Screen-printed Sensors Research Articles

Effect of different modification by gold nanoparticles on the electrochemical performance of screen-printed sensors with boron-doped diamond electrode

Screen-printed sensors with chemically deposited boron-doped diamond electrodes (BDDE) were modified with different types of gold nanoparticles (AuNPs) according to a new original procedure. Physically and electrochemically deposited AuNPs had various sizes and also nanoporous character. They also differ in shape and density of surface coverage. The developed sensors were characterized using scanning electron microscopy and Raman spectroscopy. Their electrochemical properties were studied using cyclic voltammetry and electrochemical impedance spectrometry of selected outer sphere ([Ru(NH3)6]Cl3) and inner sphere (K3[Fe(CN)6], dopamine) redox markers. The application possibilities of such novel screen-printed sensors with BDDE modified by AuNPs were verified in the analysis of the neurotransmitter dopamine. The best analytical performance was achieved using printed sensors modified with the smallest AuNPs. The achieved limit of detection values in nanomolar concentrations (2.5 nmol L−1) are much lower than those of unmodified electrodes, which confirms the significant catalytic effects of gold nanoparticles on the surface of the working electrode. Sensors with the best electrochemical properties were successfully applied in the analysis of a model solution and spiked urine samples.

A Wearable Co-Located Neural-Mechanical Signal Sensing Device for Simultaneous Bimodal Muscular Activity Detection.

The co-located and concurrent measurement of both muscular neural activity and muscular deformation is considered necessary in many applications, such as medical robotics, assistive exoskeletons and muscle function evaluations. Nevertheless, conventional muscle-related signal perception systems either detect only one of these modalities, or are made with rigid and bulky components that cannot provide conformal and flexible interface. Herein, a flexible, easy-to-fabricate, bimodal muscular activity sensing device, which collects neural and mechanical signal at the same muscle location, is reported. The sensing patch includes a screen-printed sEMG sensor, and a pressure-based muscular deformation sensor (PMD sensor) based on a highly sensitive, co-planar iontronic pressure sensing unit. Both sensors are integrated on a super-thin (25 μm) substrate. The sEMG sensor shows a high signal-to-noise ratio of 37.1 dB, and the PMD sensor sensor exhibits a high sensitivity of 70.9 kPa -1. The responses of the sensor to three types of muscle activities (isotonic, isometric, and passive stretching) were analyzed and validated by ultrasound imaging. Bimodal signals during dynamic walking experiments with different level-ground walking speeds were also investigated. The application of the bimodal sensor was verified in gait phase estimation, and results show that the assembly of both modalities significantly reduce (p < 0.05) the average estimation error across all subjects and all walking speeds to 3.82%. Demonstrations show the potential of this sensing device for informative evaluation of muscular activities, and its abilities in human-robot interaction.

A fully printed sensor with optical readout for real-time flow monitoring

In recent years, there has been a growing interest in the development of flexible thermal flow sensing devices due to their wide-ranging applications. In this study, we present the fabrication of a screen-printed flow sensor with optical readout on a 125 μm polyethylene terephthalate substrate in a three-layer configuration. The device comprises electrodes made from a commercial silver (Ag) ink, a heating area using a commercial carbon ink, and a thermochromic (TC) layer employing a commercial ink with a standard activation temperature of 31 °C. We designed a specialized experimental setup to evaluate the performance of the optical flow sensor under static and dynamic conditions. To analyze the device’s thermal response and performance across various flow conditions, we utilized a combination of electrical measurements and infrared (IR)-optical imaging techniques. The all-printed device operates on the basis of a thermodynamic cycle frequency, which activates the TC ink, causing it to blink at a frequency related to the flow passing over the sensor. The results of our preliminary testing are highly promising, as the sensor successfully demonstrated a clear relationship between flow and optical duty cycle. This innovative device offers a contactless, low-cost, easy-to-use flow detection method and holds significant potential for various practical applications.

Silver Nanoparticles Modified Screen-Printed Electrochemical Sensor: Tool for Control of Pollutants of Emerging Concern in Bee Pollen

Silver Nanoparticles Modified Screen-Printed Electrochemical Sensor: Tool for Control of Pollutants of Emerging Concern in Bee Pollen

Screen-Printed Piezoelectric Sensors on Tattoo Paper Combined with All-Printed High-Performance Organic Electrochemical Transistors for Electrophysiological Signal Monitoring.

