A team of researchers at Carnegie Mellon University developed an edible battery that can be used to power ingestible medical devices.
Ingestible medical devices have been a reality for a while: Roughly 20 years ago, scientists created a camera that could be swallowed by a patient undergoing an endoscopy. These devices are battery-powered, but still contain toxic components that would be dangerous to the body if anything should malfunction.
In a one-time use device, like the camera, using such a battery is less risky. But in applications that need to be repeated on a single patient, the risk of something going wrong increases considerably.
That’s where the Carnegie Mellon team comes in: Its battery is made with melanin pigments that are naturally found in the skin, hair and eyes.
Melanin pigment absorbs ultraviolet light to suppress free radicals and bind and unbind metallic ions—basically, just like a battery.
The research team experimented with designs using melanin pigments at the positive or negative terminals, using different electrode materials, such as manganese oxide and sodium titanium phosphate, and cations, such as copper and iron.
While the capacity of the edible battery is low compared with, say, a lithium-ion battery, it’s still high enough to power an ingestible drug-delivery or sensing device.
“The beauty is that by definition an ingestible, degradable device is in the body for no longer than 20 hours or so,” Christopher Bettinger, who leads the research group, said. “Even if you have marginal performance, which we do, that’s all you need.”
Other applications for the battery could be releasing medicine in response to gut microbiome changes, or supplying bursts of a vaccine over several hours, he added.
Bettinger and his group are also working on creating edible batteries from other materials, such as pectin, found naturally in plants, and plan to develop packaging materials to safely deliver the battery to the body.
The group’s research was presented at a meeting of the American Chemical Society in August.
Out-of-this-world robotic glove gets new life on Earth
The RoboGove is the product of a nine-year collaboration between General Motors and NASA, initially developed as part of a project that launched a humanoid robot, the Robonaut 2 (R2) into space in 2011.
One of the design requirements of the R2 was that it be able to operate any tools a human could. Designers succeeded in giving the robot unprecedented hand dexterity, and that same technology was applied to the RoboGlove.
The glove is a battery-powered wearable that mimics the nerves, muscles and tendons in a human hand using sensors, actuators and synthetic tendons. It’s also force-multiplying, giving the wearer extra strength and reducing strain on the human hand while doing repetitive tasks—ideal for workers in an assembly line.
Thanks to a recent licensing agreement between GM and Bioservo, a Swedish medical technology company, the RoboGlove will be refined for use in manufacturing, health care and industrial applications.
“Combining the best of three worlds—space technology from NASA, engineering from GM and medtech from Bioservo—in a new industrial glove could lead to industrial scale use of the technology,” Bioservo CEO Tomas Ward said.
The company will be using technology from its own SEM (soft extra muscle) Glove to develop a new grasp assist for the RoboGlove and address other issues, such as different hand fit sizes, before it hits the market. Bioservo will also optimize the glove for other medical rehabilitation uses where extra grip strength is needed.
GM still intends to be the first US manufacturer to use the RoboGlove in its plants once it’s ready for production.
Heat-responsive, 3D printed structures‘remember’ shapes
MIT and Singapore University of Technology and Design (SUTD) researchers developed 3D printed structures that spring back to their original shapes after being twisted, stretched and bent at different angles.
The researchers used shape-memory polymers and a pioneering 3D printing process called microstereolithography to create the structures, which revert back into shape after being heated to a certain temperature.
The applications for this kind of technology are numerous: Soft actuators that turn solar panels toward the sun, deployable aerospace structures, soft robotics, wearable sensors. But biomedical applications stand out to Nicholas X. Fang, associate professor of mechanical engineering at MIT.
“We ultimately want to use body temperature as a trigger,” Fang said. “If we can design these polymers properly, we may be able to form a drug-delivery device that will only release medicine at the sign of a fever.”
One of the issues that arises when 3D printing shape-memory polymers is size restriction. Other researchers couldn’t design details smaller than a few millimeters on these materials. The size of the structure affects the time of the reaction, too: The smaller the features, the faster the structure will spring into shape.
Microstereolithography uses light from a project to print patterns on successive layers of material. First, a CAD model is created, then sliced into hundreds of pieces to form a bitmap. The shape of bitmap is then projected and etched onto the material using light.
This method of printing, along with an ideal mix of polymers, allowed the team to create features on the structures that were at least one-tenth the size as those created on other printed shape-memory materials. It made the process much faster, too. When this particular polymer mix reached between 40–180° Celsius, it snapped back into shape.
“Because we’re using our own printers that offer much smaller pixel size,” Fang said, “we’re seeing much faster response, on the order of seconds. If we can push to even smaller dimensions, we may also be able to push their response time, to milliseconds.”
