Comprehensive assessment of chlorination disinfection on microplastic-associated biofilms.

Chlorination on microplastic (MP) biofilms was comprehensively investigated with respect to disinfection efficiency, morphology, and core microbiome. The experiments were performed under various conditions: i) MP particles; polypropylene (PP) and polystyrene (PS), ii) MP biofilms; Escherichia coli for single-species and river water microorganisms for multiple-species, iii) different chlorine concentrations, and iv) different chlorine exposure periods. As a result, chlorination effectively inactivated the MP biofilm microorganisms. The disinfection efficiency increased with increasing the free chlorination concentration and exposure periods for both single- and multiple-species MP biofilms. The multiple-species MP biofilms were inactivated 1.3-6.0 times less than single-species MP biofilms. In addition, the PP-MP biofilms were more vulnerable to chlorination than the PS-MP biofilms. Morphology analysis verified that chlorination detached most MP biofilms, while a small part still remained. Interestingly, chlorination strongly changed the biofilm microbiome on MPs; the relative abundance of some microbes increased after the chlorination, suggesting they could be regarded as chlorine-resistant bacteria. Some potential pathogens were also remained on the MP particles after the chlorination. Notably, chlorination was effective in inactivating the MP biofilms. Further research should be performed to evaluate the impacts of residual MP biofilms on the environment.

Rethinking the effects of micro/nanoplastics from the global environmental change and systematic perspective: An aquatic environmental system-based comprehensive assessment approach of micro/nanoplastic impacts.

The study on micro/nanoplastic pollution should embrace complexity. Here, we aim to develop an aquatic environmental system-based comprehensive assessment approach of micro/nanoplastic impacts (ACAM) to evaluate the effects of micro/nanoplastics on aquatic ecosystems from the global environmental change (GEC) and systematic perspective. A case study for freshwater systems in Saskatchewan, Canada was conducted to evaluate the comprehensive effects of multiple GEC factors (polystyrene-nanoplastics (PS-NPs), N, P, salinity, dissolved organic matter (DOM), pH, hardness) on Asterococcus superbus based on ten ecologically relevant endpoints. It is found that at the cellular level, PS-NPs and N had an antagonistic interaction on microalgal growth in the Saskatchewan freshwater ecosystem; at the molecular level, the PS-NP-induced changes in lipid composition in microalgae were regulated by P, DOM, and pH. The significance ranking of factor effects suggested that instead of PS-NPs pollution, the fluctuations in pH level, DOM and N concentrations should be paid attention to first in Saskatchewan. Under the combined impact of PS-NPs and other GEC factors, microalgae at station 14 (Qu'Appelle River near highway 56) might have the minimum growth rate with [-0.048, 0.094] d-1 in Saskatchewan. These findings demonstrate the efficacy of the developed ACAM in a more comprehensive and context-specific assessment of MNP risks, providing new insight for the management of MNP pollution.

Cost-Effective Control of Molecular Weight in Ultrasound-Assisted Emulsion Polymerization of Styrene.

This paper focuses on the determination of economically most feasible conditions to obtain polystyrene with various target molecular weights through ultrasound-assisted emulsion polymerization. Briefly, batch polymerizations of styrene have been performed by ultrasound-assisted emulsion polymerization process using different reaction feed compositions. Polymerization rates were calculated using the monomer conversions at various reaction times. Also, molecular weights of the synthesized polymers, as well as the Mark-Houwink constants, were determined by intrinsic viscosity and gel permeation chromatography measurements. It was found that the polydispersity index of the polymers is ranging from 1.2 to 1.5, and the viscosity average molecular weights are in between 100000-1500000 g/mol depending on the reaction conditions. Finally, model equations were also developed for response variables, and the most economical ways of reaching various target molecular weights were interpreted by response surface methodology based multi objective optimization.

An Inkjet-Printed PEDOT:PSS-Based Stretchable Conductor for Wearable Health Monitoring Device Applications.

