Sensor Electrode Research Articles

Methanol detection with Au-nanoparticles decorated-PPyC-SnO2 nanocomposites using PEDOT:PSS polymer by differential pulse voltammetry

In this approach, sensitive development of methanol electrochemical sensor based on Au-nanoparticles decorated polypyrrole carbon with tin dioxide nanocomposites (Au NPs-PPyC-SnO2 NCs) were prepared and deposited onto glassy carbon electrode (GCE) to make sensor probe using PEDOT:PSS polymer as a conducting binder. The newly developed Au NPs-PPyC-SnO2 NCs were prepared through wet chemical and photo-reduction techniques in lab-made experimental scales, resulting in a morphology that promotes electrochemical reactions for detecting unsafe methanol under ambient conditions using three-electrode systems by differential pulse voltammetry (DPV). The sensor exhibited higher sensitivity (4.2373 µAµM-1cm−2), lower limit of detection (LOD; 2.39 ± 0.12 µM), and a wide linear detection range (LDR; 30.0 to 300.0 µM), which measured from the slope of the calibration curve from concentration variation analyses by considering the active surface area of the coated GCE. To validate its practical application, the fabricated Au NPs-PPyC-SnO2 NCs/GCE sensor electrode was tested for several real samples. It was found a satisfactory performance in the detection of methanol that was observed by using the electrochemical DPV technique with the recovery approach for the fabricated Au NPs-PPyC-SnO2 NCs/GCE sensor probe. It has introduced a new route for the sensitive detection of target methanol with gold-decorated nanocomposite materials in the protection of environmental and ecological fields using an electrochemical approach on a large scale.

Self-supporting nickel-doped V2O5 nanoarrays as bifunctional electrodes for wearable aqueous zinc-ion batteries and pressure sensors

Vanadium pentoxide (V2O5), due to its distinctive open-framework construction and significant theoretical capacity, has widespread applications in the rapid development of aqueous zinc-ion batteries (AZIBs) and pressure sensors. However, V2O5 exhibits rapid capacity degradation and poor cycling stability due to its low electrical conductivity and ion diffusion rate, limiting its vast application prospects. Therefore, the self-supporting V2O5 nanoarrays employing a Ni doping strategy on flexible carbon substrates act as an AZIBs cathode material (Ni–V2O5@CNTF), which possesses an enlarged interlayer space and high ion conductivity to provide a stable crystal structure for fast and reversible Zn2+ insertion/extraction. More notably, the assembled Zn/Ni–V2O5@CNTF battery achieves a high capacity of 398.85 mAh cm−3 at 0.1 A cm−3, superior rate performance and cycling stability for 2000 cycles. In addition, the V2O5 nanoarrays grown on carbon cloth serving as the functional electrode material (Ni–V2O5@CC) are applied in a flexible resistive pressure sensor, exhibiting a high sensitivity of 0.8 kPa−1 from 0 to 5.0 kPa and stable sensing capabilities from 0 to 25 kPa. Furthermore, extensive applications are investigated in monitoring human activities and anti-intrusion pre-alarm systems. This work demonstrates a dual-functional fabric electrode based on Ni–V2O5, offering new guidelines for the next generation of multifunctional flexible electronic products.

Efficient Amperometric Detection of Ornidazole: An Antibiotic Drug Based on Rare-Earth Metal Oxide Entrapped with Graphene Nanosheets Nanocomposite

The use of nitro aromatic compounds for the treatment of protozoal infections as well as anaerobic bacteria is widespread. The global use of antiprotozoal drugs causes significant ecological impact on living systems. In this study, electrochemical detection of the antiprotozoal drug ornidazole (ODZ) was demonstrated through neodymium oxide/graphene nanosheets (Nd2O3/GNS) based electrocatalyst. This hybrid material was prepared with a sonochemical probe method. We characterized the Nd2O3/GNS nanocomposite using various analytical and spectroscopic techniques. For rapid ODZ drug determination, we used Nd2O3/GNS nanocomposite-based slurry to modify the glassy carbon electrode (GCE) surface. The electrocatalysis of ODZ using Nd2O3/GNS/GCE showed a good linear range (0.01–221 μM), excellent detection limit (0.001 μM), and high sensitivity, along with long-term stability. The practicality of the sensor electrode for ODZ was successfully determined in water and human urine samples, yielding satisfactory recoveries. Thus the results indicated that Nd2O3 with conductive carbon support including graphene, carbon nanotubes (CNT), carbon nanofibers, etc., can be used as a sensitive sensor electrode for the real-time detection of antibiotic drugs that cause human and environment by continuous consumption and improper disposal from the pharmaceutical industries, respectively.

