Subcellular Distribution and Chemical Forms of Pb in Corn: Strategies Underlying Tolerance in Pb Stress

Studying the accumulation position and forms of heavy metals (HMs) in organisms and cells is helpful to understand the transport process and detoxification mechanism. As typical HMs, lead (Pb) subcellular content, localization, and speciation of corn subcellular fractions were studied by a series of technologies, including transmission electron microscopy, inductively coupled plasma mass spectrometry, and X-ray absorption near edge structure. The results revealed that the electrodense granules of Pb were localized in the cell wall, intercellular space, and plasma membranes. About 71% Pb was localized at the cell wall and soluble fraction. In cell walls, the total amount of pyromorphite and Pb carbonate was about 80% and the remaining was Pb stearate. In the nuclear and chloroplast fraction, which demonstrated significant changes, major speciations were Pb sulfide (72%), basic Pb carbonate (16%), and Pb stearate (12%). Pb is blocked by cell walls as pyromorphite and Pb carbonate sediments and compartmentalized by vacuoles, which both play an inportant role in cell detoxification. Besides, sulfur-containing compounds form inside the cells

Facile Fabrication of NiO-Decorated Double-Layer Single-Walled Carbon Nanotube Buckypaper for Glucose Detection

A novel NiO-decorated flexible buckypaper (NiO-BP) was fabricated by a simple and scalable vacuum filtration method for electrochemical detection of glucose. The NiO-BP consists of two layers: one side is composed of purified single-walled carbon nanotubes, serving as the supporting layer, whereas the other side comprises NiO-loaded single-walled carbon nanotubes, serving as the catalyst layer. The morphology and structure of NiO-BP were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Raman spectroscopy. The fabricated NiO-BP was applied to the electrochemical detection of glucose. Under optimized conditions, the sensor exhibited a wide linear range of 0.1–9 mM for the determination of glucose with high sensitivity (2701 μA mM–1 cm–2) and a short response time (<2.5 s). The present work reveals that the buckypaper with a unique double-layer structure is promising for wearable biosensors

CuO/CoZn-Layered Double-Hydroxide Nanowires on Carbon Cloth as an Enzyme-Free H₂O₂ Sensor

Transition metal layered double hydroxides (LDHs) have attracted much attention as catalysts due to their multiple valence states and high electrocatalytic activity. Traditional enzyme-based electrochemical H2O2 sensor is limited by short lifetime, instability, and complicated fabrication procedure, making it difficult to be widely used. Instead of natural enzymes, transition metal based LDHs can be applied as electrocatalysts for enzyme-free H2O2 sensor. In this work, CoZn-LDH nanosheets grown on CuO nanowires (NWs) were synthesized on carbon cloth (CC) by electrodeposition and hydrothermal methods for the electrochemical enzyme-free detection of H2O2. For this purpose, CuO NWs were first electrodeposited on CC substrate, on which CoZn bimetal LDH nanosheets were synthesized by the hydrothermal technique. Herein, CC provides an ideal conductive substrate for the growth of CuO NWs and CoZn-LDH, so that the sythesized CuO/CoZn-LDH NWs can be evenly dispersed, exposing more active sites for the enhancement of their electrocatalytic activity. As a result, CuO/CoZn-LDH NWs display excellent electrocatalytic activity for the reduction of H2O2. The fabricated sensor has a good linear response in the concentration range of 0.01–16 mM for the electrochemical detection of H2O2, with low detection limit of 0.46 μM and high sensitivity of 760.64 μA mM–1 cm–2. In real sample mouthwash detection, the proposed sensor demonstrates the efficient recovery of H2O2, indicating the ability of CuO/CoZn-LDH NWs to quantitatively detect real samples

Facile Synthesis of ZnMn₂O₄@rGO Microspheres for Ultrasensitive Electrochemical Detection of Hydrogen Peroxide from Human Breast Cancer Cells

