Highly Stretchable and Sensitive SBS/Graphene Composite Fiber for Strain Sensors

Flexible strain sensors have attracted tremendous interests due to the emergence of intelligent wearable technology. Electrically conductive fibers are desirable candidates for flexible strain sensors, but up til now, there still exist enormous challenges to obtain conductive fibers exhibiting simultaneously high stretchability and high strain sensitivity. This paper introduces a poly (styrene‐butadiene‐styrene) (SBS)/graphene (Gr) composite fiber‐based flexible strain sensor fabricated by a facile and highly scalable wet spinning method. The results demonstrate that the graphene content has significant influence on the morphology, mechanical properties, and electromechanical properties of the composite fibers. The fibers with 5 wt% graphene have a wide response range of up to 100% strain, a high electrical sensitivity with the gauge factor of 10083.98 at 100% strain, and meanwhile, a high level of stability for 2100 stretching–releasing cycles under an applied strain of 20%. Furthermore, the SBS‐5%Gr composite fibers display excellent sensing performance in detecting human upper limb movements at different joints including hand joints, wrist joints, elbow joints, and shoulder joints.     

Graphene-Based Sensors for the Detection of Bioactive Compounds: A Review

Over the last years, different nanomaterials have been investigated to design highly selective and sensitive sensors, reaching nano/picomolar concentrations of biomolecules, which is crucial for medical sciences and the healthcare industry in order to assess physiological and metabolic parameters. The discovery of graphene (G) has unexpectedly impulsed research on developing cost-effective electrode materials owed to its unique physical and chemical properties, including high specific surface area, elevated carrier mobility, exceptional electrical and thermal conductivity, strong stiffness and strength combined with flexibility and optical transparency. G and its derivatives, including graphene oxide (GO) and reduced graphene oxide (rGO), are becoming an important class of nanomaterials in the area of optical and electrochemical sensors. The presence of oxygenated functional groups makes GO nanosheets amphiphilic, facilitating chemical functionalization. G-based nanomaterials can be easily combined with different types of inorganic nanoparticles, including metals and metal oxides, quantum dots, organic polymers, and biomolecules, to yield a wide range of nanocomposites with enhanced sensitivity for sensor applications. This review provides an overview of recent research on G-based nanocomposites for the detection of bioactive compounds, providing insights on the unique advantages offered by G and its derivatives. Their synthesis process, functionalization routes, and main properties are summarized, and the main challenges are also discussed. The antioxidants selected for this review are melatonin, gallic acid, tannic acid, resveratrol, oleuropein, hydroxytyrosol, tocopherol, ascorbic acid, and curcumin. They were chosen owed to their beneficial properties for human health, including antibiotic, antiviral, cardiovascular protector, anticancer, anti-inflammatory, cytoprotective, neuroprotective, antiageing, antidegenerative, and antiallergic capacity. The sensitivity and selectivity of G-based electrochemical and fluorescent sensors are also examined. Finally, the future outlook for the development of G-based sensors for this type of biocompounds is outlined.     

硝基化合物的电还原方法

概述了硝基化合物还原的主要方法,介绍了在不同介质体系下不同种类的硝基化合物的电还原进展,并重点归纳出不同介质体系中电还原的优缺点。     

Affibody Functionalized Beads for the Highly Sensitive Detection of Cancer Cell-Derived Exosomes

Exosomes belong to the class of extracellular vesicles of endocytic origin, which are regarded as a promising source of cancer biomarkers in liquid biopsy. As a result, an accurate, sensitive, and specific quantification of these nano-sized particles is of significant importance. Affinity-based approaches are recognized as the most valuable technique for exosome isolation and characterization. Indeed, Affibody biomolecules are a type of protein scaffold engineered with small size and enjoy the features of high thermal stability, affinity, and specificity. While the utilization of antibodies, aptamers, and other biologically active substances for exosome detection has been reported widely, there are no reports describing Affibody molecules’ usage for exosome detection. In this study, for the first time, we have proposed a novel strategy of using Affibody functionalized microbeads (AffiBeads) for exosome detection with a high degree of efficiency. As a proof-of-concept, anti-EGFR-AffiBeads were fabricated and applied to capture and detect human lung A549 cancer cell-derived EGFR-positive exosomes using flow cytometry and fluorescent microscopy. Moreover, the capture efficiency of the AffiBeads were compared with its counterpart antibody. Our results showed that the Affibody probe had a detection limit of 15.6 ng exosomes per mL (~12 exosomes per AffiBead). The approach proposed in the current study can be used for sensitive detection of low expression level markers on tumor-derived exosomes, providing a basis for early-stage cancer diagnosis.     