Facile synthesis of sub-10 nm Cu-MOF nanofibers as electrochemical sensor element for picomolar chloramphenicol detection

Precise detection of antibiotics in aquatic environments is significant for human health and ecological environment development due to the excessive use of antibiotics. However, the accurate detection of ultralow-level antibiotics, such as picomolar level, has always been an extremely challenging task. Herein, we synthesized the sub-10 nm copper-based metal–organic framework nanofibers (Cu-MOF NFs) with a large specific area and high conductivity for achieving the electrochemical detection of picomolar-level chloramphenicol (CAP) in real water samples. As a result, by optimization of synthesis time and detection conditions, Cu-MOF NFs with a diameter of about 5 nm exhibited the ultralow limit of detection with 0.03 pM and wide detection range with 0.1––1.0 × 106 pM for CAP detection, as well as the designed sensor electrode has the excellent specificity, reproducibility, and stability. Importantly, the prepared sensor electrode exhibits reliable analytical results for CAP in real water samples, such as tap water, bottled water, and milk, indicating that designed sensor electrode has great application potential for the precise detection of antibiotics in practical samples.

Platinum decorated phosphorous doped graphitic carbon nitride supported molecularly imprinted carbon fibre electrode as a nano-interface for the detection of butylated hydroxy anisole

This research generated an electrochemical sensor using a carbon fibre (CFP) paper electrode coated using platinum-decorated phosphorous doped graphitic carbon nitride (Pt/PgCN). This sensor was designed to detect butylated hydroxy anisole (BHA) selectively and sensitively. The molecularly imprinted polymers (MIPs) were synthesized onto the Pt/PgCN coated CFP surface through electropolymerization using BHA as a template and 3-thiophene acetic acid as monomer. Numerous analytical methods were used to characterise the sensor electrode, including cyclic voltammetry, impedance spectroscopy, and electron microscopy. The results showed that the synergetic effect of PgCN, Pt nanoparticles, and PTAA, PgCN and Pt had a positive impact on the electrochemical detection, the sensor's linear range was determined to be between 5 × 10−10 M and 2.1 × 10−7 M. The sensor demonstrated excellent stability, good reproducibility, and high selectivity for detecting BHA. Moreover, the proposed sensor successfully detected BHA in real samples.

Electrochemical difference between single‐ and poly‐crystalline LaF3 for a compact and low‐price fluoride ion sensor

AbstractFluoride ion sensor electrodes that use polycrystalline LaF3 prepared by low‐temperature sintering can reduce sensor size and fabrication costs; however, decreasing the sintering temperature deteriorates sensor performance. Further, it is unclear why the performance of polycrystalline LaF3 prepared at low temperatures is inferior to that of the single‐crystal LaF3. Thus, in this study, we investigated factors that deteriorate sensor response under low sintering temperatures, such as solution penetration, fluorine conductivity, and ion exchange. To this end, LaF3 was prepared by changing the sintering temperature, and the electrical characteristics and sensor performance were evaluated and compared with those of the single‐crystal LaF3. The sensor performances of LaF3 sintered at 900 °C (−9.3 mV/dec) and 1000 °C (−5.8 mV/dec) were inferior to that of a single‐crystal LaF3 (−49.9 mV/dec). LaF3 prepared by sintering over 800 °C achieved fluorine removal and showed lower ion conductivity and ion exchange compared to that of the single‐crystal LaF3. LaF3 sintered at 700 °C did not show a sensor response because of solution penetration into the through‐pore. Our results confirmed that solution penetration, ion conductivity, and ion exchange influence the sensor performance of LaF3. Finally, we discussed approaches to achieve high sensor performance with LaF3 prepared by low‐temperature sintering. The proposed approaches are expected to contribute to expanding the utility of fluoride ion sensor electrodes with LaF3.

