Latest ArticlesFluorescence switch plays a vital role in bioelectronics and bioimaging. Herein, we presented a new kind of facile electrostatic complex nanoparticles (ECNs) for fluorescence switching in cells and marking of individual cell. The ECNs were prepared by mixing positively charged poly(6-(2-(thiophen-3-yl)ethoxy) hexyl trimethylammonium bromide) (PT) and negatively charged diarylethene sodium salt (DAECOONa). DAE-COONa is a photoswitchable molecule which can be transformed between the ring-closed form and ring-open form under the irradiation of UV or visible light. The closed-form of DAE-COONa can efficiently quench the fluorescence of PT through intermolecular energy transfer, while the open form of DAE-COONa does not influence the emission of PT. Thus, the fluorescence of ECNs can be modulated by light irradiation, and the ECNs with good fluorescence switching performance have been employed for fluorescence imaging and individual cell lighting up process successfully. We demonstrate that the electrostatic complex strategy provides a facile method to construct fluorescence switch for selective cell marking and imaging applications.
Cu@Ag/Bi2Te3 nanocomposites were prepared for the first time by ultrasonic dispersion-rapid freezedrying method combined with spark plasma sintering (SPS). By changing the content of Cu@Ag nanoparticle, we could modulate the temperature dependent thermoelectric properties. The highest ZT value can be obtained at 450 K for 1 vol% Cu@Ag/Bi2Te3, which is benefited from the decoupling of electrical and thermal properties. With the increase of electrical conductivity, the absolute value of Seebeck coefficient lifts while the thermal conductivity declines. Meanwhile, the average ZT value between 300 K and 475 K was 0.61 for 1 vol% Cu@Ag/Bi2Te3, which is much higher than that of pristine Bi2Te3. Therefore, the decoupling effect of Cu@Ag nanoparticles incorporation could be a promising method to broaden the application of Bi2Te3 based thermoelectric materials.
The discrimination against nutritional fat emulsion injections was considered by imaging tools, which aims to elucidate the in vivo behaviors of nanoemulsions. In this study, 20% nutritional fat emulsion injections were selected from different company including original and generic products. Meanwhile, a water quenching fluorescent probe (P2) was used to label them by an incubation method. The fluorescent intensity analysis of blood-borne fluorescence reveals rapid clearance of nanoemulsion in all groups, which shows 'L'-type blood kinetic profiles. However, these kinetic parameters do not have significant difference. Following intravenous administration, the nanoemulsions in all groups concomitantly accumulated in organs of reticulo-endothelial system (RES), such as liver and spleen, and were cleared from body circulation mostly after 12 h. AUC(0-t) of organs from different groups showed dissimilar results in some organs. These intuitional results are of significance in understanding the in vivo behaviors of nanoemulsions, which can provide a new way to discriminate against nutritional fat emulsions.
It has been demonstrated that the conductivity and electrochemical properties of TiO2 nanomaterials can be significantly improved by an incorporation of carbon additives. In the study, we develop a novel Ndoped TiO2 mesoporous nanostructure via the addition of carbon quantum dots (CQDs) solution following a scalable hydrothermal process. The as-made TiO2 product shows well-defined morphology, high conductivity, large surface area, and abundant mesopores. When evaluated as anodes for sodiumion batteries, the CQDs@TiO2 product annealed at 500℃ exhibits a superior sodium storage capability. It delivers a high reversible capacity of 168.8 mAh/g at 100 mA/g over 500 cycles and long cycling stability. The remarkable performance of CQDs@TiO2 mainly arises from the large surface area and mesoporous architecture constructed by ultrathin TiO2 nanosheets, as well as the full cooperation between CQDs and TiO2.
The energy density of non-aqueous carbon-based electrochemical capacitors (cEC) is mainly determined by the specific capacitance and operational voltage range. In this study, we propose to construct an unbalanced structure to make full use of stable voltage range for improving energy density. The stable voltage range is firstly carefully explored using cyclic voltammetry. Then an unbalanced carbon-based electrochemical capacitor (ucEC) is constructed with an optimized positive electrode to negative electrode weight ratio and voltage range. Its electrochemical performance is comprehensively investigated, including energy density, power density as well as cycle life. The ucEC is capable to deliver an improved energy density up to 64.9 Wh/kg (1.4 times as high as a general cEC) without sacrificing the power density and cycle life. The electrode properties after cycling are also analyzed, illustrating the change of electrode potential caused by unbalanced structure. The proposed structure demonstrates a great potential for improving the energy density at little cost of electrode design and cell configuration.
