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Season 2, Episode 4: Lenses and Limbs

Greg Herman

In this week’s episode, we bring you two stories from the bionic frontier. In part one, Greg Herman, professor of chemical engineering, talks about his work to develop a glucose-sensing contact lens to help patients with type 1 diabetes keep an eye on their blood sugar.

In Part 2, we explore the research of John Mathews, professor and head of the School of Electrical Engineering and Computer science, whose goal is to enable people with serious spinal cord injuries to regain the use of paralyzed limbs.

Bonus Material


Today on Engineering Out Loud, we present “Lenses and Limbs,” two stories from the bionic frontier. I’m Keith Hautala.

[MUSIC: The Ether Bunny, Eyes Closed Audio, used with permissions of a  Creative Commons Attribution License ]

[AUDIO CLIP: from intro to The Six Million Dollar Man]: Gentlemen, we can rebuild him. We have the technology. We have the capability to make the world's first bionic man.

HAUTALA: That's from the intro to the popular 1970s TV show The Six Million Dollar Man. The show was about Steve Austin, a former astronaut who, after a terrible accident, is given superhuman capabilities through the use of bionic implants. It’s now being turned into a movie and, accounting for inflation, it's now the "Six Billion Dollar Man," with a B. The enduring appeal of that story is really the idea of using advanced technology to transcend the limits of human biology, restoring lost function, and enhancing human performance. The really cool part is that a lot of the stuff that was science fiction 40 years ago are the kinds of things engineers are working to develop now in real life. In this way, engineering research is helping to create a better future, one that is more inclusive for people with disabilities or life-limiting illnesses. Later in the program we'll hear from Steve Frandzel, with a story about how engineering research could offer new hope for victims of paralysis by allowing them to regain the use of paralyzed limbs. First we’re going to talk about how a new glucose-detecting technology from Oregon State could help people with type 1 diabetes keep an eye on their blood sugar. And I mean literally keep an eye on it, by embedding sensors into a contact lens.

GREG HERMAN: Essentially fabricate the sensors on very flexible, transparent substrates, and then we integrate this as a separate layer onto the contact lens, so a standard contact lens.

HAUTALA: We’ll talk with Greg Herman, professor of chemical engineering, in just a minute. First, a little background. Type 1 diabetes is a disease in which the pancreas stops producing insulin. That's a hormone that helps the body use food energy. And the body loses its ability to regulate blood sugar levels. This causes all kinds of serious health complications. It used to be called “juvenile diabetes,” because it’s often diagnosed in children. But it can show up at any age, even well into adulthood. I know a bit about this, because my friend Lisa Brockmeier was diagnosed a couple of years ago, at age 49. Here’s how she found out.

LISA BROCKMEIER: I just kept getting sicker and sicker and sicker, until one day I started throwing up all day, and then I went into respiratory distress, and that was about when I thought, "Well, I should probably call an ambulance." And, on the way to the hospital, the EMT took my blood sugar, and he said, "Are you diabetic?" And I said, "No," and he said, "Well, you are now.”

HAUTALA: Living with diabetes means Lisa has to be careful about what she eats. She also has to wear a continuous glucose monitor. It's a little electronic box that connects to her body underneath her clothes and transmits data to a handheld receiver. Before she got that, she had to test manually, carrying a supply of test strips and lancets with her everywhere and pricking her finger for drops of blood every couple of hours.

BROCKMEIER: And I would have to do that six to eight times a day. So I have to do it before every meal, and then I was supposed to do it one to two hours after the meal — sometimes I'd forget — and then I was definitely supposed to do it before bed …

[MUSIC: Pooka, Kevin MacLeod, used with permission from the YouTube Audio Library]

HAUTALA: Having to carry around all of those testing supplies, and then just stop whatever you’re doing to do a blood test. It sounds … inconvenient.

BROCKMEIER: Yes, it is. It definitely has some lifestyle implications.

HAUTALA: Here’s where the engineering comes in. This is Greg Herman, professor of chemical engineering at Oregon State. He looks at the basic building blocks of matter – atoms and molecules – specifically the way they interact where one surface meets another, and tries to find ways to modify and exploit their chemical properties to do useful things. 

HERMAN: So, we do a broad range of research that goes from looking at the interaction of atoms in surfaces related to catalysis, so automobile exhaust catalysis for example, try to make more efficient catalytic converters, but we also do a wide range of things like nanoparticle synthesis, quantum dots, synthesizing materials to make more efficient solid-state lighting, work on making flexible displays, and also what we're going to talk about today, which is our research related to using these technologies and research expertise to look at glucose sensing for type 1 diabetes patients.

