Tag Archives: sound waves

Sound waves for wearable patches that deliver drugs painlessly

While watching this video I started wondering if they were testing their research on students but that’s not the case; these wearable patches were tested on porcine (pig) skin, which is quite similar to human skin, Note: They tested a B vitamin called niacinamide so, it’s highly unlikely the pigs suffered from it,

An April 20, 2023 news item on ScienceDaily announces the research into using ultrasonic waves for drug delivery,

The skin is an appealing route for drug delivery because it allows drugs to go directly to the site where they’re needed, which could be useful for wound healing, pain relief, or other medical and cosmetic applications. However, delivering drugs through the skin is difficult because the tough outer layer of the skin prevents most small molecules from passing through it.

In hopes of making it easier to deliver drugs through the skin, MIT [Massachusetts Institute of Technology] researchers have developed a wearable patch that applies painless ultrasonic waves to the skin, creating tiny channels that drugs can pass through. This approach could lend itself to delivery of treatments for a variety of skin conditions, and could also be adapted to deliver hormones, muscle relaxants, and other drugs, the researchers say.

An April 20, 2023 Massachusetts Institute of Technology (MIT) news release (also on EurekAlert), which originated the news item, provides technical details about the research, Note: A link has been removed,

“The ease-of-use and high-repeatability offered by this system provides a game-changing alternative to patients and consumers suffering from skin conditions and premature skin aging,” says Canan Dagdeviren, an associate professor in MIT’s Media Lab and the senior author of the study. “Delivering drugs this way could offer less systemic toxicity and is more local, comfortable, and controllable.”

MIT research assistants Chia-Chen Yu and Aastha Shah are the lead authors of the paper, which appears in Advanced Materials, as part of the journal’s “Rising Stars” series, which showcases the outstanding work of researchers in the early stages of their independent careers. Other MIT authors include Research Assistant Colin Marcus and postdoc Md Osman Goni Nayeem. Nikta Amiri, Amit Kumar Bhayadia, and Amin Karami of the University of Buffalo are also authors of the paper.

A boost from sound waves

The researchers began this project as an exploration of alternative ways to deliver drugs. Most drugs are delivered orally or intravenously, but the skin is a route that could offer much more targeted drug delivery for certain applications.

“The main benefit with skin is that you bypass the whole gastrointestinal tract. With oral delivery, you have to deliver a much larger dose in order to account for the loss that you would have in the gastric system,” Shah says. “This is a much more targeted, focused modality of drug delivery.”

Ultrasound exposure has been shown to enhance the skin’s permeability to small-molecule drugs, but most of the existing techniques for performing this kind of drug delivery require bulky equipment. The MIT team wanted to come up with a way to perform this kind of transdermal drug delivery with a lightweight, wearable patch, which could make it easier to use for a variety of applications.

The device that they designed consists of a patch embedded with several disc-shaped piezoelectric transducers, which can convert electric currents into mechanical energy. Each disc is embedded in a polymeric cavity that contains the drug molecules dissolved in a liquid solution. When an electric current is applied to the piezoelectric elements, they generate pressure waves in the fluid, creating bubbles that burst against the skin. These bursting bubbles produce microjets of fluid that can penetrate through the skin’s tough outer layer, the stratum corneum.

“This works open the door to using vibrations to enhance drug delivery. There are several parameters that result in generation of different kinds of waveform patterns. Both mechanical and biological aspects of drug delivery can be improved by this new toolset,” Karami says.

The patch is made of PDMS, a silicone-based polymer that can adhere to the skin without tape. In this study, the researchers tested the device by delivering a B vitamin called niacinamide, an ingredient in many sunscreens and moisturizers.

In tests using pig skin, the researchers showed that when they delivered niacinamide using the ultrasound patch, the amount of drug that penetrated the skin was 26 times greater than the amount that could pass through the skin without ultrasonic assistance.

The researchers also compared the results from their new device to microneedling, a technique sometimes used for transdermal drug delivery, which involves puncturing the skin with miniature needles. The researchers found that their patch was able to deliver the same amount of niacinamide in 30 minutes that could be delivered with microneedles over a six-hour period.

Local delivery

With the current version of the device, drugs can penetrate a few millimeters into the skin, making this approach potentially useful for drugs that act locally within the skin. These could include niacinamide or vitamin C, which is used to treat age spots or other dark spots on the skin, or topical drugs used to heal burns.

With further modifications to increase the penetration depth, this technique could also be used for drugs that need to reach the bloodstream, such as caffeine, fentanyl, or lidocaine. Dagdeviren also envisions that this kind of patch could be useful for delivering hormones such as progesterone. In addition, the researchers are now exploring the possibility of implanting similar devices inside the body to deliver drugs to treat cancer or other diseases.

The researchers are also working on further optimizing the wearable patch, in hopes of testing it soon on human volunteers. They also plan to repeat the lab experiments they did in this study, with larger drug molecules.

“After we characterize the drug penetration profiles for much larger drugs, we would then see which candidates, like hormones or insulin, can be delivered using this technology, to provide a painless alternative for those who are currently bound to self-administer injections on a daily basis,” Shah says.

Here’s a link to and a citation for the paper,

A Conformable Ultrasound Patch for Cavitation-Enhanced Transdermal Cosmeceutical Delivery by Chia-Chen Yu, Aastha Shah, Nikta Amiri, Colin Marcus, Md Osman Goni Nayeem, Amit Kumar Bhayadia, Amin Karami, Canan Dagdeviren. Advanced Materials Volume35, Issue 23 June 8, 2023 2300066 DOI: https://doi.org/10.1002/adma.202300066 First published online: 19 March 2023

This paper is open access.