Most of the current analytical methods depend largely on laboratory-based analytical techniques that require expensive and bulky equipment, potentially incur costly testing, and involve lengthy detection processes. With increasing requirements for point-of-care testing (POCT), more attention has been paid to miniaturized analytical devices. Miniaturized electrochemical (MEC) sensors, including different material-based MEC sensors (such as DNA-, paper-, and screen electrode-based), have been in strong demand in analytical science due to their easy operation, portability, high sensitivity, as well as their short analysis time. They have been applied for the detection of trace amounts of target through measuring changes in electrochemical signal, such as current, voltage, potential, or impedance, due to the oxidation/reduction of chemical/biological molecules with the help of electrodes and electrochemical units. MEC sensors present great potential for the detection of targets including small organic molecules, metal ions, and biomolecules. In recent years, MEC sensors have been broadly applied to POCT in various fields, including health care, food safety, and environmental monitoring, owing to the excellent advantages of electrochemical (EC) technologies. This review summarized the state-of-the-art advancements on various types of MEC sensors and their applications in POCT. Furthermore, the future perspectives, opportunities, and challenges in this field are also discussed.
In this study, we report the synthesis of novel palladium nanoflowers (Pd NFs) on amino-functionalized fullerene (C60-NH2) by hydrothermal self-assembly growth using ethylenediamine (EA) as a functional reagent. The successful formation of Pd nanoflowers supported amino-functionalized fullerene (C60-NH2/Pd NFs) is evidenced by UV-vis and powder X-ray diffraction (XRD). The morphology of Pd NFs over the C60-NH2 surface has been investigated by high-resolution transmission electron microscopy (TEM) and Fourier-transform infrared (FT-IR) techniques. The supported Pd nanoflowers (Pd NFs/C60-NH2) exhibit remarkably superior catalytic activity toward the reduction of 4-nitrophenol (4-NP). It exhibits remarkable UV-vis spectra response from 4-nitrophenol to 4-aminophenol (4-AP) (99% in 2.0 min) with a turnover frequency of 12.35 min-1. Its excellent catalytic stability and durability offer the promising application in catalysis.
Polymer electrolytes are essential for next-generation lithium batteries because of their excellent safety record. However, low ionic conductivity is the main obstacle restricting their commercial application. Composites with nanoparticles are a promising route to overcome this obstacle. In this work, lithium polystyrene sulfonate brushes (LiPSS) is anchored to silicon dioxide nanoparticles with chemical bonding using atom transfer radial polymerization (SI-ATRP). The composite polymer electrolytes are made by mixing vinylene carbonate and nanoparticles via a facile in situ polymerization process. The ionic conductivity of composite polymer electrolytes is improved to 7.2 ×10-4 S/cm at room temperature, which is attributed to the low degree of crystallinity of polymer electrolyte and the fast ion transport on the surfaces of polymer brush layers that act as a conductive network. The composite polymer electrolytes show a wide electrochemical window of approximately 4.5 V vs. Li+/Li and excellent cycling performance retention of approximately 95% after 100 cycles at ambient temperature. The results also prove that surface groups of ceramic nanoparticles are an important way to increase the electrochemical properties of composite polymer electrolytes.
A versatile and efficient telescoped reaction sequence for the synthesis of tetrahydroisoquinolines (THIQs) is reported that uses TiCl4 to promote cyclization of a benzylaminoacetal derivative and Et3SiH for reduction of the intermediate 4-hydroxy-THIQ. This method is complimentary to the classical Pomeranz-Fritsch and related reactions since it tolerates electron-withdrawing substituents and allows access to 8-substituted THIQs.
High-performance anodes of sodium ion batteries (SIBs) largely depends on rational architecture design and binder-free smart hybridization. Herein, we report TiC/C core/shell nanowires arrays prepared by a one-step chemical vapor deposition (CVD) method and apply it as the anode of SIBs for the first time. The conductive TiC core is intimately decorated with carbon shell. The as-obtained TiC/C nanowires are homogeneously grown on the substrate and show core/shell heterostructure and porous architecture with high electronic conductivity and reinforced stability. Owing to these merits, the TiC/C electrode displays good rate performance and outstanding cycling performance with a capacity of 135.3 mAh/g at 0.1 A/g and superior capacity retention of 90.14% after 1000 cycles at 2 A/g. The reported strategy would provide a promising way to construct binder-free arrays electrodes for sodium ion storage.
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