研究紹介
Research Topics

研究紹介

研究テーマ
・非侵襲（ヒトにやさしい）生体計測技術の開発
・ヘルスケアIoTを指向したセンシングデバイス技術の開発
・マイクロ流体デバイスとモバイル計測システムの研究

産学・地域連携シーズ集 2022年度版

Wearable Biosensor Utilizing Chitosan Biopolymer for Uric Acid Monitoring

Paper: Journal of Robotics and Mechatronics
https://doi.org/10.20965/jrm.2023.p1131
A wearable biosensor was specifically engineered to measure uric acid, a biomarker present at wound sites. This biosensor, fabricated as a disposable and wearable device, was seamlessly integrated onto a polyethylene terephthalate (PET) substrate by utilizing carbon and silver conductive paste as the electrodes. The enzyme uricase was immobilized onto the working electrode by utilizing chitosan, a biocompatible material, to create this biosensor. Notably, the uric acid biosensor fabricated with chitosan showcased exceptional performance metrics, including remarkable output current values and impeccable stability. These findings suggest the prospective utilization of chitosan-based uric acid biosensors for the accurate measurement of uric acid on human skin in future applications.

Headset bio-sniffer with wireless CMOS camera for percutaneous ethanol vapor from the ear canal

Paper: Biosensors and Bioelectronics: X
https://doi.org/10.1016/j.biosx.2022.100169
Volatile organic compounds contained in human volatiles are related to metabolism and disease. Measurement of these components is expected to enable non-invasive and simple metabolic evaluations and disease diagnoses. In particular, skin gas can be collected continuously without constraints, a useful property for the next generation of wearable measurement devices. In this study, we develop a wearable biochemical gas sensor (biosniffer) for ethanol by constructing a headset-type unrestrained ear canal gas measurement system integrated with a complementary metal-oxide semiconductor (CMOS) camera. This system measures ethanol gas released by the skin by detecting the increase in fluorescence of NADH, which is produced during the oxidation of ethanol by alcohol dehydrogenase (ADH). In this system, excitation light from a UV-LED irradiates an ADH enzyme-immobilized membrane through a band-pass filter, and the fluorescence of NADH is detected by a small CMOS camera with Wi-Fi functionality. This system is integrated into an earmuff, forming a wearable headset. Fluorescence images shows an increased output correlated with the ethanol gas concentration. When integral analysis is used to assess the increase in fluorescence, it is possible to measure ethanol gas at 11 ppb–444 ppm, a range that includes the ethanol concentration in the skin after alcohol administration. Furthermore, when this device is attached to a human participant who is consuming alcohol, the increase and decrease output based on drinking and metabolism is confirmed, indicating the possibility of directly measuring ethanol gas from the ear canal with minimal effect of perspiration.

Biosensors and Chemical Sensors for Healthcare Monitoring: A Review

Review: IEEJ Transactions on Electrical and Electronic Engineering
https://doi.org/10.1002/tee.23580
Biosensors and chemical sensors for healthcare applications are garnering interest due to their potential to provide continuous and real-time physiological information, chemical information, and noninvasive measurements of biochemical markers in human biofluids, such as tears, saliva, sweat, interstitial fluid, and human volatiles. Recent developments have focused on electrochemical biosensors and monitoring of metabolites, proteins, chemicals, and bacteria. The measurement of biophysical quantities of the human body has been studied in healthcare and medicine. Many flexible, wearable, and detachable sensors have been developed and commercialized to monitor relevant parameters in sports, healthcare, and medicine. Here, we introduce many challenges regarding the integration of sensors and biosensors into the monitoring of biological and chemical information for the internet of things (IoT) in healthcare. IoT sensors are set to improve quality of life (QoL) and living standards.

Biosensors: Gas Sensors

Book:  Encyclopedia of Sensors and Biosensors
https://doi.org/10.1016/B978-0-12-822548-6.00066-2
In this review, we introduce various gas biosensors, including enzyme-based, cell-based, and biochemical detection methods. Exhaled breath and skin gas in humans contain volatile organic compounds (VOCs) that emanate from components of the blood. These compounds can be products of metabolism or disease; therefore, the measurement of human skin and breath volatiles could be a useful and convenient method for non-invasive disease screening in the future.

Bio-sniffer and sniff-cam

Book:  Chemical, Gas, and Biosensors for Internet of Things and Related Applications
https://doi.org/10.1016/C2017-0-03327-X
We introduce biochemical gas sensor “bio-sniffer” using biochemical reactions and characteristics of various enzymes for determination of acetone and isopropanol in the gas phase. The bio-sniffer devices were successfully applied to measure concentrations of acetone and isopropanol in exhaled air from healthy subjects and diabetes patients as volatile biomarkers of diabetes mellitus and evaluation of a lipid metabolism. In addition, two types (chemiluminescence and biofluorescence) of gas imaging system “sniffer-camera” also developed bio-optical reactions, respectively. These imaging systems measure ethanol concentrations as intensities of optical images by enzyme reaction. In future work, the bio-sniffer and imaging system in the gas phase would be applied for analysis of VOCs information from humans, transdermal analysis, evalua- tion of metabolic conditions, and noninvasive screening of some diseases.

Cavitas Sensors (Soft Contact Lens Type Biosensor, Mouth-Guard Type Sensor, etc.) for Daily Medicine

Book:  Sensors for Everyday Life Healthcare Settings
https://doi.org/10.1007/978-3-319-47319-2
We introduce “Cavitas sensors” attached to body cavities such as the contact lens and mouthguard. “No implantable” and “no wearable” sensors have many advantages for non-invasive daily medicine. Cavitas is the etymological origin of the word “cavity” in Latin. Hence collectively, cavitas sensors provide biological information from within a body cavity. Many types of contact lens (CL) sensors using electrical and optical methods have been developed for monitoring chemicals of glucose, lactate, electrical conductivity in tear fluid, and transcutaneous gases at eyelid mucosa. In addition, some mouthguard sensors have been investigated for a real-time measurement of chemicals in saliva. Here, we review the challenges regarding the integration of biosensors into monitoring for biological information and daily medicine of body cavities. The self-detachable cavitas sensors allow us to improve the quality of life and living standards in the near future.