Component-resolved diagnostic of cow’s milk allergy by immunoaffinity capillary electrophoresis – matrix assisted laser desorption/ionization mass spectrometry

Component-resolved diagnostic (CRD) of cow’s milk allergy has been performed using immunoaffinity capillary electrophoresis (IACE) coupled with matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). First, total IgE quantification in the blood serum of a milk allergic patient by IACE-UV technique was developed using magnetic beads (MBs) coated with anti-human IgE antibodies (Abs) to perform the general allergy diagnosis. Then, the immunocomplex of anti-human IgE Abs with the patient IgE Abs, obtained during the total IgE analysis, was chemically cross-linked on the MBs surface. Prepared immunosupport was used for the binding of individual milk allergens to identify the proteins triggering the allergy by IACE with UV and MALDI MS detection. Then, allergy CRD was also performed directly with milk fractions. Bovine serum albumin, lactoferrin and α-casein (S1 and S2 forms, as was revealed by MALDI MS) were found to bind with the extracted IgE Abs, indicating that the chosen patient is allergic to these proteins. The results were confirmed by performing classical enzyme-linked immunosorbent assay of total and specific IgE Abs. The present IACE-UV/MALDI MS method required only 2 μl of blood serum and allowed the performance of the total IgE quantification and CRD of the food allergy not only with the purified allergen molecules, but also directly with the food extract. Such an approach opens the possibility for direct identification of allergens molecular mass and structure, discovery of unusual allergens, which could be useful for precise personalized allergy diagnostic, allergens epitope mapping and cross-reactivity studies

Bioanalytical methods for food allergy diagnosis, allergen detection and new allergen discovery

For effective monitoring and prevention of the food allergy, one of the emerging health problems nowadays, existing diagnostic procedures and allergen detection techniques are constantly improved. Meanwhile, new methods are also developed, and more and more putative allergens are discovered. This review describes traditional methods and summarizes recent advances in the fast evolving field of the in vitro food allergy diagnosis, allergen detection in food products and discovery of the new allergenic molecules. A special attention is paid to the new diagnostic methods under laboratory development like various immuno- and aptamer-based assays, including immunoaffinity capillary electrophoresis. The latter technique shows the importance of MS application not only for the allergen detection but also for the allergy diagnosis

Analysis of major milk whey proteins by immunoaffinity capillary electrophoresis coupled with MALDI-MS

Two major milk whey proteins, β-lactoglobulin and α-lactalbumin, are among the main cowmilk allergens and can cause allergy even at a very low concentrations. Therefore, these proteins are interesting targets in food analysis, not only for food quality control but also for highlighting the presence of allergens. Herein, a sensitive analysis for β-lactoglobulin and -lactalbumin was developed using immunoaffinity capillary electrophoresis hyphenated with MALDI-MS.Magnetic beads functionalized with appropriate antibodieswere used for β-lactoglobulin and α-lactalbumin immunocapture inside the capillary. After elution from the beads, analyte focusing and separation were performed by transient isotachophoresis followed by MALDI-MS analysis performed through an automated iontophoretic fraction collection interface. A LOD in the low nanomolar range was attained for both whey proteins. The method developed was further applied to the analysis of different milk samples including fortified soy milk

Surface transportation engineering technology: prerequisite for accident-free traffic at signal-controlled intersections

Introduction: Improving intersection capacity will not be possible without accounting for traffic safety. Purpose of the study: We aim to determine the prerequisite for accident-free traffic at signal-controlled intersections with turning traffic flows. Methods: In our study, we used the methods of observation, comparison, and mathematical analysis. Results: We have carried out a field observation of traffic intensity at signal-controlled intersections in the city of Yekaterinburg, focusing on vehicles that moved when the green light was on. We have also analyzed traffic flow moving in three directions in the same lanes. We have discovered that traffic accident likelihood is the highest (54%) at four-way intersections. Three-way intersections account for 44% of traffic accidents, while the remaining 2% of accidents occur at multi-way intersections. Furthermore, we have determined the additional factors that impact safety in turning traffic flows at intersections. Our study demonstrates that in order to ensure maximum intersection capacity, the duration of the traffic signal cycle must be adjusted with the minimum safe distance between vehicles in mind. © St. Petersburg State University of Architecture and Civil Engineering

Rapid Noninvasive Skin Monitoring by Surface Mass Recording and Data Learning.

Skin problems are often overlooked due to a lack of robust and patient-friendly monitoring tools. Herein, we report a rapid, noninvasive, and high-throughput analytical chemical methodology, aiming at real-time monitoring of skin conditions and early detection of skin disorders. Within this methodology, adhesive sampling and laser desorption ionization mass spectrometry are coordinated to record skin surface molecular mass in minutes. Automated result interpretation is achieved by data learning, using similarity scoring and machine learning algorithms. Feasibility of the methodology has been demonstrated after testing a total of 117 healthy, benign-disordered, or malignant-disordered skins. Remarkably, skin malignancy, using melanoma as a proof of concept, was detected with 100% accuracy already at early stages when the lesions were submillimeter-sized, far beyond the detection limit of most existing noninvasive diagnosis tools. Moreover, the malignancy development over time has also been monitored successfully, showing the potential to predict skin disorder progression. Capable of detecting skin alterations at the molecular level in a nonsurgical and time-saving manner, this analytical chemistry platform is promising to build personalized skin care

