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1.
A novel functionalized material is synthesized using surface‐decorated fullerene (C60) to encapsulate hollow and porous palladium nanocages (PdNCs), and is applied to fabricate an electrochemiluminescence (ECL) immunosensor for the detection of Streptococcus suis Serotype 2 (SS2). PdNCs with hollow interiors and porous walls are prepared using a galvanic replacement reaction between silver nanocubes and metal precursor salts. Then, C60 reacts with l ‐cysteine (l ‐Cys) to form l ‐Cys functionalized C60 (C60‐l ‐Cys), which has a better biocompatibility, conductivity, and hydrophilicity compared to C60 and possesses abundant –SH groups on the surface. Because of the special interaction between –SH and PdNCs, the obtained C60‐l ‐Cys is adsorbed around the PdNCs to form an interesting structure with multiple spheres encapsulating the cage. The resultant functionalized material (C60‐L‐Cys‐PdNCs) has a high specific surface area, good electrocatalytic ability, and efficient photocatalytic activity, and is used to construct an ECL immunosensor for the detection of SS2. The ECL signal amplified strategy is performed by using the novel coreactant (C60‐l ‐Cys) and in situ generation of O2 thus creating the S2O82?‐O2 ECL system. As a result, a wide linear detection range of 0.1 pg mL?1 to 100 ng mL?1 is acquired with a relatively low detection limit of 33.3 fg mL?1.  相似文献   

2.
In this work, hydroxyl‐functionalized Mo2C‐based MXene nanosheets are synthesized by facilely removing the Sn layer of Mo2SnC. The hydroxyl‐functionalized surface of Mo2C suppresses the shuttle effect of lithium polysulfides (LiPSs) through strong interaction between Mo atoms on the MXenes surface and LiPSs. Carbon nanotubes (CNTs) are further introduced into Mo2C phase to enlarge the specific surface area of the composite, improve its electronic conductivity, and alleviate the volume change during discharging/charging. The strong surface‐bound sulfur in the hierarchical Mo2C‐CNTs host can lead to a superior electrochemical performance in lithium–sulfur batteries. A large reversible capacity of ≈925 mAh g ? 1 is observed after 250 cycles at a current density of 0.1 C (1 C = 1675 mAh g?1) with good rate capability. Notably, the electrodes with high loading amounts of sulfur can also deliver good electrochemical performances, i.e., initial reversible capacities of ≈1314 mAh g?1 (2.4 mAh cm?2), ≈1068 mAh g?1 (3.7 mAh cm?2), and ≈959 mAh g?1 (5.3 mAh cm?2) at various areal loading amounts of sulfur (1.8, 3.5, and 5.6 mg cm?2) are also observed, respectively.  相似文献   

3.
Assemblies of nanomaterials for biological applications in living cells have attracted much attention. Herein, graphene oxide (GO)–gold nanoparticle (Au NP) assemblies are driven by a splint DNA strand, which is designed with two regions at both ends that are complementary with the DNA sequence anchored on the surface of the GO and the Au NPs. In the presence of microRNA (miR)‐21 and epithelial cell‐adhesion molecule (EpCAM), the hybridization of miR‐21 with a molecular probe leads to the separation of 6‐fluorescein‐phosphoramidite‐modified Au NPs from GO, resulting in a decrease in the Raman signal, while EpCAM recognition reduces circular dichroism (CD) signals. The CD signals reverse from negative in original assemblies into positive when reacted with cells, which correlates with two enantiomer geometries. The EpCAM detection has a good linear range of 8.47–74.78 pg mL?1 and a limit of detection (LOD) of 3.63 pg mL?1, whereas miR‐21 detection displays an outstanding linear range of 0.07–13.68 amol ng?1RNA and LOD of 0.03 amol ng?1RNA. All the results are in good agreement with those of the Raman and confocal bioimaging. The strategy opens up an avenue to allow the highly accurate and reliable diagnosis (dual targets) of clinic diseases.  相似文献   

