films were coated onto screen-printed carbon electrodes (SPCEs) with varying thicknesses and used for the simultaneous determination of MT and 5-HT. Electrochemical responses of MT and 5-HT were evaluated using differential pulse voltammetry. The limit of detection and correlation coefficient for MT were 280 µM and 0.9797, respectively, while for 5-HT, the detection was 150 µM with a correlation coefficient of 0.9690. The precision, expressed as the relative standard deviation was 2.633% for MT and 4.668% for 5-HT. These findings suggest that CA based PU-modified electrodes hold potential in medical and biomedical applications.

Nafion/graphite-bismuth nanoplate with a vibration unit for portable heavy metal ion detection

Contamination of natural resources, particularly water sources, by heavy metal ions, even at low concentrations, poses a significant threat to ecosystems and human health, underscoring the importance of developing sensors with point-of-use (POU) applications. To that end, a vibration-unit-equipped portable electrochemical system (vPES) capable of extremely sensitive detection of Pb2+ and Cd2+ in water is reported herein. The vibration unit enhances sensitivity by facilitating sample diffusion, and its compactness makes it suitable for point-of-use applications through mobile phone connectivity. The system also integrates Nafion and a graphite/bismuth-nanoplate-functionalized screen-printed carbon electrode to detect heavy metals efficiently. The approach implemented in this study and validated through experiments and simulations suggests that vibration-based mixing leads to 540 % and 511 % higher Pb2+ and Cd2+ detection efficiencies, respectively, than those in the absence of vibration. Additionally, the sensor exhibits the limits of detection of 0.98 and 1.65 nM for Pb2+ and Cd2+, respectively, in laboratory environments. Samples collected from the Nakdong River in Korea and real environmental specimens—freshwater, soil, and serum—validate the detection performance. Overall, this study highlights the potential of vPES as a rapid, sensitive POU sensor for heavy metal detection, thereby bolstering environmental and public health monitoring efforts.

Electrochemical sensor for vascular endothelial growth factor based on self-assembling DNA aptamer structure

Developing vascular endothelial growth factor (VEGF) protein is essential for early cancer diagnosis and cancer treatment monitoring. This study presents the design and characterisation of an electrochemical sensor utilising a self-assembling DNA aptamer structure for the sensitive and selective detection of VEGF. The aptamer structure comprises three different parts of single-stranded DNA that are assembled prior to integration into the sensor. Polypyrrole (Ppy)-based layers were deposited onto screen-printed carbon electrodes (SPCEs) using an electrochemical deposition technique, followed by the entrapment of a self-assembled DNA aptamer structure within electrochemically formed Ppy matrix ((DNA aptamer)/Ppy). The response to the sensor toward VEGF was measured by the pulsed amperometric detection (PAD), highlighting the enhanced performance of DNA aptamer/Ppy configuration compared to bare Ppy. The sensor exhibited high sensitivity, achieving a limit of detection (LOD) of 0.21 nM for VEGF. The interaction behaviour between VEGF in the solution and the immobilise DNA aptamer/Ppy-based structure was analysed using Langmuir isotherm model. The developed electrochemical biosensor in promising for in vitro applications in early cancer diagnostics and treatment monitoring, enabling rapid screening of patient samples.

Miniaturized Electrochemical Gas Sensor with a Functional Nanocomposite and Thin Ionic Liquid Interface for Highly Sensitive and Rapid Detection of Hydrogen.

Hydrogen has been widely used in industrial and commercial applications as a carbon-free, efficient energy source. Due to the high flammability and explosion risk of hydrogen-air mixtures, it is vital to develop sensors featuring fast-responding and high sensitivity for hydrogen leakage detection. This paper presents a miniaturized electrochemical gas sensor by elaborately establishing a nanocomposite and thin ionic liquid interface for highly sensitive and rapid electrochemical detection of hydrogen, in which a remarkable response time and recovery time of approximately 6 s was achieved at room temperature. A screen-printed carbon electrode was modified with a reduced graphene oxide-carbon nanotube (rGO-CNT) hybrid and platinum-palladium (Pt-Pd) bimetallic nanoparticles to realize high sensitivity. To achieve miniaturization and high stability of the sensor, a thin-film room-temperature ionic liquid (RTIL) was employed as the electrolyte with a significantly decreased response time. The fast-responding hydrogen sensor demonstrates excellent performance with high sensitivity, linearity, and repeatability at concentrations below the lower explosive limit of 4 vol %. The engineered high-performance interface and gas sensor provide a promising and effective strategy for gas sensor design and rapid hazardous gas monitoring.