Squishy, autonomous ‘octobot’ born at Harvard
Researchers at Harvard demonstrated the first autonomous and entirely soft robot, dubbed the octobot. The bot was created using soft lithography, molding and 3D printing.
Soft robotics could change the way humans and robots work together, but the challenge in creating an entirely soft robot has been the power and control systems. Think rigid batteries and circuit boards. Soft robots without those components on the inside still had to be tethered to some kind of off-board system.
The octobot is the first to circumvent these issues. It’s powered by a chemical reaction inside the robot that transforms a small amount of liquid hydrogen peroxide into gas, which inflates the octobot’s arms like a balloon.
Michael Wehner, a co-first author of the paper, said, “The wonderful thing about hydrogen peroxide is that a simple reaction between the chemical and a catalyst—in this case platinum—allows us to replace rigid power sources.”
The reaction is controlled by a microfluidic logic circuit, which is a soft analog of an electronic oscillator, and acts just like a rigid circuit board. The logic circuit was based on the work of co-author George Whitesides.
Robert Wood, one of the two professors who led the project, said, “This research demonstrates that we can easily manufacture the key components of a simple, entirely soft robot, which lays the foundation for more complex designs.”
Photogrammetry explored in small-scale manufacturing
One Penn State professor thinks digital photography is the future of small-scale manufacturing. Michael Immel, instructor in the Harold and Inge Marcus Department of Industrial and Manufacturing Engineering, received a grant to explore how photogrammetry can improve manufacturing processes.
Photogrammetry is a technique that uses digital images of an object, taken at various angles, to create a point cloud. The point cloud can be used to create a 3D representation of the object and a CAD file to match. That CAD file can then be used to quickly manufacture parts that have limited variation and don’t require tight tolerances.
Immel and a team of three engineering students put the theory to the test this summer. First, the group created a studio setup for taking photographs of the part, taking several factors into consideration—even lighting and no shadows, and a contrasting background. They took photographs of the part at different angles and distances to ensure there was enough data to create the point cloud. The team tested objects that they already had a CAD file for, so they could compare the photogrammetry-created file with the original for accuracy.
The group concluded that “photogrammetry has proven to be an accurate approach for applications where tight tolerances are not necessary,” Immel said. The technology could make certain processes quicker and less costly.
“The ideal application of photogrammetry in the industry setting would be to have a vision system in a manufacturing plant that included cameras fixed on the machines making the parts, taking continuous photos,” Immel said, adding that, “Live data could be sent back to an engineer or a quality control employee and they could compare the point cloud that has been derived from the digital images to the point cloud of the original file and determine if the part is within tolerance or not.”
Saurabh Basu, an assistant professor of industrial engineering, joined Immel’s group to conduct additional research before testing the process in an industrial setting.
Synthetic diamond material gives graphene a boost
Chances are you’ve heard of graphene, the wonder-material of the future. Graphene’s properties, including its high strength, excellent electrical and thermal conductivities and notable electron mobility, make it ideal for touchscreens, semiconductors, batteries and solar cells.
These properties can only be fully realized if graphene is grown without impurities, a task that has proved challenging. But a team of scientists at the Department of Energy’s Argonne National Laboratory may have found a solution: diamonds.
The Argonne researchers, led by materials scientist Anirudha Sumant and collaborators from the University of California-Riverside, found that using a synthetic diamond material called ultrananocrystalline diamond (UNCD) as a substrate on which the graphene grows eliminates most of graphene’s impurities.
Diana Berman, the first author of the study, said, “When I first looked at the [scanning electron micrograph] and saw this nice uniform, very complete layer, it was amazing. I’d been dealing with all these different techniques of growing graphene, and you never see such a uniform, smooth surface.”
This new way of growing graphene uses lower temperatures and takes less time than the conventional methods using silicon carbide as a substrate that are widely used today. It’s also more cost-effective. The three to four silicon carbide wafers used in those methods can run up to $1200, while the UNCD material layered on silicon wafers costs under $500 to make.
Members of the Argonne research team said they secured three patents, and started working with the Swedish Institute of Space Physics and the European Space Agency to develop graphene-coated probes for the Jupiter Icy Moons Explorer (JUICE) program. The Argonne team also developed diamond and graphene needles for researchers at North Carolina University, for biosensing purposes.
Scientists at Argonne are continuing to fine-tune the process and use this new knowledge to learn more about the properties of graphene. Their research was published in the journal Nature Communications.
Edited by Digital Editor Katelyn DaMour: firstname.lastname@example.org