MXene Reinforced PAA/PEDOT:PSS/MXene Conductive Hydrogel for Highly Sensitive Strain Sensors

Conductive hydrogel has a vital application prospect in flexible electronic fields such as electronic skin and force sensors. Developing conductive hydrogel with significant toughness and high sensitivity is urgently needed for application research. In this work, a strong and sensitive strain sensor based on conductive hydrogel is demonstrated by introducing MXene (Ti3C2Tx) into the micelle crosslinked polyacrylic acid (PAA)/poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) hydrogel network. The functional polymer micelle crosslinkers can dissipate external stress by deformation, endowing the hydrogel with high strength. The combination of MXene both improves the polymer network structure and the conductive pathways, further enhancing the mechanical properties and sensing performance. Resultantly, the flexible strain sensor base on PAA/PEDOT:PSS/MXene conductive hydrogel exhibits excellent sensing performance with a high gauge factor of 20.86, a large strain detection range of 1000%, as well as good adhesion on different interfaces. Thus, it can be used to monitor various movements of the human body and identify all kinds of handwriting, showing great potential into wearable electronics.     

Review on Greener and Safer Synthesis of Nitro Compounds

The review describes the recent developments in the green synthetic methods of nitro compounds involving environmentally benign approaches such as, use of solid‐supported reagents, microwave‐assisted reactions, ionic liquids, ultrasound assisted nitration reactions, gas phase nitration and vapor phase nitration.     

Preparation of Novel Sensors Based on Polyimide Membrane for Sensitive and Selective Determination of Dopamine

Polyimides as dopamine selective membrane were prepared from 4,4′-diaminodicyclohexylmethane and different dianhydrides. The chemical structure and thermal properties of these polyimides were examined. For the voltammetric sensor applications, polyimides exhibited suitable glass transition temperature (T_g), high thermal stability, and good adhesive properties. Moreover, polyimides were coated onto Pt electrode surface for the preparation of dopamine selective electrodes. Electrochemically dopamine responses of polyimide-coated electrodes were examined by differential pulse voltammetry. The sensor characteristics such as sensitivity, linearity, selectivity, response time, and stability of the prepared sensors have been determined. Prepared polyimide-coated electrodes can be used for selective and sensitive dopamine detection.     

Investigation of the Correlations Between Nitro Group Charges and Some Properties of Nitro Organic Compounds

The so‐called nitro group charge method (NGCM) is successfully established to investigate some properties of nitro compounds including the molecular stability measured by total energy (only for isomers), the bond lengths, bond dissociation energies (BDE), and the nitrating activities, in that the method considers the molecular structure. These properties are intrinsically and especially thermodynamically consistent with each other and can be well related qualitatively and even quantitatively with nitro group charges (Q_Nitro). The correlations between Q_Nitro and the properties are: (1) for nitro isomers, the more negative the average Q_Nitro, the lower the total energy and the more stable is the isomer; (2) for any separate group of nitro compounds, the more negative Q_Nitro, the shorter the R‐nitro bond length; (3) for the bond dissociation energy, more negative Q_Nitro corresponds to a higher BDE of the R‐nitro bond; (4) by NGCM, the conditions, the reaction rates and the occurrence ratios of products of some nitration can be predicted and compared: the more negative Q_Nitro of the product, the easier and faster the nitration, and the higher the occurrence ratio of the corresponding product.     

Highly Sensitive Plus Shaped Cavity in Silicon Fiber for RI Detection of Water Samples

Silicon - Fiber grating based sensors demonstrate great potential especially for the refractive index (RI) based sensing. However, a meticulous effort is still required to improve the sensitivity...     

芳香族硝基化合物合成的最新研究进展

综述了近年来芳香族硝基化合物合成的研究进展,主要包括芳香硼酸、芳香卤化物及拟卤化物、芳香羧酸及芳烃碳-氢键的硝化反应、芳香胺及叠氮化合物的氧化及其反应机理的探讨。     

Fabrication of a Highly Sensitive Chemical Sensor Based on ZnO Nanorod Arrays

We report a novel method for fabricating a highly sensitive chemical sensor based on a ZnO nanorod array that is epitaxially grown on a Pt-coated Si substrate, with a top–top electrode configuration. To practically test the device, its O₂ and NO₂ sensing properties were investigated. The gas sensing properties of this type of device suggest that the approach is promising for the fabrication of sensitive and reliable nanorod chemical sensors.     

