Researchers from North Carolina State University have developed a wearable, wireless sensor that can monitor a person&rsquo;s skin hydration for use in applications that need to detect dehydration before it poses a health problem. The device is lightweight, flexible and stretchable and has already been incorporated into prototype devices that can be worn on the wrist or as a chest patch.&nbsp;<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1578350871924-Zhu-hydration-sensors-SIDEBAR-400.jpg">The hydration sensors consist of two electrodes made of an elastic polymer composite that contains conductive silver nanowires.&ldquo;It&rsquo;s difficult to measure a person&rsquo;s hydration quantitatively, which is relevant for everyone from military personnel to athletes to firefighters, who are at risk of health problems related to heat stress when training or in the field,&rdquo; says John Muth, a professor of electrical and computer engineering at NC&nbsp;State and co-corresponding author of a paper describing the work.&ldquo;We have developed technology that allows us to track an individual&rsquo;s skin hydration in real time,&rdquo; says Yong Zhu, an associate professor of mechanical and aerospace engineering at NC&nbsp;State and co-corresponding author of the paper. &ldquo;Our sensor could be used to protect the health of people working in hot conditions, improve athletic performance and safety, and to track hydration in older adults or in medical patients suffering from various conditions. It can even be used to tell how effective skin moisturizers are for cosmetics.&rdquo;The sensor consists of two electrodes made of an elastic polymer composite that contains conductive silver nanowires. These electrodes monitor the electrical properties of the skin. Because the skin&rsquo;s electric properties change in a predictable way based on an individual&rsquo;s hydration, the readings from the electrodes can tell how hydrated the skin is.In lab testing using custom-made artificial skins with a broad range of hydration levels, the researchers found that the performance of the wearable sensor was not affected by ambient humidity. And the wearable sensors were just as accurate as a large, expensive, commercially available hydration monitor that operates on similar principles, but utilizes rigid wand-like probes.The researchers also incorporated the sensors into two different wearable systems: a wristwatch and an adhesive patch that can be worn on the chest. Both the watch and the patch wirelessly transmit sensor data to a program that can run on a laptop, tablet or smartphone. This means the data can be monitored by the user or by a designated third party &ndash; such as a doctor in a hospital setting, or an officer in a military setting.What&rsquo;s more, the sensor is relatively inexpensive.&ldquo;The commercially available monitor we tested our system against costs more than $8,000,&rdquo; says Shanshan Yao, a Ph.D. student at NC&nbsp;State and lead author of the paper. &ldquo;Our sensor costs about one dollar, and the overall manufacturing cost of the wearable systems we developed would be no more than a common wearable device, such as a Fitbit.&rdquo;The paper, &ldquo;<a href="http://onlinelibrary.wiley.com/doi/10.1002/adhm.201601159/abstract" target="_blank">A Wearable Hydration Monitor with Conformal Nanowire Electrodes</a>,&rdquo; is published in the journal&nbsp;Advanced Healthcare Materials. The paper was co-authored by Amanda Myers and Abhishek Malhotra, Ph.D. students at NC State; Feiyan Lin, a former graduate student at NC State; and Alper Bozkurt, an associate professor of electrical and computer engineering at NC State.

The new sensor, which tracks an individual’s skin hydration in real time, can be incorporated into a wearable patch. Photo credit: Shanshan Yao.

Researchers have developed a wearable, wireless sensor that can monitor a person’s skin hydration for use in applications that need to detect dehydration before it poses a health problem.

