Visual detection of ochratoxin a based on GPE-PET bipolar electrode-electrochemiluminescence platform.

A GPE-PET (graphene-polyethylene terephthalate) bipolar electrode-electrochemiluminescence (BPE-ECL) platform was developed for ochratoxin A (OTA) detection. PET served as the electrode sheet substrate, and GPE was drop-coated onto the surface of PET to form a conductive line. On the functional sensing interface, the thiol (-SH) modified OTA aptamer (OTA-Aptamer) are fixed on the surface of the gold-plated cathode through AuS bonds.

Rapid screening of electrochemically active bacteria based on a biocathode-functional bipolar electrode-electrochemiluminescence platform.

A functional bipolar electrode-electrochemiluminescence (BPE-ECL) platform based on biocathode reducing oxygen was constructed for detecting electrochemically active bacteria (EAB) in this paper. Firstly, thiolated trimethylated chitosan quaternary ammonium salt (TMC-SH) layer was assembled on the gold-plated cathode of BPE. TMC-SH contains quaternary ammonium salt branch chain, which can inhibit the growth of microorganisms on the surface or in the surrounding environment while absorbing bacteria.

Double bipolar electrode electrochemiluminescence color switch for food-borne pathogens detection.

Color-switch electrochemiluminescence (ECL) sensing platform based on a dual-bipolar electrode (D-BPE) is reported in this work. The D-BPE was composed of a cathode filled with buffer and two anodes filled with [Ru(bpy)]-TPrA and luminol-HO solutions, respectively. Both anodes were modified with capture DNA and served as ECL reporting platforms.

Biocathodes reducing oxygen in BPE-ECL system for rapid screening of E. coli O157:H7.

After discovery of electron transfer from bacteria, most bacteria known to be electrochemically active are utilized as a self-regenerable catalyst at the anode of microbial fuel cells (MFCs). However, the reverse phenomenon, cathodic catalysts is not so widely researched. This present study demonstrated that E.

Reagentless detection of staphylococcal enterotoxin B via electrochemical interrogation of conformational changes.

An electrochemical biosensor for staphylococcal enterotoxin B (SEB) detection has been designed on the basis of electrochemical interrogation of conformational changes. Ferrocene-labeled hairpin probe (Fc-HP) and SEB aptamer are introduced for the construction of the platform. Without SEB, the rigid construction of DNA duplex that included SEB aptamer and Fc-HP prevented Fc getting access to the electrode surface, keeping the "eT-off" state in the detection system.

Temporal sensing platform based on anodic dissolution of Ag and cathodic biocatalysis of oxygen reduction for Staphylococcus aureus detection.

An Ag@C hybrid bipolar electrode (BPE) sensing platform has been established for the temporal detection of Staphylococcus aureus (S. aureus) in food. Combining the advantages of anodic dissolution of Ag and cathodic biocatalysis of oxygen (O) reduction, this strategy showed an ultralow detection limit down to 10 CFU mL.

One-step grain pretreatment for ochratoxin A detection based on bipolar electrode-electrochemiluminescence biosensor.

False positives are common and frequently occurring in detection of ochratoxin A (OTA) due to the complexity of the food matrix. In this paper, a novel bipolar electrode-electrochemiluminescence (BPE-ECL) sensing platform for sensitive OTA detection with one-step grain pretreatment was proposed. The biosensor uses cathode of closed BPE as a functional sensing interface and anode as a signal collection interface.

Sensitive electrochemical detection of aflatoxin B1 using DNA tetrahedron-nanostructure as substrate of antibody ordered assembly and template of aniline polymerization.

A novel strategy for AFB1 detection in grains was proposed based on DNA tetrahedron-structured probe (DTP) and horseradish peroxidase (HRP) triggered polyaniline (PANI) deposition. Briefly, the DNA tetrahedron nanostructures were assembled on the gold electrode, with carboxylic group designed on top vertex of them. The carboxylic group was conjugated with the AFB1 monoclonal antibody (mAb) to form DTP.

Fluorescent difference between two rhodamine-PAHs polystyrene solid-phase sensors for Hg(II) detection based on crystal structure and density functional theory calculation.