Mixed transition-metal oxides have witnessed increasing attention in catalysts and electrocatalysts. Herein, reduced graphene oxide-wrapped ZnMn2O4 microspheres (ZnMn2O4@rGO) were facilely synthesized through the solvothermal technique. The microstructure and morphology of ZnMn2O4@rGO microspheres were analyzed under Raman, X-ray photoelectron, X-ray diffraction, and energy-dispersive spectroscopies and scanning electron microscopy. The synthesized ZnMn2O4@rGO was employed as an excellent electrocatalyst for the reduction of hydrogen peroxide (H2O2). The ZnMn2O4@rGO-modified glassy carbon electrode (ZnMn2O4@rGO/GCE) exhibited a linear detection to H2O2 in a wide concentration range of 0.03–6000 μM with a detection limit of 0.012 μM. The biosensor was evaluated to determine H2O2 secreted by human breast cancer cells (MCF-7), indicating its promising applications in physiology and diagnosis

NiO-Coated CuCo₂O₄ Nanoneedle Arrays on Carbon Cloth for Non-enzymatic Glucose Sensing

Transition-metal oxide nanocomposites with a core–shell structure exhibit excellent catalytic performance because of their large surface area and the synergetic effect resulting from their special structures. In this work, a two-step hydrothermal method was used to synthesize hierarchical CuCo2O4/NiO core–shell nanoneedle arrays (NNAs) on conductive carbon cloth (CC) as a self-supported electrode. The morphology and structure of CuCo2O4/NiO NNAs/CC were studied in detail by various microscopes and spectroscopes. The synthesized CuCo2O4/NiO NNAs exhibited excellent electrocatalytic properties toward glucose oxidation due to the hierarchical core–shell structure and the resulting synergetic effect. Therefore, CuCo2O4/NiO NNAs/CC showed excellent characteristics for glucose determination with high sensitivity (4140 μA mM–1 cm–2), broad linear range (0.5–6000 μM), and outstanding selectivity and stability. Moreover, the proposed sensor was evaluated to determine glucose in human serum samples with satisfactory recovery, indicating its potential practical application in quantitative analysis of blood glucose levels

Cu–Pd Alloy Nanoparticles on Carbon Paper as a Self-Supporting Electrode for Glucose Sensing

Nanomaterials based on metals and their alloys have been paid increasing attention due to their adjustable morphology, high stability and excellent catalytic activity. In this work, Fritillaria cirrhosa-like Cu–Pd alloy nanoparticles were grown on carbon paper (Cu–Pd/CP) by one-step electrodeposition, serving as a self-supporting electrode to catalyze glucose oxidation. The morphological and structural characterizations of the Cu–Pd alloy were performed using scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results showed that Fritillaria cirrhosa-like Cu–Pd alloy nanoparticles with a size of about 600 nm were synthesized and uniformly distributed on CP. The 3D network structure composed of CP with good conductivity and Cu–Pd alloy nanoparticles with unique morphology greatly increased the specific surface area and conductivity of the material, which is beneficial to the electrocatalytic oxidation of glucose. As a self-supporting electrode, the prepared Cu–Pd/CP presented excellent electrocatalytic activity toward glucose oxidation with a wide linear range (0.003–10 mM), high sensitivity (2589 μA mM–1 cm–2), and low detection limit (1.3 μM). The proposed sensor has been successfully applied to the determination of glucose in real human serum samples, indicating that Cu–Pd/CP is a promising candidate for nonenzymatic glucose sensing

Microsphere-Fiber Interpenetrated Superhydrophobic PVDF Microporous Membranes with Improved Waterproof and Breathable Performance

Superhydrophobic membranes with extreme liquid water repellency property are good candidates for waterproof and breathable application. Different from the mostly used strategies through either mixing or postmodifying base membranes with perfluorinated compounds, we report in this work a facile methodology to fabricate superhydrophobic microporous membranes made up of pure poly­(vinylidene fluoride) (PVDF) via a high-humidity induced electrospinning process. The superhydrophobic property of the PVDF microporous membrane is contributed by its special microsphere-fiber interpenetrated rough structure. The effective pore size and porosity of the PVDF membranes could be well tuned by simply adjusting the PVDF concentrations in polymer solutions. The membrane with optimized superhydrophobicity and porous structure exhibits improved waterproof and breathable performance with hydrostatic pressure up to 62 kPa, water vapor transmission rate (WVT rate) of 10.6 kg m–2 d–1, and simultaneously outstanding windproof performance with air permeability up to 1.3 mm s–1. Our work represents a rather simple and perfluorinated-free strategy for fabricating superhydrophobic microporous membranes, which matches well with the environmentally friendly requirement from the viewpoint of practical application