Researchers Develop Wearable, Low-Cost Sensor to Measure Skin Hydration

The human heart beats approximately 35 million times every year, pumping blood via four different heart valves. Unfortunately, &nbsp;in more four million people each year, these delicate tissues malfunction due to birth defects, age-related deteriorations, and infections causing cardiac valve disease.Today, clinicians use either artificial prostheses or fixed animal and cadaver-sourced tissues to replace defective valves. While these prostheses can restore the function of the heart for a while, they are associated with adverse comorbidity and wear down and need to be replaced during invasive and expensive surgeries. Moreover, in children, implanted heart valve prostheses need to be replaced even more often as they cannot grow with the child.A team lead by&nbsp;<a href="https://www.seas.harvard.edu/directory/kkparker" target="_blank">Kevin Kit Parker</a>, Tarr Family Professor of Bioengineering and Applied Physics at the<a href="http://www.seas.harvard.edu/" target="_blank">&nbsp;Harvard John A. Paulson School of Engineering and Applied Sciences&nbsp;</a>(SEAS), recently developed a nanofiber fabrication technique to rapidly manufacture heart valves with regenerative and growth potential.Parker is also a Core Faculty member of&nbsp;<a href="http://wyss.harvard.edu/" target="_blank">Wyss Institute for Biologically Inspired Engineering at Harvard University.</a>In a paper published in&nbsp;<a href="http://www.sciencedirect.com/science/article/pii/S0142961217302685" target="_blank">Biomaterials</a>, first author Andrew Capulli and colleagues fabricated a valve-shaped nanofiber network that mimics the mechanical and chemical properties of the native valve extracellular matrix (ECM). The team used the Parker lab&rsquo;s proprietary rotary jet spinning technology &ndash; in which a rotating nozzle extrudes an ECM solution into nanofibers that wrap themselves around heart valve-shaped mandrels.&ldquo;Our setup is like a very fast cotton candy machine that can spin a range of synthetic and natural occurring materials,&rdquo; said Parker. &ldquo;In this study, we used a combination of synthetic polymers and ECM proteins to fabricate biocompatible JetValves that are hemodynamically competent upon implantation and support cell migration and re-population&nbsp;in vitro. Importantly, we can make human-sized JetValves in minutes &ndash; much faster than possible for other regenerative prostheses.&rdquo;To further develop and test the clinical potential of JetValves, Parker&rsquo;s team partnered with the translational team of Simon P. Hoerstrup, at the University of Zurich. As a leader in regenerative heart prostheses, Hoerstrup and his team in Zurich previously developed regenerative, tissue-engineered heart valves to replace mechanical and fixed-tissue heart valves. In Hoerstrup&rsquo;s approach, human cells directly deposit a regenerative layer of complex ECM on biodegradable scaffolds shaped as heart valves and vessels. The living cells are then eliminated from the scaffolds resulting in an &ldquo;off-the-shelf&rdquo; human matrix-based prostheses ready for implantation.In the paper, the cross-disciplinary team successfully implanted JetValves in sheep using a minimally invasive technique and demonstrated that the valves functioned properly in the circulation and regenerated new tissue.&ldquo;In our previous studies, the cell-derived ECM-coated scaffolds could recruit cells from the receiving animal&rsquo;s heart and support cell proliferation, matrix remodeling, tissue regeneration, and even animal growth. While these valves are safe and effective, their manufacturing remains complex and expensive as human cells must be cultured for a long time under heavily regulated conditions. The JetValve&rsquo;s much faster manufacturing process can be a game-changer in this respect. If we can replicate these results in humans, this technology could have invaluable benefits in minimizing the number of pediatric re-operations,&rdquo; said Hoerstrup.

In rotary jet spinning technology, a rotating nozzle extrudes a solution of extracellular matrix (ECM) into nanofibers that wrap themselves around heart valve-shaped mandrels. By using a series of mandrels with different sizes, the manufacturing process becomes fully scalable and is able to provide JetValves for all age groups and heart sizes. (Photo courtesy of Wyss Institute at Harvard University)

Harvard and the University of Zurich partner to create a next-generation heart valve that accurately functions upon implantation and regenerates into long-lasting heart-like tissue

