Painless paper patch test for glucose levels uses microneedles

Patches seem to be all the rage these days. There are birth control patches, nicotine patches, and transdermal medicinal patches, just to name a few. Now, a team of researchers led by Beomjoon Kim at the Institute of Industrial Science, The University of Tokyo have developed a patch of needles connected to a paper sensor for diagnosing conditions such as prediabetes. Luckily, this patch doesn’t multiply the pain and discomfort of a single hypodermic needle. In fact, these microneedles are painless and biodegradable.

Researchers have been trying to develop a practical way to use microneedles — tiny needles less than 1 mm in length — for routine do-it-yourself medical monitoring. Microneedles are so short that they stay within the skin and do not make contact with any neurons, meaning that they cause no pain. Rather than extracting blood, they draw up fluid in the skin that contains most of the important biomarkers that blood tests look for. Several types of microneedles exist, but until now, making a practical device that quickly analyzes the fluid has proved elusive. “We have overcome this problem by developing a way to combine porous microneedles with paper-based sensors,” says Kim. “The result is low-cost, disposable, and does not require any additional instruments.”

To make the patch, the researchers first made the microneedles by pouring a melted mixture of a biodegradable polymer and salt into the cone-shaped cavities of a micro-mold while applying heat. Then they flipped the mold and needles upside down and placed them on top of a piece of paper, this time applying high pressure from above. The high pressure forced the mixture into the pores of the paper, securing the attachment and allowing fluid drawn through the needles to pass effortlessly into the paper. After removal from the mold, the needles were cooled in a solution that sucked out all the salt, leaving behind thousands of holes, or pores, which are what the fluid flows through on its way to the paper. The salt concentration was a key factor they needed to optimize, testing several concentrations of salt to determine how porous the microneedles should be. To finish the patch, they used double-sided tape to attach a paper glucose sensor onto the paper base of the needle array.

The team tested the patch on an agarose gel in which glucose had been dissolved. Fluid from the gel flowed from the gel into the porous microneedles, and from there into the paper and the sensor layer. The glucose concentration was accurately recorded as color changes in the paper.

The patches are disposable, biodegradable, and using them does not require any medical expertise or training. They are also biocompatible, meaning that there is no problem if any remain in the skin when the patch is removed.

“Of course, prediabetes testing is just one application of the technology,” says first author Hakjae Lee. “The paper-based sensor can vary depending on the biomarker you wish to monitor.”

After this success, the next step will be to test the practicality of the device with human participants and to develop configurations for monitoring other substances, and in turn, determining the presence of other conditions.

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Materials provided by Institute of Industrial Science, The University of Tokyo. Note: Content may be edited for style and length.

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Synthesizing a superatom: Opening doors to their use as substitutes for elemental atoms

Superatom is a name given to a cluster of atoms that seem to exhibit properties similar to elemental atoms. Scientists have shown particular interest in superatomic structures, since they can be linked with atoms to produce molecules, and potentially be used to substitute certain elements in many applications.

But for superatoms to be effectively utilized, they must be specially tailored to resemble the characteristics of the corresponding elements. This transformation depends on the specific combination of electrons used. For example, when an aluminum atom with 3 valence electrons (outer shell electrons that can contribute to the formation of chemical bonds) is added to the superatom of aluminium-13, the properties change to those of a superatom of aluminium-14. Due to this modifiability of superatoms, investigating them and understanding them further is important. But previous research has been mainly theoretical, and largely focused on single clusters. Research has also not been able to synthesize superatomic clusters with sufficient volume and stability for practical application.

In a recent study, scientists from Tokyo Tech and ERATO Japan Science and Technology, led by Dr Tetsuya Kambe and Prof Kimihisa Yamamoto, fabricated clusters of the element gallium (Ga) in solution to demonstrate the effects of changing the number of atoms in a cluster on the properties of the cluster. The team synthesized Ga clusters of 3, 12, 13 and other numbers of atoms using a specialized superatom synthesizer. To characterize and analyze the structural differences among the synthesized clusters, transmission electron microscopic images were captured and calculations were performed using computation tools.

The mass spectrometry revealed that the 13- and 3-atom clusters had superatomic periodicity. The 13-atom cluster differed from the other clusters structurally and electrochemically. But the 3-atom cluster with hydrogen (Ga3H2) was reduced to Ga3H2- and was not detected, suggesting a low stability of this cluster when synthesized in the solution medium.

