Common food additives known as metal oxide nanoparticles may have negative effects on your gut health, according to new research from Binghamton University, State University of New York and Cornell University.
Gretchen Mahler, professor of biomedical engineering and interim vice provost and dean of the Graduate School, worked in collaboration with Cornell researchers to study five of these nanoparticles. Their findings were recently published in the Journal of Antioxidants.
“They’re all actual food additives,” said Mahler. “Titanium dioxide tends to show up as a whitening and brightening agent. Silicon dioxide tends to be added to foods to prevent it from clumping. Iron oxide tends to be added to meats, for example, to keep that red color. And zinc oxide can be used as a preservative because it’s antimicrobial.” [emphases mine]
In order to test these nanoparticles, Mahler and Elad Tako, senior author and associate professor of food science in the College of Agriculture and Life Sciences at Cornell, used the intestinal tract of chickens. A chicken’s intestinal tract is comparable to a human’s; the microbiota that they have and the bacterial components have a lot of overlap with the microbiota that you see in the human digestive system, said Mahler.
“We’ve been testing a series of nanomaterials here at Binghamton, and we’ve been looking at things like nutrient absorption, enzyme expression and some of the more subtle, functional markers,” said Mahler.
The doses of nanoparticles that were tested reflect what is typically consumed by humans. The nanoparticles were injected into the amniotic sac of broiler chicken eggs, which are specifically bred and raised for their meat. These chickens get larger faster, so the effects of the nanoparticles are more obvious earlier in development. The amniotic sac at a certain stage of development flows through the chicken intestine.
“When they hatched, we harvested tissue from the small intestine, the microbiota and the liver,” said Mahler. “We looked at gene expression, microbiota composition and the structure of the small intestine.”
The researchers found more negative effects with silicone dioxide and titanium dioxide. They also found that the nanoparticles had affected the functioning of the chicken’s intestinal lining (called the brush border membrane), the balance of bacteria in their intestinal tract and the chickens’ ability to absorb minerals.
The other nanoparticles had more neutral, or even positive, effects. Zinc oxide appeared to support intestinal development or compensatory mechanisms due to intestinal damage. Iron oxide could potentially be used for iron fortification, but with potential alterations in intestinal functionality and health.
Mahler doesn’t want to suggest that these nanoparticles need to be removed from our diets completely. Their research is meant to provide some information, and allow people to have a better understanding of what’s really in the food they consume.
“We’re eating these things, so it’s important to consider what some of the more subtle effects could be,” said Mahler. “We develop these gut models around this problem to try to understand it, and this collaboration, where we have these complementary methods to try to look at the problem, has been successful.”
According to an April 18, 2023 news item on ScienceDaily this long-lasting (100 years potentially) biobattery runs on bacteria,
A tiny biobattery that could still work after 100 years has been developed by researchers at Binghamton University, State University of New York.
Last fall [2022], Binghamton University Professor Seokheun “Sean” Choi and his Bioelectronics and Microsystems Laboratory published their research into an ingestible biobattery activated by the Ph factor of the human intestine.
Now, he and PhD student Maryam Rezaie have taken what they learned and incorporated it into new ideas for use outside the body.
A new study in the journal Small, which covers nanotechnology, shares the results from using spore-forming bacteria similar to the previous ingestible version to create a device that potentially would still work after 100 years.
“The overall objective is to develop a microbial fuel cell that can be stored for a relatively long period without degradation of biocatalytic activity and also can be rapidly activated by absorbing moisture from the air,” said Choi, a faculty member in the Department of Electrical and Computer Engineering at the Thomas J. Watson College of Engineering and Applied Science.
“We wanted to make these biobatteries for portable, storable and on-demand power generation capabilities,” Choi said. “The problem is, how can we provide the long-term storage of bacteria until used? And if that is possible, then how would you provide on-demand battery activation for rapid and easy power generation? And how would you improve the power?”
The dime-sized fuel cell was sealed with a piece of Kapton tape, a material that can withstand temperatures from -500 to 750 degrees Fahrenheit. When the tape was removed and moisture allowed in, the bacteria mixed with a chemical germinant that encouraged the microbes to produce spores. The energy from that reaction produced enough to power an LED, a digital thermometer or a small clock.
Heat activation of the bacterial spores cut the time to full power from 1 hour to 20 minutes, and increasing the humidity led to higher electrical output. After a week of storage at room temperature, there was only a 2% drop in power generation.
