Screen-printed Carbon Nanotube Research Articles

Flexible electrode on e-textile based on screen-printed silver ink carbon nanotube

Flexible electrode on e-textile based on screen-printed silver ink carbon nanotube

Exploring various carbon nanomaterials-based electrodes modified with polymelamine for the reagentless electrochemical immunosensing of Claudin18.2

Claudin18.2 (CLDN18.2) is a tight junction protein often overexpressed in various solid tumors, including gastrointestinal and esophageal cancers, serving as a promising target and potential biomarker for tumor diagnosis, treatment assessment, and prognosis. Despite its significance, no biosensor has been reported to date for the detection of CLDN18.2. Here, we present the inaugural immunosensor for CLDN18.2. In this study, an amine-rich conducting polymer of polymelamine (PM) was electrografted onto different carbon nanomaterial-based screen-printed electrodes (SPEs), including carbon (C), graphene (Gr), graphene oxide (GO), carbon nanotube (CNT), and carbon nanofiber (CNF) via cyclic voltammetry. A comparative study was performed to explore the best material for the preparation of the PM-modified electrodes to be used as in-situ redox substrate for the immunosensor fabrication. The surface chemistry and structural features of pristine and PM-deposited electrodes were analyzed using Raman and scanning electron microscopy (SEM) techniques. Our results showed that the PM deposited on Gr and CNT/SPEs exhibited the most significant and stable redox behavior in PBS buffer. The terminal amine moieties on the PM-modified electrode surfaces were utilized for immobilizing anti-CLDN18.2 monoclonal antibodies via N-ethyl-N′-(3-(dimethylamino)propyl)carbodiimide/N-hydroxysuccinimide chemistry to construct the electrochemical immunosensor platform. Differential pulse voltammetry-based immunosensing of CLDN18.2 protein on BSA/anti-CLDN18.2/PM-Gr/SPE and BSA/anti-CLDN18.2/PM-CNT/SPE exhibited excellent selectivity against other proteins such as CD1, PDCD1, and ErBb2. The limits of detection of these two immunosensor platforms were calculated to be 7.9 pg/mL and 0.104 ng/mL for the CNT and Gr immunosensors, respectively. This study demonstrated that the PM-modified Gr and CNT electrodes offer promising platforms not only for the reagentless signaling but also for covalent immobilization of biomolecules. Moreover, these platforms offer excellent sensitivity and selectivity for the detection of CLDN18.2 due to its enhanced stable redox activity. The immunosensor demonstrated promising results for the sensitive detection of CLDN18.2 in biological samples, addressing the critical need for early gastric cancer diagnosis.

“Double-high” field electron emission of screen-printed carbon nanotube cathodes

High performance cold cathodes based on carbon nanotubes (CNTs) are fabricated by using a screen-printing method. The CNT cathode shows stable electron emission with no significant deterioration and the temperature-dependent emission has been also investigated. The results demonstrate that the maximum emission current of CNT emitters can be reached to 16.9 mA at electric field of 7.6 V μm−1, corresponding to super-high current density of 562 mA cm−2 under continuous driving mode. Under pulse driving mode, the peak current of 70 mA with a high current density of 2333 mA cm−2 is further obtained at electric field of 11.5 V μm−1. The presented CNT emitters display high electron emission both in total current and current density under continuous and pulse driving modes. This work will open a new avenue towards designing “double-high” CNT cold electron sources for broad application prospects in vacuum electronic devices requiring high current and density simultaneously.

Glucose Oxidase/Egg White Protein Microparticles with a Redox Mediator for Glucose Biosensors on a Screen-Printed Electrode and a Decomposable Electrode.

Glucose oxidase (GOx) is a typical model enzyme used to create biosensors. Exploring a strategy to prepare ready-to-use functional enzymatic microparticles combining GOx and food-based proteins offers compelling advantages. However, no reports exist on the integration of egg white materials to synthesize functional biorecognition particles with glucose oxidation catalytic functions for electrochemical biosensors. Here, we demonstrate functional microparticles combining egg white proteins, GOx, and 9,10-phenanthrenequinone (PQ). The egg white proteins crosslink to form three-dimensional scaffolds to accommodate GOx and redox molecules. The PQ mediator enhances electron transfer between the electrode surface and the GOx enzyme's flavin adenine dinucleotides. The functional microparticles are directly applied to the printed electrode. The performance of these microparticles is evaluated using a screen-printed carbon nanotube (CNT)-modified electrode coated with GOx/PQ/egg white protein microparticles. The analytical performance of the system exhibits a linear range of 0.125-40 mM, with a maximum current (Imax) and a Michaelis-Menten constant (Km) being 0.2 µA and 4.6 mM, respectively. Additionally, a decomposable electrode composed of CNTs and edible oil conjugated with functional enzyme microparticles is shown to undergo degradation under gastric conditions. Utilizing food-based proteins to accommodate enzymes and to create redox-active microparticles for catalyzing glucose oxidation offers advantages in developing affordable and degradable bioelectrodes. This concept holds promise for advancing biocompatible electrodes in biosensor and bioelectronics applications.