On-Chip Spyhole Mass Spectrometry for Droplet-Based Microfluidics

For efficient coupling of droplet-based microfluidics with mass spectrometry (MS), a spyhole drilled on the top of a microchip is used to sample the passing droplets by electrostatic-spray ionization (ESTASI) MS. The technique involves placing an electrode below the chip under the spyhole and applying high-voltage pulses. Electrospray occurs directly from the spyhole, and the droplet content is analyzed by MS without a dilution or oil removal step. To demonstrate the versatility of this technique, we have successfully monitored a droplet-based tryptic digestion, as well as a biphasic reaction between β-lactoglobulin in water and α-tocopheryl acetate in 1,2-dichloroethane, where the protein extracts the antioxidant from the oil phase and becomes reduced

A self-assembled organic/metal junction for water photo-oxidation

We report the in situ self-assembly of TTF, TTF ·+ , and BF 4 - or PF 6 - into p-type semiconductors on the surface of Pt microparticles dispersed in water/acetonitrile mixtures. The visible light photoactivation of these self-assemblies leads to water oxidation forming O 2 and H + , with an efficiency of 100% with respect to the initial concentration of TTF ·+ . TTF ·+ is then completely reduced to TTF upon photoreduction with water. The Pt microparticles act as floating microelectrodes whose Fermi level is imposed by the different redox species in solution; here predominantly TTF, TTF ·+ , and HTTF + , which furthermore showed no signs of decomposition in solution.Fil: Olaya, Astrid J.. Swiss Federal Institute Of Technology Epfl; SuizaFil: Omatsu, Terumasa. Kyoto Institute Of Technology; JapónFil: Hidalgo-Acosta, Jonnathan C.. Swiss Federal Institute Of Technology Epfl; SuizaFil: Riva, Julieta Soledad. Swiss Federal Institute Of Technology Epfl; Suiza. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bassetto, Victor Costa. Swiss Federal Institute Of Technology Epfl; SuizaFil: Gasilova, Natalia. Swiss Federal Institute Of Technology Epfl; SuizaFil: Girault, Hubert. Swiss Federal Institute Of Technology Epfl; Suiz

Mass Barcode Signal Amplification for Multiplex Allergy Diagnosis by MALDI-MS

A highly sensitive method based on mass-barcoded gold nanoparticles (AuNPs) and immunomagnetic separation has been developed for multiplex allergy diagnosis by MALDI mass spectrometry in a component-resolved manner. Different analytical probes were prepared by coating AuNPs with individual allergenic proteins and mass barcode, represented by polyethylene glycol molecules of various chain lengths. Magnetic beads (MBs) functionalized with antihuman IgE antibodies (Abs) were used as immunomagnetic capture probes. IgE Abs were extracted from a patient’s blood serum by the formation of a sandwich structure between the AuNPs and MBs. Multiple specific IgE Abs were simultaneously identified by mass spectrometry detection of the mass barcodes, providing an efficient component-resolved allergy diagnosis. Because of the signal amplification provided by the mass barcodes, the developed diagnosis method is very sensitive, with a limit of detection down to picograms per milliliter level for specific IgE Abs. The method can be potentially useful when the sample amount is highly limited and a multiplex diagnostic procedure is required

Open channel-based microchip electrophoresis interfaced with mass spectrometry via electrostatic spray ionization

The coupling between open channel-based microchip electrophoresis and mass spectrometry via electrostatic spray ionization is proposed for in situ detection of fractionated analytes. Electrophoretic separation is performed in an open channel fabricated in a plastic substrate. The solvent of background electrolyte is evaporated from the open channel because of Joule heating during electrophoresis, leaving the dried electrophoretic bands to be directly analyzed by mass spectrometry via scanning electrostatic spray ionization. Proof-of-concept results are obtained with fluorescent dyes and antibiotics as the test samples, demonstrating an efficient on-chip detection platform based on the electrophoresis and electrostatic spray ionization mass spectrometry

A microchip emitter for solid phase extraction – gradient elution – mass spectrometry

A microchip electrospray emitter with a magnetic bead trap has been designed for solid phase extraction-gradient elution-mass spectrometry (SPE-GEMS). The goal of this method is the detection of analytes at low concentrations and it is here demonstrated using reverse phase coated magnetic beads (Mbs) for the preconcentration and detection of the peptides. The sample is passed through the chip, and the peptides are retained and enriched in the trap. After washing, the peptides are released sequentially by stepwise gradient elution and electrosprayed for mass spectrometry analysis. This approach allows effective sample desalting, enrichment, sequential elution and MS detection without the introduction of an additional separation step after SPE. Efficient preconcentration of model peptides by SPE and sequential release and analysis of peptides by GEMS were demonstrated for diluted sample solutions within the range of 1 µM to 10 nM. Fortified human blood serum, protein digest and fractions collected after protein digest OFFGEL separation were analysed by SPE-GEMS allowing the detection of low abundance peptides usually not observed by direct mass spectrometry analysis. A mathematical model for gradient elution is proposed