A stretchable conductor is one of the key components in soft electronics that allows the seamless integration of electronic devices and sensors on elastic substrates. Its unique advantages of mechanical flexibility and stretchability have enabled a variety of wearable bioelectronic devices that can conformably adapt to curved skin surfaces for long-term health monitoring applications. Here, we report a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-based stretchable polymer blend that can be patterned using an inkjet printing process while exhibiting low sheet resistance and accommodating large mechanical deformations. We have systematically studied the effect of various types of polar solvent additives that can help induce phase separation of PEDOT and PSS grains and change the conformation of a PEDOT chain, thereby improving the electrical property of the film by facilitating charge hopping along the percolating PEDOT network. The optimal ink formulation is achieved by adding 5 wt % ethylene glycol into a pristine PEDOT:PSS aqueous solution, which results in a sheet resistance of as low as 58 Ω/□. Elasticity can also be achieved by blending the above solution with the soft polymer poly(ethylene oxide) (PEO). Thin films of PEDOT:PSS/PEO polymer blends patterned by inkjet printing exhibits a low sheet resistance of 84 Ω/□ and can resist up to 50% tensile strain with minimal changes in electrical performance. With its good conductivity and elasticity, we have further demonstrated the use of the polymer blend as stretchable interconnects and stretchable dry electrodes on a thin polydimethylsiloxane (PDMS) substrate for photoplethysmography (PPG) and electrocardiography (ECG) recording applications. This work shows the potential of using a printed stretchable conducting polymer in low-cost wearable sensor patches for smart health applications.

Towards improving ELISA surfaces: SPR assessment of polystyrene modification efficiency for promoting immobilization of biomolecules.

The enzyme-linked immunosorbent assay (ELISA) is a widely used diagnostic technique. In ELISA, detection of the target biomolecules is achieved through selective capture by appropriate antibody immobilized on a solid support. Our study addresses the application of surface plasmon resonance to an assessment of the polystyrene modification efficiency for promoting adsorption of biomolecules. A method facilitating the development of advanced immobilization strategies for biofunctionalization of polystyrene surface was evolved. The proposed approach uses formation of a thin layer of polystyrene over the SPR chip surface, thus enabling a detailed characterization of biomolecular interactions at the polystyrene surface.

Analysis and modeling of coolants and coolers for specimen transportation.

Maintaining cold chain while transporting medical supplies and samples is difficult in remote settings. Failure to maintain temperature requirements can lead to degraded sample quality and inaccuracies in sample analysis. We performed a systematic analysis on different types of transport coolers (polystyrene foam, injection-molded, and rotational molded) and transport coolants (ice, cold packs, frozen water bottles) frequently in use in many countries. Polystyrene foam coolers stayed below our temperature threshold (6°C) longer than almost all other types of coolers, but were not durable. Injection-molded coolers were durable, but warmed to 6°C the quickest. Rotational molded coolers were able to keep temperatures below our threshold for 24 hours longer than injection molded coolers and were highly durable. Coolant systems were evaluated in terms of cost and their ability to maintain cold temperatures. Long lasting commercial cold packs were found to be less cost effective and were below freezing for the majority of the testing period. Frozen plastic water bottles were found to be a reusable and economical choice for coolant and were only below freezing briefly. Finally, we modeled the coolers performance at maintaining internal temperatures below 6°C and built a highly accurate linear model to predict how long a cooler will remain below 6°C. We believe this data may be useful in the planning and design of specimen transportation systems in the field, particularly in remote or resource limited settings.

Assessment of the shock adsorption properties of bike helmets: a numerical/experimental approach.

In this paper, a numerical and experimental study of the shock absorption properties of bike helmets is presented. Laboratory compression and tensile tests were carried out on samples of expanded polystyrene (EPS) and polycarbonate (PC), respectively constituting the internal shock absorption layer and the external hard shell of composite helmets. The measured responses of the two materials were then exploited to calibrate the relevant elasto-plastic constitutive models, adopted in full-scale finite element analyses of a helmet subject to standardized impacts. The simulations allowed assessing the time evolution of the acceleration measured inside the headform (according e.g., to EN 1078) and the failure mechanisms of the helmet, if any, as induced by the localization of plastic deformations.

3D super-resolution microscopy performance and quantitative analysis assessment using DNA-PAINT and DNA origami test samples.

