Imprinted proteins for determination of ovalbumin.

A strategy to design imprinted proteins (IPs) able to detect a glycoprotein (ovalbumin, OVA) was proposed. Glucose oxidase (GOx) was used as a matrix for obtaining the binding cavities with high specificity towards the template protein. The effective method to purify the obtained IPs from the template molecules was developed based on a combination of dialysis and gel filtration.

A novel electrochemical sensor for the detection of fipronil and its toxic metabolite fipronil sulfone using TiO-polytriazine imide submicrostructured composite as an efficient electrocatalyst.

For the first time, a simple and sensitive electrochemical sensor based on a screen printed electrode (SPE) modified with titanium dioxide (TiO) and polytriazine imide submicrostructured composite (TiO-PTI) has been developed for the simultaneous detection of fipronil (FIP) and its toxic metabolite fipronil sulfone (FIP-S). The submicrostructured composite material based on TiO and PTI was obtained by simple hydrothermal treatment of the Ti peroxocomplexes in the presence of pristine. This carbon nitride allotrope has better crystallinity and conductivity than its graphitic analog.

Structural and biochemical insights into CRISPR RNA processing by the Cas5c ribonuclease SMU1763 from Streptococcus mutans.

The cariogenic pathogen Streptococcus mutans contains two CRISPR systems (type I-C and type II-A) with the Cas5c protein (SmuCas5c) involved in processing of long CRISPR RNA transcripts (pre-crRNA) containing repeats and spacers to mature crRNA guides. In this study, we determined the crystal structure of SmuCas5c at a resolution of 1.72 Å, which revealed the presence of an N-terminal modified RNA recognition motif and a C-terminal twisted β-sheet domain with four bound sulphate molecules.

Recent advances in electrochemical monitoring of zearalenone in diverse matrices.

The current manuscript summarizes different electrochemical sensing systems developed within the last 5 years for the detection of zearalenone (ZEN) in diverse matrices such as food, feed, and biofluids. ZEN is one of the most prevalent non-steroidal mycotoxins that is often found in pre- and post-harvest crops. Crops contamination with ZEN and animal exposure to it via contaminated feed, is a global health and economic concern.

Homogenous FRET-based fluorescent immunoassay for deoxynivalenol detection by controlling the distance of donor-acceptor couple.

Semiconductor quantum dots (QDs) are one of the most popular luminescent labels that are widely used in food and medical analysis. Their unique optical properties establish QDs as excellent tools for highly sensitive biosensors based on Förster resonance energy transfer (FRET). To provide a convenient analytical system with long-term optical stability, a FRET pair consisting of QDs as energy donor and gold nanoparticles (GNs) as energy acceptor was developed.

Novel multiplex capacitive sensor based on molecularly imprinted polymers: A promising tool for tracing specific amphetamine synthesis markers in sewage water.

The development of a sensing system for amphetamine (AMP), N-formyl amphetamine (NFA), and benzyl methyl ketone (BMK) in sewage is a strict requirement for enabling the on-site detection and tracing of the consumption of AMP, and the production and/or transportation of these target analytes. The present research is therefore devoted to the development of an on-site capacitive sensing system, based on molecularly imprinted polymers (MIPs) as recognition elements. To this end, the commercially available CapSenze capacitive sensor system was miniaturized by implementing an application-specific integrated circuit (ASIC), dedicated to the bias and read-out of the chemical sensor.

Detection of toxins involved in foodborne diseases caused by Gram-positive bacteria.

Bacterial toxins are food safety hazards causing about 10% of all reported foodborne outbreaks in Europe. Pertinent to Gram-positive pathogens, the most relevant toxins are emetic toxin and diarrheal enterotoxins of Bacillus cereus, neurotoxins of Clostridium botulinum, enterotoxin of Clostridium perfringens, and a family of enterotoxins produced by Staphylococcus aureus and some other staphylococci. These toxins are the most important virulence factors of respective foodborne pathogens and a primary cause of the related foodborne diseases.

Capacitive sensing of an amphetamine drug precursor in aqueous samples: Application of novel molecularly imprinted polymers for benzyl methyl ketone detection.