The study is funded by the [US] Office of Naval Research, and it’s easy to imagine the military applications for a power source that could be deployed on the battlefield or in remote locations. However, there would be plenty of civilian uses for such a fuel cell, too.
While these are all good results, Choi knows that a fuel cell like this needs to power up more quickly and produce more voltage to become a viable alternative to traditional batteries.
“I think this is a good start,” he said. “Hopefully, we can make a commercial product using these ideas.”
Everyone knows that humans and most other vertebrate species hear using eardrums that turn soundwave pressure into signals for our brains. But what about smaller animals like insects and arthropods? Can they detect sounds? And if so, how?
Distinguished Professor Ron Miles, a Department of Mechanical Engineering faculty member at Binghamton University’s Thomas J. Watson College of Engineering and Applied Science, has been exploring that question for more than three decades, in a quest to revolutionize microphone technology.
A newly published study of orb-weaving spiders — the species featured in the classic children’s book “Charlotte’s Web” — has yielded some extraordinary results: The spiders are using their webs as extended auditory arrays to capture sounds, possibly giving spiders advanced warning of incoming prey or predators.
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Binghamton University (formal name: State University of New York at Binghamton) has made this fascinating (to me anyway) video available,
Binghamton University and Cornell University (also in New York state) researchers worked collaboratively on this project. Consequently, there are two news releases and there is some redundancy but I always find that information repeated in different ways is helpful for learning.
It is well-known that spiders respond when something vibrates their webs, such as potential prey. In these new experiments, researchers for the first time show that spiders turned, crouched or flattened out in response to sounds in the air.
The study is the latest collaboration between Miles and Ron Hoy, a biology professor from Cornell, and it has implications for designing extremely sensitive bio-inspired microphones for use in hearing aids and cell phone
Jian Zhou, who earned his PhD in Miles’ lab and is doing postdoctoral research at the Argonne National Laboratory, and Junpeng Lai, a current PhD student in Miles’ lab, are co-first authors. Miles, Hoy and Associate Professor Carol I. Miles from the Harpur College of Arts and Sciences’ Department of Biological Sciences at Binghamton are also authors for this study. Grants from the National Institutes of Health to Ron Miles funded the research.
A single strand of spider silk is so thin and sensitive that it can detect the movement of vibrating air particles that make up a soundwave, which is different from how eardrums work. Ron Miles’ previous research has led to the invention of novel microphone designs that are based on hearing in insects.
“The spider is really a natural demonstration that this is a viable way to sense sound using viscous forces in the air on thin fibers,” he said. “If it works in nature, maybe we should have a closer look at it.”
Spiders can detect miniscule movements and vibrations through sensory organs on their tarsal claws at the tips of their legs, which they use to grasp their webs. Orb-weaver spiders are known to make large webs, creating a kind of acoustic antennae with a sound-sensitive surface area that is up to 10,000 times greater than the spider itself.
In the study, the researchers used Binghamton University’s anechoic chamber, a completely soundproof room under the Innovative Technologies Complex. Collecting orb-weavers from windows around campus, they had the spiders spin a web inside a rectangular frame so they could position it where they wanted.
The team began by using pure tone sound 3 meters away at different sound levels to see if the spiders responded or not. Surprisingly, they found spiders can respond to sound levels as low as 68 decibels. For louder sound, they found even more types of behaviors.
They then placed the sound source at a 45-degree angle, to see if the spiders behaved differently. They found that not only are the spiders localizing the sound source, but they can tell the sound incoming direction with 100% accuracy.
To better understand the spider-hearing mechanism, the researchers used laser vibrometry and measured over one thousand locations on a natural spider web, with the spider sitting in the center under the sound field. The result showed that the web moves with sound almost at maximum physical efficiency across an ultra-wide frequency range.
“Of course, the real question is, if the web is moving like that, does the spider hear using it?” Miles said. “That’s a hard question to answer.”
Lai added: “There could even be a hidden ear within the spider body that we don’t know about.”
So the team placed a mini-speaker 5 centimeters away from the center of the web where the spider sits, and 2 millimeters away from the web plane — close but not touching the web. This allows the sound to travel to the spider both through air and through the web. The researchers found that the soundwave from the mini-speaker died out significantly as it traveled through the air, but it propagated readily through the web with little attenuation. The sound level was still at around 68 decibels when it reached the spider. The behavior data showed that four out of 12 spiders responded to this web-borne signal.
