Mixture Of Multi-walled Carbon Nanotubes Research Articles

Laser‐scribed graphene toward scalable fabrication of electrochemical paper-based devices for lidocaine detection in forensic and pharmaceutical samples

Lidocaine (LID), a tertiary amine drug, is widely used as a local anesthetic for topical anesthesia and also presents antiarrhythmic and analgesic properties. Given its use can induce a temporary loss of sensory, motor, and autonomic function, it has been associated with criminal instances of drug-facilitated sexual assault. Herein, we manufactured an electrochemical paper-based analytical device (ePAD) using the laser-scribed graphene (LSG) technique for LID detection in pharmaceutical and forensic applications. The paper-based devices were characterized by scanning electron microscopy (SEM) and Raman spectroscopy, confirming the porosity and graphene-derived nature of the LSG material. In addition, to enhance the electrocatalytic properties, the LSG electrode was modified with a nanocomposite based on the mixture of multi-walled carbon nanotubes (MWCNT) and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Electrochemical characterizations of the non-modified and MWCNT/PEDOT:PSS-modified electrodes by impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV), revealed the enhancement of the electrochemical properties of the modified electrode, providing higher detectability for LID detection. An analytical curve was built using DPV technique and exhibited a linear response in the concentration range of 31 to 248 µmol L−1 LID. The limits of detection (LOD) and quantification (LOQ) of the method were 0.72 µmol L−1 and 2.39 µmol L−1, respectively. The manufacturing reproducibility of the method was assessed by testing 8 sensors from different batches and provided a relative standard deviation (RSD) of 4.92 % (n = 8). The developed sensor was applied to LID determination in a commercial anesthetic sample and, as proof of the applicability of potential use in crime scenes of drug-facilitating crimes, we analyzed spiked LID in alcoholic drinks (vodka and tequila samples). The recovery percentages ranged from 79 % to 109 %, highlighting the practical use of our portable method for in-field analysis. In addition, four seized cocaine samples containing LID were successfully analyzed to demonstrate the potential use as a LID screening tool in street drug samples.

Textile-Based Membraneless Microfluidic Double-Inlet Hybrid Microbial-Enzymatic Biofuel Cell.

This study reports the development of a textile-based colaminar flow hybrid microbial-enzymatic biofuel cell. Shewanella MR-1 was used as a biocatalyst on the anode, and bienzymatic system catalysts based on glucose oxidase and horseradish peroxidase were applied on an air-breathing cathode to address the overpotential loss in a body-friendly way. A single-layer Y-shaped channel configuration with a double-inlet was adopted. Microchannels of biofuel cells were patterned by silk screen printing with Ecoflex to maintain the flexibility of textile substrates without harm to the human body. The electrodes were fabricated with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and a mixture of multiwalled carbon nanotubes and single-walled carbon nanotubes by screen printing. The effects of electrode materials, catalyst type, catalyst concentration, and glucose concentration in the catholyte were investigated to optimize the fuel cell performance. The peak power density (44.9 μW cm-2) and maximum current density (388.9 μA cm-2) of the optimized hybrid biofuel cell were better than those of previously reported textile- or paper-substrate microscale single microbial fuel cells. The developed biofuel cell will be a useful platform as a microscale power source that is harmless to the environment and living organisms.

Effect of Microcapsules on Mechanical, Optical, Self-Healing and Electromagnetic Wave Absorption in Waterborne Wood Paint Coatings