4.
A hexafluorophosphate ionic liquid is used as a functional monomer to prepare a metal–organic framework (Zn‐MOF). Zn‐MOF is used as a template for MoS2 nanosheets synthesis and further carbonized to yield light‐responsive ZnS/C/MoS2 nanocomposites. Zn‐MOF, carbonized‐Zn‐MOF, and ZnS/C/MoS2 nanocomposites are characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, X‐ray diffraction pattern, scanning electron microscopy (SEM), element mapping, Raman spectroscopy, X‐ray photoelectron spectroscopy, fluorescence, and nitrogen‐adsorption analysis. Carcinoembryonic antigen (CEA) is selected as a model to construct an immunosensing platform to evaluate the photo‐electrochemical (PEC) performances of ZnS/C/MoS2 nanocomposites. A sandwich‐type PEC immunosensor is fabricated by immobilizing CEA antibody (Ab1) onto the ZnS/C/MoS2/GCE surface, subsequently binding CEA and the alkaline phosphatase‐gold nanoparticle labeled CEA antibody (ALP‐Au‐Ab2). The catalytic conversion of vitamin C magnesium phosphate produces ascorbic acid (AA). Upon being illuminated, AA can react with photogenerated holes from ZnS/C/MoS2 nanocomposites to generate a photocurrent for quantitative assay. Under optimized experimental conditions, the PEC immunosensor exhibits excellent analytical characteristics with a linear range from 2.0 pg mL?1 to 10.0 ng mL?1 and a detection limit of 1.30 pg mL?1 (S/N = 3). The outstanding practicability of this PEC immunosensor is demonstrated by accurate assaying of CEA in clinical serum samples.  相似文献   

5.
Yolk–shell NiO microspheres are modified by two types of functionalized graphene quantum dots (denoted as NiO/GQDs) via a facile solvothermal treatment. The modification of GQDs on the surface of NiO greatly boosts the stability of the NiO/GQD electrode during long‐term cycling. Specifically, the NiO with carboxyl‐functionalized GQDs (NiO/GQDs? COOH) exhibits better performances than NiO with amino‐functionalized GQDs (NiO/GQDs? NH2). It delivers a capacity of ≈1081 mAh g?1 (NiO contribution: ≈1182 mAh g?1) after 250 cycles at 0.1 A g?1. In comparison, NiO/GQDs? NH2 electrode holds ≈834 mAh g?1 of capacity, while the bald NiO exhibits an obvious decline in capacity with ≈396 mAh g?1 retained after cycling. Except for the yolk–shell and mesoporous merits, the superior performances of the NiO/GQD electrode are mainly ascribed to the assistance of GQDs. The GQD modification can support as a buffer alleviating the volume change, improve the electronic conductivity, and act as a reservoir for electrolytes to facilitate the transportation of Li+. Moreover, the enrichment of carboxyl/amino groups on GQDs can further donate more active sites for the diffusion of Li+ and facilitate the electrochemical redox kinetics of the electrode, thus together leading to the superior lithium storage performance.  相似文献   

6.
The instability of few‐layer black phosphorus (FL‐BP) hampers its further applications. Here, it can be demonstrated that the instability of FL‐BP can also be the advantage for application in biosensor. First, gold nanoparticle/FL‐BP (BP‐Au) hybrid is facilely synthesized by mixing Au precursor with FL‐BP. BP‐Au shows outstanding catalytic activity (K = 1120 s?1 g?1) and low activation energy (17.53 kJ mol?1) for reducing 4‐nitrophenol, which is attributed to the electron‐reservoir and electron‐donor properties of FL‐BP, and synergistic interaction of Au nanoparticles and FL‐BP. Oxidation of FL‐BP after catalytic reaction is further confirmed by transmission electron microscope, X‐ray photoelectron spectroscopy, and zeta potentials. Second, the catalytic activity of BP‐Au can be reversibly switched from “inactive” to “active” upon treatment with antibody and antigen in solution, thus providing a versatile platform for label‐free colorimetric detection of biomarkers. The sensor shows a wide detection range (1 pg mL?1 to –10 µg mL?1), high sensitivity (0.20 pg mL?1), and selectivity for detecting carcinoembryonic antigen (CEA). Finally, the biosensor has been used to detect CEA in colon and breast cancer clinical samples with satisfactory results. Therefore, the instability of BP can also be the advantage for application in detecting cancer biomarker in clinic.  相似文献   

