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In this paper, an amplified fluorescence polarization (FP) aptasensor based on magnetic nanoparticles @polydopamine (MNP@PDA) was innovatively developed for sensitive detection of recombinant human erythropoietin-alpha(rHuEPO-α). The amplified FP signal was due to the large mass of protein and MNP@PDA. And this assay can be utilized for target separation or recycling based on the magnetic property...
Herein, we developed a rapid and sensitive aptamers-based sandwich assay in microfluidic devices based on multivalent aptasensor array (MAA) chip and silver aggregated amplification (SAA) strategy for the detection of two biomarkers. Firstly, aptamers-modified silver nanoparticles were dotted in array to form MAA chip. Then PDMS was used to form a microfluidic device. After that, target proteins and...
In this paper, a colorimetric silver nanoparticles aptasensor (aptamer-AgNPs) was developed for simple and straightforward detection of protein in microfluidic chip. Surface-functionalized microfluidic channels were employed as the capture platform. Then the mixture of target protein and aptamer-AgNPs were injected into the microfluidic channels for colorimetric detection. To demonstrate the performance...
We report a simple one-step hydrothermal method for the synthesis of hydrophilic luminescent upconversion nanoparticles (UCNPs) using malonic acid as the stabilizer and functional agent. Using this method, two UCNPs with different colors of upconversion luminescence were synthesized. The surface of the as-prepared UCNPs was capped with carboxyl groups, which not only resulted in the UCNPs having good...
DNA 3′-phosphatase takes an important role in DNA damage repair, replication and recombination. Here, we present a novel label-free fluorescent assay for T4 polynucleotide kinase/phosphatase (T4 PNKP) activity and its inhibitor screening by using poly(thymine)-templated fluorescent copper nanoparticles (CuNPs) as a fluorescent indicator. In this assay, we designed a simple T-rich hairpin primer with...
In this paper, we demonstrated a simple and highly sensitive fluorescence platform for protein detection. Silver nanoparticles (AgNPs) worked as carriers and quenchers for FAM labeled aptamers (FAM-apt). Biotin labeled aptamers (Bio-apt), FAM-apt functionalized AgNPs (Ag-FAM-apt), and a target protein, human platelet-derived growth factor-BB (PDGF-BB) could form a sandwich-type complex. Once the etching...
The sensitivity of pH indicators is always confined in acidic solvents used during the immobilization because of the large deviation from their color transition points. By regulating the pH of indicators using organic acid or base, the color transition points of indicators could be readily achieved and the sensitivity could be greatly enhanced. In this study, bromophenol blue was selected as an example...
An on-line preconcentration strategy combining field-amplified stacking and reversed-field stacking was developed for efficient and sensitive analysis of amino acids and vitamin B3 including lysine (Lys), taurine (Tau), and niacinamide (NA) by microchip electrophoresis with LIF detection. In this technique, the addition of a reversed-polarity step termed reversed-field stacking could enhance the preconcentration...
A kind of dealloyed nanoporous gold (NPG)/ultrathin CuO film nanohybrid for non-enzymatic glucose sensing has been prepared by a simple, in-situ, time-saving and controllable two-step electrodeposition. The three-dimensional and bicontinuous nanoporous structure of the nanocomposites have been characterized by scanning electron microscope (SEM) and transmission electron microscopy (TEM), and the electrochemical...
We report a simple, one-step synthesis of hybrid film by electropolymerizing 3,4-ethylenedioxythiophene (EDOT) on nanoporous gold (NPG) for applications in amperometric glucose biosensors. The enzyme, glucose oxidase (GOx), is entrapped into poly(3,4-ethylenedioxythiophene) (PEDOT) matrix, simultaneously. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) studies show the...
A fluorometric paper-based sensor array has been developed for the sensitive and convenient determination of seven heavy-metal ions at their wastewater discharge standard concentrations. Combining with nine cross-reactive BODIPY fluorescent indicators and array technologies-based pattern-recognition, we have obtained the discrimination capability of seven different heavy-metal ions at their wastewater...
A novel electrochemical sensor based on molecularly imprinted polymer film has been developed for aspirin detection. The sensitive film was prepared by co-polymerization of p-aminothiophenol (p-ATP) and HAuCl 4 on the Au electrode surface. First, p-ATP was self-assembled on the Au electrode surface by the formation of Au–S bonds. Then, the acetylsalicylic acid (ASA) template was assembled...
SnO 2 nanowires with an average 0.6μm in length and about 25nm in diameter were prepared by a hydrothermal method. The sensors were fabricated using SnO 2 nanowires assembled with Pd nanocrystals. The sensing properties of the sensors such as selectivity, response–recovery time and stability were tested at 290°C. After assembling Pd nanocrystals onto the surface of SnO 2 nanowires,...
We describe herein the combination of electrochemical immunoassay using nanoporous gold (NPG) electrode with horseradish peroxidase (HRP) labeled secondary antibody–gold nanoparticles (AuNPs) bioconjugates for highly sensitive detection of protein in serum. The electroactive product of o-phenylenediamine (OPD) oxidized with H 2 O 2 catalyzed by HRP was reduced in the Britton–Robinson...
Dichlorodiphenyltrichloroethane (DDT) and its metabolites are a typical kind of persistent organic pollutants (POPs). Development of a simple, cost-effective and sensitive methodology to monitor DDTs concentrations in water environment is of particular significance for understanding the fate and behavior of these pollutants. In this paper, a method on the basis of solid-phase extraction (SPE) using...
A new method was developed for determination of micro amounts of nucleic acids based on near-infrared (near-IR) fluorescence recovery, employing a two-reagent system which is composed of an anionic tetracarboxy aluminum phthalocyanine (AlC 4 Pc) and a cationic tetra-N-hexadecylpyridiniumyl porphyrin (TC 16 PyP). The fluorescence of the AlC 4 Pc, with the maximum emission...
A new focused microwave-assisted solvent extraction method using water as solvent has been developed for leaching geniposidic and chlorogenic acids from Eucommia ulmodies Oliv. The extraction procedures were optimized using a two indexes orthogonal experimental design and graphical analysis, by varying irradiation time, solvent volume, solvent composition and microwave power. The optimum extraction...
A sensitive fluorimetric method for the determination of nitrogen oxides (NO x : NO+NO 2 ) in air is described. Nitrogen dioxide (nitrogen monoxide was previously converted to nitrogen dioxide in oxide tubes) was aspirated through a fritted glass bubble at a flow rate of 500 ml min -1 for 120 min and fixed as nitrite, using 0.1 N NaOH as a trapping solution with the empirical...
This is the first report on the determination of proteins with tetra-substituted sulphonated aluminum phthalocyanine (AlS 4 Pc) by resonance light-scattering (RLS). At pH 3.0, the weak RLS of AlS 4 Pc can be enhanced by the addition of proteins. Based on this, a novel quantitative method has been developed for the determination of proteins in aqueous solutions. Under optimal conditions,...
A flow injection electrochemiluminescent inhibition method has been developed for the determination of some catechol derivatives based on studying the inhibition phenomena of these compounds to the electrochemiluminescence of luminol. The linear calibration range of 5x10 -8 to 1x10 -5 , 5x10 -8 to 1x10 -5 and 1x10 -8 to 5x10 - ...
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