Redox-Mediated Gold Nanoparticles with Glucose Oxidase and Egg White Proteins for Printed Biosensors and Biofuel Cells

Glucose oxidase (GOx)-based electrodes are important for bioelectronics, such as glucose sensors. It is challenging to effectively link GOx with nanomaterial-modified electrodes while preserving enzyme activity in a biocompatible environment. To date, no reports have used biocompatible food-based materials, such as egg white proteins, combined with GOx, redox molecules, and nanoparticles to create the biorecognition layer for biosensors and biofuel cells. This article demonstrates the interface of GOx integrated with egg white proteins on a 5 nm gold nanoparticle (AuNP) functionalized with a 1,4-naphthoquinone (NQ) and conjugated with a screen-printed flexible conductive carbon nanotube (CNT)-modified electrode. Egg white proteins containing ovalbumin can form three-dimensional scaffolds to accommodate immobilized enzymes and adjust the analytical performance. The structure of this biointerface prevents the escape of enzymes and provides a suitable microenvironment for the effective reaction. The bioelectrode's performance and kinetics were evaluated. Using redox-mediated molecules with the AuNPs and the three-dimensional matrix made of egg white proteins improves the transfer of electrons between the electrode and the redox center. By engineering the layer of egg white proteins on the GOx-NQ-AuNPs-mediated CNT-functionalized electrodes, we can modulate analytical performances such as sensitivity and linear range. The bioelectrodes demonstrate high sensitivity and can prolong the stability by more than 85% after 6 h of continuous operation. The use of food-based proteins with redox molecule-modified AuNPs and printed electrodes demonstrates advantages for biosensors and energy devices due to their small size, large surface area, and ease of modification. This concept holds a promise for creating biocompatible electrodes for biosensors and self-sustaining energy devices.

Analytical eco-scale determination of vortioxetine using advanced electrochemical platform for screen-printed disposable multiwalled carbon nanotube electrode in the presence of an anionic surfactant

A disposable screen-printed electrode, modified by multiwalled carbon nanotubes, was created as a sensor for the measurement of vortioxetine hydrobromide as an inexpensive quick and convenient method.

Overall control of field emission from carbon nanotube paste-emitters through macro-geometries for high-performance electron source applications

Field-emitted electron beams from nanometer-scale materials like carbon nanotubes (CNTs) have the potential to regenerate electron source devices based on performance, form factor, and usability. Practically, digital X-ray tubes fabricated with strongly adhesive CNT paste-emitters produce very short and exact X-ray pulses compared with conventional thermionic devices, providing greatly enhanced X-ray images with minimal X-ray dose. Although screen-printed CNT paste-emitters have been studied for a relatively long time, their field electron emissions have not been fully understood or optimally designed for specific electron source applications, because of the complexity arising from the intrinsic printing property, along with process reproducibility and device configurations. Here, we report an approach for the overall control of field electron emissions from multi-dot CNT paste-emitters, including electron-beam trajectories based on emitter dot size, dot array distribution, and triode configurations, using experiments and computational simulations. The crucial factors, such as the unit dot size of the CNT emitters and the aspect ratio of the triode structure, were successfully extracted, and can be used in designing and producing high-performance field-emitted electron source devices.

Polymer Supported Electron Transfer Between PQQ-GDH and Screen-Printed Carbon Nanotubes Electrode With Immobilized Enzyme Modified by the Combination of Two Different Materials: poly(3,4-Ethylenedioxythiophene) and Gold or Magnetic Nanoparticles

Polymer Supported Electron Transfer Between PQQ-GDH and Screen-Printed Carbon Nanotubes Electrode With Immobilized Enzyme Modified by the Combination of Two Different Materials: poly(3,4-Ethylenedioxythiophene) and Gold or Magnetic Nanoparticles

Synergistic Effect of Screen-Printed Single-Walled Carbon Nanotubes and Phosphorylated Cellulose Nanofibrils on Thermophysiological Comfort, Thermal/UV Resistance, Mechanical and Electroconductive Properties of Flame-Retardant Fabric.