7.
Despite the recent attention for Li metal anode (LMA) with high theoretical specific capacity of ≈ 3860 mA h g?1, it suffers from not enough practical energy densities and safety concerns originating from the excessive metal load, which is essential to compensate for the loss of Li sources resulting from their poor coulombic efficiencies (CEs). Therefore, the development of high‐performance LMA is needed to realize anode‐minimized Li metal batteries (LMBs). In this study, high‐performance LMAs are produced by introducing a hierarchically nanoporous assembly (HNA) composed of functionalized onion‐like graphitic carbon building blocks, several nanometers in diameter, as a catalytic scaffold for Li‐metal storage. The HNA‐based electrodes lead to a high Li ion concentration in the nanoporous structure, showing a high CE of ≈ 99.1%, high rate capability of 12 mA cm?2, and a stable cycling behavior of more than 750 cycles. In addition, anode‐minimized LMBs are achieved using a HNA that has limited Li content ( ≈ 0.13 mg cm?2), corresponding to 6.5% of the cathode material (commercial NCM622 ( ≈ 2 mg cm?2)). The LMBs demonstrate a feasible electrochemical performance with high energy and power densities of ≈ 510 Wh kgelectrode?1 and ≈ 2760 W kgelectrode?1, respectively, for more than 100 cycles.  相似文献   

8.
Antibody–drug conjugate (ADC) targeting antigens expressed on the surface of tumor cells are an effective approach for delivering drugs into the cells via antigen‐mediated endocytosis. One of the well‐known tumor antigens, the CD20 of B‐lymphocyte, has long been suggested to be noninternalizing epitope, and is thus not considered a desirable target for ADCs. Here, sortase A (srtA)‐mediated transpeptidation is used to specifically conjugate triple glycine‐modified monomethyl auristatin E (MMAE), a highly toxic antimitotic agent, to anti‐CD20 ofatumumab (OFA) equipped with a short C‐terminal LPETG (5 amino acids) tag at heavy chain (HL), which generates ADCs that show extremely strong potency in killing CD20 positive cancer cells. One of the srtA‐generated ADCs with a cleavable dipeptide linker (valine‐citrulline, vc), OFA‐HL‐vcMMAE, shows IC50 values ranging from 5 pg mL?1 to 4.1 ng mL?1 against CD20+ lymphoma cells. Confocal laser scanning microscopy confirms that OFA‐HL‐vcMMAE internalization by Ramos cells is significantly improved compared to OFA alone, consistent with the high antitumor activity of the new ADC. OFA‐HL‐vcMMAE, at 5 mg kg?1 dose, is able to eliminate tumors with mean volume ≈400 mm3 while no obvious drug‐related toxicity is observed. The results show that srtA‐generated OFA‐MMAE conjugate system provides a viable strategy for targeting CD20+ B lineage lymphomas.  相似文献   

9.
This study introduces multifunctional lipid nanoparticles (LNPs), mimicking the structure and compositions of low‐density lipoproteins, for the tumor‐targeted co‐delivery of anti‐cancer drugs and superparamagnetic nanocrystals. Paclitaxel (4.7 wt%) and iron oxide nanocrystals (6.8 wt%, 11 nm in diameter) are co‐encapsulated within folate‐functionalized LNPs, which contain a cluster of nanocrystals with an overall diameter of about 170 nm and a zeta potential of about ‐40 mV. The folate‐functionalized LNPs enable the targeted detection of MCF‐7, human breast adenocarcinoma expressing folate receptors, in T2‐weighted magnetic resonance images as well as the efficient intracellular delivery of paclitaxel. Paclitaxel‐free LNPs show no significant cytotoxicity up to 0.2 mg mL?1, indicating the excellent biocompatibility of the LNPs for intracellular drug delivery applications. The targeted anti‐tumor activities of the LNPs in a mouse tumor model suggest that the low‐density lipoprotein‐mimetic LNPs can be an effective theranostic platform with excellent biocompatibility for the tumor‐targeted co‐delivery of various anti‐cancer agents.  相似文献   