Assessment of the imaging quality in localisation-based super-resolution techniques relies on an accurate characterisation of the imaging setup and analysis procedures. Test samples can provide regular feedback on system performance and facilitate the implementation of new methods. While multiple test samples for regular, 2D imaging are available, they are not common for more specialised imaging modes. Here, we analyse robust test samples for 3D and quantitative super-resolution imaging, which are straightforward to use, are time- and cost-effective and do not require experience beyond basic laboratory and imaging skills. We present two options for assessment of 3D imaging quality, the use of microspheres functionalised for DNA-PAINT and a commercial DNA origami sample. A method to establish and assess a qPAINT workflow for quantitative imaging is demonstrated with a second, commercially available DNA origami sample.

A new electrochemical platform based on low cost nanomaterials for sensitive detection of the amoxicillin antibiotic in different matrices.

A new electrochemical device based on a combination of nanomaterials such as Printex 6L Carbon and cadmium telluride quantum dots within a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate film was developed for sensitive determination of amoxicillin. The morphological, structural and electrochemical characteristics of the nanostructured material were evaluated using X-ray diffraction, confocal microscopy, transmission electron microscopy and voltammetric techniques. The synergy between these materials increased the electrochemical activity, the electron transfer rate and the electrode surface area, leading to a high magnitude of the anodic peak current for the determination of amoxicillin. The electrochemical determination of the antibiotic was carried out using square-wave voltammetry. Under the optimised experimental conditions, the proposed sensor showed high sensitivity, repeatability and stability to amoxicillin determination, with an analytical curve in the amoxicillin concentration range from 0.90 to 69 µmol L-1, and a low detection limit of 50 nmol L-1. No significant interference in the electrochemical signal of amoxicillin was observed from potential biological interferences and drugs widely used, such as uric acid, paracetamol, urea, ascorbic acid and caffeine. It was demonstrated that without any sample pre-treatment and using a simple measurement device, the sensor could be an alternative method for not only the analysis of pharmaceutical products (commercial tablets) and clinical samples (urine), but also to examine food quality (milk samples).

Polystyrene microplastic particles: In vitro pulmonary toxicity assessment.

Microplastics (MPs) have become a global environmental concern. Recent studies have shown that MPs, of which the predominant type is often polystyrene (PS; known as PS-MPs), can extend to and affect remote, sparsely inhabited areas via atmospheric transport. Although exposure to inhaled MPs may induce lung dysfunction, further experimental verification of the pulmonary toxic potential of MPs and the mechanism underlying the toxicity is needed. Here we used normal human lung epithelial BEAS-2B cells to clarify the association between pulmonary toxicity and PS-MPs. Results revealed that PS-MPs can cause cytotoxic and inflammatory effects in BEAS-2B cells by inducing reactive oxygen species formation. PS-MPs can decrease transepithelial electrical resistance by depleting zonula occludens proteins. Indeed, decreased α1-antitrypsin levels in BEAS-2B cells suggest that exposure to PS-MPs increases the risk for chronic obstructive pulmonary disease, and high concentrations of PS-MPs can induce these adverse responses. While low PS-MP levels can only disrupt the protective pulmonary barrier, they may also increase the risk for lung disease. Collectively, our findings indicate that PS-MP inhalation may influence human respiratory health.

A low-cost and high-efficiency carbazole-based porous organic polymer as a novel sorbent for solid-phase extraction of triazine herbicides in vegetables.

In this study, a porous organic polymer (denoted as Car-DMB) was fabricated by a simple one-step crosslinking polymerization of carbazole and p-dimethoxybenzene for the first time. Then the Car-DMB was served as adsorbent of solid phase extraction to enrich triazine herbicides from white gourd, tomato and soybean milk samples prior to their determination by high performance liquid chromatography. Under the optimal conditions, the response linearity was in the range of 0.3-100.0 ng g-1 for white gourds and tomato samples, and 0.5-100.0 ng mL-1 for soybean milk, with the coefficient of determination higher than 0.996. The detection limits were 0.1-0.2 ng g-1 for white gourd and tomato samples, and 0.15-0.3 ng mL-1 for soybean milk. The adsorption mechanism of the Car-DMB for the triazines was attributed to the strong H-bonding and weak π-π interactions. The efficient extraction for several other compounds demonstrated that Car-DMB holds great potential for diverse analysis applications.

Inkjet-printed PEDOT:PSS multi-electrode arrays for low-cost in vitro electrophysiology.