Fabrication of Silver Nanoparticle Loaded into Nanocellulose Derived from Hemp and Poly(vinyl alcohol)-Based Composite as an Electrode for Electrochemical Sensors for Lactate Determination.

Nanocellulose derived from hemp (HNC) with the addition of silver nanoparticles (AgNPs) is utilized for improving the electrochemical sensing performances for lactate detection. Initially, HNC is chemically extracted and purified by using alkali treatment and acid hydrolysis. Then, AgNPs are nucleated in situ by the self-reduction process prior to forming a composite with poly(vinyl alcohol) (PVA). This nanocomposite significantly improves the electrochemical properties of the electrode, including electrochemical conductivity and electrocatalysis. The morphologies and chemical alterations of the HNC/AgNPs-PVA nanocomposite are investigated by field emission scanning electron microscopy. It demonstrates a three-dimensional network with random orientation of the nanocellulose fiber. The AgNPs are well-dispersed in the nanocomposite. Moreover, the nanocomposite provides high thermal stability up to 450 °C. Then, it is remarkably noted that 10 wt % HNC/AgNPs-PVA modified on the electrode provides the highest current responses, with a standard redox couple [(Fe(CN)6]3-/4-]. For lactate detection, this modified screen-printed graphene electrode with nonimmobilized lactate oxidase exhibits an increase in the current signal with the increment of lactate concentration and offered a linear range of 0-25 mM, covering a cutoff value (12.5 mM) for muscle fatigue indication. Eventually, this sensor is successfully applied for lactate detection with high potential for a wearable lactate sensor.

Analytical modeling and optimization of electrostatic particle sensors for particle number detection: incorporating particle size influence

Developing measurement devices and methods to track increasingly stringent emission standards, including particle number, is crucial. This paper presents a novel analytical model to describe the signal response of an electrostatic particle sensor not only to particle mass concentration, but also to the particle number concentration of in-flowing particles. The uniqueness of this model lies in its ability to calculate the signal as a function of particle diameter, enabling the determination of particle number concentration from the signal. The model considers the effects of aerosol flow, electrode voltage and temperature, and can be used for the optimization of the sensor geometry parameters, length, width, and electrode gap. The model was designed to optimize the sensor’s geometry and signal retrieval as well as the optimization of the electric field between the electrodes. Comparative analysis was conducted between the proposed model and a model from the literature as well as experimental data from literature and experimental data collected in this paper.

Multiplex electrochemical sensing platforms for the detection of breast cancer biomarkers.

Herein, advancements in electroanalytical devices for the simultaneous detection of diverse breast cancer (BC) markers are demonstrated. This article identifies several important areas of exploration for electrochemical diagnostics and highlights important factors that are pivotal for the successful deployment of novel bioanalytical devices. We have highlighted that the limits of detection (LOD) reported for the multiplex electrochemical biosensor can surpass the sensitivity displayed by current clinical standards such as ELISA, FISH, and PCR. HER-2; a breast cancer marker characterised by increased metastatic potential, more aggressive development, and poor clinical outcomes; can be sensed with a LOD of 0.5 ng/ml using electrochemical multiplex platforms, which falls within the range of that measured by ELISA (from picogram/ml to nanogram/ml). Electrochemical multiplex biosensors are reported with detection limits of 0.53 ng/ml and 0.21 U/ml for MUC-1 and CA 15-3, respectively, or 5.8 × 10-3 U/ml for CA 15-3 alone. The sensitivity of electrochemical assays is improved when compared to conventional analysis of MUC-1 protein which is detected at 11-12 ng/ml, and ≤30 U/ml for CA 15-3 in the current clinical blood tests. The LOD for micro-ribonucleic acid (miRNA) biomarkers analyzed by electrochemical multiplex assays were all notedly superior at 9.79 × 10-16 M, 3.58 × 10-15 M, and 2.54 × 10-16 M for miRNA-155, miRNA-21, and miRNA-16, respectively. The dogma in miRNA testing is the qRT-PCR method, which reports ranges in the ng/ml level for the same miRNAs. Breast cancer exosomes, which are being explored as a new frontier of biosensing, have been detected electrochemically with an LOD of 103-108 particles/mL and can exceed detection limits seen by the tracking and analysis of nanoparticles (∼ 107 particles/ml), flow cytometry, Western blotting and ELISA, etc. A range of concentration at 78-5,000 pg/ml for RANKL and 16-1,000 pg/ml for TNF is reported for ELISA assay while LOD values of 2.6 and 3.0 pg/ml for RANKL and TNF, respectively, are demonstrated by the electrochemical dual immunoassay platform. Finally, EGFR and VEGF markers can be quantified at much lower concentrations (0.01 and 0.005 pg/ml for EGFR and VEGF, respectively) as compared to their ELISA assays (EGRF at 0.31-20 ng/ml and VEGF at 31.3-2,000 pg/ml). In this study we hope to answer several questions: (1) Are the limits of detection (LODs) reported for multiplex electrochemical biosensors of clinical relevance and how do they compare to well-established methods like ELISA, FISH, or PCR? (2) Can a single sensor electrode be used for the detection of multiple markers from one blood drop? (3) What mechanism of electrochemical biosensing is the most promising, and what technological advancements are needed to utilize these devices for multiplex POC detection? (4) Can nanotechnology advance the sensitive and selective diagnostics of multiple BC biomarkers? (5) Are there preferred receptors (antibody, nucleic acid or their combinations) and preferred biosensor designs (complementary methods, sandwich-type protocols, antibody/aptamer concept, label-free protocol)? (6) Why are we still without FDA-approved electrochemical multiplex devices for BC screening?