Single-walled carbon nanotubes (SWCNTs) and phosphorylated nanocellulose fibrils (PCNFs) were used as functional screen-print coatings on flame-retardant (FR) fabric, to improve its thermal resistance and thermophysiological comfort (wetting, water vapour and heat transmission) properties, while inducing it with electrical conductivity and UV protection. The effect of PCNF printing, followed by applying a hydrophobic polyacrylate (AP), on the same (back/B, turned outwards) or other (front/F, turned towards skin) side of the fabric, with and without the addition of 0.1–0.4 wt% SWCNTs, was studied by determining the amount of applied coating and its distribution (microscopic imaging), and measuring the fabric’s colour, air permeability, thickness, mechanical, flame and abrasion resistance properties. Due to the synergistic effect of PCNF and SWCNTs, both-sided printed fabric (front-side printed with PCNF and back-side with SWCNTs within AP) resulted in an increased heat transfer (25%) and an improved thermal resistance (shift of degradation temperature by up to 18 °C towards a higher value) and UV protection (UPF of 109) without changing the colour of the fabric. Such treatment also affected the moisture management properties with an increased water-vapour transfer (17%), reduced water uptake (39%) and asymmetric wettability due to the hydrophilic front (Contact Angle 46°) and hydrophobic back (129°) side. The increased tensile (16%) and tear (39%) strengths were also assessed in the warp direction, without worsening the abrasion resistance of the front-side. A pressure-sensing electrical conductivity (up to 4.9∙10−4 S/cm with an increase to 12.0∙10−4 S/cm at 2 bars) of the SWCNT-printed side ranks the fabric among the antistatic, electrostatic discharge (ESD) or electromagnetic interference (EMI) shielding protectives.

A Cylindrical Triode Ultrahigh Vacuum Ionization Gauge with a Carbon Nanotube Cathode.

In this study, a cylindrical triode ultrahigh vacuum ionization gauge with a screen-printed carbon nanotube (CNT) electron source was developed, and its metrological performance in different gases was systematically investigated using an ultrahigh vacuum system. The resulting ionization gauge with a CNT cathode responded linearly to nitrogen, argon, and air pressures in the range from ~4.0 ± 1.0 × 10−7 to 6 × 10−4 Pa, which is the first reported CNT emitter-based ionization gauge whose lower limit of pressure measurement is lower than its hot cathode counterpart. In addition, the sensitivities of this novel gauge were ~0.05 Pa−1 for nitrogen, ~0.06 Pa−1 for argon, and ~0.04 Pa−1 for air, respectively. The trend of sensitivity with anode voltage, obtained by the experimental method, was roughly consistent with that gained through theoretical simulation. The advantages of the present sensor (including low power consumption for electron emissions, invisible to infrared light radiation and thermal radiation, high stability, etc.) mean that it has potential applications in space exploration.

Facile Screen-Printed Carbon Nanotube Electrode on Porous Substrate with Gold Nanoparticle Modification for Rapid Electrochemical Gas Sensing

Gas sensors have attracted extensive attentions due to their vital roles in various applications. However, gas sensors featuring long lifetime, fast response and low cost still remain challenging. This paper presents a facile screen-printed carbon nanotube electrode on porous polytetrafluoroethylene (PTFE) with room temperature ionic liquid (RTIL) for rapid gas sensing. Screen printing technique was implemented on porous PTFE substrate to form three-electrode system using carbon nanotube ink and silver ink. Thus, gases can directly diffuse through the porous substrate rather than supporting electrolyte for rapid detection. RTIL was utilized as the supporting electrolyte that ensures long sensor lifetime. With gold nanoparticles modification, the sensor exhibited enhanced electrochemical performance for gas detection. Chronoamperometry was conducted to evaluate the sensor performance from 2.1% oxygen to 12.6% oxygen, validating good sensitivity and linearity. The sensor also presented good repeatability, stability and reproducibility in the tests. Due to the unique porous substrate of the sensor, the response time can be as low as ∼14 s that achieves rapid oxygen sensing. In summary, the sensor was validated with satisfactory performance, which is promising for wearable gas sensing and acute gas exposure alerting.