Those reactions proved that the spiders could hear through the webs, and Lai was thrilled when that happened: “I’ve been working on this research for five years. That’s a long time, and it’s great to see all these efforts will become something that everybody can read.”
The researchers also found that, by crouching and stretching, spiders may be changing the tension of the silk strands, thereby tuning them to pick up different frequencies. By using this external structure to hear, the spider could be able to customize it to hear different sorts of sounds.
Future experiments may investigate how spiders make use of the sound they can detect using their web. Additionally, the team would like to test whether other types of web-weaving spiders also use their silk to outsource their hearing.
“It’s reasonable to guess that a similar spider on a similar web would respond in a similar way,” Ron Miles said. “But we can’t draw any conclusions about that, since we tested a certain kind of spider that happens to be pretty common.”
Lai admitted he had no idea he would be working with spiders when he came to Binghamton as a mechanical engineering PhD student.
“I’ve been afraid of spiders all my life, because of their alien looks and hairy legs!” he said with a laugh. “But the more I worked with spiders, the more amazing I found them. I’m really starting to appreciate them.”
Charlotte’s web is made for more than just trapping prey.
A study of orb weaver spiders finds their massive webs also act as auditory arrays that capture sounds, possibly giving spiders advanced warning of incoming prey or predators.
In experiments, the researchers found the spiders turned, crouched or flattened out in response to sounds, behaviors that spiders have been known to exhibit when something vibrates their webs.
The paper, “Outsourced Hearing in an Orb-weaving Spider That Uses its Web as an Auditory Sensor,” published March 29 [2022] in the Proceedings of the National Academy of Sciences, provides the first behavioral evidence that a spider can outsource hearing to its web.
The findings have implications for designing bio-inspired extremely sensitive microphones for use in hearing aids and cell phones.
A single strand of spider silk is so thin and sensitive it can detect the movement of vibrating air particles that make up a sound wave. This is different from how ear drums work, by sensing pressure from sound waves; spider silk detects sound from nanoscale air particles that become excited from sound waves.
“The individual [silk] strands are so thin that they’re essentially wafting with the air itself, jostled around by the local air molecules,” said Ron Hoy, the Merksamer Professor of Biological Science, Emeritus, in the College of Arts and Sciences and one of the paper’s senior authors, along with Ronald Miles, professor of mechanical engineering at Binghamton University.
Spiders can detect miniscule movements and vibrations via sensory organs in their tarsi – claws at the tips of their legs they use to grasp their webs, Hoy said. Orb weaver spiders are known to make large webs, creating a kind of acoustic antennae with a sound-sensitive surface area that is up to 10,000 times greater than the spider itself.
In the study, the researchers used a special quiet room without vibrations or air flows at Binghamton University. They had an orb-weaver build a web inside a rectangular frame, so they could position it where they wanted. The team began by putting a mini-speaker within millimeters of the web without actually touching it, where sound operates as a mechanical vibration. They found the spider detected the mechanical vibration and moved in response.
They then placed a large speaker 3 meters away on the other side of the room from the frame with the web and spider, beyond the range where mechanical vibration could affect the web. A laser vibrometer was able to show the vibrations of the web from excited air particles.
The team then placed the speaker in different locations, to the right, left and center with respect to the frame. They found that the spider not only detected the sound, it turned in the direction of the speaker when it was moved. Also, it behaved differently based on the volume, by crouching or flattening out.
Future experiments may investigate whether spiders rebuild their webs, sometimes daily, in part to alter their acoustic capabilities, by varying a web’s geometry or where it is anchored. Also, by crouching and stretching, spiders may be changing the tension of the silk strands, thereby tuning them to pick up different frequencies, Hoy said.
Additionally, the team would like to test if other types of web-weaving spiders also use their silk to outsource their hearing. “The potential is there,” Hoy said.
Miles’ lab is using tiny fiber strands bio-inspired by spider silk to design highly sensitive microphones that – unlike conventional pressure-based microphones – pick up all frequencies and cancel out background noise, a boon for hearing aids.
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Here’s a link to and a citation for the paper,
Outsourced hearing in an orb-weaving spider that uses its web as an auditory sensor by Jian Zhou, Junpeng Lai, Gil Menda, Jay A. Stafstrom, Carol I. Miles, Ronald R. Hoy, and Ronald N. Miles. Proceedings of the National Academy of Sciences (PNAS) DOI: https://doi.org/10.1073/pnas.2122789119 Published March 29, 2022 | 119 (14) e2122789119
This paper appears to be open access and video/audio files are included (you can heat the sound and watch the spider respond).