Enhanced Potentiometric Hydrogen Sensing Response Based on the Ba0.5Sr0.5Co1-yFeyO3-δ Electrode with Unusual Polarity.

In this work, unusual potentiometric hydrogen sensing of mixed conducting Ba0.5Sr0.5Co0.8Fe0.2O3-δ was reported. Inspired by the unusual polarity, a dual sensing electrode (SE) potentiometric hydrogen sensor was fabricated by pairing Ba0.5Sr0.5Co0.8Fe0.2O3-δ with electronic conducting ZnO to enhance the hydrogen response. Hydrogen sensing measurements suggested that significantly higher response, larger sensitivity, and lower limit of detection (LOD) were achieved by the dual SE sensor when compared with the single SE sensor based on Ba0.5Sr0.5Co0.8Fe0.2O3-δ or ZnO. A high response of 97.3 mV for 500 ppm hydrogen and a low LOD of 2.5 ppm were obtained by the dual SE sensor at 450 °C. Furthermore, the effect of the Fe doping concentration in Ba0.5Sr0.5Co1-yFeyO3-δ (y = 0.2, 0.5, and 0.8) on hydrogen sensing response was investigated. The potentiometric response values to hydrogen increased monotonically with increasing Fe doping concentration. With the Fe/Co atomic ratio increased from 0.25 to 4, the responses to 500 ppm hydrogen raised by 69.6 and 94% at 350 and 450 °C, respectively. The sensing behaviors of unusual Ba0.5Sr0.5Co1-yFeyO3-δ may be ascribed to the predominant surface electrostatic effect. These results show that mixed conducting Ba0.5Sr0.5Co1-yFeyO3-δ is desirable for developing high-performance dual SE hydrogen sensors.

Construction of hierarchical NiCo2 S4 /2D-Carbyne nanohybrid onto nickel foam for high performance supercapacitor and non-enzymatic electrochemical glucose sensor applications.

Synthesising and designing pseudocapacitive material with good electrochemical and electrocatalytic behaviour is essential to use as supercapacitor as well as non-enzymatic glucose sensor electrode. In this work, NiCo2 S4 nanoparticles decorated onto the 2D-Carbyne nanosheets are achieved by the solvothermal process. The as-prepared NiCo2 S4 @2D-Carbyne provides rich reaction sites and better diffusion pathways. On usage as an electrode for supercapacitor application, the NiCo2 S4 @2D-Carbyne exhibits the specific capacitance of about 2507 F g-1 at 1 A g-1 . In addition, the fabricated hybrid device generates an energy density of 52.2 Wh kg-1 at a power density of 1.01 kW kg-1 . Besides, the glucose oxidation behaviour of NiCo2 S4 @2D-Carbyne modified GCE has also been performed. The diffusion of glucose from the electrolyte to the electrode obeys the kinetic control process. Furthermore, the fabricated NiCo2 S4 @2D-Carbyne non-enzymatic glucose sensor exhibits a limit of detection of about 34.5 μM with a sensitivity of about 135 μA mM-1 cm-2 . These findings highlight the need to design and synthesis electrode materials with adequate electrolyte-electrode contact, strong structural integrity, and rapid ion/electron transport.