Engineering heart valves for the many

What if running the 26.2 miles of a marathon only felt like running 24.9 miles, or if you could improve your average running pace from 9:14 minutes/mile to 8:49 minutes/mile without weeks of training? Researchers at the<a href="http://seas.harvard.edu/" target="_blank">&nbsp;Harvard John A. Paulson School of Engineering and Applied Sciences&nbsp;</a>(SEAS) and the&nbsp;<a href="http://wyss.harvard.edu/" target="_blank">Wyss Institute for Biologically Inspired Engineering at Harvard University</a> have demonstrated that a tethered soft exosuit can reduce the metabolic cost of running on a treadmill by 5.4 percent compared to not wearing the exosuit, bringing those dreams of high performance closer to reality.&quot;Homo sapiens has evolved to become very good at distance running, but our results show that further improvements to this already extremely efficient system are possible,&rdquo; said author Philippe Malcolm, former postdoctoral research fellow at SEAS and the Wyss Institute, and now Assistant Professor at the University of Nebraska, Omaha, where he continues to collaborate on this work.The study appears today in&nbsp;<a href="http://robotics.sciencemag.org/content/2/6/eaan6708" target="_blank">Science Robotics</a>.Running is a naturally more costly form of movement than walking, so any attempt to reduce its strain on the body must impose a minimal additional burden. The soft exosuit technology developed in the lab of <a href="https://www.seas.harvard.edu/directory/walsh" target="_blank">Conor Walsh</a>, John L. Loeb Associate Professor of Engineering and Applied Sciences at SEAS and Wyss Core Faculty member, represents an ideal platform for assisted running, as its textile-based design is lightweight and moves with the body.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1577273403478-Exosuit-Running.jpg" style="width: 1114px;" class="fr-fic fr-dib">A team of scientists in Walsh&rsquo;s lab led by postdoctoral fellow Giuk Lee performed the study with an exosuit that incorporated flexible wires connecting apparel anchored to the back of the thigh and waist belt to an external actuation unit. As subjects ran on a treadmill wearing the exosuit, the actuation unit pulled on the wires, which acted as a second pair of hip extensor muscles applying force to the legs with each stride. The metabolic cost was measured by analyzing the subjects&rsquo; oxygen consumption and carbon dioxide production while running.The team tested two different &ldquo;assistance profiles,&rdquo; or patterns of wire-pulling. One was based on human biology that applied force starting at the point of maximum hip extension observed in normal running. The other was based on a simulation of exoskeleton-assisted running from<a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0163417#abstract0" target="_blank">&nbsp;a group at Stanford University</a>, which applied force slightly later in the running stride. The Stanford study suggested that the optimal point to provide assistive force might not be the same as the biological norm. Confirming this suspicion, Lee and colleagues found that the simulation-based profile outperformed the biology-based profile in reducing metabolic cost by about a factor of two.As the authors note in the paper, &ldquo;Our finding supports a paradigm shift toward the concept that mimicking our current understanding of biology is not necessarily always optimal.&rdquo;To clarify why applying force later in running stride improved metabolic expenditure so dramatically, the team analyzed what was happening to the subjects&rsquo; other joints when their hip joints were being assisted by the actuating wires. They found that the simulation-based profile also affected knee extension and the forces between the foot and the ground, while the biology-based profile did not.&ldquo;The biological profile only takes into account the amount of torque in the hip joint, but the human body is not a series of independently acting parts - it&rsquo;s full of muscles that act on multiple joints to coordinate movement,&rdquo; said Lee. &ldquo;Applying force to the hip affects the whole body system, and we need to consider that in order to give the best assistance.&rdquo;While the study&rsquo;s results suggest that the increased biomechanical involvement of the simulation-based assistance profile is responsible for the reduction in metabolic cost, further biomechanical analyses are needed to confirm its findings.The team hopes to continue this research to reduce the metabolic cost of running even more.&ldquo;We only tested two actuation profiles in this study, so it will be interesting to see how much more the cost of running can be reduced with further optimization of the system,&rdquo; said Malcolm.&ldquo;Our goal is to develop a portable system with a high power-to-weight ratio so that the benefit of using the suit greatly offsets the cost of wearing it. We believe this technology could augment the performance of recreational athletes and/or help with recovery after injury,&rdquo; said Lee.The days of a battery-powered exosuit for high-performance runners are still beyond the horizon, as the actuator unit (including motors, electronics, and power supply) in this study was off-board, but the authors say technology is moving toward making an untethered assistive exosuit possible in the near future.&ldquo;This study is a great example of how our team can quickly leverage its experience and expertise in wearable technology and biomechanics to demonstrate how human performance can be improved in new application areas,&rdquo; said Walsh.

Researchers have demonstrated a tethered soft exosuit that can reduce the metabolic cost of running on a treadmill by 5.4 percent compared to not wearing the exosuit (Image courtesy of The Wyss Institute)

New robotic exosuit could push the limits of human performance and lead to new wearable technologies for athletes and consumers