As you might suspect, a neuristor is based on a memristor .(For a description of a memristor there’s this Wikipedia entry and you can search this blog with the tags ‘memristor’ and neuromorphic engineering’ for more here.)
Being new to neuristors ,I needed a little more information before reading the latest and found this Dec. 24, 2012 article by John Timmer for Ars Technica (Note: Links have been removed),
Computing hardware is composed of a series of binary switches; they’re either on or off. The other piece of computational hardware we’re familiar with, the brain, doesn’t work anything like that. Rather than being on or off, individual neurons exhibit brief spikes of activity, and encode information in the pattern and timing of these spikes. The differences between the two have made it difficult to model neurons using computer hardware. In fact, the recent, successful generation of a flexible neural system required that each neuron be modeled separately in software in order to get the sort of spiking behavior real neurons display.
But researchers may have figured out a way to create a chip that spikes. The people at HP labs who have been working on memristors have figured out a combination of memristors and capacitors that can create a spiking output pattern. Although these spikes appear to be more regular than the ones produced by actual neurons, it might be possible to create versions that are a bit more variable than this one. And, more significantly, it should be possible to fabricate them in large numbers, possibly right on a silicon chip.
The key to making the devices is something called a Mott insulator. These are materials that would normally be able to conduct electricity, but are unable to because of interactions among their electrons. Critically, these interactions weaken with elevated temperatures. So, by heating a Mott insulator, it’s possible to turn it into a conductor. In the case of the material used here, NbO2, the heat is supplied by resistance itself. By applying a voltage to the NbO2 in the device, it becomes a resistor, heats up, and, when it reaches a critical temperature, turns into a conductor, allowing current to flow through. But, given the chance to cool off, the device will return to its resistive state. Formally, this behavior is described as a memristor.
To get the sort of spiking behavior seen in a neuron, the authors turned to a simplified model of neurons based on the proteins that allow them to transmit electrical signals. When a neuron fires, sodium channels open, allowing ions to rush into a nerve cell, and changing the relative charges inside and outside its membrane. In response to these changes, potassium channels then open, allowing different ions out, and restoring the charge balance. That shuts the whole thing down, and allows various pumps to start restoring the initial ion balance.
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Here’s a link to and a citation for the research paper described in Timmer’s article,
A scalable neuristor built with Mott memristors by Matthew D. Pickett, Gilberto Medeiros-Ribeiro, & R. Stanley Williams. Nature Materials 12, 114–117 (2013) doi:10.1038/nmat3510 Published online 16 December 2012
A future android brain like that of Star Trek’s Commander Data might contain neuristors, multi-circuit components that emulate the firings of human neurons.
Neuristors already exist today in labs, in small quantities, and to fuel the quest to boost neuristors’ power and numbers for practical use in brain-like computing, the U.S. Department of Defense has awarded a $7.1 million grant to a research team led by the Georgia Institute of Technology. The researchers will mainly work on new metal oxide materials that buzz electronically at the nanoscale to emulate the way human neural networks buzz with electric potential on a cellular level.
A July 28, 2017 Georgia Tech news release, which originated the news item, delves further into neuristors and the proposed work leading to an artificial retina that can learn (!). This was not where I was expecting things to go,
But let’s walk expectations back from the distant sci-fi future into the scientific present: The research team is developing its neuristor materials to build an intelligent light sensor, and not some artificial version of the human brain, which would require hundreds of trillions of circuits.
But an artificial retina that can learn autonomously appears well within reach of the research team from Georgia Tech and Binghamton University. Despite the term “retina,” the development is not intended as a medical implant, but it could be used in advanced image recognition cameras for national defense and police work.
At the same time, it would significantly advance brain-mimicking, or neuromorphic, computing. The research field that takes its cues from what science already does know about how the brain computes to develop exponentially more powerful computing.
The retina would be comprised of an array of ultra-compact circuits called neuristors (a word combining “neuron” and “transistor”) that sense light, compute an image out of it and store the image. All three of the functions would occur simultaneously and nearly instantaneously.
“The same device senses, computes and stores the image,” Doolittle said. “The device is the sensor, and it’s the processor, and it’s the memory all at the same time.” A neuristor itself is comprised in part of devices called memristors inspired by the way human neurons work.