Fast and In-Depth Reconstruction of Two-Dimension Cobalt-Based Zeolitic Imidazolate Framework in Glucose Oxidation Processes.

Currently, metal-organic frameworks (MOFs) have emerged as viable candidates for enduring electrode materials in nonenzyme glucose sensing. However, given the inherent water susceptibility of MOFs and their complete self-reconstruction during the process of electrochemical oxygen evolution in alkaline conditions, we are motivated to explore the truth of MOFs catalyzing glucose oxidation. In this work, we fabricated a two-dimensional cobalt-based zeolitic imidazolate framework (ZIF-L) as the electrode material for catalyzing glucose oxidation in alkaline conditions. Our explorations revealed that while the initial glucose catalytic response varied among ZIF-L samples with differing thicknesses, the ultimate steady-state catalytic performance remained largely consistent. This phenomenon arose from the transformation of ZIF-L with distinct thicknesses into CoOOH with uniform morphological and structural characteristics during the glucose catalysis process. And in situ Raman spectroscopy elucidated the sustained equilibrium within the glucose catalytic system, wherein the dynamic interconversion between CoOOH and Co(OH)2 governs the overall process. This study contributes to an enhanced understanding of the glucose catalytic mechanism aspects of nonenzymatic glucose sensor electrode materials, offering insights that serve as inspiration for the development of advanced glucose electrode materials.

Efficient Amperometric Detection of H2O2 using Gold Nanoparticle decorated Polythiophene/Hematite Ore Nanocomposite

In the present work, we developed a cheap and sensitive H2O2 electrochemical sensor. Herein we fabricated an electrochemical sensor electrode using a naturally extracted hematite ore decorated with conducting polythiophene (Pth) and gold nanoparticles (AuNPs). A simple synthesis route was adopted for the electrocatalyst synthesis, where Pth was synthesized through oxidative polymerization and then combined with Hematite Ore nanostructure via a simple ultrasonication process. Later a simple photo-reduction approach was used to develop a 1%Au@5%Pth/Hematite Ore nanocomposite. The as-fabricated Au@Pth/Hematite Ore nanocomposite was successfully characterized by applying X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), High-Resolution Transmission Electron Microscope (HR-TEM), and Field Emission Scanning Electron Microscope (FE-SEM) techniques. The obtained results reveal that undoped naturally extracted hematite ore is composed of Fe2O3 and Fe3O4 phases. The catalytic efficiency of the newly designed nanocomposite and its sensing ability towards H2O2 were assessed using electrochemical techniques including electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and highly sensitive amperometric (i-t) techniques. The Au@Pth/Hematite Ore/GCE sensor showed a wide linear dynamic range of 0.50–9.50 mM with high sensitivity of 69.18 μAmM−1cm−2. The limit of detection (LOD) was estimated to be 5.18 μM. The examined sensor demonstrated acceptable reproducibility, repeatability as well as stability. The sensor electrode also showed anti-interference behavior in the presence of different inorganic and organic interfering ions or molecules during the H2O2 determination. Moreover, the proposed sensor exhibits acceptable recovery of H2O2 in real sample analysis. Hence, this novel sensor is regarded as a promising contender in scientific and industrial domains.

Manipulation of Conducting Polymer Hydrogels with Different Shapes and Related Multifunctionality.

Maneuver of conducting polymers (CPs) into lightweight hydrogels can improve their functional performances in energy devices, chemical sensing, pollutant removal, drug delivery, etc. Current approaches for the manipulation of CP hydrogels are limited, and they are mostly accompanied by harsh conditions, tedious processing, compositing with other constituents, or using unusual chemicals. Herein, a two-step route is introduced for the controllable fabrication of CP hydrogels in ambient conditions, where gelation of the shape-anisotropic nano-oxidants followed by in-situ oxidative polymerization leads to the formation of polyaniline (PANI) and polypyrrole hydrogels. The method is readily coupled with different approaches for materials processing of PANI hydrogels into varied shapes, including spherical beads, continuous wires, patterned films, and free-standing objects. In comparison with their bulky counterparts, lightweight PANI items exhibit improved properties when those with specific shapes are used as electrodes for supercapacitors, gas sensors, or dye adsorbents. The current study therefore provides a general and controllable approach for the implementation of CP into hydrogels of varied external shapes, which can pave the way for the integration of lightweight CP structures with emerging functional devices.