Tethered soft exosuit reduces the metabolic cost of running

<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1569983765878-HeartSleeveInVirtoFinal_0.gif" style="width: 633px;" class="fr-fic fr-dib">In vitro demonstration of the pumping of the soft robotic sleeve (Video courtesy of Ellen Roche/Harvard University)&nbsp;Harvard University and Boston Children&rsquo;s Hospital researchers have developed a customizable soft robot that fits around a heart and helps it beat, potentially opening new treatment options for people suffering from heart failure.The soft robotic sleeve twists and compresses in synch with a beating heart, augmenting cardiovascular functions weakened by heart failure. Unlike currently available devices that assist heart function, Harvard&rsquo;s soft robotic sleeve does not directly contact blood. This reduces the risk of clotting and eliminates the need for a patient to take potentially dangerous blood thinner medications. The device may one day be able to bridge a patient to transplant or to aid in cardiac rehabilitation and recovery.&ldquo;This research demonstrates that the growing field of soft robotics can be applied to clinical needs and potentially reduce the burden of heart disease and improve the quality of life for patients,&rdquo; said Ellen T. Roche, the paper&rsquo;s first author and former PhD student at the&nbsp;<a href="http://seas.harvard.edu/" target="_blank">Harvard John A. Paulson School of Engineering and Applied Sciences</a> (SEAS) and&nbsp;<a href="http://wyss.harvard.edu/" target="_blank">The Wyss Institute&nbsp;</a><a href="http://wyss.harvard.edu/" target="_blank">of</a><a href="http://wyss.harvard.edu/" target="_blank">&nbsp;Biologically Inspired Engineering at Harvard University</a>. &nbsp;Roche is currently a postdoctoral fellow at the National University of Ireland Galway.The research, published in&nbsp;<a href="http://stm.sciencemag.org/" target="_blank">Science Translational Medicine</a>, was a collaboration between SEAS, the Wyss Institute and&nbsp;<a href="http://www.childrenshospital.org/" target="_blank">Boston Children&rsquo;s Hospital</a>.&ldquo;This work represents an exciting proof of concept result for this soft robot, demonstrating that it can safely interact with soft tissue and lead to improvements in cardiac function. We envision many other future applications where such devices can delivery&nbsp;<a href="https://wyss.harvard.edu/disruptive-mechanotherapeutics-from-drugs-to-wearables-2/" target="_blank">mechanotherapy</a> both inside and outside of the body,&rdquo; said&nbsp;<a href="https://www.seas.harvard.edu/directory/walsh" target="_blank">Conor Walsh</a>, senior author of the paper and the John L. Loeb Associate Professor of Engineering and Applied Sciences at SEAS and Core Faculty Member at the Wyss Institute.Heart failure affects 41 million people worldwide. Today, some of the options to treat it are mechanical pumps called&nbsp;<a name="OLE_LINK2" id="OLE_LINK2" target="_blank"></a><a id="OLE_LINK1" name="OLE_LINK1" target="_blank">ventricular assist devices&nbsp;</a>(VADs), which pump blood from the ventricles into the aorta, and heart transplant. While VADs are continuously improving, patients are still at high risk for blood clots and stroke.To create an entirely new device that doesn&rsquo;t come into contact with blood, Harvard researchers took inspiration from the heart itself. The thin silicone sleeve uses soft pneumatic actuators placed around the heart to mimic the outer muscle layers of the mammalian heart. &nbsp;The actuators twist and compress the sleeve in a similar motion to the beating heart.The device is tethered to an external pump, which uses air to power the soft actuators.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1569983812883-HeartSleeveFinalGif1.gif" style="width: 766px;" class="fr-fic fr-dib">In vivo demonstration of cardiac assist in a porcine model of acute heart failure (Video courtesy of Ellen Rouche/Harvard SEAS)The sleeve can be customized for each patient, said Roche. If a patient has more weakness on the left side of the heart, for example, the actuators can be tuned to give more assistance on that side. The pressure of the actuators can also increase or decrease over time, as the patient&rsquo;s condition evolves.The sleeve is attached to the heart using a combination of a suction device, sutures and a gel interface to help with friction between the device and the heart.The SEAS and Wyss engineers worked with surgeons at Boston Children&rsquo;s Hospital to develop the device and determine the best ways to implant the device and test it on animal models.&ldquo;The cardiac field had turned away from idea of developing heart compression instead of blood-pumping VADs due to technological limitations, but now with advancements in soft robotics it&rsquo;s time to turn back,&rdquo; said Frank Pigula, a cardiothoracic surgeon and co-corresponding author on the study, who was formerly clinical director of pediatric cardiac surgery at Boston Children&rsquo;s Hospital and is now a faculty member at University of Louisville and division chief of pediatric cardiac surgery at Norton Children&rsquo;s Hospital. &ldquo;Most people with heart failure do still have some function left; one day the robotic sleeve may help their heart work well enough that their quality of life can be restored.&quot;More research needs to be done before the sleeve can be implanted in humans but the research is an important first step towards an implantable soft robot that can augment organ function.Harvard&rsquo;s<a href="http://otd.harvard.edu/" target="_blank">&nbsp;Office of Technology Development&nbsp;</a>has filed a patent application and is actively pursuing commercialization opportunities.&ldquo;This research is really significant at the moment because more and more people are surviving heart attacks and ending up with heart failure,&rdquo; said Roche. &ldquo;Soft robotic devices are ideally suited to interact with soft tissue and give assistance that can help with augmentation of function, and potentially even healing and recovery.&rdquo;