Brain vs. PC
That cuts out loads of processing and memory lag time that are inherent in traditional computing.
Take the device you’re reading this article on: Its microprocessor has to tap a separate memory component to get data, then do some processing, tap memory again for more data, process some more, etc. “That back-and-forth from memory to microprocessor has created a bottleneck,” Doolittle said.
A neuristor array breaks the bottleneck by emulating the extreme flexibility of biological nervous systems: When a brain computes, it uses a broad set of neural pathways that flash with enormous data. Then, later, to compute the same thing again, it will use quite different neural paths.
Traditional computer pathways, by contrast, are hardwired. For example, look at a present-day processor and you’ll see lines etched into it. Those are pathways that computational signals are limited to.
The new memristor materials at the heart of the neuristor are not etched, and signals flow through the surface very freely, more like they do through the brain, exponentially increasing the number of possible pathways computation can take. That helps the new intelligent retina compute powerfully and swiftly.
Terrorists, missing children
The retina’s memory could also store thousands of photos, allowing it to immediately match up what it sees with the saved images. The retina could pinpoint known terror suspects in a crowd, find missing children, or identify enemy aircraft virtually instantaneously, without having to trawl databases to correctly identify what is in the images.
Even if you take away the optics, the new neuristor arrays still advance artificial intelligence. Instead of light, a surface of neuristors could absorb massive data streams at once, compute them, store them, and compare them to patterns of other data, immediately. It could even autonomously learn to extrapolate further information, like calculating the third dimension out of data from two dimensions.
“It will work with anything that has a repetitive pattern like radar signatures, for example,” Doolittle said. “Right now, that’s too challenging to compute, because radar information is flying out at such a high data rate that no computer can even think about keeping up.”
Smart materials
The research project’s title acronym CEREBRAL may hint at distant dreams of an artificial brain, but what it stands for spells out the present goal in neuromorphic computing: Cross-disciplinary Electronic-ionic Research Enabling Biologically Realistic Autonomous Learning.
The new materials have already been created, and they work, but the researchers don’t yet fully understand why.
Much of the project is dedicated to examining quantum states in the materials and how those states help create useful electronic-ionic properties. Researchers will view them by bombarding the metal oxides with extremely bright x-ray photons at the recently constructed National Synchrotron Light Source II.
Grant sub-awardee Binghamton University is located close by, and Binghamton physicists will run experiments and hone them via theoretical modeling.
‘Sea of lithium’
The neuristors are created mainly by the way the metal oxide materials are grown in the lab, which has advantages over building neuristors in a more wired way.
This materials-growing approach is conducive to mass production. Also, though neuristors in general free signals to take multiple pathways, Georgia Tech’s neuristors do it much more flexibly thanks to chemical properties.
“We also have a sea of lithium, and it’s like an infinite reservoir of computational ionic fluid,” Doolittle said. The lithium niobite imitates the way ionic fluid bathes biological neurons and allows them to flash with electric potential while signaling. In a neuristor array, the lithium niobite helps computational signaling move in myriad directions.
“It’s not like the typical semiconductor material, where you etch a line, and only that line has the computational material,” Doolittle said.
Commander Data’s brain?
“Unlike any other previous neuristors, our neuristors will adapt themselves in their computational-electronic pulsing on the fly, which makes them more like a neurological system,” Doolittle said. “They mimic biology in that we have ion drift across the material to create the memristors (the memory part of neuristors).”
Brains are far superior to computers at most things, but not all. Brains recognize objects and do motor tasks much better. But computers are much better at arithmetic and data processing.
Neuristor arrays can meld both types of computing, making them biological and algorithmic at once, a bit like Commander Data’s brain.
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The research is being funded through the U.S. Department of Defense’s Multidisciplinary University Research Initiatives (MURI) Program under grant number FOA: N00014-16-R-FO05. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of those agencies.
Using this new sunscreen does mean slathering on salmon sperm, more or lees, (read the Methods section of the academic paper cited later in this post). Considering that you’ve likely eaten (insect parts in chocolate) and slathered on more discomfiting stuff already and this development gives you access to an all natural, highly effective sunscreen, if it ever makes its way out of the laboratory, it might not be so bad. From a July 26, 2017 article by Sarah Knapton for The Telegraph,
Sunscreen made from DNA [deoxyribonucleic acid] which acts like a second skin to prevent sun damage is on the horizon.