Two-Dimensional Nickel Porphyrinic Metal-Organic Framework-Modified Electrode for Electrochemical Sensing.

Due to their highly exposed active sites and high aspect ratio caused by their substantial lateral dimension and thin thickness, two-dimensional (2D) metal-organic framework (MOF) nanosheets are currently considered a potential hybrid material for electrochemical sensing. Herein, we present a nickel-based porphyrinic MOF nanosheet as a versatile and robust platform with an enhanced electrochemical detection performance. It is important to note that the nickel porphyrin ligand reacted with Cu(NO3)2·3H2O in a solvothermal process, with polyvinylpyrrolidone (PVP) acting as the surfactant to control the anisotropic development of creating a 2D Cu-TCPP(Ni) MOF nanosheet structure. To realize the exceptional selectivity, sensitivity, and stability of the synthesized 2D Cu-TCPP(Ni) MOF nanosheet, a laser-induced graphene electrode was modified with the MOF nanosheet and employed as a sensor for the detection of p-nitrophenol (p-NP). With a detection range of 0.5-200 μM for differential pulse voltammetry (DPV) and 0.9-300 μM for cyclic voltammetry (CV), the proposed sensor demonstrated enhanced electrochemical performance, with the limit of detection (LOD) for DPV and CV as 0.1 and 0.3 μM, respectively. The outstanding outcome of the sensor is attributed to the 2D Cu-TCPP(Ni) MOF nanosheet's substantial active surface area, innate catalytic activity, and superior adsorption capacity. Furthermore, it is anticipated that the proposed electrode sensor will make it possible to create high-performance electrochemical sensors for environmental point-of-care testing since it successfully detected p-NP in real sample analysis.

Electrostatic interaction energy between the electrodes of a concentric coplanar sensor

The capacitive testing method using coplanar capacitive sensors represents a relatively new technique for non-destructive evaluation of the properties of a given material. The most conventional design of a coplanar capacitive sensor is that of two oppositely charged coplanar electrodes located at some separation distance from each other. The electrodes can have any shape including designs with circular symmetry. The concentric coplanar sensor is a special case of a device with circular symmetry. It comprises a disk as the inner electrode and an annulus as the outer one. In this work we analyze the features of the electrostatic interaction energy between the two electrodes of a concentric coplanar sensor by considering a model consisting of a uniformly charged disk and a uniformly charged annulus that is concentric and coplanar to the disk. For the sake of generality, we assume that the two objects carry an arbitrary amount of net charge and their dimensions are arbitrary. We obtain an exact expression for the electrostatic interaction energy of the system as a function of three important length scales, radius of disk and inner/outer radii of the annulus. The interplay between these parameters determines the features of the electrostatic interaction energy between the electrodes as well as the overall performance of the sensor.

Effects of silver diffusement on TiO2-B2O3 nanocomposite sensor towards hydrogen sensing

ABSTRACT Various finger dimensions of interdigitated electrodes in TiO2-B2O3 nanocomposite sensors were proposed in this study. To study the silver diffusement effect on the hydrogen sensing characteristics at different operating temperatures. The result showed that some of the silver particles diffused to the surface of the TiO2-B2O3 nanocomposite sensor after the annealing process at 500°C. The amount of silver particles diffused into the TiO2-B2O3 surface was contributed by the finger dimension of the interdigitated electrode used in the nanocomposite sensor. The results revealed that the structure of interdigitated electrodes in T65 nanocomposite sensor enhanced the performance at low hydrogen concentrations with response values were approximately 4.78, 11.47, 14.47, 16.58, and 20.00 for 100 ppm, 300 ppm, 500 ppm, 700 ppm, and 1000 ppm, respectively, at the optimum operating temperature of 200°C. The activation energy for all nanocomposite sensors was approximately in the range of 40–70 kJ/mol.