A mixture of multiwalled carbon nanotubes (CNTs) and carbonyl iron powder (Iron(0) pentacarbonyl, CIP) was used as a core material, and a melamine-formaldehyde resin was used as a wall material to prepare CIP/CNTs microcapsules. A core-wall ratio, content of CNTs in the core material, stirring speed, and reaction time were carried out to explore the most significant factor affecting the coverage rate and yield of microcapsules. The most important factor affecting the preparation of CIP/CNTs microcapsules was the content of CNTs in the core material. The optimized CIP/CNTs microcapsules were mixed with shellac microcapsules, and the optimal ratio was explored by analyzing their optical, mechanical, and electromagnetic wave absorption properties in order to prepare coatings with superior performance. The lower the addition amount of CIP/CNTs microcapsules, the lower the effect on the color difference of the coating. The gloss and adhesion of waterborne wood paint coatings decreased with increasing CIP/CNTs microcapsule addition. The hardness, impact resistance and tensile properties of the coatings showed a tendency of increasing and then decreasing with the addition of CIP/CNTs microcapsules. The surface roughness of the coating basically tended to increase with the increase of CIP/CNTs microcapsule content. When the content of added CNTs in the core material was 3.0% and the content of microcapsules was 9.0%, the coating had the highest elongation at break of 12.4% and the highest repair rate of 34.3%, respectively. The mixed shellac microcapsules and CIP/CNTs microcapsules achieved a theoretical minimum reflection loss of −13.52 dB at 16.2 GHz, and the electromagnetic wave absorption band of less than −5 dB was 15.3 GHz–18.0 GHz. The results provide technical references for the preparation of self-healing composite electromagnetic wave absorption coatings on wood substrates.

Carbon nanotubes as a suitable material for electrochemical sensor used in voltammetric determinations of titanium

AbstractWe report the use of carbon nanotubes as a material for the preparation of an electrochemical sensor that acts as a substrate for film metal electrodes used in stripping voltammetry. The sensor is based on a mixture of multiwall carbon nanotubes, glassy carbon spherical powder, and epoxy resin. The properly selected composition of the sensor made it possible to obtain a new substrate, competitive in relation to glassy carbon, for creating film metal electrodes. In this work, the proposed new sensor was used to determine the trace amounts of Ti(IV) on the lead film electrode. Measurements were carried out with in situ mode in an acetate buffer by adsorption stripping voltammetry with the use of cupferron as a complexing agent. Linear response to Ti(IV) ions in the concentration range of 7 × 10–10–7 × 10–8 mol L−1 and the limit of detection (LODs) 2.4 × 10–10 were obtained, respectively. These promising results revealed that a mixture of carbon nanotubes, epoxy resin, and spherical glassy carbon powder used for the determination of titanium ions on PbFE might represent an important addition to existing electrochemical sensor technologies. The proposed procedure was successfully used as a new and powerful analytical tool for determination of Ti(IV) in horsetail extracts.

Influence of the Synergistic Effect of Multi-Walled Carbon Nanotubes and Carbon Fibers in the Rubber Matrix on the Friction and Wear of Metals during the Mixing Process.

As a piece of high-intensity running equipment, the wear of an internal mixer determines the quality of rubber and its life. In general, the wear of an internal mixer is caused by the friction between the rubber and metal during the mixing process, and the most severe wear position is the end face of the equipment. In this paper, a mixture of multi-walled carbon nanotubes (MWCNTs) and carbon fibers (CFs) are added to rubber by mechanical compounding to obtain MWCNT/CF/carbon black (CB) composites. By investigating the synergistic mechanism of MWCNTs and CFs, we analyze the effect of the MWCNT/CF ratio on the frictional wear of metal on the end face of the internal mixer. At the microscopic level, MWCNTs and CFs form a spatial meshwork with CB particles through synergistic interactions. The CB particles can be adsorbed on the spatial meshwork to promote the dispersion of CB particles. In addition, the formation of oil film can be slowed down due to the spatial meshwork, which could hinder the spillage of aromatic oil. Meanwhile, the spatial meshwork serves as a physical isolation layer between the rubber and metal to reduce friction. Therefore, it dramatically impacts the dispersion degree of CB particles, the friction coefficient, the roughness of the surface, and the wear of metal. It shows that the synergistic effect of MWCNT/CF and CB particles is best when the CF content of the rubber matrix is 5 phr, showing the most stable spatial network structure, the best dispersion of CB particles, and minor wear on the end face of the internal mixer.