Electrochemiluminescence of Carbon Dots and Nitrogen-Doped Carbon Dots from a Microwave-Assisted Method

This research focuses on the use of carbon dots (CDs) and nitrogen-doped carbon dots (NCDs) synthesized using a microwave-assisted method as electrochemiluminescence (ECL) luminophores. CDs have been synthesized using citric acid, while various concentrations of nitrogen-doped CDs have been successfully obtained by varying the amount of urea from 1 to 3 g with citric acid to produce NCD1, NCD,2 and NCD3. The ECL mechanism of CDs and NCDs on screen-printed electrodes has been studied using cyclic voltammetry (CV). ECL emission from as-prepared CDs and NCDs was observed in PBS with potassium persulfate (K2S2O8) as a co-reactant. The addition of potassium chloride (KCl) as a supporting electrolyte displays fast electroreduction of CDs and K2S2O8 to expedite the generation of CDs and peroxydisulfate radicals that simultaneously increase ECL intensity. Furthermore, as the concentration of nitrogen-doped CDs increases, so does the intensity of the ECL. NCD3 shows the highest ECL intensity by an increment of 86.4% in comparison to CDs in PBS with the addition of K2S2O8 and KCl. Finally, optimization of ECL measurement was carried out in terms of CV potential range, concentration of luminophore, supporting electrolyte, and co-reactant using NCD3 luminophore. The CV potential range at 0 to -2 V shows 50 mV of early CV reverse onset potential that resulted in an increase of 52.9% ECL intensity. Meanwhile, 30x dilution of NCD3, 0.1 M of supporting electrolyte KCl, and 0.1 M of co-reactant K2S2O8 show the optimum value to obtain high ECL intensity.

Modification Of a Screen-Printed Carbon Electrode with Nanoporous Gold by Electrodeposition and Dealloying of a Gold-Copper Alloy

In this study, a three-dimensional structure of nanoporous gold (NPG) was made by selectively corroding copper (Cu) from gold-copper (Au-Cu) alloys using a two-step electrochemical method. Given its large surface area and interconnected porous network, nanoporous gold is a suitable material for the advancement of electrochemical sensors. The screen-printed carbon electrode (SPCE) modified with nanoporous gold (NPG/SPCE) was fabricated by electrodepositing a gold-copper alloy from gold ion (Au3+) and copper ion (Cu2+) solution via cyclic voltammetry (CV) by scanning from -0.3 V to -0.8 V for 80 cycles. The copper is then removed via a dealloying process in 3M HNO3 using the cyclic voltammogram (CV) method by scanning potential from 0 V to +1.0 V for 100 cycles at 100 mV/s. The morphology, elemental composition, and electrochemical active surface area (ECSA) of NPG/SPCE electrodes were characterized using FESEM, EDX, and CV analysis, respectively. The electrochemical performance of the NPG/SPCE was compared with bare SPCE in a 10 mM potassium ferrocyanide (K4FeCN6) solution using cyclic voltammetry. The morphological study using FESEM revealed that the NPG/SPCE had an average pore diameter of 53 nm. The quantification of elements using EDX shows that 84 % of the copper in the electrodeposited gold-copper alloy electrode was successfully removed by the dealloying process. The higher number of cycles during the dealloying process led to producing NPG with higher ECSA electrodes. The ECSA of NPG/SPCE is 12 times greater than that of bare or unmodified SPCE in an equivalent geometrical area. NPG/SPCE has a much better electron transfer surface than bare SPCE due to its high surface area and gold surface properties, making it a potential sensing material for biosensing applications.

Hierarchical Au@Pt nanoparticle/amino benzoic acid polymer-based hybrid material for labeled and label-free detection of interleukin-6: a comparative assessment.

Interleukin-6 (IL6) is a cytokine mainly involved in inflammatory processes associated with various diseases, from rheumatoid arthritis and pathogen-caused infections to cancer, where malignant cells exhibit high proliferation and overexpression of cytokines, including IL6. Furthermore, IL6 plays a fundamental role in detecting and differentiating tumor cells, including colorectal cancer (CRC) cells. Therefore, given its range of biological activities and pathological role, IL6 determination has been claimed for the diagnosis/prognosis of immune-mediated diseases. Herein, a comparative study is presentedof labeled and label-free electrochemical immunosensors involving a hierarchical Au@Pt nanoparticle/polymer hybrid material for detecting IL6. The electrochemical immunosensors were independently coupled to the surface of screen-printed carbon electrodes (SPCEs) previously modified with polymeric layers. While in the label-free immunosensor, an anti-IL6 antibody (IL6-Ab) was covalently bound to the modified SPCE surface, in the sandwich-like amperometric immunosensor, an anti-biotinylated-IL6 antibody (B-IL6-Ab) was attached to the electrode through biotin-avidin affinity interactions. The label-free format employed a straightforward detection of IL6 by differential pulse voltammetry (DPV). The resulting electrochemical immunosensors exhibited a linear dynamic range from 50 to 750pg/mL IL6, with detection limits (LOD) of 14.4 and 6.0pg/mL for label-free and sandwich-like immunosensors, respectively. This outstanding performance makes them versatile platforms for clinical analysis of a panel of biomarkers for early diagnosis/prognosis of inflammatory processes associated with oncological diseases, among other pathologies.

Modification of Screen-Printed Carbon Electrode with Nanogold for Detection of Glucose

Modification of Screen-Printed Carbon Electrode with Nanogold for Detection of Glucose