Sustainable Soft Electronics Combining Recyclable Metal Nanowire Circuits and Biodegradable Gel Film Substrates

AbstractDirect disposal of used soft electronics into the environment can cause severe pollution to the ecosystem due to the inability of most inorganic materials and synthetic polymers to biodegrade. Additionally, the loss of the noble metals that are commonly used in soft electronics leads to a waste of scarce resources. Thus, there is an urgent need to develop “green” and sustainable soft electronics based on eco‐friendly manufacturing that may be recycled or biodegraded after the devices’ end of life. Here an approach to fabricating sustainable soft electronics is demonstrated where the expensive functional materials can be recycled and the soft substrate can be biodegradable. A stretchable agarose/glycerol gel film is used as the substrate, and silver nanowires (AgNWs) are printed on the film to fabricate the soft electronic circuits. The mechanical and chemical properties of the agarose/glycerol gel films are characterized, and the functionality of the printed AgNW electrodes for electrophysiological sensors is demonstrated. The demonstration of the biodegradability of the agarose/glycerol and the recyclability of AgNWs points toward ways to develop sustainable and eco‐friendly soft electronics.

Nanogold-decorated reduced graphene oxide/chitosan composite for electrochemical sensing of N-acetyl-4-aminophenol

In this study, a novel electrocatalyst designed by doping gold nanoparticles (AuNPs) over the reduced graphene oxide (rGO)/Chitosan (CTSN) matrix for the determination of N-acetyl-4-aminophenol, i.e. acetaminophen (AC) in phosphate buffer solution has been reported. The catalyst was synthesized via a simple ultra-sonication process followed by a photo-reduction technique to obtain 1%AuNPs@5%rGO/CTSN nanocomposite. The conductivity of the CTSN biopolymer was enhanced by coupling rGO and thereafter rGO/CTSN surface was decorated with nano-Au particles to improve the catalytic efficiency. The structural and surface properties of the as-fabricated nanocomposite have been thoroughly investigated using cutting–edge microscopic and spectroscopic techniques. The catalytic and sensing phenomena were systematically studied with several well-known electrochemical techniques. Using differential pulse voltammetry (DPV), the peak current was found to be linear across the AC concentration range of 0.50 μM–39.31 μM, with a high sensitivity of 2.358 μAμM−1cm−2 and a low limit of detection (LOD) of 0.06 μM. Moreover, under optimal experimental conditions, the amperometric (i-t) study showed a high sensitivity value of 0.935 μA μM−1cm−2, a wide AC detection range (5.0 μM–160 μM), and LOD 0.151 μM. The proposed sensor also demonstrated high selectivity in the existence of common interfering species. In addition, this newly fabricated sensor electrode exhibited admirable reproducibility, repeatability, and remarkable storage and operational stability. It was also successfully applied to AC recovery tests in real samples as a pharmaceutical formulation.

Naturally manufactured biochar materials based sensor electrode for the electrochemical detection of polystyrene microplastics

In recent times, microplastics have become a disturbance to both aquatic and terrestrial ecosystems and the ingestion of these particles can have severe consequences for wildlife, aquatic organisms, and even humans. In this study, two types of biochars were manufactured through the carbonization of naturally found starfish (SF-1) and aloevera (AL-1). The produced biochars were utilized as sensing electrode materials for the electrochemical detection of ∼100 nm polystyrene microplastics (PS). SF-1 and AL-1 based biochars were thoroughly analyzed in terms of morphology, structure, and composition. The detection of microplastics over biochar based electrodes was carried out by electrochemical studies. From electrochemical results, SF-1 based electrode exhibited the detection efficiency of ∼0.2562 μA/μM∙cm2 with detection limit of ∼0.44 nM whereas, a high detection efficiency of ∼3.263 μA/μM∙cm2 was shown by AL-1 based electrode and detection limit of ∼0.52 nM for PS (100 nm) microplastics. Process contributed to enhancing the sensitivity of AL-1 based electrode might associate to the presence of metal-carbon framework over biochar's surfaces. The AL-1 biochar electrode demonstrated excellent repeatability and detection stability for PS microplastics, suggesting the promising potential of AL-1 biochar for electrochemical microplastics detection.