Multiwalled Carbon Nanotube/PEDOT: PSS Coated on Pineapple Fiber Paper Based Flexible Electrode for Electrochemical Application

In this study, a green electrode made from natural fiber paper was investigated. A pineapple fiber paper was used as electrode support material. A mixture of multiwalled carbon nanotubes and PEDOT: PSS (MWCNTs/ PEDOT: PSS) was used as active electrode material. PEDOT: PSS, a conducting polymer, was applied as binder to connect between MWCNTs and the surface of pineapple fiber paper, and this setup showed decrease in electrode resistivity. Varying the MWCNT concentration mixed with PEDOT: PSS on pineapple fiber paper was explored. The 3 wt.% MWCNT device gave the maximum conductivity value of 10.87 S cm-1. Cyclic voltammetry and impedance analysis indicated that 3 wt.% MWCNT device showed considerable promise as a flexible electrode for electrochemical devices for energy storage applications.

Ultrahigh‐Energy‐Density Flexible Lithium‐Metal Full Cells based on Conductive Fibrous Skeletons

AbstractDespite extensive studies on lithium‐metal batteries (LMBs) that have garnered considerable attention as a promising high‐energy‐density system beyond current state‐of‐the‐art lithium‐ion batteries, their application to flexible power sources is staggering due to the difficulty in simultaneously achieving electrochemical sustainability and mechanical deformability. To address this issue, herein, a new electrode architecture strategy based on conductive fibrous skeletons (CFS) is proposed. Lithium is impregnated into nickel/copper‐deposited conductive poly(ethylene terephthalate) nonwovens via electrochemical plating, resulting in self‐standing CFS–Li anodes. The CFS–Li anodes exhibit stable Li plating/stripping cyclability and mechanical deformability. To achieve high‐capacity flexible cathodes, over‐lithiated layered oxide (OLO) particles are compactly embedded in conductive heteronanomats (fibrous mixtures of multiwalled carbon nanotubes and functional polymer nanofibers). The conductive heteronanomats, as CFS of OLO cathodes, provide bicontinuous electron/ion conduction pathways without heavy metallic current collectors and chelate metal ions dissolved from OLO, thus improving the areal capacity, redox kinetics, and cycling retention. Driven by the attractive characteristics of the CFS–Li anodes and CFS–OLO cathodes, the resulting CFS–LMB full cells provide improvements in the cyclability, rate performance, and more notably, (cell‐based) gravimetric/volumetric energy density (506 Wh kgcell−1/765 Wh Lcell−1) along with the exceptional mechanical flexibility.

Laser-assisted decoration of carbon nanotubes with palladium nanoparticles for application in electrochemical methanol oxidation

Multi-walled carbon nanotubes (MWCNTs) were decorated with palladium nanoparticles (Pd NPs) by laser-ablation of a physical mixture of MWCNTs and Pd NPs without using any reducing agent. The morphology and composition of MWCNT/Pd were analysed by complementary techniques involving Fourier transform infrared spectrometry, transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. Using cyclic voltammetry and chronoamperometry, the electrocatalytic activity and stability of CNT/Pd were evaluated for the electrochemical oxidation of methanol in a basic medium. Comparative investigations were provided with laser-ablated Pd NPs (LA Pd) catalyst concerning catalytic activity and stability. MWCNT/Pd exhibited remarkably high catalytic activity (104.20 mA mg−1) in comparison to the LA Pd catalyst (14.41 mA mg−1). The catalyst was found to exhibit long-term stability even after 3600 s of operation and high resistance towards CO poisoning. It is suggested that the MWCNT/Pd would be valuable as an active electrocatalyst for its commercial applications in direct methanol fuel cells.

On the Synergistic Effect of Multi-Walled Carbon Nanotubes and Graphene Nanoplatelets to Enhance the Functional Properties of SLS 3D-Printed Elastomeric Structures.