Multi-electrode arrays (MEAs) have become a key element in the study of cellular phenomena in vitro. Common modern MEAs are still based on costly microfabrication techniques, making them expensive tools that researchers are pushed to reuse, compromising the reproducibility and the quality of the acquired data. There is a need to develop novel fabrication strategies, able to produce disposable devices that incorporate advanced technologies beyond the standard metal electrodes on rigid substrates. Here we present an innovative fabrication process for the production of polymer-based flexible MEAs. The device fabrication exploited inkjet printing, as this low-cost manufacturing method allows for an easy and reliable patterning of conducting polymers. Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) was used as the sole conductive element of the MEAs. The physical structure and the electrical properties of the plastic/printed MEAs (pMEAs) were characterised, showing a low impedance that is maintained also in the long term. The biocompatibility of the devices was demonstrated, and their capability to successfully establish a tight coupling with cells was proved. Furthermore, the pMEAs were used to monitor the extracellular potentials from cardiac cell cultures and to record high quality electrophysiological signals from them. Our results validate the use of pMEAs as in vitro electrophysiology platforms, pushing for the adoption of innovative fabrication techniques and the use of new materials for the production of MEAs.

Novel adsorptive materials by adenosine 5'-triphosphate imprinted-polymer over the surface of polystyrene nanospheres for selective separation of adenosine 5'-triphosphate biomarker from urine.

In this study, we have developed a method to assess adenosine 5'-triphosphate by adsorptive extraction using surface adenosine 5'-triphosphate-imprinted polymer over polystyrene nanoparticles (412 ± 16 nm) for selective recognition/separation from urine. Molecularly imprinted polymer was synthesized by emulsion copolymerization reaction using adenosine 5'-triphosphate as a template, functional monomers (methacrylic acid, N-isopropyl acrylamide, and dimethylamino ethylmethacrylate) and a crosslinker, methylenebisacrylamide. The binding capacities of imprinted and non-imprinted polymers were measured using high-performance liquid chromatography with UV detection with a detection limit of 1.6 ± 0.02 µM of adenosine 5'-triphosphate in the urine. High binding affinity (QMIP , 42.65 µmol/g), and high selectivity and specificity to adenosine 5'-triphosphate compared to other competitive nucleotides including adenosine 5'-diphosphate, adenosine 5'-monophosphate, and analogs such as adenosine, adenine, uridine, uric acid, and creatinine were observed. The imprinting efficiency of imprinted polymer is 2.11 for urine (QMIP , 100.3 µmol/g) and 2.51 for synthetic urine (QMIP , 48.5 µmol/g). The extraction protocol was successfully applied to the direct extraction of adenosine 5'-triphosphate from spiked human urine indicating that this synthesized molecularly imprinted polymer allowed adenosine 5'-triphosphate to be preconcentrated while simultaneously interfering compounds were removed from the matrix. These submicron imprinted polymers over nano polystyrene spheres have a potential in the pharmaceutical industries and clinical analysis applications.

Assessment of portal image resolution improvement using an external aluminum target and polystyrene electron filter.

BACKGROUND: In this study, an external 8 mm thick aluminum target was installed on the upper accessory tray mount of a medical linear accelerator head. The purpose of this study was to determine the effects of the external aluminum target beam (Al-target beam) on the portal image quality by analyzing the spatial and contrast resolutions. In addition, the image resolutions with the Al-target beams were compared with those of conventional 6 megavoltage (MV) images. METHODS: The optimized Al-target beam was calculated using Monte Carlo simulations. To validate the simulations, the percentage depth dose and lateral profiles were measured and compared with the modeled dose distributions. A PTW resolution phantom was used for imaging to assess the image resolution. The spatial resolution was quantified by determining the modulation transfer function. The contrast resolution was determined by a fine contrast difference between the 27 measurement areas. The spatial and contrast resolutions were compared with the those of conventional portal images. RESULTS: The measured and calculated percentage depth dose of the Al-target beam were consistent within 1.6%. The correspondence of measured and modelled profiles was evaluated by gamma analysis (3%, 3 mm) and all gamma values inside the field were less than one. The critical spatial frequencies (f50) of the images obtained with the Al-target beam and conventional imaging beam were 0.745 lp/mm and 0.451 lp/mm, respectively. The limiting spatial frequencies (f10) for the Al-target beam image and the conventional portal image were 2.39 lp/mm and 1.82 lp/mm, respectively. The Al-target beam resolved the smaller and lower contrast objects better than that of the MV photon beam. CONCLUSION: The Al-target beams generated by the simple target installation method provided better spatial and contrast resolutions than those of the conventional 6 MV imaging beam.

