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407 results on '"Shleev, Sergey"'

5. Monoolein-Based Wireless Capacitive Sensor for Probing Skin Hydration.

Author

Chaturvedi, Vivek, Falk, Magnus, Björklund, Sebastian, Gonzalez-Martinez, Juan F., and Shleev, Sergey

Subjects
CAPACITIVE sensors, QUARTZ crystal microbalances, MONOOLEIN, DIELECTRIC properties, HYDRATION, HUMIDITY, WATER vapor, DEIONIZATION of water
Abstract

Capacitive humidity sensors typically consist of interdigitated electrodes coated with a dielectric layer sensitive to varying relative humidity levels. Previous studies have investigated different polymeric materials that exhibit changes in conductivity in response to water vapor to design capacitive humidity sensors. However, lipid films like monoolein have not yet been integrated with humidity sensors, nor has the potential use of capacitive sensors for skin hydration measurements been fully explored. This study explores the application of monoolein-coated wireless capacitive sensors for assessing relative humidity and skin hydration, utilizing the sensitive dielectric properties of the monoolein–water system. This sensitivity hinges on the water absorption and release from the surrounding environment. Tested across various humidity levels and temperatures, these novel double functional sensors feature interdigitated electrodes covered with monoolein and show promising potential for wireless detection of skin hydration. The water uptake and rheological behavior of monoolein in response to humidity were evaluated using a quartz crystal microbalance with dissipation monitoring. The findings from these experiments suggest that the capacitance of the system is primarily influenced by the amount of water in the monoolein system, with the lyotropic or physical state of monoolein playing a secondary role. A proof-of-principle demonstration compared the sensor's performance under varying conditions to that of other commercially available skin hydration meters, affirming its effectiveness, reliability, and commercial viability. [ABSTRACT FROM AUTHOR]

Published
2024
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45. Photobioanodes Based on Nanoimprinted Electrodes and Immobilized Chloroplasts.

Author

Aleksejeva, Olga, Nilsson, Nicklas, Genevskiy, Vladislav, Thulin, Kristian, and Shleev, Sergey

Subjects
CHLOROPLASTS, PLANT organelles, BIOELECTROCHEMISTRY, NANOIMPRINT lithography, OPEN-circuit voltage, GOLD electrodes, ELECTROCHEMICAL electrodes
Abstract

As the global energy demand continues to increase, the interest in photosynthetic energy conversion is growing accordingly. Chloroplasts, photosynthetic organelles present in plants and algae, are attractive candidates for construction of bio solar cells; however, they have been less studied because of their complex membrane system, which restricts electrochemical communication with an electrode surface. Nevertheless, in this work photobioanodes based on planar and nanoimprinted gold substrates modified with chloroplasts were designed and evaluated. Apparently, nanoimprint lithography contributed to higher photocurrent densities, not only owing to the enlarged real surface area, but also due to boosting electrochemical communication between the photosynthetic organelles and the electrode. Combining chloroplast‐modified nanoimprinted gold electrodes with a capacitive part made of a planar gold substrate, coated with a conductive polymer, resulted in a dual‐feature photobioanode providing a lower open‐circuit potential, i. e. −0.11 V vs. Ag|AgCl|KClsat, and an enhanced capacitance of ca. 37 F m−2 upon illumination of 400 W m−2. [ABSTRACT FROM AUTHOR]

Published
2022
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50. Direct Electrochemistry of Proteins and Enzymes

Author

Ferapontova, Elena E., primary, Shleev, Sergey, additional, Ruzgas, Tautgirdas, additional, Stoica, Leonard, additional, Christenson, Andreas, additional, Tkac, Jan, additional, Yaropolov, Alexander I., additional, and Gorton, Lo, additional

Published
2005
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