The ability to alter the clusters reinforces the concept that structural change can be induced in superatoms. Describing the implications of their findings, the scientists explain: “These series of results demonstrate that it is possible to change the valence electrons in superatomic clusters in solution by controlling the number of constituent atoms. This in turn enables the designing and preparation of superatoms.”

This study paves the way for future research to investigate the use of superatoms as substitutes for elements. As Dr Kambe, Prof Yamamoto and team reiterate, “the superatom reveals an attractive strategy for creating new building blocks through the use of cluster structures.”

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Materials provided by Tokyo Institute of Technology. Note: Content may be edited for style and length.

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IEEE Spectrum

CES 2020: The Best—and Wildest—Gadgets

At CES, among the bigger, brighter TVs, mock smart homes that seem to know more about you than you do, and all the Alexa- and Google-Assistant-enabled devices eager to talk to you, are a few products that defy categorization. Some of these new products grabbed my attention because they involve truly innovative technology. Some are just clever and cheap enough to catch on, and some are a little too wild to find a big market—but it’s still impressive when a developer realizes an extreme dream.

So, as CES 2020 retreats into history, here is my top 10 list of CES gadgets that at least got my attention, if not a spot on my shopping list. There is no way to rank these in order of importance, so I’ll list them roughly by size, from small to big. (The largest products demonstrated at CES, like John Deere’s AI-powered crop sprayer, Brunswick’s futuristic speedboat, or Hyundai’s flying taxi developed in partnership with Uber Elevate can’t be called gadgets, so didn’t make this roundup.)

IEEE Spectrum

Long-lasting Lithium-Sulfur Battery Promises to Double EV Range

Lithium-sulfur batteries seem to be ideal successors to good old lithium-ion. They could in theory hold up to five times the energy per weight. Their low weight makes them ideal for electric airplanes: firms such as Sion Power and Oxis Energy are starting to test their lithium-sulfur batteries in aircraft. And they would be cheaper given their use of sulfur instead of the rare-earth metals used in the cathode today.

But the technology isn’t yet commercial mainly because of its short life span. The cathode starts falling apart after just 40 to 50 charge cycles.

By designing a novel robust cathode structure, researchers have now made a lithium-sulfur battery that can be recharged several hundred times. The cells have an energy capacity four times that of lithium-ion, which typically holds 150 to 200 watt-hours per kilogram (Wh/kg). If translatable to commercial devices, it could mean a battery that powers a phone for five days without needing to recharge, or quadruples the range of electric cars.

That’s unlikely to happen, since energy capacity drops when cells are strung together into battery packs. But the team still expects a “twofold increase at battery pack level when [the new battery is] introduced to the market,” says Mahdokht Shaibani, a mechanical and aerospace engineer at Australia’s Monash University who led the work published recently in the journal Science Advances.

Shaibani likens the sulfur cathode in a lithium-sulfur battery to a hard-working, overtaxed office worker. It can take on a lot, but the job demands cause stress and hurt productivity. In battery terms, during discharge the cathode soaks up a large amount of lithium ions, forming lithium sulfide. But in the process, it swells enormously, and then contracts when the ions leave during battery charging. This repeated volume change breaks down the cathode.


Improved 3D nanoprinting technique to build nanoskyscrapers

Nanowalls, nanobridges, nano “jungle gyms”: it could seem the description of a Lilliputian village, but these are actual 3D-printed components with tremendous potential applications in nanoelectronics, smart materials and biomedical devices. Researchers at the Center for Soft and Living Matter (CSLM), within the Institute for Basic Science (IBS, South Korea) have improved the 3D nanoprinting process that enables to build precise, self-stacked, tall-and-narrow nanostructures. As shown in their latest publication in Nano Letters, the team also used this technique to produce transparent nanoelectrodes with high optical transmission and controllable conductivity.

The near-field electrospinning (NFES) technique consists of a syringe filled with a polymer solution suspended above a platform, which collects the ejected nanofiber and is pre-programmed to move left-and-right, back-and-forth, depending on the shape of the desired final product. The syringe and the platform have opposite charges, so that the polymer jet coming out from the needle of the syringe is attracted to the platform, forming a continuous fiber that solidifies on the platform. Since the electrospun jets are difficult to handle, this technique was limited to two-dimensional (2D) structures or hollow cylindrical three-dimensional (3D) structures, often with relatively large fiber diameters of a few micrometers.

IBS researchers were able to achieve a better control of the nanofiber deposition on the platform, by adding an appropriate concentration of sodium chloride (NaCl) to the polymer solution. This ensured the spontaneous alignment of the nanofiber layers stacked on top of each other forming walls.