Solid-State rGO-PEDOT:PSS Transducing Material for Cost-Effective Enzymatic Sensing.

Performance of a sensing device is dependent on its construction material, especially for components that are directly involved in transporting and translating signals across the device. Understanding the morphology and characteristics of the material components is therefore crucial in the development of any sensing device. This work examines the morphological and electrochemical characteristics of reduced graphene oxide interspersed with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (rGO-PEDOT:PSS) used as a transducer material deposited on a commercially available screen-printed carbon electrode (SPCE). Electron microscopy shows that PEDOT:PSS is interspersed between rGO layers. Raman and XRD analyses suggest that the graphene crystallinity in GO-PEDOT:PSS and rGO-PEDOT:PSS remains intact. Instead, PEDOT:PSS undergoes a change in structure to allow PEDOT to blend into the graphene structure and partake in the π-π interaction with the surface of the rGO layers. Incorporation of PEDOT:PSS also appears to improve the electrochemical behavior of the composite, leading to a higher peak current of 1.184 mA, as measured by cyclic voltammetry, compared to 0.522 mA when rGO is used alone. The rGO-PEDOT:PSS transducing material blended with glucose oxidase was tested for glucose detection. The sensitivity of glucose detection was shown to be 57.3 µA/(mM·cm²) with a detection limit of 86.8 µM.

Study on the influence of optical absorption on polarization characterization of tissues.

Absorption effect is a basic optical phenomenon and an important feature in tissue imaging and characterization. Based on our Monte Carlo simulation on the anisotropic tissue model (sphere-cylinder birefringence model), combined with our experiments of tissue phantoms, we demonstrate the influence of absorption effect on Mueller matrix and particularly on depolarization, linear retardance, and diattenuation parameters. The simulation and experimental results show a good consistency on the suppressed depolarization and scatterering induced retardance, and the enhanced diattenuation caused by the absorption, and also indicate the birefringence induced retardance insensitive to the absorption. Study of the phase function of different incident polarized lights and the distribution of scattering number gives a preliminary explanation about the above results.

A low cost PS based microfluidic platform to investigate cell cycle towards developing a therapeutic strategy for cancer.

Inhibition of DNA damage response pathway in combination with DNA alkylating agents may enhance the selective killing of cancer cells leading to better therapeutic effects. MDM2 binding protein (MTBP) in human has a role in G1 phase (interphase of cell cycle) and its overexpression leads to breast and ovarian cancers. Sld7 is an uncharacterized protein in budding yeast and a potential functional homologue of MTBP. To investigate the role of Sld7 as a therapeutic target, the behavior of the wild-type cells and sld7∆ mutants were monitored in 0.5 nL microbioreactors. The brightfield microscopy images were used to analyze the change in the cell size and to determine the durations of G1 and S/G2/M phases of wild type cells and mutants. With the administration of the alkylating agent, the cell size decreased and the duration of cell cycle increased. The replacement of the medium with the fresh one enabled the cells to repair their DNA. The application of calorie restriction together with DNA alkylating agent to mutant cells resulted in smaller cell size and longer G1 phase compared to those in control environment. For therapeutic purposes, the potential of MTBP in humans or Sld7 in yeast as a drug target deserves further exploration. The fabrication simplicity, robustness and low-cost of this microfluidic bioreactor made of polystyrene allowed us to perform yeast culturing experiments and show a potential for further cell culturing studies. The device can successfully be used for therapeutic applications including the discovery of new anti-microbial, anti-inflammatory, anti-cancer drugs.

Inferring diameters of spheres and cylinders using interstitial water.