This work demonstrates sensitive and low-cost piezoelectric sensors on skin-friendly, ultrathin, and conformable substrates combined with organic electrochemical transistors (OECTs) for the detection and amplification of alternating low-voltage input signals. The fully screen-printed (SP) piezoelectric sensors were manufactured on commercially available tattoo paper substrates, while the all-printed OECTs, relying on an extended gate electrode architecture, were manufactured either by solely using SP or by combining SP and aerosol jet printing (AJP) on PET substrates. Applying a low-voltage signal (±25 mV) to the gate electrode of the SP+AJP OECT results in approximately five times higher current modulation as compared to the fully SP reference OECT. The tattoo paper-based substrate enables transfer of the SP piezoelectric sensor to the skin, which in turn allows for radial pulse monitoring when combined with the SP+AJP OECT; this is possible due to the ability of the conformable sensor to convert mechanical vibrations into voltage signals along with the highly sensitive current modulation ability of the transistor device to further amplify the output signal. The results reported herein pave the way toward all-printed fully conformable wearable devices with high sensitivity to be further utilized for the real-time monitoring of electrophysiological signals.

Non-enzymatic glucose detection with screen-printed chemiresistive sensor using green synthesised silver nanoparticle and multi-walled carbon nanotubes-zinc oxide nanofibers

Non-enzymatic screen-printed chemiresistive interdigitated electrodes (SPCIE) were designed and fabricated using a low-cost screen-printing method for detection of the glucose. The interdigitated electrodes (IDE) pattern was printed using conductive graphene ink on the glossy surface of the photo paper. The proposed glossy photo paper-based SPCIE are functionalized with multi-walled carbon nanotubes-zinc oxide (MWCNTs-ZnO) nanofibers to create the chemiresistive matrix. Further, to bind these nanofibers with the graphene electrode surface, we have used the green synthesized silver nanoparticles (AgNPs) with banana flower stem fluid (BFSF) as a binder solution. AgNPs with BFSF form the conductive porous natural binder layer (CPNBL). It does not allow to increase the resistivity of the deposited material on graphene electrodes and also keeps the nanofibers intact with paper-based SPCIE. The synthesized material of MWCNT-ZnO nanofibers and green synthesized AgNPs with BFSF as a binder were characterized by Ultraviolet-visible spectroscopy (UV–vis), scanning electron microscope (SEM), x-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The amperometric measurements were performed on the proposed SPCIE sensor to detect the glucose sample directly. The innovative paper-based SPCIE glucose sensor exhibits a linear corelation between current measurements and glucose concentration in the range between 45.22 μm and 20 mm, with a regression coefficient (R 2) of 0.9902 and a lower limit of detection (LoD) of 45.22 μm (n = 5). The sensitivity of the developed SPCIE sensor was 2178.57 μAmM−1cm−2, and the sensor’s response time determined was approximately equal to 18 s. The proposed sensor was also tested for real blood serum sample, and relative standard deviation (RSD) was found equal to 2.95%.

Laser-Induced Graphene for Screen-Printed Strain Sensors

Laser-Induced Graphene for Screen-Printed Strain Sensors

Zirconium Oxide Nanostructure Integrated Screen-Printed Mirabegron Voltammetric Sensors

The present study introduced the fabrication and electroanalytical characterization of a novel mirabegron (MIR) voltammetric screen-printed sensor. The sensing platform was based on zirconium oxide nanoparticles (ZrO2NPs) integrated printing carbon ink with enhanced electrocatalytic activity towards the electrooxidation of the MIR molecule at the electrode surface. Under the optimum measuring parameters, MIR exhibited an irreversible oxidation peak at 0.922 V with a diffusion-controlled reaction and the participation of one electron/proton in the electrooxidation process. The zirconium oxide nanoparticles based screen-printed electrodes (ZrO2NPs/SPEs) showed improved performance within the linear MIR concentration ranged from 10.0 to 261.8 ng ml−1 and limit of detection (LOD) value of 2.72 ng ml−1. The introduced ZrO2NPs/SPEs offered higher sensitivity with the possibility of mass production and miniaturization compared with other MIR sensors. Based on the achieved selectivity, the presented electrodes can be applied for the simultaneous differential pulse voltammetric (DPV) monitoring of MIR in the presence of various degradation contaminates and excipients. Furthermore, the presented electroanalytical approach was tested for the sensitive quantification of MIR in biological samples and pharmaceutical formulations with acceptable recovery values in agreement with the official method.

