55 research outputs found
Double-shell CeO2:Yb, Er@SiO2@Ag upconversion composite nanofibers as an assistant layer enhanced near-infrared harvesting for dye-sensitized solar cells
Double-shell CeO2:Yb,Er@SiO2@ Ag upconversion composite nanofibers are synthesized by electro- spinning and subsequent process. CeO2:Yb,Er@SiO2@ Ag nanofibers show high upconversion luminescence property due to the coating of amorphous SiO2 and the surface plasmon resonance effect of Ag nanoparticles. CeO2:Yb,Er@SiO2@ Ag nanofibers act as an assistant layer in dye-sensitized solar cells (DSSCs) and enhance the photoelectric conversion efficiency (PCE) to 8.17%. The photocurrent-voltage characteristic is obtained under 980 nm laser as illumination light source. In addition, the absorption of the incident photon-to-current conversion efficiency curve in 900-1000 nm near-infrared light confirms that the introduction of the upconversion nanomaterial broadens the absorption range, improves the utilization rate of the sunlight and increases the PCE of DSSCs. (C) 2018 Elsevier B.V. All rights reserved
Electrochemistry/Photoelectrochemistry-Based Immunosensing and Aptasensing of Carcinoembryonic Antigen
Recently, electrochemistry- and photoelectrochemistry-based biosensors have been regarded as powerful tools for trace monitoring of carcinoembryonic antigen (CEA) due to the fact of their intrinsic advantages (e.g., high sensitivity, excellent selectivity, small background, and low cost), which play an important role in early cancer screening and diagnosis and benefit people’s increasing demands for medical and health services. Thus, this mini-review will introduce the current trends in electrochemical and photoelectrochemical biosensors for CEA assay and classify them into two main categories according to the interactions between target and biorecognition elements: immunosensors and aptasensors. Some recent illustrative examples are summarized for interested readers, accompanied by simple descriptions of the related signaling strategies, advanced materials, and detection modes. Finally, the development prospects and challenges of future electrochemical and photoelectrochemical biosensors are considered
Calix[4,6,8]arenesulfonates Functionalized Reduced Graphene Oxide with High Supramolecular Recognition Capability: Fabrication and Application for Enhanced Host–Guest Electrochemical Recognition
Reduced graphene oxide (rGO) modified with three kinds
of water-soluble p-sulfonated calixÂ[4,6,8]Âarene sodium (SCn: SC4,
SC6, SC8) were successfully prepared by using a simple wet chemical
strategy. Three obtained SCn-rGO nanocomposites were characterized
by Fourier transform infrared spectroscopy, Ultraviolet–visible
spectroscopy, static contact angle measurement, thermogravimetric
analysis, scanning electron microscope and electrochemical impedance
spectroscopy, which confirmed that different amount of SCn molecules
had been effectively loaded onto the surface of rGO, and the water-dispersity
and stability of SCn-rGO increased with the increase of the value
of n in SCn (<i>n</i> = 4, 6, 8). More significantly, cyclic
voltammetry measurement showed that the SCn-rGO could exhibit high
supramolecular recognition and enrichment capability and consequently
displayed excellent electrochemical response toward four probe molecules
(biological and organic dye molecules). Especially, SC8-rGO exhibited
an excellent electrochemical performance for dopamine with high current
densities of 73.04 mA mM<sup>–1</sup> L cm<sup>–2</sup>, broad linear range (1 × 10<sup>–8</sup> to 2.1 ×
10<sup>–5</sup> M) and very low detection limit (8 × 10<sup>–9</sup> M) at a signal-to-noise ratio of 3
Smart Combination of Cyclodextrin Polymer Host–Guest Recognition and Mg<sup>2+</sup>-Assistant Cyclic Cleavage Reaction for Sensitive Electrochemical Assay of Nucleic Acids
A novel enzyme-free
electrochemical sensing strategy was proposed for sensitive monitoring
of DNA and miRNA by smart combination of the cyclic cleavage reaction
of Mg<sup>2+</sup>-dependent DNAzyme and the host–guest inclusion
between ferrocene-labeled hairpin probe (H-1) and nitrogen-doped reduced
graphene oxide/β-cyclodextrin polymer (NRGO/β-CDP) nanocomposites.
The synthesized NRGO/β-CDP nanocomposites with high electrocatalytic
activity and recognition capability were modified on the glassy carbon
electrode to construct the sensing platform. Upon the hybridization
reaction of subunit DNA in the loop region with target sequence, the
active DNAzyme was liberated from the caged structure, which bound
with H-1 to catalyze its cleavage in the presence of Mg<sup>2+</sup> and triggered the target recycling amplification for the cleavage
of a large number of H-1. Each cleaved H-1 was divided into two single-stranded
oligonucleotides, leading to an obvious enhancement of peak current
by the molecular recognition of β-CDP on the electrode. Thus,
the constructed biosensor showed high sensitivity and selectivity
for DNA and miRNA assays, with wide concentration ranges of 0.01–1000
and 0.05–500 pM and low detection limits of 3.2 and 18 fM,
respectively. This developed sensing strategy may become a promising
nucleic acid detection method in bioassays and clinical diagnosis
Catalytic wet peroxide oxidation of aniline in wastewater using copper modified SBA-15 as catalyst
Crystal Structures and Optical Properties of Two Novel 1,3,5-Trisubstituted Pyrazoline Derivatives
Two novel 1,3,5-trisubstituted pyrazoline derivatives—1-acetyl-3-(4-methoxyphenyl)-5-(6-methoxy-2-naphthyl)-pyrazoline (2a) and 1-(4-nitrophenyl)-3-(4-methoxyphenyl)-5-(6-methoxy-2-naphtyl)-pyrazoline (2b)—were synthesized and their structures were determined by single crystal X-ray crystallography. Both of the two crystals exhibit twisted structures due to the large dihedral angles between the pyrazolinyl ring and the aromatic ring at the 5-position (88.09° for 2a and 71.26° for 2b). The optical⁻physical properties of the two compounds were investigated. The fluorescent emission of 2b arises from the 1,3-disubstituted pyrazoline chromophores and exhibits a red shift in polar solvents and solid-state, which could be attributed to photo-induced intramolecular charge transfer (ICT) from N1 to C3 in the pyrazoline moiety and the intermolecular interactions within the crystal. The fluorescent emissions of 2a (λmax 358⁻364 nm) in solvents and solid-state both come from 6-methoxy-2-naphthyl chromophores, which are fairly insensitive to the solvent polarity
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