Scientists in the US have developed a film from the DNA of salmon which gets better at protecting the skin from ultraviolet light the more it is exposed to the Sun.
It also helps lock in moisture beneath the surface which is usually lost during tanning.
“Ultraviolet (UV) light can actually damage DNA, and that’s not good for the skin,” said Guy German, assistant professor of biomedical engineering at Binghamton University. “We thought, let’s flip it. What happens instead if we actually used DNA as a sacrificial layer? So instead of damaging DNA within the skin, we damage a layer on top of the skin.”
German and a team of researchers developed thin and optically transparent crystalline DNA films and irradiated them with UV light. They found that the more they exposed the film to UV light, the better the film got at absorbing it.
“If you translate that, it means to me that if you use this as a topical cream or sunscreen, the longer that you stay out on the beach, the better it gets at being a sunscreen,” said German.
As an added bonus, the DNA coatings are also hygroscopic, meaning that skin coated with the DNA films can store and hold water much more than uncoated skin. When applied to human skin, they are capable of slowing water evaporation and keeping the tissue hydrated for extended periods of time.
German intends to see next if these materials might be good as a wound covering for hostile environments where 1) you want to be able to see the wound healing without removing the dressing, 2) you want to protect the wound from the sun and 3) you want to keep the wound in a moist environment, known to promote faster wound healing rates.
“Not only do we think this might have applications for sunscreen and moisturizers directly, but if it’s optically transparent and prevents tissue damage from the sun and it’s good at keeping the skin hydrated, we think this might be potentially exploitable as a wound covering for extreme environments,” he said.
Boron nitride has been exciting members of the scientific community most recently as an alternative to carbon. A Dec. 22, 2015 news item on ScienceDaily,
When mixed with lightweight polymers, tiny carbon tubes reinforce the material, promising lightweight and strong materials for airplanes, spaceships, cars and even sports equipment. While such carbon nanotube-polymer nanocomposites have attracted enormous interest from the materials research community, a group of scientists now has evidence that a different nanotube — made from boron nitride — could offer even more strength per unit of weight.
A Dec. 22, 2015 American Institute of Physics (AIP) news release by Catherine Meyers, which originated the news item, describes why carbon nanotubes have interested scientists and the advantages presented by boron nitride nanotubes (Note: A link has been removed),
Carbon nanotubes are legendary in their strength — at least 30 times stronger than bullet-stopping Kevlar by some estimates. When mixed with lightweight polymers such as plastics and epoxy resins, the tiny tubes reinforce the material, like the rebar in a block of concrete, promising lightweight and strong materials for airplanes, spaceships, cars and even sports equipment.
While such carbon nanotube-polymer nanocomposites have attracted enormous interest from the materials research community, a group of scientists now has evidence that a different nanotube — made from boron nitride — could offer even more strength per unit of weight. …
Boron nitride, like carbon, can form single-atom-thick sheets that are rolled into cylinders to create nanotubes. By themselves boron nitride nanotubes are almost as strong as carbon nanotubes, but their real advantage in a composite material comes from the way they stick strongly to the polymer.
“The weakest link in these nanocomposites is the interface between the polymer and the nanotubes,” said Changhong Ke, an associate professor in the mechanical engineering department at the State University of New York at Binghamton. If you break a composite, the nanotubes left sticking out have clean surfaces, as opposed to having chunks of polymer still stuck to them. The clean break indicates that the connection between the tubes and the polymer fails, Ke noted.
Plucking Nanotubes
Ke and his colleagues devised a novel way to test the strength of the nanotube-polymer link. They sandwiched boron nitride nanotubes between two thin layers of polymer, with some of the nanotubes left sticking out. They selected only the tubes that were sticking straight out of the polymer, and then welded the nanotube to the tip of a tiny cantilever beam. The team applied a force on the beam and tugged increasingly harder on the nanotube until it was ripped free of the polymer.
The researchers found that the force required to pluck out a nanotube at first increased with the nanotube length, but then plateaued. The behavior is a sign that the connection between the nanotube and the polymer is failing through a crack that forms and then spreads, Ke said.
The researchers tested two forms of polymer: epoxy and poly(methyl methacrylate), or PMMA, which is the same material used for Plexiglas. They found that the epoxy-boron nitride nanotube interface was stronger than the PMMA-nanotube interface. They also found that both polymer-boron nitride nanotube binding strengths were higher than those reported for carbon nanotubes — 35 percent higher for the PMMA interface and approximately 20 percent higher for the epoxy interface.