Highly selective molecularly imprinted polymers (MIPs) towards benzyl methyl ketone (BMK) were synthesized for application as recognition elements in a capacitive sensor. A computational approach was employed to select the most appropriate monomers and cross-linkers. Using the selected compounds, different polymerization techniques and protocols were compared in order to study the effect on the MIP performance and characteristics.

Recent developments in electrochemical detection of illicit drugs in diverse matrices.

Drug abuse is a global problem, requiring an interdisciplinary approach. Discovery, production, trafficking, and consumption of illicit drugs have been constantly growing, leading to heavy consequences for environment, human health, and society in general. Therefore, an urgent need for rapid, sensitive, portable and easy-to-operate detection methods for numerous drugs of interest in diverse matrices, from police samples, biological fluids and hair to sewage water has risen.

Capacitive sensor based on molecularly imprinted polymers for detection of the insecticide imidacloprid in water.

This manuscript reports on the development of a capacitive sensor for the detection of imidacloprid (IMD) in water samples based on molecularly imprinted polymers (MIPs). MIPs used as recognition elements were synthesized via a photo-initiated emulsion polymerization. The particles were carefully washed using a methanol (MeOH) /acetic acid mixture to ensure complete template removal and were then dried.

Silanized Luminescent Quantum Dots for the Simultaneous Multicolor Lateral Flow Immunoassay of Two Mycotoxins.

A critical point for the successful development of a fluorescent quantum dot (QD)-based immunoassay is maintaining the high fluorescence quantum yield of QDs during hydrophilization and bioconjugation. In this paper, we carefully designed CdSe/CdS and CdSe/CdS/ZnS core-shell heterostructures and extended them with silica coating of different surface composition allowing preservation of fluorescence quantum yield as high as 70% in aqueous media. The silanized QDs containing epoxy and carboxy surface groups were bioconjugated with monoclonal antibodies.

Immunochemical approaches for detection of aflatoxin B1 in herbal medicines.

Introduction: Aflatoxin B1 (AFB1) is a toxic low-molecular-weight secondary metabolite of Aspergillus flavus and A. parasiticus. AFB1 was classified as a Group I carcinogen by the World Health Organisation for Research on Cancer in 1993.

Soft glass multi-channel capillaries as a platform for bioimprinting.

Multi-channel capillaries (MC) formed from thousands individual microcapillaries with diameters ranging 10-100 μm are of a great interest for their use as platforms for molecular imprinting due to their relatively large surface area, high mechanical stability and possibility of facile integration in sensor systems. The manuscript proposes a new format of immunoassay based on imprinted protein immobilized on a MC inner surface modified with poly-l-lysine. The combination of the environmentally friendly, easy-to-produce and cheap recognition element with the carrier allowing to increase the assay sensitivity makes the described technique a perspective alternative for the existing screening tests.

Gel electrophoresis separation and origins of light emission in fluorophores prepared from citric acid and ethylenediamine.

We investigated light emission of hydrothermally treated citric acid and ethylenediamine (EDA) with various precursor ratios using gel-electrophoresis. We show that this relatively simple approach can deliver significant insights into the origins of photoluminescence. We found that products of the synthesis consist of both positively and negatively charged species and exhibit large dispersion in electrophoretic mobility (i.

Silanization of quantum dots: Challenges and perspectives.

Here we report the facile strategies for synthesis of silica-coated quantum dots (QDs). Due to their small size, chemical and optical stability and high luminescence quantum yield these particles can be further applicable in chemical and biomedical analysis, and in vivo imaging. The article gives a structured and detailed overview of the silanization strategies and potential pitfalls and common technical issues in function of the stability of the obtaining QDs.

Development of a validated direct injection-liquid chromatographic tandem mass spectrometric method under negative electrospray ionization for quantitation of nine microcystins and nodularin-R in lake water.

Microcystins (MCs) are cyclic heptapeptide toxins produced by various cyanobacterial genera that are toxic to both animals and humans. In this study, a novel strategy was proposed for the quantitation of nine MCs and Nodularin-R (NOD) in lake water using UHPLC-MS/MS under negative ionization mode, in which only centrifugation was employed during sample preparation. As a result, limits of quantification (LOQ) ranging from 0.