10.
Nanohybrid anode materials for Na‐ion batteries (NIBs) based on conversion and/or alloying reactions can provide significantly improved energy and power characteristics, while suffering from low Coulombic efficiency and unfavorable voltage properties. An NIB paper‐type nanohybrid anode (PNA) based on tin sulfide nanoparticles and acid‐treated multiwalled carbon nanotubes is reported. In 1 m NaPF6 dissolved in diethylene glycol dimethyl ether as an electrolyte, the above PNA shows a high reversible capacity of ≈1200 mAh g?1 and a large voltage plateau corresponding to a capacity of ≈550 mAh g?1 in the low‐voltage region of ≈0.1 V versus Na+/Na, exhibiting high rate capabilities at a current rate of 1 A g?1 and good cycling performance over 250 cycles. In addition, the PNA exhibits a high first Coulombic efficiency of ≈90%, achieving values above 99% during subsequent cycles. Furthermore, the feasibility of PNA usage is demonstrated by full‐cell tests with a reported cathode, which results in high specific energy and power values of ≈256 Wh kg?1 and 471 W kg?1, respectively, with stable cycling.  相似文献   

11.
Readily commercializable and cost‐effective next‐generation CsPbBr3 perovskite nanocrystals (PNCs) based X‐ray detectors are demonstrated. The PNCs‐based X‐ray detector exhibits higher spatial resolution (9.8 lp mm?1 at modulation transfer function (MTF) = 0.2 and 12.5–8.9 lp mm?1 for a linear line chart), faster response time (≈200 ns), and comparable stability (>40 Gyair s?1 of X‐ray exposure) compared with the commercialized terbium‐doped gadolinium oxysulfide (GOS)‐based detectors (spatial resolution = 6.2 lp mm?1 at MTF = 0.2 and 6.3 lp mm?1 for a linear line chart, response time = ≈1200 ns) because the PNCs‐based scintillator has ≈5.6‐fold faster average photoluminescence lifetime and stronger emission than the GOS‐based one.  相似文献   

12.
Ultrathin graphitic carbon nitride (g‐C3N4) nanosheets, due to their interesting two‐dimensional graphene‐like structure and unique physicochemical properties, have attracted great research attention recently. Here, a new approachis developed to prepare, for the first time, proton‐functionalized ultrathin g‐C3N4 nanosheets by sonication‐exfoliation of bulk g‐C3N4 under an acid condition. This method not only reduces the exfoliation time from more than 10 h to 2 h, but also endows the nanosheets with positive charges. Besides retaining the properties of g‐C3N4, the obtained nanosheets with the thickness of 2–4 nm (i.e., 6–12 atomic monolayers) also exhibit large specific surface area of 305 m2 g?1, enhanced fluorescence intensity, and excellent water dispersion stability due to their surface protonation and ultrathin morphology. The well‐dispersed protonated g‐C3N4 nanosheets are able to interact with negatively charged heparin, which results in the quenching of g‐C3N4 fluorescence. A highly sensitive and highly selective heparin sensing platform based on protonated g‐C3N4 nanosheets is established. This metal‐free and fluorophore label‐free system can reach the lowest heparin detection limit of 18 ng mL?1.  相似文献   

