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Liu Y.,Berkeley Sensor and Actuator Center | Lin S.,University of California at Berkeley | Lin L.,University of California at Berkeley
2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2015 | Year: 2015

This work reports the technique to selectively sense different gases using a single graphene field effect transistor (FET) by measuring real time conductance as a function of gate voltage. Compare to the state-of-art, three distinctive advancements have been achieved: (1) first demonstration of selective gas sensing (NO2, NH3, H2O and CH3OH) using a single graphene FET; (2) experimental proof of linear dependence between the reciprocal of carrier mobility limited by long-range scattering and the Dirac Point voltage upon gas molecule exposure; (3) utilizations of such linear characteristic for selective gas sensing. As such, the proposed sensing scheme and results could open up a new class of graphene-based, selective gas sensing devices for practical uses as well as fundamental scientific research. © 2015 IEEE. Source


News Article
Site: http://phys.org/technology-news/

Specifically, it is for a flexible sensor system that can measure metabolites and electrolytes in sweat, calibrate the data based upon skin temperature and sync the results in real time to a smartphone. While health monitors have exploded onto the consumer electronics scene over the past decade, researchers say this device, reported in the Jan. 28 issue of the journal Nature, is the first fully integrated electronic system that can provide continuous, non-invasive monitoring of multiple biochemicals in sweat. The advance opens doors to wearable devices that alert users to health problems such as fatigue, dehydration and dangerously high body temperatures. "Human sweat contains physiologically rich information, thus making it an attractive body fluid for non-invasive wearable sensors," said study principal investigator Ali Javey, a UC Berkeley professor of electrical engineering and computer sciences. "However, sweat is complex and it is necessary to measure multiple targets to extract meaningful information about your state of health. In this regard, we have developed a fully integrated system that simultaneously and selectively measures multiple sweat analytes, and wirelessly transmits the processed data to a smartphone. Our work presents a technology platform for sweat-based health monitors." Javey worked with study co-lead authors Wei Gao and Sam Emaminejad, both of whom are postdoctoral fellows in his lab. Emaminejad also has a joint appointment at the Stanford School of Medicine, and all three have affiliations with the Berkeley Sensor and Actuator Center and the Materials Sciences Division at Lawrence Berkeley National Laboratory. To help design the sweat sensor system, Javey and his team consulted exercise physiologist George Brooks, a UC Berkeley professor of integrative biology. Brooks said he was impressed when Javey and his team first approached him about the sensor. "Having a wearable sweat sensor is really incredible because the metabolites and electrolytes measured by the Javey device are vitally important for the health and well-being of an individual," said Brooks, a co-author on the study. "When studying the effects of exercise on human physiology, we typically take blood samples. With this non-invasive technology, someday it may be possible to know what's going on physiologically without needle sticks or attaching little, disposable cups on you." The prototype developed by Javey and his research team packs five sensors onto a flexible circuit board. The sensors measure the metabolites glucose and lactate, the electrolytes sodium and potassium, and skin temperature. "The integrated system allows us to use the measured skin temperature to calibrate and adjust the readings of other sensors in real time," said Gao. "This is important because the response of glucose and lactate sensors can be greatly influenced by temperature." Adjacent to the sensor array is the wireless printed circuit board with off-the-shelf silicon components. The researchers used more than 10 integrated circuit chips responsible for taking the measurements from the sensors, amplifying the signals, adjusting for temperature changes and wirelessly transmitting the data. The researchers developed an app to sync the data from the sensors to mobile phones, and fitted the device onto "smart" wristbands and headbands. They put the device - and dozens of volunteers - through various indoor and outdoor exercises. Study subjects cycled on stationary bikes or ran outdoors on tracks and trails from a few minutes to more than an hour. "We can easily shrink this device by integrating all the circuit functionalities into a single chip," said Emaminejad. "The number of biochemicals we target can also be ramped up so we can measure a lot of things at once. That makes large-scale clinical studies possible, which will help us better understand athletic performance and physiological responses to exercise." Javey noted that a long-term goal would be to use this device for population-level studies for medical applications. Brooks also noted the potential for the device to be used to measure more than perspiration. "While Professor Javey's wearable, non-invasive technology works well on sweating athletes, there are likely to be many other applications of the technology for measuring vital metabolite and electrolyte levels of healthy persons in daily life," said Brooks. "It can also be adapted to monitor other body fluids for those suffering from illness and injury." Explore further: Paper-thin e-skin responds to touch by lighting up


