(Press-News.org) It cannot be denied that, over the past few decades, the miniaturization of electronic devices has taken huge strides. Today, after pocket-size smartphones that could put old desktop computers to shame and a plethora of options for wireless connectivity, there is a particular type of device whose development has been steadily advancing: wearable biosensors. These tiny devices are generally meant to be worn directly on the skin in order to measure specific biosignals and, by sending measurements wirelessly to smartphones or computers, keep track of the user's health.
Although materials scientists have developed many types of flexible circuits and electrodes for wearable devices, it has been challenging to find an appropriate power source for wearable biosensors. Traditional button batteries, like those used in wrist watches and pocket calculators, are too thick and bulky, whereas thinner batteries would pose capacity and even safety issues. But what if we were the power sources of wearable devices ourselves?
A team of scientists led by Associate Professor Isao Shitanda from Tokyo University of Science, Japan, are exploring efficient ways of using sweat as the sole source of power for wearable electronics. In their most recent study, published in the Journal of Power Sources, they present a novel design for a biofuel cell array that uses a chemical in sweat, lactate, to generate enough power to drive a biosensor and wireless communication devices for a short time. The study was carried out in collaboration with Dr. Seiya Tsujimura from University of Tsukuba, Dr. Tsutomu Mikawa from RIKEN, and Dr. Hiroyuki Matsui from Yamagata University, all in Japan.
Their new biofuel cell array looks like a paper bandage that can be worn, for example, on the arm or forearm. It essentially consists of a water-repellent paper substrate onto which multiple biofuel cells are laid out in series and in parallel; the number of cells depends on the output voltage and power required. In each cell, electrochemical reactions between lactate and an enzyme present in the electrodes produce an electric current, which flows to a general current collector made from a conducting carbon paste.
This is not the first lactate-based biofuel cell, but some key differences make this novel design stand out from existing lactate-based biofuel cells. One is the fact that the entire device can be fabricated via screen printing, a technique generally suitable for cost-effective mass production. This was possible via the careful selection of materials and an ingenious layout. For example, whereas similar previous cells used silver wires as conducting paths, the present biofuel cells employ porous carbon ink. Another advantage is the way in which lactate is delivered to the cells. Paper layers are used to collect sweat and transport it to all cells simultaneously through the capillary effect--the same effect by which water quickly travels through a napkin when it comes into contact with a water puddle.
These advantages make the biofuel cell arrays exhibit an unprecedented ability to deliver power to electronic circuits, as Dr. Shitanda remarks: "In our experiments, our paper-based biofuel cells could generate a voltage of 3.66 V and an output power of 4.3 mW. To the best of our knowledge, this power is significantly higher than that of previously reported lactate biofuel cells." To demonstrate their applicability for wearable biosensors and general electronic devices, the team fabricated a self-driven lactate biosensor that could not only power itself using lactate and measure the lactate concentration in sweat, but also communicate the measured values in real-time to a smartphone via a low-power Bluetooth device.
As explained in a previous study also led by Dr. Shitanda, lactate is an important biomarker that reflects the intensity of physical exercise in real-time, which is relevant in the training of athletes and rehabilitation patients. However, the proposed biofuel cell arrays can power not only wearable lactate biosensors, but also other types of wearable electronics. "We managed to drive a commercially available activity meter for 1.5 hours using one drop of artificial sweat and our biofuel cells," explains Dr. Shitanda, "and we expect they should be capable of powering all sorts of devices, such as smart watches and other commonplace portable gadgets."
Hopefully, with further developments in wearable biofuel cells, powering portable electronics and biosensors will be no sweat!
INFORMATION:
About the Tokyo University of Science
Tokyo University of Science (TUS) is a well-known and respected university, and the largest science-specialized private research university in Japan, with four campuses in central Tokyo and its suburbs and in Hokkaido. Established in 1881, the university has continually contributed to Japan's development in science through inculcating the love for science in researchers, technicians, and educators.
With a mission of "Creating science and technology for the harmonious development of nature, human beings, and society", TUS has undertaken a wide range of research from basic to applied science. TUS has embraced a multidisciplinary approach to research and undertaken intensive study in some of today's most vital fields. TUS is a meritocracy where the best in science is recognized and nurtured. It is the only private university in Japan that has produced a Nobel Prize winner and the only private university in Asia to produce Nobel Prize winners within the natural sciences field.
Website: https://www.tus.ac.jp/en/mediarelations/
About Associate Professor Isao Shitanda from Tokyo University of Science
Dr. Isao Shitanda graduated from Tokyo University of Science in 2001 and then got a PhD from The University of Tokyo, Japan, in 2006. Since 2012, he has been an Associate Professor at the Department of Pure and Applied Chemistry at Tokyo University of Science, where he leads the Itagaki/Shitanda lab. He specializes in electrochemical micro/nanosystems, physical and analytical chemistry, bio-related chemistry, and environmental chemistry, among other fields. He has published over 180 papers and holds seven patents.
Funding information
This study was partially supported by JST-ASTEP Grant Number JPMJTS1513, JSPS Grant Number 17H02162, the Private University Research Branding Project (2017-2019) from the Ministry of Education, Culture, Sports, Science and Technology, and the Tokyo University of Science Grant for President's Research Promotion.