Two novel rhodamine-polystyrene solid-phase fluorescence sensors PS-RB-2 and PS-R6G-2 with pyrene or naphthalene as fluorophore were synthesized for Hg(II) detection. Their structures were characterized by Fourier transform infrared (FTIR) spectra and scanning electron micrographs (SEM). Sensor PS-RB-2 displayed higher selectivity and sensitivity to Hg(II), with a lower detection limit of 0.

Development of a real-time PCR assay for the identification and quantification of bovine ingredient in processed meat products.

In order to find fraudulent species substitution in meat products, a highly sensitive and rapid assay for meat species identification and quantification is urgently needed. In this study, species-specific primers and probes were designed from the mitochondrial cytb (cytochrome b) fragment for identification and quantification of bovine ingredient in commercial meat products. Bovine samples and non-bovine ones were used to identify the specificity, sensitivity, and applicability of established assay.

Simultaneous fluorescent detection of multiplexed miRNA of liver cancer based on DNA tetrahedron nanotags.

The level of miRNA-21, miRNA-122, and miRNA-223 are always elevated when liver cancer is present at an early stage. In this paper, a novel assay to simultaneous detect miRNA-21, miRNA-122, and miRNA-223 was proposed based on DNA tetrahedron nanotags and fluorescence resonance energy transfer (FRET), which used a single laser stimulate wavelengh from one nucleic acid stain TOTO-1 to three diverse organic dyes (Cy3, Cy3.5, Cy5).

Ultrasensitive detection of Staphylococcal enterotoxin B in milk based on target-triggered assembly of the flower like nucleic acid nanostructure.

A rapid and ultrasensitive method is described for the detection of Staphylococcal enterotoxin B (SEB). It is based on the formation of the flower like nucleic acid nanostructure by integrating (a) target-induced triggering of DNA release with (b) signal amplification by a hybridization chain reaction (HCR). Firstly, partially complementary pairing of aptamer and trigger DNA forms a duplex structure.

Screen printed bipolar electrode for sensitive electrochemiluminescence detection of aflatoxin B1 in agricultural products.

In order to avoid the occurrence of false positives and false negatives caused by improper pretreatment during the detection of aflatoxin B1 by enzyme linked immunosorbent assay (ELISA). In this paper, we developed a screen printed bipolar electrode (BPE) for sensitive electrochemiluminescence (ECL) detection of aflatoxin B1 in agricultural products. The sensor uses a cathode of closed BPE as a functional sensing interface and an anode as a signal collection interface.

Chronocoulometric aptamer based assay for staphylococcal enterotoxin B by target-triggered assembly of nanostructured dendritic nucleic acids on a gold electrode.

A rapid and ultrasensitive method is described for the detection of staphylococcal enterotoxin B (SEB). It is based on the formation of a dendritic DNA superstructure by integrating (a) target-induced triggering of DNA release with (b) signal amplification by a hybridization chain reaction. Partially complementary pairing of aptamer and trigger DNA forms a duplex structure.

Impedimetric determination of Staphylococcal enterotoxin B using electrochemical switching with DNA triangular pyramid frustum nanostructure.

An electrochemical switching strategy is presented for the sensitive determination of Staphylococcus enterotoxin B (SEB). It is based on the use of DNA triangular pyramid frustum nanostructure (TPF) consisting of (a) three thiolated probes, (b) one auxiliary probe, and (c) an aptamer against SEB. The TPF was assembled on the gold electrode, with the SEB aptamer designed on top of the TPF.

Ultrasensitive electrochemical detection of poly (ADP-ribose) polymerase-1 via polyaniline deposition.

Recent findings have thrust poly ADP (ADP: adenosine diphosphate)-ribose polymerase-1 (PARP-1) into the limelight as potential chemotherapeutic target because it is closely related to the development of tumor. So, studies on its detection and inhibitors evaluation have attracted more attention. It is interesting that poly (ADP-ribose) (PAR), the catalytic product of PARP-1 in the existence of nicotinamide adenine dinucleotide (NAD), possess twice charge density of DNA strands.

Visual, Label-Free Telomerase Activity Monitor via Enzymatic Etching of Gold Nanorods.