分子内氨基对C-NO2影响的理论研究

首次以化合物中硝基集居总数作为硝基吸电子力,将其作为衡量硝基化合物(C—NO2键必须是分子中最弱的键)感度大小的一个标准,即硝基吸电子力越大,化合物的感度越低。B3LYP／6—31G^**水平下,系统研究苯、甲苯氨基硝基衍生物表明：当氨基硝基处于共轭体系中时,氨基加强C—NO2键的次序为邻位强于对位,而间位氨基会削弱C—NO2键;当氨基硝基不处于共轭体系中时,氨基对C-NO2键的影响主要是诱导效应和空间效应．当氨基和硝基相隔数个原子时,这些效应将变得十分微弱。     

Highly Sensitive Fluorescence Probe Based on Functional SBA-15 for Selective Detection of Hg<Superscript>2+</Superscript>

An inorganic–organic hybrid fluorescence chemosensor (DA/SBA-15) was prepared by covalent immobilization of a dansylamide derivative into the channels of mesoporous silica material SBA-15 via (3-aminopropyl)triethoxysilane (APTES) groups. The primary hexagonally ordered mesoporous structure of SBA-15 was preserved after the grafting procedure. Fluorescence characterization shows that the obtained inorganic–organic hybrid composite is highly selective and sensitive to Hg²⁺ detection, suggesting the possibility for real-time qualitative or quantitative detection of Hg²⁺ and the convenience for potential application in toxicology and environmental science.     

芳香族硝基化合物的水合肼催化还原反应的研究

研究了以８０％水合肼为还原剂,在ＦｅＣｌ３·６Ｈ２Ｏ／Ｃ存在下,回流３～８ｈ,将芳香族硝基化合物转变成芳香族氨基化合物的还原反应。相应的氨基化合物的产率达到８５％～９８％。     

硝基芳香族化合物废水处理技术研究进展

综述了硝基芳香化合物废水物理、化学、生物处理技术的研究现状及在实际工程中的应用现状,并展望了此类废水处理技术的应用前景.     

水中水合肼还原芳香族硝基化合物的研究

以NaOH溶液沉淀FeCl3溶液制备了催化剂FeO(OH)。在水中用FeO(OH)催化水合肼还原9种芳香族硝基化合物得到相应的芳胺,收率96%-99%。并以邻硝基甲苯为反应底物考察了水合肼用量、催化剂用量、反应温度和反应时间对产物收率的影响。较优的反应条件为:n(水合肼)∶n(邻硝基甲苯)=2∶1;催化剂FeO(OH)的用量为0.015 g/mmol邻硝基甲苯,80℃反应50 min,邻甲苯胺的收率达98%。     

Electrochemical Sensors for Detection of Markers on Tumor Cells

In recent years, the increasing incidence and mortality of cancer have inspired the development of accurate and rapid early diagnosis methods in order to successfully cure cancer; however, conventional methods used for detecting tumor cells, including histopathological and immunological methods, often involve complex operation processes, high analytical costs, and high false positive rates, in addition to requiring experienced personnel. With the rapid emergence of sensing techniques, electrochemical cytosensors have attracted wide attention in the field of tumor cell detection because of their advantages, such as their high sensitivity, simple equipment, and low cost. These cytosensors are not only able to differentiate tumor cells from normal cells, but can also allow targeted protein detection of tumor cells. In this review, the research achievements of various electrochemical cytosensors for tumor cell detection reported in the past five years are reviewed, including the structures, detection ranges, and detection limits of the cytosensors. Certain trends and prospects related to the electrochemical cytosensors are also discussed.     

Liquid Hybridization and Solid Phase Detection: A Highly Sensitive and Accurate Strategy for MicroRNA Detection in Plants and Animals

MicroRNAs (miRNAs) play important roles in nearly every aspect of biology, including physiological, biochemical, developmental and pathological processes. Therefore, a highly sensitive and accurate method of detection of miRNAs has great potential in research on theory and application, such as the clinical approach to medicine, animal and plant production, as well as stress response. Here, we report a strategic method to detect miRNAs from multicellular organisms, which mainly includes liquid hybridization and solid phase detection (LHSPD); it has been verified in various species and is much more sensitive than traditional biotin-labeled Northern blots. By using this strategy and chemiluminescent detection with digoxigenin (DIG)-labeled or biotin-labeled oligonucleotide probes, as low as 0.01–0.25 fmol [for DIG-CDP Star (disodium2-chloro-5-(4-methoxyspiro{1,2-dioxetane-3,2′-(5′-chloro)tricyclo[3.3.1.13,7]decan}-4-yl)phenyl phosphate) system], 0.005–0.1 fmol (for biotin-CDP Star system), or 0.05–0.5 fmol (for biotin-luminol system) of miRNA can be detected and one-base difference can be distinguished between miRNA sequences. Moreover, LHSPD performed very well in the quantitative analysis of miRNAs, and the whole process can be completed within about 9 h. The strategy of LHSPD provides an effective solution for rapid, accurate, and sensitive detection and quantitative analysis of miRNAs in plants and animals.     

芳香族硝基化合物还原合成芳香羟胺的研究进展

芳香羟胺是一种重要的精细有机化工中间体,广泛应用于阻聚剂、抗氧剂、农药、医药、化妆品的合成.根据反应机理与还原剂的不同,对文献中报道的以芳香族硝基化合物为起始原料的芳香羟胺的选择性还原合成方法进行了分类阐述,并对其进行了简要分析.