“Although it is highly applicable to various fields, it is difficult to build stacked nanofibers with multiple designs using the conventional electrospinning techniques,” says Yoon-Kyoung Cho, the corresponding author of the study. “Our experiment showed that salt did the trick.”

The benefit provided by salt is related to the charges. The difference in voltage between the syringe and the platform creates positive charges in the polymer solution and negative charges in the platform, but a residual positive charge stays in the solidified fibers on the platform. The team found that applying salt to the polymer solution enhances the charge dissipation, leading to higher electrostatic attraction between the nanofiber jet and the fibers deposited on the platform.

Based on this mechanism, the team was able to produce tall-and-narrow nanowalls, with a minimum width of around 92 nanometers and a maximum height of 6.6 micrometers, and construct a variety of 3D nanoarchitectures, such as curved nanowall arrays, nano “jungle gyms,” and nanobridges, with controllable dimensions.

To demonstrate the potential application of these nanostructures, the researchers in collaboration with Hyunhyub Ko, professor at Ulsan National Institute of Science and Technology (UNIST), prepared 3D nanoelectrodes with silver-coated nanowalls embedded in transparent and flexible polydimethylsiloxane (PDMS) films. They confirmed that electrical resistance could be tuned with the number of nanofiber layers (the taller the nanowalls, the smaller the resistance), without affecting light transmission.

“Interestingly, this method can potentially avoid the trade-off between optical transmittance and sheet resistance in transparent electrodes. Arrays of 3D silver nanowires made with 20, 40, 60, 80, or 100 layers of nanofibers had variable conductivity, but stable light transmission of around 98%,” concludes Yang-Seok Park, the first author of the study.

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Materials provided by Institute for Basic Science. Note: Content may be edited for style and length.

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3D Printing Industry

ALTANA and dp polar launch the AMpolar i2 industrial 3D printer

3D printers with rotating print platforms, and other rotating elements, seem to be making somewhat of a return to the industry. At least based on a couple of exhibitors seen during formnext 2019 last week.  German chemical group, ALTANA AG, and partner dp polar have announced the AMpolar i2 3D printer. ALTANA acquired a stake […]

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Author: Michael Petch

IEEE Spectrum

Driving Tests Coming for Autonomous Cars

The three laws of robotic safety in Isaac Asimov’s science fiction stories seem simple and straightforward, but the ways the fictional tales play out reveal unexpected complexities. Writers of safety standards for self-driving cars express their goals in similarly simple terms. But several groups now developing standards for how autonomous vehicles will interact with humans and with each other face real-world issues much more complex than science fiction.

Advocates of autonomous cars claim that turning the wheel over to robots could slash the horrific toll of 1.3 million people killed around the world each year by motor vehicles. Yet the public has become wary because robotic cars also can kill. Documents released last week by the U.S. National Transportation Safety Board blame the March 2018 death of an Arizona pedestrian struck by a self-driving Uber on safety failures by the car’s safety driver, the company, and the state of Arizona. Even less-deadly safety failures are damning, like the incident where a Tesla in Autopilot mode wasn’t smart enough to avoid crashing into a stopped fire engine whose warning lights were flashing.

Safety standards for autonomous vehicles “are absolutely critical” for public acceptance of the new technology, says Greg McGuire, associate director of the Mcity autonomous vehicle testing lab at the University of Michigan. “Without them, how do we know that [self-driving cars] are safe, and how do we gain public trust?” Earning that trust requires developing standards through an open process that the public can scrutinize, and may even require government regulation, he adds.

Companies developing autonomous technology have taken notice. Earlier this year, representatives from 11 companies including Aptiv, Audi, Baidu, BMW, Daimler, Infineon, Intel, and Volkswagen collaborated to write a wide-ranging whitepaper titled “Safety First for Automated Driving.” They urged designing safety features into the automated driving function, and using heightened cybersecurity to assure the integrity of vital data including the locations, movement, and identification of other objects in the vehicle environment. They also urged validating and verifying the performance of robotic functions in a wide range of operating conditions.

On 7 November, the International Telecommunications Union announced the formation of a focus group called AI for Autonomous and Assisted Driving. It’s aim: to develop performance standards for artificial intelligence (AI) systems that control self-driving cars. (The ITU has come a long way since its 1865 founding as the International Telegraph Union, with a mandate to standardize the operations of telegraph services.)