Highly enhanced field emission properties of a carbon nanotube cathode on a titanium alloy substrate modified by alkali

Field emission electron sources with low turn-on electric fields, high emission current density, and good stability are of paramount importance in widespread applications, and in particular vacuum nanoelectronic equipment. Herein, an alkali modification approach was rationally designed to tailor the morphology of the commonly used compact and planar titanium alloy substrate. As expected, the modified substrate exhibited an interconnected porous network morphology, which offers remarkably strengthened adhesion with the screen-printed carbon nanotube cathode atop. As a result, the devices delivered comprehensively improved performance. Specifically, in the continuous driving mode, the turn-on electric field was as low as 0.79 V/μm, while the emission current of 85.13 mA/cm2 was relatively high. In parallel, in the pulse driving mode, the emission current density reached 1.266 A/cm2 under an electric field of 6.1 V/μm. Encouragingly, the cathode exhibited rather decent emission stability even under continuous operation for hours. This work provides a practical strategy for further enhancement of the field emission performance of carbon nanotube cathodes and highlights the significance of engineering titanium alloy substrates in future development.

Nanohybrid electrochemical enzyme sensor for xanthine determination in fish samples.

An amperometric biosensor for xanthine was designed, based on covalent immobilization of xanthine oxidase (XO) of Bacillus pumilus RL-2d onto a screen-printed multi-walled carbon nanotubes gold nanoparticle-based electrodes (Nano-Au/c-MWCNT). The carboxyl groups at the electrode surface were activated by the use of 1-Ethyl-3-(3-dimethylaminopropyl carbodiimide) (EDC) and N-hydroxysuccinimide (NHS). The working electrode was then coated with 6 μL of xanthine oxidase (0.273 U/mg protein). The cyclic voltammetry (CV) study was done for the characterization of the sensor using [K3Fe(CN)6] as an artificial electron donor. The sensitivity (S) and the limit of detection (LOD) of the biosensor were 2388.88 µA/cm2/nM (2.388 µA/cm2/µM) and 1.14nM, respectively. The developed biosensor was used for determination of fish meat freshness.

Screen-printed Dual-Particle-Containing Multicomponent-Blending Carbon Nanotube Cathode: Enhancement of Electron Emission Characteristics, Current Emission Stability, and Uniformity

The electron emission characteristics, current emission stability, and uniformity of screen-printed carbon nanotube were enhanced by introducing a novel dual-particle-containing multicomponent-blending carbon nanotube cathode via the comprehensive combination of baking in the air and sintering in the inert gas atmosphere. The dual-particle-containing multicomponent-blending carbon nanotube cathode’s design and manufacturing improvements ensured its steeper emission curve variation amplitude, larger maximum emission current, better electron emission current of 806.7 μA was only 2.56 V/μm. When it was increased from 2.78 to 2.91 V/μm, the enhancing current emission amplitude of the proposed cathode was increased by 600.7 μA versus 324.1 μA of the conventional non-blending carbon nanotube cathode. The maximum emission current of the proposed cathode was 3762.5 μA. After the vacant static state of 72 h, the measured emission current had no obvious attenuation, and the fluctuation rate of emission current did not exceed 5%. The backlight unit with dual-particle-containing multicomponent-blending carbon nanotube cathode was sealed, and the obtained emission image had high luminescence brightness and uniformity.

Monitoring pH Using Alizarin-modified Commercial Screen-printed Electrodes

A pH-sensor based on alizarin-modified screen-printed multiwalled carbon nanotubes (MWCNT-SPE, Orion High Technologies) imbedded in Nafion® shows a linear dependence between the oxidation potential and the pH from pH 0 to pH 10. This modified MWCNT-SPE is compared to a commercial alizarin SPE (DRP 110ALI, Metrohm - DropsSens). In addition to this technical application, these pH sensors seem to be a good didactic alternative to the widely used pH glass electrode, which many students find hard to understand.

Flexible Screen-Printed CNT Electrode on Porous PTFE Substrate with Gold Nanoparticle Modification for Rapid Electrochemical Gas Sensing

Flexible Screen-Printed CNT Electrode on Porous PTFE Substrate with Gold Nanoparticle Modification for Rapid Electrochemical Gas Sensing

Amperometric detection of triclosan with screen-printed carbon nanotube electrodes modified with Guinea Grass (Panicum maximum) peroxidase

Triclosan is a compound with antimicrobial activity broadly used in consumer products. Because of its well documented toxicity, the amount of triclosan present in different products needs to be tightly controlled. This paper outlines a new amperometric sensor for triclosan detection consisting of a screen-printed carbon nanotube electrode (SPCNE) modified w ith Guinea grass peroxidase (GGP). The GGP-modified S PCNE was a ble t o d etect an enhanced electrochemical response of triclosan, unlike the bare SPCNE. The cyclic voltammograms of the GGP-modified SPCNE in a solution of potassium ferrocyanide showed an increase in the current values and linearity between scan rates and oxidation peak currents, suggesting a surface controlled process. The GGP-modified SPCNEs howed an excellent electrocatalytic activity to triclosan oxidation, at a redox potential of 370 mV, in the presence of hydrogen peroxide, exhibiting a linear response between 20 mM to 80 mM and a detection limit of 3 µM. This new amperometry system, based on carbon nanotubes integrated with GGP, becomes a potential tool for environmental analysis and food quality control.