Graphene/gadolinium oxide composite modified screen-printed electrochemical sensor for detection of diclofenac sodium

This study investigates the electrochemical sensing of diclofenac sodium. A bare single screen-printed carbon electrode was modified with graphene/gadolinium (III) oxide (Gd2O3) where graphene serves as the conductive support material for the electrode. The interaction between the elements of graphene/Gd2O3 composite and diclofenac with graphene/Gd2O3 composite has been studied by density functional theory (DFT). The characterization of the nanocomposite underwent through some sophisticated characterization techniques like field-emission scanning electron microscopy (FE-SEM), Energy Dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD). Electrochemical techniques like cyclic voltammetry (CV) were used for studying the chemical kinetics and absorbance of the nanocomposite while Differential Pulse Voltammetry (DPV) was used to study the oxidation of Diclofenac. The electrochemical studies exhibit a linear range of detection from 5.89 µM to 66.7 µM concentration of the analyte. Importantly, in-silico studies based on the semi-empirical (PM6) approach strongly favoured the experimental outcomes especially, the binding features involved the both the dimer complex versus the trimer complex. The binding energy of the three components-based model (Graphene-Gd2O3-Diclofenac) has been calculated to be extremely larger than that of the two components-based model (Graphene-Diclofenac). This novel Diclofenac biosensor showed satisfactory results and it has the potential to create a great platform in the environmental monitoring system.

Enzyme-immobilized Screen-printed Sensor for One Drop of Sample Using Porous Silica Spheres

Enzyme-immobilized Screen-printed Sensor for One Drop of Sample Using Porous Silica Spheres

Recombinase polymerase amplification in combination with electrochemical readout for sensitive and specific detection of PIK3CA point mutations

As part of the ongoing evolution towards personalized anticancer therapy, mutation screening is becoming increasingly important and, therefore, also alternative detection strategies that allow for fast genetic diagnostics at the point of care. In the case of breast cancer, detecting cancer-associated point mutations in the PIK3CA gene is of particular importance for treatment decisions. We developed a recombinase polymerase amplification assay combined with an enzyme-linked electrochemical assay on multi-channel screen-printed gold sensors for specific and highly sensitive detection of three PIK3CA point mutations (H1047R, E545K, and E542K). Recombinase polymerase amplification (RPA) of the target sequences was optimized and characterized with a real-time RPA assay. Comparison with real-time PCR reveals that RPA is slightly inferior in terms of efficiency and sensitivity. However, the desired target DNA is successfully amplified at initial concentrations down to 100 copies μL−1. For electrochemical readout, biotinylated dCTP is used to label the target DNA during RPA. Single-stranded target DNA is produced with either asymmetric RPA or symmetric RPA followed by lambda exonuclease digestion. Characterization of the two different approaches in terms of sensitivity results in comparable detection limits (229 copies μL−1 and 224 copies μL−1, respectively), though RPA followed by lambda exonuclease digestion yields significantly higher currents. Finally, this method, together with a designed wild-type blocking oligo that inhibits binding of the wild-type target DNA during probe-target hybridization, allows for detecting the PIK3CA point mutations H1047R, E545K, and E542K in the presence of wild-type target DNA when the proportion of mutant target DNA is >20%.

Synthesis and Applications of Crown Ether-Linked Metal–Organic Framework Composite-Based Sensors for Stripping Voltammetric Determination of Lead

The present work demonstrates the construction and electrochemical characterization of novel disposable screen-printed carbon sensors integrated with functionalized MIL-53-NH2 metal–organic framework cross-linked with crown ethers and calixarene macrocyclic compounds for sensitive differential pulse voltammetric determination of lead ions in tap, surface water and biological fluid samples. The electroanalytical parameters were optimized regarding the nature of the electrode modifier, supporting electrolyte, the working pH value, scan rate, deposition potential, deposition time, reproducibility of measurement and the operational lifetime. Working electrodes dropcasted with MIL-53-NH2-dibenzo-24-crown-8-ether nanocomposite (MOFCE24) showed the proper performance within the lead concentration ranging from 13.75 to 217.83 ppb with LOD and LOQ values of 3.18 and 9.62 ppb, respectively. The synergistic effect of the metal–organic frameworks as transducer and dibenzo 24-crown-8-ether as sensing elements accelerates the electron transfer process at the electrode surface and improves the sensor selectivity through complexation of the lead ions with the crown ether moiety. The fabricated sensors showed high measuring reproducibility with long operational life time (60 days), which can be attributed to the formation of cross-linked ionophore/metal–organic framework with limited leaching of the sensing element in the measuring solution. The introduced sensors were utilized for the onsite voltammetric determination of lead in environmental and biological samples with acceptable average recoveries comparable with the graphite furnace atomic absorption spectrometric method.