HAUTALA: Greg wants to put these biosensors on contact lenses to monitor blood sugar through the tear fluid that is continuously being produced on the surface of the eye.

HERMAN: And, ideally, what you can do with these lenses, is since you'll be wearing them all the time, you're going to have continuous glucose monitoring, then it'll give much more accurate, up-to-date information on when your glucose levels are getting too high, or getting too low, and when you need to have insulin injected to control the glucose levels.So, you could have a smartphone app that's gonna tell you to do the self-injection; the other work we've been involved with is called the artificial, or bionic pancreas. And the idea with that work is that you actually integrate a pump with a catheter that delivers your insulin, and that your glucose sensors from your contact lenses are then gonna tell the pump, "OK, the patient needs insulin now." So, really, then it becomes totally hands-free, no involvement from the patient at all, other than making sure they're wearing the pump and change their contacts occasionally.

HAUTALA: On the molecular scale, there are a few different strategies for how to create a sensor to get this job done.

HERMAN: Our first studies, we've been working with a small company up in Portland, Pacific Diabetes Technologies, and with that, we're using essentially what you'd call an electrochemical approach, which is sort of like using a battery to sense glucose, and to do that, we're using enzymes. So, the enzyme we're using is glucose oxidase, and this enzyme only will react with glucose, and when it reacts with glucose, it creates another molecule, hydrogen peroxide, which we can then detect electrochemically.

HAUTALA: That’s the electrochemical approach, and like Greg said, it works sort of like a battery, where the chemical reaction creates an electrical current that can then be measured. But there’s another approach, called field-effect sensing, which is more like a transistor. It uses a semiconducting material, and when molecules bond to its surface, its conductance changes, and it’s actually that change in conductance that you measure to determine the presence of that molecule. As it turns out, the field-effect approach has some distinct advantages over the electrochemical approach.

HERMAN: So, the benefit of the new approach, the field effect approach, compared to the electrochemical approach, is twofold. One is we can make the field-effect fully transparent, which gives us some flexibility in how we can use it, but also we can actually get much higher sensitivity than we could with the electrochemical approach.

HAUTALA: There are actually a number of groups working on this idea of a glucose-sensing contact lens. And it’s a pretty safe bet that we will see this technology become available to consumers, probably sooner rather than later. So now, it’s sort of a race to see who can develop the best, most commercially feasible technology and get it to market.

[MUSIC: Pooka, Kevin MacLeod, used with permission from the YouTube Audio Library]

HAUTALA: A couple of years ago, you might have seen headlines when some of the really smart folks over at Google — yes, Google has skin in this game — secured a patent for a glucose-sensing contact lens. But Greg thinks he might have them beat in at least a couple of ways.

HERMAN: So, if you look at the announcements that were done with the Google contact lenses, for example, those were set up primarily for sensing glucose concentrations for type 1 diabetes patients. And they are using the electrochemical approach that I talked about before. And the electrochemical approach, as I mentioned, if you try to get smaller and smaller, the sensitivity becomes reduced; and then the other thing with the glucose sensor is it's non-transparent, so it's this black spot that you have on your contact lens, and if you look at pictures of the contact lens, there's actually a lot of different features that you can see on the contact lens, which, cosmetically, could be an issue for some people. You've gotta limit the real estate that you use for the contact lens, because then it can't be used right right above your pupil. So, I think our contact lens, using the fully transparent sensor, that it gives us flexibility in terms of location. I do believe that we would leverage a lot of the development that Google has in terms of communication and power storage on the contact lens, but also we're looking at ways of making those transparent as well.

HAUTALA: So, once you’ve got a smart contact lens that’s loaded up with biosensors and connected with your smartphone you can do way more with it than just check blood sugar.

HERMAN: Well, I think that's the most exciting part about this research. I think the glucose sensing is the initial start, but there's a tremendous amount of health diagnostics that are currently being studied in terms of what can be measured in tears.  There's precursors that are related to cancer. There's precursors that are related to, well, essentially drug metabolite. So, there's a wide range of research. And the thing that I'm really excited about with this technology, not only transparent, but the electrochemical technology, as you scale it — so, if you want more and more sensors on your contact, the signal becomes smaller and smaller for the electrochemical, since it scales with area. With this glucose, the field effect glucose sensors, we get smaller and smaller, so more and more sensors, we actually get more and more signal, so there's the benefit: transparency, shrinking sizes increase the signal. So we can actually try to monitor things that are extremely low concentrations with this. So, there’s a broad range of technology we can pursue.