News Article
Site: http://www.cemag.us/rss-feeds/all/rss.xml/all

When UC Berkeley engineers say they are going to make you sweat, it is all in the name of science. Specifically, it is for a flexible sensor system that can measure metabolites and electrolytes in sweat, calibrate the data based upon skin temperature, and sync the results in real time to a smartphone. While health monitors have exploded onto the consumer electronics scene over the past decade, researchers say this device, reported in the journal Nature, is the first fully integrated electronic system that can provide continuous, non-invasive monitoring of multiple biochemicals in sweat. The advance opens doors to wearable devices that alert users to health problems such as fatigue, dehydration and dangerously high body temperatures. “Human sweat contains physiologically rich information, thus making it an attractive body fluid for non-invasive wearable sensors,” says study principal investigator Ali Javey, a UC Berkeley professor of electrical engineering and computer sciences. “However, sweat is complex and it is necessary to measure multiple targets to extract meaningful information about your state of health. In this regard, we have developed a fully integrated system that simultaneously and selectively measures multiple sweat analytes, and wirelessly transmits the processed data to a smartphone. Our work presents a technology platform for sweat-based health monitors.” Javey worked with study co-lead authors Wei Gao and Sam Emaminejad, both of whom are postdoctoral fellows in his lab. Emaminejad also has a joint appointment at the Stanford School of Medicine, and all three have affiliations with the Berkeley Sensor and Actuator Center and the Materials Sciences Division at Lawrence Berkeley National Laboratory. To help design the sweat sensor system, Javey and his team consulted exercise physiologist George Brooks, a UC Berkeley professor of integrative biology. Brooks said he was impressed when Javey and his team first approached him about the sensor. “Having a wearable sweat sensor is really incredible because the metabolites and electrolytes measured by the Javey device are vitally important for the health and well-being of an individual,” says Brooks, a co-author on the study. “When studying the effects of exercise on human physiology, we typically take blood samples. With this non-invasive technology, someday it may be possible to know what’s going on physiologically without needle sticks or attaching little, disposable cups on you.” The prototype developed by Javey and his research team packs five sensors onto a flexible circuit board. The sensors measure the metabolites glucose and lactate, the electrolytes sodium and potassium, and skin temperature. “The integrated system allows us to use the measured skin temperature to calibrate and adjust the readings of other sensors in real time,” says Gao. “This is important because the response of glucose and lactate sensors can be greatly influenced by temperature.” Adjacent to the sensor array is the wireless printed circuit board with off-the-shelf silicon components. The researchers used more than 10 integrated circuit chips responsible for taking the measurements from the sensors, amplifying the signals, adjusting for temperature changes and wirelessly transmitting the data. The researchers developed an app to sync the data from the sensors to mobile phones, and fitted the device onto “smart” wristbands and headbands. They put the device — and dozens of volunteers — through various indoor and outdoor exercises. Study subjects cycled on stationary bikes or ran outdoors on tracks and trails from a few minutes to more than an hour. “We can easily shrink this device by integrating all the circuit functionalities into a single chip,” says Emaminejad. “The number of biochemicals we target can also be ramped up so we can measure a lot of things at once. That makes large-scale clinical studies possible, which will help us better understand athletic performance and physiological responses to exercise.” Javey notes that a long-term goal would be to use this device for population-level studies for medical applications. Brooks also notes the potential for the device to be used to measure more than perspiration. “While Professor Javey’s wearable, non-invasive technology works well on sweating athletes, there are likely to be many other applications of the technology for measuring vital metabolite and electrolyte levels of healthy persons in daily life,” says Brooks. “It can also be adapted to monitor other body fluids for those suffering from illness and injury.” The Berkeley Sensor and Actuator Center and the National Institutes of Health helped support this work.


So H.,Berkeley Sensor and Actuator Center | Lee K.,University of California at Berkeley | Seo Y.H.,Kangwon National University | Murthy N.,University of California at Berkeley | Pisano A.P.,Berkeley Sensor and Actuator Center
ACS Applied Materials and Interfaces | Year: 2014

This letter reports an efficient and compatible silicon membrane combining the physical properties of nanospikes and microchannel arrays for mechanical cell lysis. This hierarchical silicon nanospikes membrane was created to mechanically disrupt cells for a rapid process with high throughput, and it can be assembled with commercial syringe filter holders. The membrane was fabricated by photoelectrochemical overetching to form ultrasharp nanospikes in situ along the edges of the microchannel arrays. The intracellular protein and nucleic acid concentrations obtained using the proposed membrane within a short period of time were quantitatively higher than those obtained by routine, conventional acoustic and chemical lysis methods. © 2014 American Chemical Society. Source


White R.M.,University of California at Berkeley | White R.M.,Berkeley Sensor and Actuator Center | Paprotny I.,University of California at Berkeley | Paprotny I.,Berkeley Sensor and Actuator Center | And 5 more authors.
EM: Air and Waste Management Association's Magazine for Environmental Managers | Year: 2012

Recent advances in both sensors and wireless communication provide opportunities for improved exposure assessment and increasing community involvement in reducing levels of human exposure to airborne contaminants. These new technologies can enhance data collection to answer science and policy questions related to the health and environmental effects of air pollution. Copyright 2012 Air & Waste Management Association. Source

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