Elastomer-based porous structures realized by selective laser sintering (SLS) are emerging as a new class of attractive multifunctional materials. Herein, a thermoplastic polyurethane (TPU) powder for SLS was modified by 1 wt.% multi-walled carbon nanotube (MWCNTs) or a mixture of MWCNTs and graphene (GE) nanoparticles (70/30 wt/wt) in order to investigate on both the synergistic effect provided by the two conductive nanostructured carbonaceous fillers and the correlation between formulation, morphology, and final properties of SLS printed porous structures. In detail, porous structures with a porosity ranging from 20% to 60% were designed using Diamond (D) and Gyroid (G) unit cells. Results showed that the carbonaceous fillers improve the thermal stability of the elastomeric matrix. Furthermore, the TPU/1 wt.% MWCNTs-GE-based porous structures exhibit excellent electrical conductivity and mechanical strength. In particular, all porous structures exhibit a robust negative piezoresistive behavior, as demonstrated from the gauge factor (GF) values that reach values of about −13 at 8% strain. Furthermore, the G20 porous structures (20% of porosity) exhibit microwave absorption coefficients ranging from 0.70 to 0.91 in the 12–18 GHz region and close to 1 at THz frequencies (300 GHz–1 THz). Results show that the simultaneous presence of MWCNTs and GE brings a significant enhancement of specific functional properties of the porous structures, which are proposed as potential actuators with relevant electro-magnetic interference (EMI) shielding properties.

A new method for preparing buckypaper by pressing a mixture of multi-walled carbon nanotubes and amorphous carbon

In this paper, a mixture of carbon nanotubes and amorphous carbon was pressed to fabricate a tablet-shaped structure of buckypaper. First, multi-walled carbon nanotubes were synthesized by the mechanothermal method. Subsequently, the multi-walled carbon nanotubes and ball-milled amorphous carbon were mixed. Then, they were put pressured to fabricate buckypaper. The results of Raman analysis of the produced buckypaper showed that the proposed method by forming a network of carbon nanotubes can be introduced as a novel way for the synthesizing of the buckypaper without any solvents. Scale-up fabrication, non-destruction of the structure of the nanotubes and subsequently maintaining the maximum quality of the carbon nanotubes, and flexibility of the process are the unique features of this approach.

Antagonistic effects of multi-walled carbon nanotubes and BDE-47 in zebrafish (Danio rerio): Oxidative stress, apoptosis and DNA damage

In natural environments, organisms are often exposed to several environmental pollutants at any one time, and the potential effects of such co-exposures on human and environmental health are of considerable concern. It is thought that multi-walled carbon nanotubes (MWCNTs) may interact with other pollutants in aquatic systems and induce considerably different effects compared with exposure to a single contaminant. The objective of this study was to evaluate the potential acute combined effects of mixtures of MWCNTs and 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) on embryonic development stages, oxidative stress, apoptosis and DNA damage in developing zebrafish (Danio rerio). The embryos were treated with BDE-47 (5, 10, and 50 μg/L) and MWCNTs (50 mg/L), either combined or individually, for 96 h. Following exposure, BDE-47 induced significant acute toxicity, while the MWCNTs exhibited slight toxicity. When compared with BDE-47-only exposure, the inhibited growth induced by BDE-47 was weakened in the presence of MWCNTs. Similarly, the levels of oxidative stress biomarkers (reactive oxygen species, superoxide dismutase, catalase activities and malondialdehyde), apoptosis (apoptosis rate, caspase-3 and caspase-9 activities) and DNA damage (comet assay and comet olive tails) decreased in the presence of MWCNTs compared to those exposed to BDE-47 alone. These results demonstrate that MWCNTs can weaken the developmental inhibition, oxidative stress, apoptosis and DNA damage induced by BDE-47 in the early stages of zebrafish development.