Data_Sheet_1_Cultureless enumeration of live bacteria in urinary tract infection by single-cell Raman spectroscopy.docx

Urinary tract infections (UTIs) are the most common outpatient infections. Obtaining the concentration of live pathogens in the sample is crucial for the treatment. Still, the enumeration depends on urine culture and plate counting, which requires days of turn-around time (TAT). Single-cell Raman spectra combined with deuterium isotope probing (Raman-DIP) has been proven to identify the metabolic-active bacteria with high accuracy but is not able to reveal the number of live pathogens due to bacteria replication during the Raman-DIP process. In this study, we established a new approach of using sodium acetate to inhibit the replication of the pathogen and applying Raman-DIP to identify the active single cells. By combining microscopic image stitching and recognition, we could further improve the efficiency of the new method. Validation of the new method on nine artificial urine samples indicated that the exact number of live pathogens obtained with Raman-DIP is consistent with plate-counting while shortening the TAT from 18 h to within 3 h, and the potential of applying Raman-DIP for pathogen enumeration in clinics is promising.</p

Mn₃O₄–CeO₂ Hollow Nanospheres for Electrochemical Determination of Hydrogen Peroxide

Introducing hollow structure by self-assembly and hard-templating methods enables the increase of specific surface areas and reaction sites toward boosting the electrochemical sensing performance of the manganese oxide-based materials. In this work, a strategy of synthesizing Mn3O4–CeO2 with nanosized hollow spheres was developed by employing cerium oxide as the support skeleton for a superior catalyzing effect toward hydrogen peroxide (H2O2) electroreduction. Herein, the effect of molar ratios of Ce and Mn on the structure and electrocatalytic property of synthesized Mn3O4–CeO2 hollow nanospheres was investigated. Profiting from abundant active sites, high porosity, large specific surface area, and the synergy of Mn3O4 and CeO2, the resulting Mn3O4–CeO2 hollow nanospheres display a wide linear range response (0.005–17 mM) with high sensitivity (176.4 μA mM–1 cm–2) for H2O2 determination. The developed sensor shows excellent stability, selectivity, and recovery for detecting H2O2 in actual samples. This work finds an efficient way to construct hollow structure through self-assembly on a hard-templating surface, providing special insight into the electrochemical properties of transition-metal oxides

Microsphere-Fiber Interpenetrated Superhydrophobic PVDF Microporous Membranes with Improved Waterproof and Breathable Performance

Superhydrophobic membranes with extreme liquid water repellency property are good candidates for waterproof and breathable application. Different from the mostly used strategies through either mixing or postmodifying base membranes with perfluorinated compounds, we report in this work a facile methodology to fabricate superhydrophobic microporous membranes made up of pure poly­(vinylidene fluoride) (PVDF) via a high-humidity induced electrospinning process. The superhydrophobic property of the PVDF microporous membrane is contributed by its special microsphere-fiber interpenetrated rough structure. The effective pore size and porosity of the PVDF membranes could be well tuned by simply adjusting the PVDF concentrations in polymer solutions. The membrane with optimized superhydrophobicity and porous structure exhibits improved waterproof and breathable performance with hydrostatic pressure up to 62 kPa, water vapor transmission rate (WVT rate) of 10.6 kg m^–2 d^–1, and simultaneously outstanding windproof performance with air permeability up to 1.3 mm s^–1. Our work represents a rather simple and perfluorinated-free strategy for fabricating superhydrophobic microporous membranes, which matches well with the environmentally friendly requirement from the viewpoint of practical application