Huanyu “Larry” Cheng, PhD, Assistant Professor of Engineering Science and Mechanics at Penn State talks about a wearable device for biomedical monitoring.
What is your specific area for wearable devices?
CHENG: For us, we primary work on the wearable devices for biomedical application and actually includes two areas. One is the epidermal surface where we get to pick up the information from outside the skin. And the other is the implantable devices that gets into the human body and then pick up the information. Afterwards, they can safely dissolve without a need for a second surgical operation.
Describe for me what it is that you and your colleagues have developed.
CHENG: This concept actually comes from maybe half a century ago. People start to think about how we can leverage electronics on the skin surface to capture all of the vital signs. But it didn’t get realized into practice until 2000. And a group of scientists start to figure out a way to configure electronic circuits into a stretchable form. Because with the flexible device is really something we can work on the – for example, arm, finger. But if you think about the fingertip, it’s really this really complicated geometry. You can now wrap a piece of paper on top. So this stretchable electronics come into play. And this electronics is really like how we transform the globe in 3-D onto the planet. And that’s how we transform this global map in 3-D onto the 2-D map. And we get to stretch the North and South Pole a little bit. And that’s why if you look at Russia on the 3D it’s much smaller than the 2-D map. So the same idea on the stretchable. It is something we leverage to make sure our device is stretchable and then we can laminate that soft and conformal electronics on the skin surface wherever we want, whether it’s on the chest and arm, on the fingertip. And then we’ll just be able to conform in a uniform manner without breaking the device. And through that, we’ll be able to pick up all the vital information in terms of the heart rate, respiration, sweat analysis. And that’s really something unique. You know, that way that we can analyze a lot of biomarker in this way that correlates well with what we have in the blood. And that will just be noninvasive. So we don’t need to do the blood sampling all the time. And we’ll be able to analyze glucose and the other biomarker that are relevant to the health condition.
Can you run through a list of body mechanics that can be measured with these flexible monitors?
CHENG: Here we actually have a few different classes of problems that we can measure. And the first one is physical. That includes the temperature on the skin surface. And I just want to mention one more thing about that, because this parameter is something really unique, you know, in a way that we can build on top of that to measure something different, for example, blood velocity. And this is something we can measure with temperature sensors as well. Think about the blood vessel. We have three temperature sensors on top of the skin surface. And we drive the heat in the center one and the downstream and upstream sensor will pick up the heat in a different manner because the blood will drive the heat downstream. So by correlating the temperature in between the two, we’ll be able to (unintelligible) the blood velocity. So that’s really something we can do with a basic sensor. But let’s get back. We can monitor the temperature sensor. We can monitor temperature, the hydration, the electrophysiological signal like heartbeat, heart rate, muscle signal, brain signal. That’s what we call the ECG, EMG, EEG.
What kinds of things you can monitor? You were mentioning it’s EKG and some of the other monitors it would take the place of.
CHENG: We talked about the sensor that can monitor the electrophysiological signal. And I include the ECG, EMG, and EEG. They stand for the signal we have in the heart in the muscle and in the brain. And that allows to correlate the information with the muscle tissue, all the cells in the different places. And (unintelligible) we can also measure the UV exposure from the sun and alert people who might have the potential exposure. And that would damage their skin. And we can also do the information of the kind of swelling. Because if we have different information that will be able to be picked up by the skin sensor. And that’s also useful because we can characterize the softness of the skin. Because as we age, the softness will just change. And we’ll be able to see how that will be correlated with aging and how that can be useful as another parameter for the health condition monitoring. So that’s about the physical sensor. And for chemical sensor, we – actually our focus will be more towards the sweat, interstitial fluids, saliva and tears. And they have a direct correlation with the blood inside the human body. But if we just married these bio fluids, we can get rid of the blood sampling, but rather to measure the biophysical or biochemical signal inside. So from that part, we can measure glucose, lactate, sodium, potassium and the other biomarker. And that’s actually related to the biological signal, how we like to mention a bit later.
What are these sensors made of? What are some of the unique challenges you’ve had to work around to get this to work?
CHENG: If we only think about a single sensor, that can be a bit easier. But if we want to marry a lot of different parameters that are really required by the physician to make an informed decision about particular disease diagnostics. And that can be challenging. And so the challenge we face right now is pretty much on how we can integrate this multimodal sensing system with different sensing modalities within the small patch we have. And also there’s another challenge to apply the sensors on the skin surface because the skin is dynamically moving. And if you have something that is stationary, it’s not really a big deal. But if you have the daily activity from walking, jumping around, doing exercise and also go taking a shower or go swimming, you can imagine the environment is rapidly changing all the time. And the skin motion is different. And that may just have a device peel off from the wiring case. So that’s why here, if we want to think about this conformal device on the skin all the time and without breaking the device but still able to capture all of this vital information, that can be challenging as well.