Harvard researchers have developed a customizable soft robot that fits around a heart and helps it beat, potentially opening new treatment options for people suffering from heart failure. The device is tethered to an external pump, which uses air to power the soft actuators

Sleeve attaches directly around the heart

Soft robot helps the heart beat

<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1570181911758-inputtest2.jpeg" style="width: 461px;" class="fr-fic fr-dib">Study participants tapped Morse Code into Google Glass after four hours&nbsp;It&rsquo;s not exactly beating something into someone&rsquo;s head. More like tapping it into the side.Researchers at the Georgia Institute of Technology have developed a system that teaches people Morse code within four hours using a series of vibrations felt near the ear. Participants wearing Google Glass learned it without paying attention to the signals &mdash;they played games while feeling the taps and hearing the corresponding letters. After those few hours, they were 94 percent accurate keying a sentence that included every letter of the alphabet and 98 percent accurate writing codes for every letter.This is the latest chapter of passive haptic learning (PHL) studies at Georgia Tech. The same method &mdash; using vibrations while participants aren&rsquo;t paying attention &mdash;&nbsp;<a href="https://www.news.gatech.edu/2014/06/23/wearable-computing-gloves-can-teach-braille-even-if-you%E2%80%99re-not-paying-attention" target="_blank">has taught people braille</a>,&nbsp;<a href="https://www.news.gatech.edu/2008/11/07/reinventing-way-people-learn-play-piano" target="_blank">how to play the piano</a> and&nbsp;<a href="https://www.news.gatech.edu/hg/item/140221" target="_blank">improved hand sensation for those with partial spinal cord injury.</a>The PHL projects are all led by Georgia Tech Professor Thad Starner and his Ph.D. student Caitlyn Seim. The team decided to use Glass for this study because it has both a built-in speaker and tapper (Glass&rsquo;s bone-conduction transducer).In the study, participants played a game while feeling vibration taps between their temple and ear. The taps represented the dots and dashes of Morse code and passively &ldquo;taught&rdquo; users through their tactile senses &mdash; even while they were distracted by the game.&nbsp;The taps were created when researchers sent a very low-frequency signal to Glass&rsquo;s speaker system. At less than 15 Hz, the signal was below hearing range but, because it was played very slowly, the sound was felt as a vibration.&nbsp;Half of the participants in the study felt the vibration taps and heads a voice prompt for each corresponding letter. The other half &mdash; the control group &mdash; felt no taps to help them learn.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1570181952817-tap2.jpeg" style="width: 630px;" class="fr-fic fr-dib">The findings demonstrate silent, eyes-free text entry on a mobile device without a keyboard (participants touched on Glass&#39;s touchpad to enter Morse code during quizzes). &nbsp;Many mobile or wearable devices cannot accommodate a full keyboard, so it is a challenge to enable text entry on these devices. This research demonstrates a successful system and a rapid, low-effort way to learn it. Participants were tested throughout the study on their knowledge of Morse code and their ability to type it. &nbsp;After less than four hours of feeling every letter, everyone was challenged to type the alphabet in Morse code in a final test.The control group was accurate only half the time. &nbsp;Those who felt the passive cues were nearly perfect.The research was recently presented in Germany at the 20th International Symposium on Wearable Computers.&ldquo;Does this new study mean that people will rush out to learn Morse code? Probably not,&rdquo; said Starner. &ldquo;It shows that PHL lowers the barrier to learn text-entry methods &mdash; something we need for smartwatches and any text-entry that doesn&rsquo;t require you to look at your device or keyboard.&rdquo;Previous research on PHL used custom hardware to provide the tactile stimuli, but here researchers use an existing wearable device.&nbsp;&ldquo;This research also shows that other common devices with an actuator could be used for passive haptic learning,&rdquo; he says. &ldquo;Your smartwatch, Bluetooth headset, fitness tracker or phone.&rdquo;&ldquo;In our Braille and piano PHL studies, people felt vibrations on their fingers, then used their fingers for the task,&rdquo; said Seim. &ldquo;This study was different and surprising. People were tapped on their heads, but the skill they learned was using their finger.&rdquo;Seim&rsquo;s next study will go a step further, investigating whether PHL can teach people how to type on the trusted QWERTY keyboard. That would mean several letters assigned to the same finger, rather than using only one finger like Morse code.

human augmentation

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Latest Posts

Researchers Develop Wearable, Low-Cost Sensor to Measure Skin Hydration

Engineering heart valves for the many

Tethered soft exosuit reduces the metabolic cost of running

Soft robot helps the heart beat

Learning Morse Code without Trying