Nanobiotechnology for health-care

A liquid crystal optical sensor for monitoring acetone vapor in exhalation
Mykytyuk Z.M., Barylo H.I., Kremer I.P., Ivakh M.S.
Electronic devices department, Lviv Polytechnic National University, S. Bandery Str., 12, Lviv-79013, Ukraine.
E-mail: mariia.s.ivakh@lpnu.ua 

Exhaled air contains a large number of products of metabolism of the human body. Types of gases in this air and their concentration are related to human health, which can be used to detect certain diseases. Thus, the presence of acetone in exhalation is a gas marker of diabetes, methane - liver cirrhosis, CO - asthma, etc. [1]. Traditionally, laboratory methods are used to determine the increased content of acetone bodies in human blood and urine [2]. Therefore, the use of a non-invasive method of studying the air contents during exhalation is important for rapid diagnosis of the diseases.  The advantage of the above method, compared to traditional ones, is not only its non-invasiveness, but also painlessness and simplicity of research. Therefore, monitoring of such volatile substances in exhalation as acetone is an urgent problem.
We investigated the interaction of the BLO-62 cholesterol liquid crystal and its mixture with the 5CB nematic as a sensitive medium for an acetone vapor optical sensor. The spectral characteristics of such a medium change from the shift of the minimum in the transmission spectrum to the long-wavelength region. This property is the basis of the developed optical sensor. The hardware of the sensor is implemented according to the typical structure of the optical sensor [3].

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