How close are you and your colleagues to something that could be used in a doctor’s office or in a lab to having a consumer use for what you’re developing?
CHENG: Previous efforts, people tend to use this photolithography process where people go into the clean room and use the sophisticated equipment and a lot of different equipment as well. And that’s on one hand very efficient if you make thousands of billions of sensors, that’s what actually is done in (unintelligible). But the question is that’s not really something suitable for the really small scale and startup companies. And that’s why here we switched from that activity into the rapid manufacture of the devices. So here we have been using the laser based and printing based method to create the sensors in a rapid manner. So as opposed to maybe two weeks or even months of effort to create this sensor system on the skin surface, we can do that all within a few minutes. And that’s much easier for us to do this turnaround of different sensors. In the lab if we find something that is not working well, we can easily go back and reproduce the sensors. So that’s much easier. And also, we found out the sensing system will on average have a capability that the in house are sensing performance as well. Because, for example, one thing I’m going to show you momentarily is the laser-induced graphing form. And that’s 3-D geometry with highly pore structure. And that will allow us to have a much easier interaction with the gas molecules around us. Or with the glucose within the biofluids, it can easily pick up the signal at a much higher response rate. So we’ll be able to pick up the signal using the manner as well.
Are you to the point where you’ve formed a company for commercial production?
CHENG: That’s really another thing we want to highlight with is rapid manufacturing process because it’s rapid. And it’s easier for us to get started in the commercial marketplace. And that’s why we have explored a few efforts along this direction. For one, we have been working with a local company. It’s called Actuated Medical in Bellefonte. And there has been really successful with this commercialization of different products. And working with them, we are trying to apply our technology in their commercial marketplace from one side to go through the so-called verification and validation process. We start to learn that process and to see how we can mature our technology in the lab into the commercial place. And on the other side, they are really excited about technology where we can drive down the cost dramatically, where they have to spend this really complicated process in the clean room beforehand. And that’s why we started work with them on this process. We have a joint effort in terms of the SBRI and NIH support for this activity. We have also innovation – a lot of different opportunities are there. Because of the interest from the start up even to the big company, we were approached by a group of researchers, actually, Amazon. And they are trying to commercialize not at this stage, but they are really interested in the technology and would like to see how we can get this into a small scale demonstration. And then they can pick up the technology in their marketplace. Because I didn’t know that, because I know Apple, Samsung and the other places are trying to do these wearable devices. By I recently learned that Amazon is also in the business, I think, since last year, probably around August. And they launched a new product on this wearable device as well. And that’s why that’s probably why they approached us on some an opportunity that they may explore in the future. So for us, we also have a really small startup company trying to commercialize the other technology that are really early in the stage. My students who are working on these different technologies are also interested in this. So that’s why we have the students trying to get this technology from the lab into the small scale demonstration. Because of this activity, we also recruit a lot of students actually one already who is actually in the industry. And he actually learns the potential of this technology and approached me and would like to do a PhD with me. And afterwards he may explore additional opportunities. When we get the company running, he may be the leading force in the company.
Does this have to be FDA approved as a device and are you through that process yet or?
CHENG: We are trying to engage with the different stakeholders, including FDA. So for our current collaboration with Actuated Medical, we are pretty much done the first phase from the early demonstration to the small scale fabrication. We start to engage the FDA probably later this year. And also we learn from the interaction with different people, including the official from FDA. And this device will be much easier to approve in the FDA because of the materials we use are actually applied in the previous medical devices already. And they are on all size skin surface. And it’s much easier to get that through the FDA approval process.
Walk me through how this would work and how quickly you could pick up something that’s going on within the body.
CHENG: For the sensors, they are able to lamin on the skin surface. So they will be able to contact the skin surface and pick up the information in terms of the previously mentioned physical and chemical sensor signals. And that signal will just be able to be picked up by the sensor and then analyze on board with the circuits and then transmit it to the smartphone. And that information can be directly visualized on the smartphone. And that can also be streamed to the Cloud. So the house professionals analyze the data. And in the demonstration, I’m going to show you the sensor, because that’s really the most critical part, because we want to make sure the sensor attaches to the skin without any damage or without any gap. Otherwise, you will pick up the information that is not something we want to measure. Because some people may think about, for example, Apple watch or the other devices, they can also pick up this information. But if they are not direct contact with your skin surface, the temperature they pick up may just be the temperature in the ambient environment rather than information from yourself. And the same thing applies to the other sensing signal we would like to measure. So that’s why I just want to highlight the sensor, because for the other part and from a data analysis and also streaming onto a smartphone, that’s really something widely accomplished in the past in the field as well.
Interview conducted by Ivanhoe Broadcast News.
END OF INTERVIEW
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