Enhanced Functional Properties of Low-Density Polyethylene Nanocomposites Containing Hybrid Fillers of Multi-Walled Carbon Nanotubes and Nano Carbon Black.

In this work, hybrid filler systems consisting of multi-walled carbon nanotubes (MWCNTs) and nano carbon black (nCB) were incorporated by melt mixing in low-density polyethylene (LDPE). To hybrid systems a mixture of MWCNTs and nCB a mass ratio of 1:1 and 3:1 were used. The purpose was to study if the synergistic effects can be achieved on tensile strength and electrical and thermal conductivity. The dispersion state of carbon nanofillers in the LDPE matrix has been evaluated with scanning electron microscopy. The melting and crystallization behavior of all nanocomposites was not significantly influenced by the nanofillers. It was found that the embedding of both types of carbon nanofillers into the LDPE matrix caused an increase in the value of Young’s modulus. The results of electrical and thermal conductivity were compared to LDPE nanocomposites containing only nCB or only MWCNTs presented in earlier work LDPE/MWCNTs. It was no synergistic effects of nCB in multi-walled CNTs and nCB hybrid nanocomposites regarding mechanical properties, electrical and thermal conductivity, and MWCNTs dispersion. Since LDPE/MWCNTs nanocomposites exhibit higher electrical conductivity than LDPE/MWCNTs + nCB or LDPE/nCB nanocomposites at the same nanofiller loading (wt.%), it confirms our earlier study that MWCNTs are a more efficient conductive nanofiller. The presence of MWCNTs and their concentration in hybrid nanocomposites was mainly responsible for the improvement of their thermal conductivity.

Enzymatic degradation of ginkgolic acid by laccase immobilized on novel electrospun nanofiber mat.

Ginkgo biloba leaf extract contains many active ingredients that are beneficial for health. However, ginkgolic acid, one of the major components found in G. biloba extract, may cause serious allergic and toxic side effects. The purpose of this study is to immobilize the laccase system on the electrospun nylon fiber mat (NFM) to hydrolyze the ginkgolic acid in G. biloba leaf extract efficiently. Novel electrospinning technology successfully produced high-quality nanoscopic fiber mats made of a mixture of multi-walled carbon nanotube and nylon 6,6. Laccase that was immobilized onto the NFM exhibited much higher efficiency in the catalyzation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) than nylon 6,6 pellets. After being immobilized onto the NFM, the pH and temperature stability of laccase were significantly improved. The NFM-immobilized laccase could maintain more than 50% of its original activity even after 40 days of storage or 10 operational cycles. The kinetic parameters, including rate constant (K), the time (τ50) in which 50% of ginkgolic acid hydrolysis was reached, the time (τcomplete) required to achieve complete ginkgolic acid hydrolysis, Km and Vmax were determined, and were 0.07 ± 0.01 min-1 , 8.97 ± 0.55 min, 45.45 ± 2.79 min, 0.51 ± 0.09 mM and 0.49 ± 0.03 mM min-1 mg-1 , respectively. The result successfully demonstrated the strong potential of using novel electrospun nanofiber mats as enzyme immobilization platforms, which could significantly enhance enzyme activity and stability. © 2020 Society of Chemical Industry.

Development and validation of an analytical method for detecting chlorantraniliprole residues in fresh tea leaves

An efficient method using multiwalled carbon nanotubes (MWCNTs) as dispersive solid-phase extraction sorbent was established for determining chlorantraniliprole residues in fresh tea leaves, which are known to be a troublesome matrix containing abundant pigments, via gas chromatography with an electron capture detector. Acetonitrile was used as the extraction solvent, with sodium chloride enhancing the analyte partition in the organic phase. The optimal mixture of MWCNTs and primary secondary amine (PSA) was based on the distribution of the target analyte recovery and on the clean-up efficiency; while matrix-matched calibration was recommended to combat the matrix effect. Mean recoveries of 95.2%–108.8% were obtained with intraday and interday precisions of less than 7.9% and 10.3%, respectively. Good linearity was observed for concentrations of 0.02–1.0mg/kg with a correlation coefficient of 0.9984. The limits of detection and quantification were 0.005 mg/kg and 0.02 mg/kg, respectively. The method was employed to investigate the dissipation dynamics of chlorantraniliprole in fresh tea leaves with real field samples. Consequently, the dissipation rates of chlorantraniliprole in fresh tea leaves followed pseudo-first-order kinetics with a half-life of 1.9 d, and the average chlorantraniliprole residue content was below 0.02 mg/kg with a harvest withholding period of 14 d.