Researchers from North Carolina State University have found a way to fine-tune the molecular assembly line that creates antibiotics via engineered biosynthesis. The work could allow scientists to improve existing antibiotics as well as design new drug candidates quickly and efficiently.
Bacteria - such as E. coli - harness biosynthesis to create molecules that are difficult to make artificially.
"We already use bacteria to make a number of drugs for us," says Edward Kalkreuter, former graduate student at NC State and lead author of a paper describing the ...
University of Maryland School of Medicine (UMSOM) researchers have shown that psilocybin--the active chemical in "magic mushrooms"-- still works its antidepressant-like actions, at least in mice, even when the psychedelic experience is blocked. The new findings suggest that psychedelic drugs work in multiple ways in the brain and it may be possible to deliver the fast-acting antidepressant therapeutic benefit without requiring daylong guided therapy sessions. A version of the drug without, or with less of, the psychedelic effects could loosen restrictions on who could receive the therapy, and lower costs, making the benefits of psilocybin more available to more people in need.
In all clinical ...
The "three-body problem," the term coined for predicting the motion of three gravitating bodies in space, is essential for understanding a variety of astrophysical processes as well as a large class of mechanical problems, and has occupied some of the world's best physicists, astronomers and mathematicians for over three centuries. Their attempts have led to the discovery of several important fields of science; yet its solution remained a mystery.
At the end of the 17th century, Sir Isaac Newton succeeded in explaining the motion of the planets around the sun through ...
PLYMOUTH MEETING, PA [April 13, 2021] -- The April 2021 issue of JNCCN--Journal of the National Comprehensive Cancer Network publishes new research from Memorial Sloan Kettering Cancer Center (MSK) and Gustave Roussy Institute, which suggests that baseline brain imaging should be considered in most patients with metastatic kidney cancer. The researchers studied 1,689 patients with metastatic renal cell carcinoma (mRCC) who had been considered for clinical trial participation at either of the two institutions between 2001 and 2019 and had undergone brain imaging in this context, without clinical suspicion for brain involvement. The researchers discovered 4% had asymptomatic brain metastases in this setting. This group was found to have a low median 1-year ...
ITHACA, N.Y. - We've all seen them: political ads on television that promise doom gloom if Candidate X is elected, and how all your problems will be solved if you choose Candidate Y. And Candidate Y, of course, approves this message.
Beyond attempting to move a large swath of the population to vote one way or another, the seemingly constant bombardment of negativity in the name of our democratic process is anxiety-inducing, researchers have found.
"Many of my friends and family members wind up quite stressed out, for lack of a better word, during each election season," said Jeff Niederdeppe, professor in the Department of Communication in the College of ...
With 'Eyecam' they now present the prototype of a webcam that not only looks like a human eye, but imitates its movements realistically. "The goal of our project is not to develop a 'better' design for cameras, but to spark a discussion. We want to draw attention to the fact that we are surrounded by sensing devices every day. That raises the question of how that affects us," says Marc Teyssier. In 2020, the French scientist completed his doctorate on the topic of anthropomorphic design in Paris. Now he is a postdoctoral researcher in the Human-Computer Interaction Lab at Saarland University in Germany.
The research team at Saarland Informatics Campus has developed ...
Human non-alcoholic fatty liver disease (NAFLD) is a little-understood condition that significantly increases the risk of inflammation, fibrosis and liver cancer and ultimately requires liver transplant.
"NAFLD has been difficult to study mainly because we had no good animal model," said corresponding author Dr. Karl-Dimiter Bissig, who was at Baylor during the development of this project and is now at Duke University.
The disease has both genetic and nutritional components, which have been hard to understand in human studies, and murine models ...
A new study verifies the age and origin of one of the oldest specimens of Homo erectus--a very successful early human who roamed the world for nearly 2 million years. In doing so, the researchers also found two new specimens at the site--likely the earliest pieces of the Homo erectus skeleton yet discovered. Details are published today in the journal Nature Communications.
"Homo erectus is the first hominin that we know about that has a body plan more like our own and seemed to be on its way to being more human-like," said Ashley Hammond, an assistant curator in the American Museum of Natural History's Division of Anthropology and the lead author of the new study. "It had longer lower limbs than upper limbs, a torso ...
ITHACA, N.Y. - The muon is a tiny particle, but it has the giant potential to upend our understanding of the subatomic world and reveal an undiscovered type of fundamental physics.
That possibility is looking more and more likely, according to the initial results of an international collaboration - hosted by the U.S. Department of Energy's Fermi National Accelerator Laboratory - that involved key contributions by a Cornell team led by Lawrence Gibbons, professor of physics in the College of Arts and Sciences.
The collaboration, which brought together 200 scientists from 35 institutions in seven countries, set out to confirm the findings of a 1998 experiment that startled physicists by indicating that muons' magnetic ...
In the Cascadia subduction zone, medium and large-sized "intraslab" earthquakes, which take place at greater than crustal depths within the subducting plate, will likely produce only a few detectable aftershocks, according to a new study.
The findings could have implications for forecasting aftershock seismic hazard in the Pacific Northwest, say Joan Gomberg of the U.S. Geological Survey and Paul Bodin of the University of Washington in Seattle, in their paper published in the Bulletin of the Seismological Society of America.
Researchers now calculate aftershock forecasts in the region based in part on data from subduction zones around the world. ...