13.
Conventional cathodes of Li‐ion batteries mainly operate through an insertion–extraction process involving transition metal redox. These cathodes will not be able to meet the increasing requirements until lithium‐rich layered oxides emerge with beyond‐capacity performance. Nevertheless, in‐depth understanding of the evolution of crystal and excess capacity delivered by Li‐rich layered oxides is insufficient. Herein, various in situ technologies such as X‐ray diffraction and Raman spectroscopy are employed for a typical material Li1.2Ni0.2Mn0.6O2, directly visualizing O?? O? (peroxo oxygen dimers) bonding mostly along the c‐axis and demonstrating the reversible O2?/O? redox process. Additionally, the formation of the peroxo O? O bond is calculated via density functional theory, and the corresponding O? O bond length of ≈1.3 Å matches well with the in situ Raman results. These findings enrich the oxygen chemistry in layered oxides and open opportunities to design high‐performance positive electrodes for lithium‐ion batteries.  相似文献   

14.
The clinical applications of silver nanoparticles (AgNPs) remain limited due to the lack of well‐established methodologies for studying their nanokinetics. Hereby, the primary goal is to adapt a suite of analytical‐based methodologies for examining the in vitro absorption, distribution, metabolism, and elimination of AgNPs. Vero 76 and HEK 293 cells are exposed to ≈10‐nm spherical AgNPs+ and AgNPs? at relevant concentrations (0–300 µg mL?1) and times (4–48 h). Absorption: Inductively coupled plasma optical emission spectroscopy (ICP‐OES) demonstrates that the two AgNP formulations are not bioequivalent. For example, different bioavailabilities (C maximum < 20.7 ± 4% and 6.82 ± 0.4%), absorption times (T maximum > 48 and ≈24 h), and absorption rate laws (first‐ and zeroth‐order at 300 µg mL?1) are determined in Vero 76 for AgNPs+ and AgNPs?, respectively. Distribution: Raman and CytoViva hyperspectral imaging show different cellular localizations for AgNPs+ and AgNPs?. Metabolism: Cloud point extraction (CPE)‐tangential flow filtration (TFF) reveal that ≤ 11% ± 4% of the administered, sublethal AgNPs release Ag+ and contribute to the observed cytotoxicity. Elimination: ICP‐OES‐CPE suggests that AgNPs are cleared via exocytosis.  相似文献   

15.
Whispering gallery mode (WGM) microresonators have been used as optical sensors in fundamental research and practical applications. The majority of WGM sensors are passive resonators that require complex systems, thereby limiting their practicality. Active resonators enable the remote excitation and collection of WGM‐modulated fluorescence spectra, without requiring complex systems, and can be used as alternatives to passive microresonators. This paper demonstrates an active microresonator, which is a microdisk laser in a hyperboloid‐drum (HD) shape. The HD microdisk lasers are a combination of a rhodamine B‐doped photoresist and a silica microdisk. These HD microdisk lasers can be utilized for the detection of label‐free biomolecules. The biomolecule concentration can be as low as 1 ag mL?1, whereas the theoretical detection limit of the biosensor for human IgG in phosphate buffer saline is 9 ag mL?1 (0.06 aM). Additionally, the biosensors are able to detect biomolecules in an artificial serum, with a theoretical detection limit of 9 ag mL?1 (0.06 aM). These results are approximately four orders of magnitude more sensitive than those for the typical active WGM biosensors. The proposed HD microdisk laser biosensors show enormous detection potential for biomarkers in protein secretions or body fluids.  相似文献   

16.
17.
High‐performance unipolar n‐type polymer semiconductors are critical for advancing the field of organic electronics, which relies on the design and synthesis of new electron‐deficient building blocks with good solubilizing capability, favorable geometry, and optimized electrical properties. Herein, two novel imide‐functionalized thiazoles, 5,5′‐bithiazole‐4,4′‐dicarboxyimide (BTzI) and 2,2′‐bithiazolothienyl‐4,4′,10,10′‐tetracarboxydiimide (DTzTI), are successfully synthesized. Single crystal analysis and physicochemical study reveal that DTzTI is an excellent building block for constructing all‐acceptor homopolymers, and the resulting polymer poly(2,2′‐bithiazolothienyl‐4,4′,10,10′‐tetracarboxydiimide) (PDTzTI) exhibits unipolar n‐type transport with a remarkable electron mobility (μe) of 1.61 cm2 V?1 s?1, low off‐currents (Ioff) of 10?10?10?11 A, and substantial current on/off ratios (Ion/Ioff) of 107?108 in organic thin‐film transistors. The all‐acceptor homopolymer shows distinctive advantages over prevailing n‐type donor?acceptor copolymers, which suffer from ambipolar transport with high Ioffs > 10?8 A and small Ion/Ioffs < 105. The results demonstrate that the all‐acceptor approach is superior to the donor?acceptor one, which results in unipolar electron transport with more ideal transistor performance characteristics.  相似文献   