The Advantages of Boron Nitride Nanotubes
Boron nitride nanotubes likely bind more strongly to polymers because of the way the electrons are arranged in the molecules, Ke explained. In carbon nanotubes, all carbon atoms have equal charges in their nucleus, so the atoms share electrons equally. In boron nitride, the nitrogen atom has more protons than the boron atom, so it hogs more of the electrons in the bond. The unequal charge distribution leads to a stronger attraction between the boron nitride and the polymer molecules, as verified by molecular dynamics simulations performed by Ke’s colleagues in Dr. Xianqiao Wang’s group at the University of Georgia.
Boron nitride nanotubes also have additional advantages over carbon nanotubes, Ke said. They are more stable at high temperatures and they can better absorb neutron radiation, both advantageous properties in the extreme environment of outer space. In addition, boron nitride nanotubes are piezoelectric, which means they can generate an electric charge when stretched. This property means the material offers energy harvesting as well as sensing and actuation capabilities.
The news release does note that boron nitride nanotubes have a drawback ,
The main drawback to boron nitride nanotubes is the cost. Currently they sell for about $1,000 per gram, compared to the $10-20 per gram for carbon nanotubes, Ke said. He is optimistic that the price will come down, though, noting that carbon nanotubes were similarly expensive when they were first developed.
“I think boron nitride nanotubes are the future for making polymer composites for the aerospace industry,” he said.
The researchers haven’t published a study and they have used fruit flies as their testing mechanism (animal models) so, it’s a little difficult (futile) to analyze the work at this stage but it is intriguing. A June 9, 2015 news item on Azonano announces a research collaboration designed to examine the impact engineered nanoparticles have on the gut and the gut microbiome,
Researchers at Binghamton University believe understanding nano particles’ ability to influence our metabolic processing may be integral to mediating metabolic disorders and obesity, both of which are on the rise and have been linked to processed foods.
Anthony Fiumera, associate professor of biological sciences, and Gretchen Mahler, assistant professor of biomedical engineering, are collaborating on a research project funded by a Binghamton University Transdisciplinary Areas of Excellence (TAE) grant to discover the role ingested nanoparticles play in the physiology and function of the gut and gut microbiome.
The gut microbiome is the population of microbes living within the human intestine, consisting of tens of trillions of microorganisms (including at least 1,000 different species of known bacteria). Nanoparticles, which are often added to processed foods to enhance texture and color, have been linked to changes in gut function. As processed foods become more common elements of our diet, there has been a significant increase in concentrations of these particles found in the human body.
Fiumera works in vivo with fruit flies while Mahler works in vitro using a 3-D cell-culture model of the gastrointestinal (GI) tract to understand how ingesting nanoparticles influences glucose processing and the gut microbiome. By using complementary research methods, the researchers have helped advance each other’s understanding of nanoparticles.
Using fruit flies, Fiumera looks at the effects of nanoparticles on development, physiology and biochemical composition, as well as the microbial community in the GI tract of the fly. The fly model offers two advantages: 1) research can be done on a wide range of traits that might be altered by changes in metabolism and 2) the metabolic processes within the fly are similar to those in humans. Fiumera also aims to investigate which genes are associated with responses to the nanoparticles, which ultimately may help us understand why individuals react differently to nanoparticles.
For this project, Mahler expanded her GI tract model to include a commensal intestinal bacterial species and used the model to determine a more detailed mechanism of the role of nanoparticle exposure on gut bacteria and intestinal function. Early results have shown that nanoparticle ingestion alters glucose absorption, and that the presence of beneficial gut bacteria eliminates these effects.
Mahler was already investigating nanoparticles when she reached out to Fiumera and proposed they combine their respective expertise. With the help of undergraduate students Gabriella Shull and John Fountain and graduate student Jonathan Richter, Fiumera and Mahler have begun to uncover some effects of ingesting nanoparticles. Since they are using realistic, low concentrations of nanoparticles, the effects are slight, but eventually may be additive.
The most interesting aspect of this research (to me) is the notion that the impact may be additive. In short, you might be able to tolerate a few more nanoparticles in your gut but as more engineered nanoparticles become part of our food and drink (including water) and your gut receives more and more that tolerance may no longer possible.