OBJECT: Most early methods to infer axon diameter distributions using magnetic resonance imaging (MRI) used single diffusion encoding sequences such as pulsed gradient spin echo (SE) and are thus sensitive to axons of diameters > 5 µm. We previously simulated oscillating gradient (OG) SE sequences for diffusion spectroscopy to study smaller axons including the majority constituting cortical connections. That study suggested the model of constant extra-axonal diffusion breaks down at OG accessible frequencies. In this study we present data from phantoms to test a time-varying interstitial apparent diffusion coefficient. MATERIALS AND METHODS: Diffusion spectra were measured in four samples from water packed around beads of diameters 3, 6 and 10 µm; and 151 µm diameter tubes. Surface-to-volume ratios, and diameters were inferred. RESULTS: The bead pore radii estimates were 0.60±0.08 µm, 0.54±0.06 µm and 1.0±0.1 µm corresponding to bead diameters ranging from 2.9±0.4 µm to 5.3±0.7 µm, 2.6±0.3 µm to 4.8±0.6 µm, and 4.9±0.7 µm to 9±1 µm. The tube surface-to-volume ratio estimate was 0.06±0.02 µm-1 corresponding to a tube diameter of 180±70 µm. CONCLUSION: Interstitial models with OG inferred 3-10 µm bead diameters from 0.54±0.06 µm to 1.0±0.1 µm pore radii and 151 µm tube diameters from 0.06±0.02 µm-1 surface-to-volume ratios.

Toxicological assessment of nanomaterials: the role of in vitro Raman microspectroscopic analysis.

The acceleration of nanomaterials research has brought about increased demands for rapid analysis of their bioactivity, in a multi-parametric fashion, to minimize the gap between potential applications and knowledge of their toxicological properties. The potential of Raman microspectroscopy for the analysis of biological systems with the aid of multivariate analysis techniques has been demonstrated. In this study, an overview of recent efforts towards establishing a 'label-free high content nanotoxicological assessment technique' using Raman microspectroscopy is presented. The current state of the art for cellular toxicity assessment and the potential of Raman microspectroscopy are discussed, and the spectral markers of the cellular toxic responses upon exposure to nanoparticles, changes on the identified spectral markers upon exposure to different nanoparticles, cell death mechanisms, and the effects of nanoparticles on different cell lines are summarized. Moreover, 3D toxicity plots of spectral markers, as a function of time and dose, are introduced as new methodology for toxicological analysis based on the intrinsic properties of the biomolecular changes, such as cytoplasmic RNA aberrations, protein and lipid damage associated with the toxic response. The 3D evolution of the spectral markers are correlated with the results obtained by commonly used cytotoxicity assays, and significant similarities are observed between band intensity and percentage viability obtained by the Alamar Blue assay, as an example. Therefore, the developed 3D plots can be used to identify toxicological properties of a nanomaterial and can potentially be used to predict toxicity, which can provide rapid advances in nanomedicine. Graphical Abstract Spectral markers of cytotoxicity as a function of time and dose.

Paper-Based Analytical Biosensor Chip Designed from Graphene-Nanoplatelet-Amphiphilic-diblock-co-Polymer Composite for Cortisol Detection in Human Saliva.

Cortisol has been identified as a biomarker in saliva to monitor psychological stress. In this work, we report a label-free paper-based electrical biosensor chip to quantify salivary cortisol at a point-of-care (POC) level. A high specificity of the sensor chip to detect cortisol with a detection limit of 3 pg/mL was achieved by conjugating anticortisol antibody (anti-CAB) on top of gold (Au) microelectrodes using 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester (DTSP) as a self-assembled monolayer (SAM) agent. The electrode design utilized poly(styrene)-block-poly(acrylic acid) (PS67-b-PAA27) polymer and graphene nanoplatelets (GP) suspension coated on filter paper to increase the sensitivity of the immune response. A biosensor chip was then integrated with a lab-built low-cost miniaturized printed circuit board (PCB) to provide an electrical connection and to wirelessly transmit/receive electrical signals using MATLAB. This fully integrated proposed hand-held device successfully exhibited a wide cortisol-detection range from 3 pg/mL to 10 µg/mL, with a sensitivity of 50 Ω (pg mL-1)-1. The performance of the proposed cortisol sensor chip was validated using an enzyme-linked immunosorbent assay (ELISA) technique with a regression value of 0.9951. The advantages of the newly developed cortisol immune biosensor over previously reported chips include an improved limit of detection, no need for additional redox medium for electron exchange, faster response to achieve stable data, excellent shelf life, and its economical production.