18.
Ferromagnetic insulators (FMIs) are one of the most important components in developing dissipationless electronic and spintronic devices. However, FMIs are innately rare to find in nature as ferromagnetism generally accompanies metallicity. Here, novel room‐temperature FMI films that are epitaxially synthesized by deliberate control of the ratio between two B‐site cations in the double perovskite Sr2Fe1+xRe1‐xO6 (?0.2 ≤ x ≤ 0.2) are reported. In contrast to the known FM metallic phase in stoichiometric Sr2FeReO6, an FMI state with a high Curie temperature (Tc ≈ 400 K) and a large saturation magnetization (MS ≈ 1.8 µB f.u.?1) is found in highly cation‐ordered Fe‐rich phases. The stabilization of the FMI state is attributed to the formation of extra Fe3+? Fe3+ and Fe3+? Re6+ bonding states, which originate from the relatively excess Fe ions owing to the deficiency in Re ions. The emerging FMI state created by controlling cations in the oxide double perovskites opens the door to developing novel oxide quantum materials and spintronic devices.  相似文献   

19.
Semiconducting nanowires are promising ultrasensitive, label‐free sensors for small molecules, DNA, proteins, and cellular function. Nanowire field‐effect transistors (FETs) function by sensing the charge of a bound molecule. However, solutions of physiological ionic strength compromise the detection of specific binding events due to ionic (Debye) screening. A general solution to this limitation with the development of a hybrid nanoelectronic enzyme‐linked immunosorbent assay (ne‐ELISA) that combines the power of enzymatic conversion of a bound substrate with electronic detection is demonstrated. This novel configuration produces a local enzyme‐mediated pH change proportional to the bound ligand concentration. It is shown that nanowire FETs configured as pH sensors can be used for the quantitative detection of interleukin‐2 in physiologically buffered solution at concentrations as low as 1.6 pg mL?1. By successfully bypassing the Debye screening inherent in physiological fluids, the ne‐ELISA promises wide applicability for ligand detection in a range of relevant solutions.  相似文献   

20.
A facile methodology for the large‐scale production of layer‐controlled MoS2 layers on an inexpensive substrate involving a simple coating of single source precursor with subsequent roll‐to‐roll‐based thermal decomposition is developed. The resulting 50 cm long MoS2 layers synthesized on Ni foils possess excellent long‐range uniformity and optimum stoichiometry. Moreover, this methodology is promising because it enables simple control of the number of MoS2 layers by simply adjusting the concentration of (NH4)2MoS4. Additionally, the capability of the MoS2 for practical applications in electronic/optoelectronic devices and catalysts for hydrogen evolution reaction is verified. The MoS2‐based field effect transistors exhibit unipolar n‐channel transistor behavior with electron mobility of 0.6 cm2 V?1 s?1 and an on‐off ratio of ≈10³. The MoS2‐based visible‐light photodetectors are fabricated in order to evaluate their photoelectrical properties, obtaining an 100% yield for active devices with significant photocurrents and extracted photoresponsivity of ≈22 mA W?1. Moreover, the MoS2 layers on Ni foils exhibit applicable catalytic activity with observed overpotential of ≈165 mV and a Tafel slope of 133 mV dec?1. Based on these results, it is envisaged that the cost‐effective methodology will trigger actual industrial applications, as well as novel research related to 2D semiconductor‐based multifaceted applications.  相似文献   

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