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Поступила в редакцию 4 ноября 2017 г. Принята 17 ноября 2017 г.Актуальность. На сегодняшний день вопрос детектирования различных штаммов бактерии H. pylori приобрел большую значимость ввиду распространенности этой бактерии по всему миру и той роли, которую она играет в развитии множества серьезных желудочных и внежелудочных заболеваний. При этом не все штаммы бактерии H. pylori являются агрессивными и требуют лечения с использованием антибиотиков. Таким образом, возникает вопрос о необходимости дифференциации этих бактерий по их факторам вирулентности. Недорогой и общедоступной технологией для решения этой задачи могут стать современные сенсорные устройства. Цель работы. Цель работы состоит в разработке сенсорного устройства нового типа для дифференциального распознавания штаммов H. pylori на основе анализа смеси газов, выдыхаемых человеком. Такое устройство может быть создано на основе точечно-контактного газового сенсора. Материалы и методы. Фундаментальные свойства точечных контактов, используемых в микроконтактной спектроскопии Янсона, позволили сформировать на основе соединений TCNQ точечно-контактную мезоскопическую матрицу, чувствительную к малым концентрациям веществ в составе сложной газовой смеси. Анализируемым веществом служил газ, выдыхаемый человеком. Результаты. Газочувствительные точечно-контактные сенсоры на основе соединений TCNQ имеют сложные кривые отклика с двумя экстремумами, которые можно называть спектральными профилями сложной газовой смеси. Используя спектральные профили выдыхаемого газа различных пациентов можно дифференцировать различные состояния организма человека, вызванные бактерией H. pylori. Выводы. Показано, что продукты метаболизма канцерогенных штаммов бактерии H. pylori доминантно влияют на электропроводность сенсора и предопределяют поведение особенностей на кривых отклика сенсоров. В результате, используя точечно-контактные сенсоры на основе соединений TCNQ возможно дифференцировать штаммы H. pylori по их канцерогенному Background: The problem of detecting the different strains of H. pylori has gained great importance today due to the worldwide prevalence of this bacterium and its role in the pathogenesis of a number of serious gastric and extragastric diseases. However, not all H. pylori strains are aggressive and require antibiotic treatment. Thus, the question arises about the necessity of differentiating these bacterium strains with respect to their virulence factors. In accordance with the IV Maastricht Consensus Report, among the variety of ways to diagnose H. pylori infection, non-invasive methods should be given preference. Most of them are based on the analysis of gas which is exhaled by a human. Mass spectrometry, gas chromatography, and IR spectroscopy are currently the mostly used ones. However, despite the obvious advantages, these techniques have a number of disadvantages that make them difficult to use in everyday medical practice. Modern sensor devices can become an inexpensive and easy to access alternative to these technologies. Objectives: The aim of the w...

The 7,7,8,8-tetracyanoquinodimethane (TCNQ) radical anion salt compound was used as the sensitive material of gas point contact sensors. The phase composition and surface morphology of the obtained sensor films were established. It was found correlation between surface morphology of the point-contact transducer and definite type of the sensor response curve observed under action of the human breath gas. If the sensor sample is formed from numerical crystals of the same or similar sizes having a uniform shape, similar to a shell, and clearly defined external borders it indicates to the creation of defect-free Yanson point contacts in the process of soft electrochemical synthesis. As a result, the surface of the sensor is a complex multistructure of a numerous number of Yanson point contacts, which generates a large output signal from the sensor in response to the action of the analyte. When crystals of Cu-TCNQ compound forming samples under investigation have lower density, large size, distorted and full of fractures boundaries, it prevents the formation of high-quality point contacts. These morphologic peculiarities are typical for samples with low level of response signal. In the case of extremely low density of Cu-TCNQ crystals observed in the sample surface the sample does not show any response to the action of the human breath gas.

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Significant progress in development of noninvasive diagnostic tools based on breath analysis can be expected if one employs a real-time detection method based on finding a spectral breath profile which would contain some energy characteristics of the analyzed gas mixture. Using the fundamental energy parameters of a quantum system, it is possible to determine with a high accuracy its quantitative and qualitative composition. Among the most efficient tools to measure energy characteristics of quantum systems are sensors based on Yanson point contacts. This paper reports the results of serotonin and melatonin detection as an example of testing the human hormonal background with point-contact sensors, which have already demonstrated their high efficiency in detecting carcinogenic strains of Helicobacter pylori and selective detection of complex gas mixtures. When comparing the values of serotonin and melatonin with the characteristic parameters of the spectral profile of the exhaled breath of each patient, high correlation dependences of the concentration of serotonin and melatonin with a number of characteristic parameters of the response curve of the point-contact sensor were found. The performed correlation analysis was complemented with the regression analysis. As a result, empiric regression relations were proposed to realize in practice the new non-invasive breath test for evaluation of the human hormonal background. Registration of the patient’s breath profile using point-contact sensors makes it possible to easily monitor the dynamics of changes in the human hormonal background and perform a quantitative evaluation of serotonin and melatonin levels in the human body in real time without invasive interventions (blood collection) and expensive equipment or reagents.

In this paper, we consider new quantum mechanisms for selective detection in complex gaseous media which provide the highest possible efficiency of quantum sensors. On the basis of these quantum mechanisms, the concepts of quantum detection and innovative methods of analysis are developed, which are virtually impossible to implement in the conventional conductive sensors and nanosensors. Examples of original solutions to problems in the field of detection and analysis of human breath using point-contact sensors are considered. A new method of analysis based on detection of metastable quantum states of the "point-contact sensor – breath" system in dynamic mode is proposed. The conductance histogram of dendritic Yanson point contacts recorded for this system is a unique energy signature of breath which allows differentiation between the states of human body. We demonstrate that nanosized Yanson point contacts, which, thanks to their quantum properties, can replace a massive spectrometer, open up wide opportunities for solving complex problems in the field of breath analysis using a new generation of portable high-tech quantum sensor devices.