ITU intends the standards to be “an equivalent of a Turing Test for AI on our roads,” says focus group chairman Bryn Balcombe of the Autonomous Drivers Alliance. A computer passes a Turing Test if it can fool a person into thinking it’s a human. The AI test is vital, he says, to assure that human drivers and the AI behind self-driving cars understand each other and predict each other’s behaviors and risks.

A planning document says AI development should match public expectations so:

• AI never engages in careless, dangerous, or reckless driving behavior

• AI remains aware, willing, and able to avoid collisions at all times

• AI meets or exceeds the performance of a competent, careful human driver


These broad goals for automotive AI algorithms resemble Asimov’s laws, insofar as they bar hurting humans and demand that they obey human commands and protect their own existence. But the ITU document includes a list of 15 “deliverables” including developing specifications for evaluating AIs and drafting technical reports needed for validating AI performance on the road.

A central issue is convincing the public to entrust the privilege of driving—a potentially life-and-death activity—to a technology which has suffered embarrassing failures like the misidentification of minorities that led San Francisco to ban the use of facial recognition by police and city agencies.

Testing how well an AI can drive is vastly complex, says McGuire. Human adaptability makes us fairly good drivers. “We’re not perfect, but we are very good at it, with typically a hundred million miles between fatal traffic crashes,” he says. Racking up that much distance in real-world testing is impractical—and it is but a fraction of the billions of vehicle miles needed for statistical significance. That’s a big reason developers have turned to simulations. Computers can help them run up virtual mileage needed to find potential safety flaws that might arise only rare situations, like in a snowstorm or heavy rain, or on a road under construction.

It’s not enough for an automotive AI to assure the vehicle’s safety, says McGuire. “The vehicle has to work in a way that humans would understand.” Self-driving cars have been rear-ended when they stopped in situations where most humans would not have expected a driver to stop. And a truck can be perfectly safe even when close enough to unnerve a bicyclist.

Other groups are also developing standards for robotic vehicles. ITU is covering both automated driver assistance and fully autonomous vehicles. Underwriters Laboratories is working on a standard for fully-autonomous vehicles. The Automated Vehicle Safety Consortium, a group including auto companies, plus Lyft, Uber, and SAE International (formerly the Society of Automotive Engineers) is developing safety principles for SAE Level 4 and 5 autonomous vehicles. The BSI Group (formerly the British Institute of Standards) developed a strategy for British standards for connected and autonomous vehicles and is now working on the standards themselves.

How long will it take to develop standards? “This is a research process,” says McGuire. “It takes as long as it takes” to establish public trust and social benefit. In the near term, Mcity has teamed with the city of Detroit, the U.S. Department of Transportation, and Verizon to test autonomous vehicles for transporting the elderly on city streets. But he says the field “needs to be a living thing that continues to evolve” over a longer period.

IEEE Spectrum

Google’s Quantum Tech Milestone Excites Scientists and Spurs Rivals

Quantum computing can already seem like the realm of big business these days, with tech giants such as Google, IBM, and Intel developing quantum tech hardware. But even as rivals reacted to Google’s announcement of having shown quantum computing’s advantage over the most powerful supercomputer, scientists have welcomed the demonstration as providing crucial experimental evidence to back up theoretical research in quantum physics.


This Inexpensive Tool Turns Large PVC Pipes Into Furniture and More

It may not always seem like it, but consumer products in the modern world are incredibly affordable. If you make $20 an hour, two hours of work is enough to “trade” for a solid metal and wood end table at your local big box store. Just a couple of centuries ago, that same table would have taken a craftsman days to build. That affordability is all thanks to mass production. In an ideal world, we could take advantage of the cost-effectiveness of mass production to build custom products, which is exactly what the Pipeline Project is intended for.

The Pipeline Project is essentially a big CNC (Computer Numerical Control) router designed to work with large-diameter PVC pipes. That is an ideal material for many products, because it’s strong and durable. Even more importantly, it’s mass-produced, and is therefore very affordable. Because PVC pipes are commonly used for plumbing, they can be purchased easily anywhere in the world. It’s even possible to use salvaged PVC pipes. The Pipeline Project tool can take those PVC pipes and cut them into custom shapes to create a variety of useful products.

The tool itself is also affordable, because it uses standard CNC components — including an Arduino Uno. The scale is large, but it’s just a standard 3-axis CNC router with one of the axes converted into rotary motion to spin the PVC pipe. What users can create with the Pipeline Project is just up to their imagination. The creator, Christophe Machet, has demonstrated that it can be used to make attractive chairs, tables, and even a skateboard deck. The Pipeline Project is still under development, but it appears that Machet plans to release the design files in the future.

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Author: Cameron Coward