Determination of a natural (17β-estradiol) and a synthetic (17α-ethinylestradiol) hormones in pharmaceutical formulations and urine by adsorptive stripping voltammetry

An efficient, fast and sensitive method for the determination of 17β-estradiol, (E2) and 17α-ethinylestradiol (EE2) in pharmaceutical formulations and in urine was developed and validated using a hanging mercury drop electrode (HMDE), screen printed carbon electrodes (SPCE), and screen printed carbon nanotube electrodes (SPCNTE). Both analytes are adsorbed on the working electrodes. To obtain sensitive and selective methods, the effects of various parameters such as pH, adsorption potential, and time (Eads, tads) were optimized. The optimum experimental conditions chosen for the two analytes were pH: 10.0; Eads: −0.60 and tads: 30 s, when HMDE was used. Under these conditions, one reduction signal was found at −1.31 V for E2 and two reduction signals at −0.23 V and −1.20 V for EE2. The detection limits (DLs) were found to be 0.3 μg L−1 for E2, 14.8 μg L−1 for EE2 at −0.23 V, and 9.7 μg L−1 for EE2 at −1.20 V. On the other hand, in screen printed electrodes E2 and EE2 present oxidation of the phenolic hydroxyl groups at 0.30, 0.31, 0.32, and 0.33 V (pH:10) with DLs of 242, 277; 182, and 191 μg L−1 for SPCE and SPCNTE, respectively. The method was successfully applied to the determination of these analytes in Primaquin® (E2), Gynera® (EE2), spiked urine (with EE2), and urine samples of women who used Tinelle® (EE2) as contraceptive drug.

A hybrid glucose fuel cell based on electrodeposited carbon nanotubes and platinized carbon.

Herein, we report on a hybrid fuel cell using electrodeposited multi-walled carbon nanotubes (MWCNTs) as a bioanode template for the immobilization of pyrolloquinoline quinone glucose dehydrogenase (PQQ-GDH) and electrodeposited platinized screen printed carbon nanotubes as the cathode. By depositing these nanostructures, high surface area is realized, wherein efficient direct electron transfer and excellent bioelectrocatalytic performance is achieved. The hybrid fuel cell comprised Nafion/PQQ-GDH/MWCNTs as the bioanode and a platinized carbon as the cathode to oxidize the glucose fuel and reduce oxygen, respectively. The hybrid fuel cell generated an open circuit voltage and a short circuit current density of 345 mV and 352.48 μA/cm2, respectively. The maximum power density of 58.08 μW/cm2 at a cell voltage of 198.5 mV is achieved at physiological conditions. This hybrid glucose fuel cell may be helpful for exploiting novel nanostructure carbon and platinum derived electrode substrate framework that incorporates the advantages of both enzymatic and non-enzymatic glucose fuel cells. The method employed herein further shows promise in the development of biomedical power source to drive bio-implantable devices without the use of batteries.

Effects of short-time plasma treatment in the magnetron sputtering equipment on various carbon nanotubes for applied to LCD backlight unit

The field emission and luminescent properties of various (single-walled CNTs, double-walled CNTs, multi-walled CNTs, and carbon nanofibers) screen-printed carbon nanotubes (SP-CNTs) that were straightened using plasma treatment in the magnetron sputtering equipment (MSE) for a short time were investigated. The SP-CNTs investigated CNT field emitter arrays for back light unit (BLU) in liquid crystal display (LCD). The plasma treatment in the MSE enhanced the emission properties of the single-walled CNTs (SWCNTs) and double-walled CNTs (DWCNTs): the emission uniformity and number of emission sites increased. Recurring problems associated with SW and DW SP-CNTs such as bent and/or buried CNTs and degradation of binder–residue-induced emission were ameliorated by inducing protrusion from the binder and permanent straightening of the SW and DW SP-CNTs as a result of treatment. The multi-walled CNTs (MWCNTs) and carbon nanofibers (CNFs) had partial emission sites with poor emission factors. The results of the present study suggest that plasma treatment in the MSE of SW and DW SP-CNTs is an effective method for achieving uniform field emission and reducing the aging.