Portable Multiplex Immunochromatographic Assay for Quantitation of Two Typical Algae Toxins Based on Dual-Color Fluorescence Microspheres.

A multiplex immunochromatographic assay (ICA) based on dual-color fluorescent microspheres (FMs) as a sensitive label was developed for the first time. Two typical algae toxins, microcystin-LR (MC-LR) and okadaic acid (OA), were chosen as proof-of concept targets to evaluate the feasibility of this ICA format. Commercial red- and green-colored FMs were selected to couple with monoclonal antibodies as fluorescent probes.

Bioimprinting for multiplex luminescent detection of deoxynivalenol and zearalenone.

A sensitive tool for simultaneous quantitative determination of two analytes in a single spot with the use of a bioimprinted protein is presented for the first time. BSA is chosen as a scaffold for generation of binding sites specific towards two compounds. A multiplex immunosorbent assay for screening of two cereal-born mycotoxins, deoxynivalenol and zearalenone, in wheat and maize is realized with the use of fluorescent silica coated quantum dots as labels.

Imprinted proteins as a receptor for detection of zearalenone.

A strategy to design an immunoassay based on imprinted proteins to detect a foodborne toxin zearalenone (ZEN) has been proposed. Proteins were used as scaffolds for generation of binding cavities with a high specificity against ZEN. Different proteins and different bioimprinting approaches were tested.

Antibody immobilization strategy for the development of a capacitive immunosensor detecting zearalenone.

A highly sensitive flow-injection capacitive immunosensor was developed for detection of the mycotoxin zearalenone (ZEN). Different strategies for immobilization of an anti-ZEN antibody on the surface of a gold electrode, i.e.

Capacitive sensor for detection of benzo(a)pyrene in water.

An affinity sensor based on capacitive transduction was developed to detect benzo(a)pyrene (BaP) in river water. Two types of recognition elements, the synthetic receptor analogues molecularly imprinted polymers (MIPs) and natural monoclonal antibody (mAb) were tested for this type of biosensor. Different polymerization strategies to obtain MIPs were compared.

Simple, high efficiency detection of microcystins and nodularin-R in water by fluorescence polarization immunoassay.

This manuscript describes the development of a sensitive, fast and easily-performed fluorescence polarization immunoassay (FPIA) for detection of microcystins (MCs) and nodularin-R (NOD) in water. MCs and NOD, the most widespread cyanobacterial toxin are hepatotoxins and tumor promoters, and their acute exposure may result in severe health problems in animals and humans. The fluorescein-based tracers were synthesized, and for the first time preparative high performance liquid chromatography (HPLC) was employed for their purification.

A Dual-Color Quantum Dots Encoded Frit-Based Immunoassay for Visual Detection of Aflatoxin M and Pirlimycin Residues in Milk.

Mycotoxins and antibacterial agents are the main chemical hazards that lead to several health problems. Nowadays, multiplex immunoassay is a primary goal throughout the world. Here, aflatoxin M and pirlimycin were selected as models, and a novel dual colorimetric encoded frit-based immunoassay was developed for simultaneously screening of aflatoxin M and pirlimycin residues in milk.

Fluorescently labelled multiplex lateral flow immunoassay based on cadmium-free quantum dots.

A sensitive tool for simultaneous qualitative detection of two mycotoxins based on use of non-cadmium quantum dots (QDs) is presented for the first time. QDs have proven themselves as promising fluorescent labels for biolabeling and chemical analysis. With an increasing global tendency to regulate and limit the use of hazardous elements, indium phosphide (InP) QDs are highlighted as environmentally-friendly alternatives to the highly efficient and well-studied, but potentially toxic Cd- and Pb-based QDs.

Lanthanide-to-quantum dot Förster resonance energy transfer (FRET): Application for immunoassay.

Förster resonance energy transfer (FRET) between lanthanide ion complexes (L) acting as donors and luminescent semiconductor quantum dots (QD) acting as acceptors is discussed in the terms of advantages and disadvantages for its application in immunoassay. L-QD-FRET is potentially a powerful tool that can be used to detect and confirm formation of immunocomplexes, but until now it had very limited practical analytical application. Therefore, the main aim of this review is to analyze all possibilities, advantages, and disadvantages of L-QD-FRET in immunoassay applications.