HAUTALA: We started off talking about The Six Billion Dollar Man. And while the research to create any kind of technology like this is going to require a substantial investment of resources up front, in the end, on a per-unit cost basis? It’s looking like this thing could be surprisingly affordable to produce.

HERMAN: The goal is that everything integrated together shouldn't add more than, say, a dollar a lens, and you know, with scaling, it should come down from that. But, say the sensor itself is a proven technology in the display industry. Essentially, it's a thin-film transistor than we then functionalize with chemistry. Thin-film transistors are used for displays, and if you have a hundred thin-film transistors on a display, those are only gonna cost about a penny, in terms of manufacturing, and other costs.

[MUSIC: Albany New York, The 126ers, used with permission from the YouTube Audio Library]

HAUTALA: I told Lisa, you remember my friend from the top of the show? I told her about the work Greg’s doing with the contact lens. Here’s what she had to say. [00:12:31]

BROCKMEIER: That sounds like really interesting technology to me. And it does have the potential to make a lot of things easier for a lot of people.

HAUTALA: We want to thank Greg Herman for taking the time to talk with us today. You can look for links on our website to read more about his work at Engineering Out Loud dot Oregon State dot E-D-U. I’m going to hand things over now to Steve Frandzel, with a story about how engineers can help restore movement to paralyzed limbs with the use of electrode implants. 

[MUSIC: Opus One, Audiotronix, used with a Creative Commons attribution license] 

STEVE FRANDZEL: An instant after you decided to grab your phone and listen to Engineering Out Loud, your body orchestrated a remarkable sequence of events to make that happen. The motor cortex in your brain fired off electrical impulses, which raced down neurons in your spinal cord. They branched out to peripheral nerve cells in your arms and hands, which released a chemical that activated the muscles needed to grasp and lift. It all happened in the about an eye blink of time. That’s how it goes for most of us, whether it’s walking to the mailbox, eating a pizza, or petting a dog. We don’t give it a second thought. But that all changes when a spinal cord injury paralyzes legs, arms, or both. 

[MUSIC: Infa (инфа) Kosta T. used with permission of an attribution Creative Commons license] 

JOHN MATHEWS: What the spinal cord injury does is it severs the connection between the brain and the nerves in the limbs. The transmission of that information cannot take place anymore, therefore, even though the brain is working and the nerves are working, you cannot communicate between the nerves and the brain. So the legs, the arms do not know that it needs to move or what to do. 

FRANDZEL: I talked with John Mathews, professor and head of the School of Electrical Engineering and Computer science. Along with colleagues at Oregon State and the University of Utah, he’s investigating technology that bypasses the spinal cord injury and re-establishes the link between the brain and paralyzed limbs. If it all works as planned, paralyzed individuals may be able to take a walk again, pick up a knife and fork, and do many of the things we take for granted. 

MATHEWS: So one of the questions we ask is can we compensate for this lost connection, and provide paralyzed people with the sensation of movement again. 

FRANDZEL: This is an incredibly ambitious goal, but one that is closer to becoming a reality than most people had dreamed possible. 

[MUSIC: Stopping by The Inn, Twin Musicon, used with permission of a Creative Commons attribution license] 

Let’s break down all the pieces that must fall into place to pull it off. First, there has to be a way to determine accurately what a paralyzed person wants an immobile limb to do. What’s their intent? Bend a knee? Wiggle toes? Make a fist? That starts with the person thinking about a specific movement while researchers record the corresponding signals streaming from the brain. This part of the equation falls in the realm of signal processing, which is Mathews’ area of expertise. 

MATHEWS: What we need to do is to first figure out what information that we can extract from the brain that contains information about the intent. It can be done using implanted electrodes in the brain or through surface electrodes, which does not include surgery and things like that. If I can get access to that information in some form, I can decode the intent, from that signal. The idea is that you will have to develop systems, decoders, that are trained to figure out what each signal that comes from the brain means. 

FRANDZEL: In a way, he’s teaching the machine to read minds. 

MATHEWS: We train our systems to learn what the intent is over time. So you collect a lot of data for which you actually know the intent, and then use the information in some form of learning system. 

FRANDZEL: The next link in the system is a controller, which converts the decoded intent into electrical pulses and transmit them to electrodes implanted strategically in nerves of the paralyzed muscles. But these are no ordinary electrodes. Mathews and his group are working with an ingenious device called the Utah Slanted Electrode Array, developed by his research partners at the University of Utah. 

MATHEWS: It’s a four by four millimeter base on which there are a hundred electrodes, each of them have slightly different lengths. 