Flexible Screen-Printed Amperometric Sensors Functionalized With Spray-Coated Carbon Nanotubes and Electrodeposited Cu Nanoclusters for Nitrate Detection

In this work, we present a novel, sensitive, easy-to-fabricate, flexible amperometric sensor constituted by screen-printed silver (Ag) electrodes functionalized with a copper (Cu) film electrodeposited on top of a spray coated network of single-walled carbon nanotubes (SWCNTs). The Cu/SWCNTs/Ag electrode showed excellent catalytic activity towards the electro-reduction of nitrate ions at neutral pH with a significant increase in cathodic peak currents in comparison with the electrode without SWCNTs (Cu/Ag). The developed Cu/SWCNTs/Ag sensor showed a wide linear detection range from 0.5 μM to 6.0 mM (0.31 mg/l to 372.02 mg/l) with good sensitivity (18.39 μA/mM) and a calculated limit of detection (LOD) of 0.166 nM (10.29 μg/l). It also showed a good selectivity (maximum standard deviation (SD) was 3.25 μA) towards different interfering ions (Fe2+, Na+, Cu2+, SO42-, CH3COO-, Cl-, NO2- and HCO3-), as well as good reproducibility, mechanical durability, time and temperature stability. In real sample analysis (tap and river water), the sensor exhibited good agreement with the compared outcome of high-performance liquid chromatography (HPLC) measurements, proving to be a promising analytical tool for the detection of nitrate in water.

A nanoporous screen-printed carbon sensor for environmental and clinical monitoring of the antibiotic ciprofloxacin

A very sensitive, fast and simple electrochemical procedure using a nanoporous screen-printed carbon electrode (NPSPCE) was developed for the determination of the fluoroquinolone antibiotic ciprofloxacin (CFX). Changes in the surface morphology and electrochemical properties of the SPCE before and after pre-anodization were examined using scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). CV studies also demonstrated unequivocally adsorption controlled and irreversible oxidation of CFX. Using optimized conditions, the developed procedure is characterized by excellent selectivity and high sensitivity, allowing to achieve a very low limit detection (6.3 × 10−11 mol/L). The measurements taken allow us to consider the NPSPCE as a very effective tool for direct determination of CFX in samples with a complex matrix such as sewage and body fluids. The developed environment friendly sensor and procedure meet the requirements of green chemistry (reduction of toxic chemicals/reagents, and generation of minimal waste).

Voltammetric analysis of mephenoxalone drug in pharmaceutical and biological samples using novel screen-printed sensor with boron-doped diamond electrode

A novel screen-printed sensor (SPE) with boron-doped diamond electrode (BDDE) for determination of a muscle relaxant and mild anxiolytic mephenoxalone (MNL) was developed. The sensor utilizes the electrochemical oxidation of MNL, which was firstly studied in aqueous solution using oxygen terminated BDDE. MNL provided an irreversible anodic signal at a potential of + 1380 mV (vs. Ag/AgCl/KCl sat.) over a wide pH range. Britton-Robinson buffer (pH 9) was selected as a suitable electrolyte and the square-wave voltammetric method (SWV) was developed. The low detection limit (55 nmol L–1), wide linear dynamic range (0.1–30 µmol L−1), and good recovery in the analysis of model and pharmaceutical samples (RSD < 1.77%) were attained. Subsequently, the new method was successfully transferred to SPE, which can find application in point-of-care testing. These sensors proved excellent sensitivity and reproducibility in the analysis of biological samples (RSD < 4.94%) without pretreatment and no need of electrolyte. Based on gas chromatography with mass spectrometry (GC-MS) analysis of preparative electrolysis products, a mechanism of the electrochemical oxidation of MNL was proposed, describing the oxidative cleavage of the alkoxybenzene ring. These results were supported with HOMO spatial distribution calculations and atomic charges calculations for arising radical cations, and with spectroelectrochemical measurements.

A Portable Nanoporous Gold Modified Screen-Printed Sensor for Reliable and Simultaneous Multi-Vitamins Analysis

A Portable Nanoporous Gold Modified Screen-Printed Sensor for Reliable and Simultaneous Multi-Vitamins Analysis

Zirconium copper oxide microflowers based non-enzymatic screen-printed electrochemical sensor for the detection of glucose in saliva, urine, and blood serum.

