tenniskale4
tenniskale4
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A periodic nano-porous surface on quartz crystal electrodes was carefully fabricated for increasing the mass-sensitive areas. Detailed porous structures were prepared by analyzing Au electrochemical reduction process of PS layer coated quartz crystals. The sensitivity measurement of the porous quartz crystals was performed with several traditional methods, and an optimized reduction time for higher sensitivity was determined. The frequency shift of the nano-porous quartz crystals showed 10 times bigger change with the same concentration of target solutions in self-assembly procedures. In the procedures, the freshly increased surface portion did not produce additional molecular slip-effects on the measured resonant resistance values, thus, the periodic porous chips showed another side merit for the mass sensor applications. We propose a possible use of the current porous surface as a platform for developing other high-performance sensors and analyses. miRNAs are small non-coding RNAs for gene regulation, which serve as promising biomarkers for the diagnosis of certain diseases. In this contribution, we have proposed a convenient electrochemical biosensing strategy based on the interaction between DNA modified gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs). In principle, citrate capped AuNPs and AgNPs can be co-decorated on the electrode successively. However, with the modification of DNA on AuNPs surface, a strong negative layer is formed. AuNPs@DNA modified electrode could then inhibit subsequent adsorption of AgNPs due to the electrostatic repulsion and steric hindrance effect. As a result, electrochemical response from AgNPs is significantly decreased. On the other hand, in the presence of target miRNA, DNA on AuNPs hybridizes with miRNA and can thus be cyclically digested by duplex-specific nuclease (DSN). Without the shield of DNA, AgNPs can be relaunched at the AuNPs modified electrode. By analyzing the silver stripping peak, highly sensitive detection of miRNA can be achieved. This biosensor exhibits the limit of detection as low as 0.62 fM and a broad linear range from 1 fM to 1 pM. It may hold great potential utility for miRNA assay in the applications of biomedical researches and early clinical diagnosis. Thermal field-flow fractionation (ThFFF) was successfully coupled online to size exclusion chromatography (SEC) in a comprehensive two-dimensional configuration. In the first dimension, fractionation according to chemical composition based on the interplay of thermal and translational diffusion took place in the ThFFF channel. Fractions from the first dimension were comprehensively transferred to the second dimension, SEC, and separated according to hydrodynamic volume which is a function of molar mass. To illustrate the capabilities of this novel two-dimensional fractionation approach, polystyrene-poly (methyl methacrylate) block copolymers were comprehensively fractionated and characterized. Blends of homopolymers, homo- and copolymers, and copolymers with different compositions were fractionated and the effects of experimental conditions, the components' molar masses and compositions were investigated. The results illustrated the molar mass independence of the thermal diffusion coefficient in ThFFF. Translational diffusion coefficients were quantitatively determined via dynamic light scattering. The study aimed at proving the versatility of the comprehensive online coupling of ThFFF and SEC for the analysis of complex polymers having the ability to provide detailed molecular information (chemical composition and molar mass distribution) as well thermal and translational diffusion information in a single analysis. Finally, the merits of using information-rich detectors are highlighted. Viscum album lectin 1 (Viscumin) is one of the most important plant-based protein of potential adjuvant in cancer treatment. Therefore, the use of nano-biosensor technology as a novel emerges of biosensors is crucial to detect this modal agent in pharmacological study. Molecular imprinted polymer using 9-mer peptides sequence (epitope) was applied as a template. Using ultraviolet light, hydrogen bonding attained between the functional monomer and epitope, leading to the formation of a molecularly imprinted polymer. In the following, the epitope was derived from the surface of the polymer by sodium dodecyl sulfate (SDS) 2.5% and acetic acid 0.6% w/w. Finally, the designed nano-biosensor was exposed to different concentrations of the epitope. The selectivity of the nano-biosensor was tested in complex matrices such as blood plasma and urine. The scatchard analysis was covered for a consequence of the dissociation constants and the numbers of binding sites. Based on the results, the designed nano-biosensor has a limit of detection of 0.117 ng/μl and limit of quantification of 0.517 ng/μl in PBS buffer, respectively. These amounts stood 0.5 ng/μl and 0.8 ng/μl for urine environment and 1.25 ng/μl and 5 ng/μl for human blood fresh frozen plasma in the presence of ricin as the most homologue of viscumin (ML1) in fixed concentration (121), respectively. The time of detection and optimum pH was 8.0 min and 7.4, respectively. Designed and synthesized nano-biosensor is adequately qualified to be used in diverse complex areas, due to good efficiency. Chlorophenols (CPs) are known as a class of pollutants posing a great threat to the environment and human health because of their carcinogenesis and teratogenesis, and thus exploring convenient and efficient methods for their detection and identification becomes particularly important. Herein, we report a recyclable colorimetric sensor array according to the oxidase-mimicking catalytic characteristics of Fe3O4@MnOx for the high-performance quantification and differentiation of typical CPs. click here The core-shell Fe3O4@MnOx prepared by growing oxidase-like MnOx nanoflakes on the surface of magnetic Fe3O4 particles via a hydrothermal process can exhibit excellent catalytic activity to trigger the color reaction of CPs and 4-aminoantipyrine with the participation of O2. By utilizing the Fe3O4@MnOx-catalyzed color reaction, high-sensitivity quantitative analysis of CPs, taking 2-chlorophenol as a model, was realized, providing a detection limit as low as 0.85 μM. Given different chlorine substitution places and numbers in CPs impact the reaction kinetics diversely, a new nanozyme-based colorimetric sensor array was further constructed for the successful differentiation of various CPs with the help of hierarchical cluster analysis and principal component analysis.

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