Thin films formation of electrically conductive carbon nanostructures with laser modification for hypersensitive biocompatible strain sensors to register obstructive sleep apnea syndrome
Anastasia S. Morozova1, Alexander Yu. Gerasimenko1,2; 1National Research University of Electronic Technology, Moscow, Zelenograd, Russia, 2I.M. Sechenov First Moscow State Medical University, Moscow, Russia
Abstract
Flexible strain sensors based on thin films of multi-walled carbon nanotubes designed to detect respiratory disorders in obstructive sleep apnea syndrome have been developed. The films were obtained by spray deposition from dispersions, the optical properties of which were previously investigated. Strain-sensitive topologies on thin films were obtained using laser lithography at a wavelength of 1064 nm and an average radiation power of 0.887 W, which made it possible to increase the sensitivity of the sensor by 5 times. A study of the volt-ampere characteristics of sensors with topology showed high stability and linearity, with a hysteresis of less than 3%. The effect of laser radiation power on morphology and electrical characteristics during irradiation of the entire surface of films in vacuum was studied. After laser exposure with a wavelength of 1064 nm and a beam diameter of 35 microns, average power of 0.035 W, a 2-fold increase in electrical conductivity was detected. Scanning electron microscopy has shown that carbon nanotubes are structured and oriented under the influence of laser radiation. Moreover, during irradiation, the total concentration of nanotubes on the films decreased, and the electrical conductivity increased, indicating the formation of covalent bonds and a conductive percolation network of nanotubes. The cytotoxicity of the sensors was also studied using fluorescent staining, which showed a high degree of cell proliferation on the sensor surface during 48 hours of observation. To register respiratory disorders, cyclic tests of sensors based on films with and without topology were carried out, integrated into the design of an adjustable soft belt that was attached to a person in the area of the lower chest opening and a developed electronic signal conversion module from sensors and an imaging program.
Speaker
Anastasia S. Morozova
National Research University of Electronic Technology, Moscow, Zelenograd, Russia
Russia
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