Carbon nanotubes and carbon fibers in a flash: an easy and convenient preparation of carbon nanostructures using a conventional microwave

The growing interest in nanomaterials in different application fields calls for the implementation of simple, economically appealing, and efficient preparative methods. Among the wide variety of nanomaterials, carbon nanostructures have a special place due to their potential technological applications. Here, we present a fast, cheap, and easy-to-implement microwave-assisted method for the preparation of carbon nanotubes (CNTs) and carbon fibers (CFs) at room pressure conditions. The synthesis involves heating a mixture of graphite and ferrocene contained in a simple glass tube using a conventional microwave oven. A mixture of multi-walled carbon nanotubes (MWCNTs) and Fe3O4 magnetic nanoparticles were obtained quickly (less than 30 s) and in good yields. The products were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and Raman spectroscopy.

Effect of sonication time on the evaporation rate of seawater containing a nanocomposite.

Sonication time has a significant contribution to the stability and properties of nanofluids (mixtures of nanoparticles and a base fluid). Finding the optimum sonication time can help to save energy and ensure optimal design. The present study deals with the sonication time effect on the evaporation rate of seawater containing a nanocomposite (i.e., a mixture of multi-walled carbon nanotubes and graphene nanoplates). For indoor experiments, a solar simulator was employed as the radiation source. At first, the nanofluid with a concentration of 0.01% wt. was sonicated in an ultrasonic bath for different times of 30, 60, 90, 120, 180, 240 min, and the associated zeta potential values were recorded to evaluate the stability. Next, the best time function was used to appraise the effect of concentration variations (0.001, 0.002, 0.004, 0.01, 0.02 and 0.04% wt.) and the light intensities (1.6, 2.6, and 3.6 suns) on the rate of solar steam generation. The results indicate that for a concentration of 0.01% wt. and under 3.6 suns, the highest evaporation efficiency of 61.3% would be achieved at 120 min sonication time.

Preparation of Carbon Encapsulated Magnetic FeCo Alloy Nanoparticles Supported on Carbon Nanotubes for Enhanced Microwave Absorption

A mixture of multi-walled carbon nanotubes in an ethanol solution of Fe(NO3)3.9H2O and Co(NO3)2.6H2O, were used to prepare an Fe2O3-CoO catalyst supported on carbon nanotubes by a supercritical fluid drying method. The carbon encapsulated FeCo nanoparticles were prepared by the catalytic decomposition of methane over the catalyst at 850°C for 30 mins. The morphology and microstructure of the catalyst and carbon encapsulated nanoparticles (CEP) were characterized by XRD, FESEM, EDS and TEM analyses. The electromagnetic characteristics and microwave absorption properties of the CEP product were also studied. Results show that the CEP product possesses high complex permittivity and good permeability in the microwave frequency range from 2 to 18 GHz. The maximum absorption peak was observed at 9.44 GHz for a large reflection loss (R) of 13.3 dB, with a band width of 7.4 GHz and 2.56 GHz, at R <- 5 dB and R <- 10 dB, respectively.