Zirconium copper oxide microflowers (Zr/CuO MF) based non-enzymatic sensor was developed for glucose detection in saliva, urine, and blood. An easy urea hydrolysis method was employed for the synthesis of the metal oxide and further calcined to improve the catalytic property. The flower-like morphology of the Zr/CuO was confirmed by SEM analysis and the presence of copper and zirconium was examined using energy dispersive X-ray analysis (EDAX). The Zr/CuO MF modified screen-printed electrodes exhibited excellent glucose sensing performance in 0.15M NaOH medium and could quantify glucose in the range from 10µM to 27mM. A high sensitivity of 1.815 ± 0.003mAmM-1cm-2 was obtained for lower glucose concentration from 15µM to 3mM and 1.250 ± 0.006mAmM-1cm-2 for higher concentration glucose from 3 to 27mM. The limit of detection of the fabricated sensor was found to be 0.8µM. The sensor displayed high selectivity and stability towards glucose in different body fluids like saliva, urine, and blood serum at a working potential of 0.6V (vs. Ag/AgCl). In saliva, urine, and serum samples, the sensor exhibited excellent recovery of 95-108, 92-108, and 93-101% in saliva, urine, and serum, respectively, with a relative standard deviation of less than 10%, demonstrating high accuracy and reliability of the sensor. The developed sensor is promising for developing an invasive and non-invasive point-of-care testing device for glucose detection.

Comparison of printing techniques for the fabrication of flexible carbon nanotube-based ammonia chemiresistive gas sensors

Even though a plethora of printing technologies are currently available and their potential for the fabrication of low-cost and flexible sensors has been widely investigated, systematically based, and statistically sustained comparative studies are missing in the literature. In this work, we compare screen, inkjet, and dispense printing for the fabrication of carbon nanotube (CNT)-based ammonia (NH3) chemiresistive flexible gas sensors for the first time. Moreover, we report the first CNT-based gas sensor fabricated via Voltera printer. The devices were made of a thin layer of spray-coated CNTs and printed silver-based interdigitated electrodes. To draw a thoughtful comparison the same sensor layout, materials, and fabrication flow were used. The device morphological features were acquired through microscopic, atomic force microscope, and 3D images; additionally, the response to NH3 as well as the printing process characteristics for each technique was analyzed. From 300 µm nominal spacing between lines, we obtained a decrease of 25%, 13%, and 5% on the printed spacings with dispense, screen, and inkjet printing, respectively. At 100 ppm of NH3, a maximum response of 33%, 31%, and 27% with the dispense-, inkjet-, and screen-printed sensors were found, respectively. Statistical differences were observed between the mean values on the NH3 response of dispense- compared to the inkjet- and screen-printed sensors, which in effect showed the highest response in the Tukey test. This demonstrated that the fabrication technique employed can induce a different response mainly driven by the printed outcomes. Following a holistic approach that includes the sensor response, the application, the market perspective, and the process versatility, we suggest screen printing as the most suitable method for CNT-based NH3 gas sensor fabrication.

Circular Sensing of Nitrate Levels in Water With Flexible Screen-Printed Sensors on Biodegradable Cellulose Substrate

Circular Sensing of Nitrate Levels in Water With Flexible Screen-Printed Sensors on Biodegradable Cellulose Substrate

Quantification of Statins in Pharmaceutical Products Using Screen-Printed Sensors Based of Multi-Walled Carbon Nanotubes and Gold Nanoparticles

This study describes the use of electrochemical sensors to detect and quantify several statins (rosuvastatin and simvastatin) in pharmaceutical products. Two types of commercially screen-printed sensors were used and compared: one based on carbon (SPCE) and the other modified with gold nanoparticles and multi-walled carbon nanotubes (SPE/GNP-MWCNT). Cyclic voltammetry was employed for determination. The AuNP-MWCNTs/SPCE sensor outperformed the SPCE sensor, displaying excellent electrochemical properties. It demonstrated high sensitivity with low limits of detection (LOD) and quantification (LOQ) values: 0.15 µM and 5.03 µM, respectively, for rosuvastatin and 0.30 µM and 1.01 µM, respectively, for simvastatin. The sensor had a wide linear range of 20–275 µM for rosuvastatin and 50–350 µM for simvastatin. Using the AuNP-MWCNTs/SPCE sensor, rosuvastatin and simvastatin were successfully quantified in pharmaceutical products. The results were validated towards producer-reported values (standardized drugs) and a conventional analysis method (FTIR). The sensor exhibited excellent stability, reproducibility, and analytical recovery ranging from 99.3% to 106.6% with a low relative standard deviation (RSD) of less than 1%. In conclusion, the AuNP-MWCNTs/SPCE sensor proved to be a reliable and sensitive tool for detecting and quantifying statins in pharmaceutical products. Its superior electrochemical properties, low LOD and LOQ values, wide linear range, and high analytical recovery make it a promising choice for pharmaceutical quality control.