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A simple, rapid, and sensitive homogeneous electrochemical bleomycin (BLM) bioassay has been successfully developed through the target-induced specific/efficient cleavage reaction. The designed probe, denoted as MB-DNA, contains both methylene blue (MB) and target recognizable sequences, and presents relatively low electrochemical signal. Upon the addition of BLM, the recognition/cleavage reaction...
Since the lack of detection diversity of the single-signal readout strategy, it is urgent to develop fast and multisignal assay strategies. A highly selective and sensitive assay method with colorimetric and fluorometric dual signals readouts is presented in this paper. It is based on the principle that the target induced conjunction of split aptamer fragments assembled on the surface of Au nanoparticles...
Simple and fast detection of alkaline phosphatase (ALP) activity is of great importance for diagnostic and analytical applications. In this work, we report a turn-off approach for the real-time detection of ALP activity on the basis of the charge transfer induced fluorescence quenching of the Cu(BCDS)22- (BCDS = bathocuproine disulfonate) probe. Initially, ALP can enzymatically hydrolyze the substrate...
Mutations in Kras gene may be used as a diagnostic marker and a target for treatment of the broad spectrum of human cancers. In this study, we developed a new class of amplification assay, double-hairpin molecular beacon (DHMB)-based cascade rolling circle amplification (RCA), for ultrasensitive and selective detection of Kras gene in a homogenous solution. Specifically, target DNA can hybridize with...
In this work, we designed and synthesized a carbazole-type molecule that can form carbazolyl radicals in chloroform solution under the irradiation of UV light. The process is accompanied by an obvious change in the emission color from blue to bright green. The radicals and the neutral molecules assemble together and form nanospheres through synergistic effect of π-π stacking, intermolecular hydrogen...
Reliable, selective and sensitive approaches for trinitrophenol (TNP) detection are highly desirable with respect to national security and environmental protection. Herein, a simple and novel fluorescent strategy for highly sensitive and specific TNP assay has been successfully developed, which is based on the quenching of the fluorescent poly(thymine)-templated copper nanoclusters (DNA-CuNCs), through...
MicroRNAs (miRNAs) play an important role in many biological processes, and have been regarded as potential targets and biomarkers in cancer diagnosis and therapy. Also, to meet the big challenge imposed by the characteristics of miRNAs, such as small size and vulnerability to enzymatic digestion, it is of great importance to develop accurate, sensitive and simple miRNA assays. Herein, we developed...
In the present study, chitosan (CHI) functionalized Fe3O4 magnetic microspheres coated with polyaniline (PANI) were synthesized for the first time. The chitosan-functionalized magnetic microspheres (Fe3O4@CHI) were synthesized by a co-precipitation method, and then aniline was polymerized on the magnetic core. The obtained Fe3O4@CHI@PANI microspheres were spherical core–shell structure with uniform...
In this work, the competitive interaction between dibucaine and three fluorescent probes (i.e., berberine, palmatine, and coptisine) for occupancy of the cucurbit[7]uril (CB[7]) cavity was studied by fluorescence spectra, UV–visible absorption spectra, 1 H NMR spectra, and theoretical calculations in acidic aqueous solution. Based on the fluorescence enhancement of berberine, palmatine, and...
Determination of squamous cell carcinoma antigen (SCCA) in human serum plays an important role in diagnosis of cervical squamous cell carcinoma. In this work, Au/Ag/Au core/double shell nanoparticles (Au/Ag/Au NPs) were prepared by a simple approach and were used as novel enzyme-mimetic labels for development of a sandwich-type electrochemical immunosensor for SCCA. The nanostructure of Au/Ag/Au NPs...
In the present study, a rapid and repeatable microemulsion electrokinetic chromatography (MEEKC) method was developed for the simultaneous determination of three isomers (α-, β- and γ-asarone) in Acorus tatarinowii by using ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF 6 ) as oil phase. Experimental parameters including the microemulsion compositions (concentrations...
A simple and effective strategy was proposed for synthesis of AuNPs@polyaniline (AuNPs@PANI) core–shell nanocomposites. AuNPs@PANI nanocomposites were prepared by one-step chemical oxidative polymerization of aniline using chloroaurate acid as the oxidant and AuNPs as the seeds. The synthesized AuNPs@PANI nanocomposites were characterized with transmission electron microscope and UV–vis absorption...
A novel electrochemical sensing platform by modification of electroactive thionine (Th) onto gold electrode surface was constructed, which was realized by diazotization of 4-aminothiophenol (ATP) self-assembled monolayer, followed by coupling of Th with the diazonium group to form a covalent diazo bond. A pair of well-defined redox peaks of Th was observed in the cyclic voltammetric measurement. The...
The supramolecular interaction of a homologous series of cucurbit[n]uril (CB[n], n=5, 6, 7, 8) hosts and coptisine (COP) was studied by spectrofluorimetry. All of the CB[n]s were found to react with COP to form 1:1 host–guest stable complexes and the fluorescence intensity of the complexes was greatly enhanced. The apparent association constants of the complexes were 1.44×10 4 , 1.28×10 ...
A new method for the determination of palladium was developed by dispersive liquid–liquid microextraction preconcentration and graphite furnace atomic absorption spectrometry detection. In the proposed approach, diethyldithiocarbamate (DDTC) was used as a chelating agent, and carbon tetrachloride and ethanol were selected as extraction and dispersive solvent. Some factors influencing the extraction...
A simple and reliable one-pot approach was established for the development of a novel hydrogen peroxide (H 2 O 2 ) biosensor based on in situ covalent immobilization of horseradish peroxidase (HRP) into biocompatible material through polysaccharide-incorporated sol–gel process. Siloxane with epoxide ring and trimethoxy anchor groups was applied as the bifunctional cross-linker and...
Single-stranded deoxyribonucleic acid (ssDNA)-wrapped single-walled carbon nanotubes (SWNTs) were modified on the surface of glassy carbon electrode (GCE) by covalent modification technique. Field emission scanning electron microscope (FE-SEM), X-ray photoelectron spectrum (XPS), electrochemical impedance spectroscopy (EIS), and cyclic voltammetric (CV) were used to characterize the properties of...
In this article interaction of transition metal complexes with DNA and its applications in electrochemical DNA biosensors as hybridization indicator or electroactive marker of DNA are reviewed. Special emphasis has been given to the efforts for the development of new transition metal complexes and their interaction to DNA. DNA and polymers covalently conjugated with transition metal complexes were...
An interfacial organic–inorganic hybridization concept was applied to the preparation of a new spherical imprinted material for protein recognition. The functional biopolymer chitosan (CS), shaped as microsphere and high-density cross-linked, constituted of the polysaccharide core for surface imprinting. After the model template protein, bovine serum albumin, was covalently immobilized by forming...
Platinum nanoparticles (PtNPs) attached to glass slide surface was successfully prepared by using a simple in situ chemical reduction method. In this method, a ∼10nm gold layer was first sputtered uniformly onto the glass slide surface, PtNPs could be grown directly on the gold layer by immersing the glass slide into the grown solution containing H 2 PtCl 4 and ascorbic acid. The gold...
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