FRANDZEL: If you’ve ever seen a photo of that old circus trick of someone lying on a bed of nails, you get an idea of what the electrode array looks like, except that each row of spikes gets steadily longer, from half a millimeter to one-and-a-half millimeters long. And, the whole thing fits on your pinky fingernail with room to spare. There’s a picture of it on our website. The slanting pattern is crucial to its function. 

MATHEWS: So In order to access different nerve fibers located in different bundles, you need to actually have electrodes with different lengths. Once the electrical signals are applied to these electrodes, the nerves will cause the muscles to twitch or move. If you do everything in a coordinated manner, the movements will be graceful, natural.  

FRANDZEL: The research group in Utah has used the array to make anesthetized cats stand up. Anesthesia was used to paralysis. 

MATHEWS: We have been able to make movements of the limbs in a very smooth and controlled and natural manner. The next step would be to apply this kinds of technologies to multiple limbs and muscles so that we can have coordinated movements.  

FRANDZEL: The Array has been used elsewhere by paralyzed individuals to manipulate a robotic arm. The application that Mathews is working on – one that allows people to recover use of their own limbs – probably won’t be ready for humans trials for at least another five years. But even basic achievements on that front will have an enormous impact. 

MATHEWS: Right now if you're paralyzed, you might be lying in the bed most of the time. They might get bedsores. It would actually help them to get up and move around occasionally, at least a little bit. It would make their life so much easier. So the early uses of this technology may actually allow a person, a paralyzed person, to get up and take a few steps with the help of a walker without another person actually assisting him or her. Even these kinds of small steps can make an enormous impact in the quality of someone's life. 


[MUSIC: Prelude in C, J.S. Bach, by Kevin MacLeod, used with permission of a Creative Commons attribution license]


FRANDZEL: The system is much closer to becoming a practical tool for amputees. In their case, the arrays are implanted in nerves above the point of amputation. Because the spinal cord is intact, the remaining part of the limb still gets signals directly from the brain, but those signals need to be decoded and transformed into the desired motion of a prosthetic device. So the general idea is the same for both groups: Turn thought into action. 

MATHEWS: The way we use electrodes for prosthetic limbs and for paralyzed people are not particularly different from each other. With the prosthetic limbs, we have two goals. One, you want to make the movements you want to have. Second, you want to have a sense of what you're doing. For example, if you're touching something you want to know if it's soft or hard, you'd want to know if it's hot or cold, etc. An then the question is, can you use your thoughts to control the prosthetic device so that the movement of the prosthetic arm and the leg is very much like what the natural arm and the leg would have done.  

FRANDZEL: Development of this aspect of the technology is much further along. 

MATHEWS: We have implanted these electrode arrays at this time I believe on five different patients. The patients are able to move virtual arms, that is you have the arm on the computer, and that arm on the computer is connected to the electrode array that's implanted on your arm. So right now we can make simple movements of the hands, make the patient open a door and things like that. 

FRANDZEL: But to be truly useful – for either group of people – all of the hardware that links to implanted electrode arrays needs to shrink. Right now, the system inhabits big, cumbersome computers.

MATHEWS: So the hope is that a paralyzed person may one day wear a smart-phone- sized control box that would deliver electrical stimulations through the electrodes implanted in their peripheral nerves and would restore some basic movements at least. 

FRANDZEL: And for amputees: 

MATHEWS: The goal is in a span of five years time – we are in year two of the program – in the fifth year we want to send several patients home with a prosthetic device attached to the arms and we want them to use the prosthetic device without interference from us for a whole month. We are doing everything in a way where we are meeting all the goals we have set for ourselves, so I think at the end of year five you'll see a very successful product out there. 

[MUSIC: Opus One, Audiotronix, used with permission of a Creative Commons attribution license] 

[MUSIC: The Ether Bunny, Eyes Closed Audio, used with permissions of a  Creative Commons license .]

This episode was produced by Keith Hautala and Steve Frandzel, with additional editing by Miriah Reddington. Our intro music is  by Eyes Closed Audio on SoundCloud and used with permission of a Creative Commons attribution license. Other music in this episode includes Opus One by Audionautix; Infa, by Kosta T.; Stopping by the Inn by Twin Musicon; and Prelude in C by Johann Sebastian Bach, played by Kevin MacLeod.

All sound effects in this episode were used with appropriate licenses. Links to music and sound effects can be found on our website.

For more episodes, visit engineering outloud.oregonstate.edu, or subscribe by searching Engineering Out Loud on your favorite podcast app.