There is increasing concern about engineered nanoparticles as they cycle through environment and the US Environmental Protection Agency (EPA) funded a programed by Arizona State University (ASU), LCnano Network (part of the EPA’s larger Life Cycle of Nanomaterials project). You can find out more about the ASU program in my April 8, 2014 post (scroll down about 50% of the way).
Getting back to Binghamton, I look forward to hearing more about the research as it progresses.
The first news item I’m going to highlight was posted on Nanowerk, March 8, 2012 and is focused on the use of silver nanoparticles in mouthwashes and dentures to prevent yeast infections,
Yeasts which cause hard-to-treat mouth infections are killed using silver nanoparticles in the laboratory, scientists have found. These yeast infections, caused by Candida albicans and Candida glabrata target the young, old and immuno-compromised. Professor Mariana Henriques, University of Minho [Portugal], and her colleagues hope to test silver nanoparticles in mouthwash and dentures as a potential preventative measure against these infections.
Professor Henriques and her team, who published their research in the Society for Applied Microbiology’s journal Letters in Applied Microbiology(“Silver nanoparticles: influence of stabilizing agent and diameter on antifungal activity against Candida albicans and Candida glabrata biofilms”), looked at the use of different sizes of silver nanoparticles to determine their anti-fungal properties …
The scientists used artificial biofilms in conditions which mimic those of saliva as closely as possible. They then added different sizes and concentrations of silver nanoparticles and found that different sizes of nanoparticles were equally effective at killing the yeasts. Due to the diversity of the sizes of nanoparticles demonstrating anti-fungal properties the researchers hope this will enable the nanoparticles to be used in many different applications.
Some researchers have expressed concerns around the safety of nanoparticle use but the authors stress this research is at an early stage and extensive safety trials will be carried out before any product reaches the market. [emphasis mine]
Following on the notion of safety and gargling silver nanoparticles, coincidentally, there was another news item also dated March 8, 2012 on Nanowerk, this one about the impact that nanoparticles may have on nutrient uptake,
Nanoparticles are everywhere. From cosmetics and clothes, to soda and snacks. But as versatile as they are, nanoparticles also have a downside, say researchers at Binghamton University and Cornell University in a recent paper published in the journal Nature Nanotechnology (“Oral exposure to polystyrene nanoparticles affects iron absorption”). These tiny particles, even in low doses, could have a big impact on our long-term health.
According to lead author of the article, Gretchen Mahler, assistant professor of bioengineering at Binghamton University, much of the existing research on the safety of nanoparticles has been on the direct health effects. But what Mahler, Michael L. Shuler of Cornell University and a team of researchers really wanted to know was what happens when someone gets constant exposure in small doses – the kind you’d get if you were taken a drug or supplement that included nanoparticles in some form. [e.g. silver nanoparticles in your mouthwash or on your dentures]
“We thought that the best way to measure the more subtle effects of this kind of intake was to monitor the reaction of intestinal cells,” said Mahler. “And we did this in two ways: in vitro, through human intestinal-lining cells that we had cultured in the lab; and in vivo, through the intestinal linings of live chickens. Both sets of results pointed to the same thing – that exposure to nanoparticles influences the absorption of nutrients into the bloodstream.”
As for why the researchers focused on iron and tested polystyrene nanoparticles (from the news item),
The uptake of iron, an essential nutrient, was of particular interest due to the way it is absorbed and processed through the intestines. The way Mahler and the team tested this was to use polystyrene nanoparticles because of its easily traceable fluorescent properties.
“What we found was that for brief exposures, iron absorption dropped by about 50 percent,” said Mahler. “But when we extended that period of time, absorption actually increased by about 200 percent. It was very clear – nanoparticles definitely affects iron uptake and transport.”
While acute oral exposure caused disruptions to intestinal iron transport, chronic exposure caused a remodeling of the intestinal villi – the tiny, finger-like projections that are vital to the intestine’s ability to absorb nutrients – making them larger and broader, thus allowing iron to enter the bloodstream much faster.
As to whether these changes are good or bad the researchers don’t speculate. They do have plans for more testing,
calcium,
copper,
zinc, and
fat-soluble vitamins A, D, E and K
They don’t mention any changes in the types of nanoparticles they might be testing in future.
In any event, our bodies have changed a lot over the centuries, you just have to visit a pyramid in Egypt or a museum that holds medieval armour to observe that humans were once much shorter than we are today.