Early diagnosis and life-long surveillance are clinically important to improve the long-term survival of cancer patients. Telomerase activity is a valuable biomarker for cancer diagnosis, but its measurement often used complex label procedures. Herein, we designed a novel, simple, visual and label-free method for telomerase detection by using enzymatic etching of gold nanorods (GNRs).

In Situ Detection and Imaging of Telomerase Activity in Cancer Cell Lines via Disassembly of Plasmonic Core-Satellites Nanostructured Probe.

The label-free localized surface plasmon resonance (LSPR) detection technique has been identified as a powerful means for in situ investigation of biological processes and localized chemical reactions at single particle level with high spatial and temporal resolution. Herein, a core-satellites assembled nanostructure of Au@Au was designed for in situ detection and intracellular imaging of telomerase activity by combining plasmonic resonance Rayleigh scattering spectroscopy with dark-field microscope (DFM). The Au@Au was fabricated by using 50 nm gold nanoparticles (Au) as core and 13 nm gold nanoparticles (Au) as satellites, both of them were functionalized with single chain DNA and gathered proximity through the highly specific DNA hybridization with a nicked hairpin DNA (O1) containing a telomerase substrate (TS) primer as linker.

A novel photoelectrochemical immunosensor by integration of nanobody and ZnO nanorods for sensitive detection of nucleoside diphosphatase kinase-A.

Nucleoside diphosphatase kinase A (NDPK-A) is a metastasis-suppressor protein and a biomarker that act on a wide range cancer cells to inhibit the potential metastasis. Herein, we present a simple photoelectrochemical immunosensor based on ZnO nanorod arrays for the sensitive detection of NDPK-A. The ZnO nanorod arrays cosensitized with CdS nanoparticles and Mn displayed a high and stable photocurrent response under irradiation.

Application of Spectral Crosstalk Correction for Improving Multiplexed MicroRNA Detection Using a Single Excitation Wavelength.

MicroRNAs (miRNAs) play crucial roles in the regulation of cellular activities and are next-generation biomarkers for early cancer detection. Simultaneous monitoring of multiplexed miRNA is very important for enhancing the accuracy of cancer diagnostics. Traditional fluorescence methods for multicomponent analysis were usually operated under multiple excitation wavelengths, because spectral crosstalk is very detrimental to detecting accuracy for multicomponent analysis.

Construction of iron-polymer-graphene nanocomposites with low nonspecific adsorption and strong quenching ability for competitive immunofluorescent detection of biomarkers in GM crops.

We developed a new immunofluorescent biosensor by utilizing a novel nanobody (Nb) and iron-polymer-graphene nanocomposites for sensitive detection of 5-enolpyruvylshikimate-3-phosphate synthase from Agrobacdterium tumefaciens strain CP4 (CP4-EPSPS), which considered as biomarkers of genetically modified (GM) crops. Specifically, we prepared iron doped polyacrylic hydrazide modified reduced graphene nanocomposites (Fe@RGO/PAH) by in-situ polymerization approach and subsequent a one-pot reaction with hydrazine. The resulting Fe@RGO/PAH nanocomposites displayed low nonspecific adsorption to analytes (11% quenching caused by nonspecific adsorption) due to electrostatic, energetic and steric effect of the nanocomposites.

A label-free ultrasensitive assay of 8-hydroxy-2'-deoxyguanosine in human serum and urine samples via polyaniline deposition and tetrahedral DNA nanostructure.

Oxidative damage is an important factor in causing various human disease and injury. As an oxidative DNA damage product, 8-hydroxy-2'-deoxyguanosine (8-OHdG) is a key marker, which is widely used to study oxidative damage mechanism in diseases. Most reported electrochemical methods were based on oxidation current of 8-OHdG.

A simple, fast, label-free colorimetric method for detection of telomerase activity in urine by using hemin-graphene conjugates.

Telomerase, a widely accepted cancer biomarker for early cancer diagnostics, is considered as an important therapeutic target. To now, it is still a challenging subject to develop a simple and sensitive strategy for telomerase activity detection. Herein, we reported a simple colorimetric strategy for label-free quantification of human telomerase activity in urine by using hemin-graphene nanomaterial (H-GNs).