Impact of Co/Mo ratio on the activity of CoMo/MgO catalyst for production of high-quality multi-walled carbon nanotubes from polyethylene waste

A simple two-stage method was used to produce multiwalled carbon nanotubes (MWCNTs) from low-density polyethylene (LDPE) plastic waste using a group of CoMo/MgO catalysts with several Co/Mo molar ratios (14.5, 6.5, 2.5, 1 and 0.4). The catalytic degradation of LDPE waste was performed using the HZSM-5 catalyst at a low temperature of 400 °C to form non-condensable gases, which were subsequently used as a carbon source for the production of MWCNTs at 700 °C. The influence of Co/Mo ratio on the yield, morphological structure, thermal stability, purity, and quality of MWCNTs was studied. The freshly calcined catalysts were characterized using BET surface area, XRD, FTIR, and H2-TPR techniques. On the other hand, Raman spectroscopy, TEM, XRD, and TGA analyses were performed for full characterization of the as-deposited carbon materials. The TPR and FTIR profiles of the fresh catalysts illustrated that the interaction between Co, Mo, and MgO increased by decreasing the Co/Mo ratio from 14.5 to 0.4. Also, the CoMo(6.5)/MgO catalyst displayed the highest surface properties compared to the other catalysts with different Co/Mo ratios. The CoMo(6.5)/MgO catalyst was the most active in terms of MWCNTs production. Moreover, the morphology, purity, and quality of the produced MWCNTs were strongly associated with the catalyst composition. TEM images illustrated that pure MWCNTs were obtained using the CoMo(14.5)/MgO catalyst, while a mixture of MWCNTs, carbon nanofibers (CNFs) and carbon nano-onions (CNOs) was produced using the CoMo(0.4)/MgO catalyst. Raman spectroscopy and TGA results proved that MWCNTs with the best quality and purity were obtained using the catalysts with Co/Mo ratios of 14.5 and 6.5.

Effect of Multi-walled Carbon Nanotubes on the Toxicity of Triphenyltin to the Marine Copepod Tigriopus japonicus.

Marine organisms are often exposed to a mixture of various pollutants in marine environment (i.e., nanoparticles, organic pollutants). The present study investigated the potential effects of multi-walled carbon nanotubes (MWCNTs) on the toxicity of triphenyltin chloride (TPTCl). The results revealed an antagonistic interaction between MWCNTs and TPTCl on the copepod through 96h acute exposure, which was attributed to the adsorption of TPTCl to MWCNTs and aggregation of MWCNTs in the test solutions. Results of 21days' chronic exposure showed that the effect concentration of MWCNTs could be 100 times lower than that of acute exposure. The exposure to binary mixture of MWCNT (1.0mg/L) and TPTCl (0.3µg/L) caused a reduction by 94% for the 3rd time spawning and 83% for the total number of hatched nauplii. The ingestion and exterior attachment of MWCNTs to the copepod might be the main reasons causing the adverse effect in reproduction.

Wearable electrochemical glove-based sensor for rapid and on-site detection of fentanyl

Rapid, on-site detection of fentanyl is of critical importance, as it is an extremely potent synthetic opioid that is prone to abuse. Here we describe a wearable glove-based sensor that can detect fentanyl electrochemically on the fingertips towards decentralized testing for opioids. The glove-based sensor consists of flexible screen-printed carbon electrodes modified with a mixture of multiwalled carbon nanotubes and a room temperature ionic liquid, 4-(3-butyl-1-imidazolio)-1-butanesulfonate. The sensor shows direct oxidation of fentanyl in both liquid and powder forms with a detection limit of 10 μM using square-wave voltammetry. The “Lab-on-a-Glove” sensors, combined with a portable electrochemical analyzer, provide wireless transmission of the measured data to a smartphone or tablet for further analysis. The integrated sampling and sensing methodology on the thumb and index fingers, respectively, enables rapid screening of fentanyl in the presence of a mixture of cutting agents and offers considerable promise for timely point-of-need screening for first responders. Such a glove-based “swipe, scan, sense, and alert” strategy brings chemical analytics directly to the user's fingertips and opens new possibilities for detecting substances of abuse in emergency situations.