Spiders can outsource hearing to their webs

A March 29, 2022 news item on ScienceDaily highlights research into how spiders hear,

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.

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.

A March 29, 2022 Binghamton University news release (also on EurekAlert) by Chris Kocher gives more detail about the work (Note: Links have been removed),

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.”

A March 29, 2022 Cornell University news release (also on EurekAlert but published March 30, 2022) by Krishna Ramanujan offers a somewhat different perspective on the work, Note: Links have been removed)

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.  

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).

Controlling the tiniest particles with sound-induced electrical fields

I find the use of sound as a research tool in this June 23, 2021 news item on ScienceDaily to be fascinating,

Engineers at Duke University [North Carolina, USL] have devised a system for manipulating particles approaching the miniscule 2.5 nanometer diameter of DNA using sound-induced electric fields. Dubbed “acoustoelectronic nanotweezers,” the approach provides a label-free, dynamically controllable method of moving and trapping nanoparticles over a large area. The technology holds promise for applications in the fields ranging from condensed matter physics to biomedicine.

A June 22, 2021 Duke University news release (also on EurekAlert) by Ben Kingery, which originated the news item, explains the interest in precise control and the use of sound in more detail,

Precisely controlling nanoparticles is a crucial ability for many emerging technologies. For example, separating exosomes and other tiny biological molecules from blood could lead to new types of diagnostic tests for the early detection of tumors and neurodegenerative diseases. Placing engineered nanoparticles in a specific pattern before fixing them in place can help create new types of materials with highly tunable properties.

For more than a decade, Tony Jun Huang, the William Bevan Distinguished Professor of Mechanical Engineering and Materials Science at Duke, has pursued acoustic tweezer systems that use sound waves to manipulate particles. However, it becomes difficult to push things around with sound when their profile drops below that of some of the smallest viruses.

“Although we’re still fundamentally using sound, our acoustoelectronic nanotweezers use a very different mechanism than these previous technologies,” said Joseph Rufo, a graduate student working in Huang’s laboratory. “Now we’re not only exploiting acoustic waves, but electric fields with the properties of acoustic waves.”

Instead of using sound waves to directly move the nanoparticles, Huang, Rufo and Peiran Zhang, a postdoc in Huang’s laboratory, use sound waves to create electric fields that provide the push. The new acoustoelectronic tweezer approach works by placing a piezoelectric substrate–a thin material that creates electricity in response to mechanical stress–beneath a small chamber filled with liquid. Four transducers are aligned on the chamber’s sides, which send sound waves into the piezoelectric substrate.

These sound waves bounce around and interact with one another to create a stable pattern. And because the sound waves are creating stresses within the piezoelectric substrate, they also create electrical fields. These couple with the acoustic waves in a way that creates electric field patterns within the chamber above.

“The vibrations of the sound waves also make the electric field dynamically alternate between positive and negative charges,” said Zhang. “This alternating electric field polarizes the nanoparticles in liquid, which serves as a handle to manipulate them.”

The result is a mechanism that mixes some of the strengths of other nanoparticle manipulators. Because the acoustoelectronic nanotweezers induce an electromagnetic response in the nanomaterials, the nanoparticles do not need to be conductive on their own or tagged with any sort of modifier. And because the patterns are created with sound waves, their positions and properties can be quickly and easily modified to create a variety of options.

In the prototype, the researchers show nanoparticles placed into striped and checkerboard patterns. They even push individual particles around in an arbitrary manner dynamically, spelling out letters such as D, U, K and E [emphasis mine]. The researchers then demonstrate that these aligned nano-patterns can be transferred onto dry films using delicate nanoparticles such as carbon nanotubes, 3.5-nanometer proteins and 1.4-nanometer dextran often used in biomedical research. And they show that all of this can be accomplished on a working area that is tens to hundreds of times larger than current state-of-the-art nanotweezing technologies [emphasis mine].

Nanotweezing technologies? This concept is new to me.How will I work it into my next conversation?

As for spelling out D, U, K, and E, that brings to mind Don Eigler (from his Wikipedia entry),

In 1989, Eigler was the first to use a scanning tunneling microscope tip to arrange individual atoms on a surface, famously spelling out the letters “IBM” with 35 xenon atoms.

Perhaps the Duke University researchers intended an ‘hommage’? or ‘tip of the hat’?

Here’s a link to and a citation for the paper,

Acoustoelectronic nanotweezers enable dynamic and large-scale control of nanomaterials by Peiran Zhang, Joseph Rufo, Chuyi Chen, Jianping Xia, Zhenhua Tian, Liying Zhang, Nanjing Hao, Zhanwei Zhong, Yuyang Gu, Krishnendu Chakrabarty & Tony Jun Huang. Nature Communications volume 12, Article number: 3844 (2021) DOI: https://doi.org/10.1038/s41467-021-24101-z Published 22 June 2021

This paper is open access.

Understanding the fundamental limits of graphene electronics by way of a new quantum phenomenon

A July 26, 2019 news item on Nanowerk takes us into the world of quantum physics and graphene (Note: Links have been removed),

A team of researchers from the Universities of Manchester, Nottingham and Loughborough have discovered quantum phenomena that helps to understand the fundamental limits of graphene electronics.

As published in Nature Communications (“Strong magnetophonon oscillations in extra-large graphene”), the work describes how electrons in a single atomically-thin sheet of graphene scatter off the vibrating carbon atoms which make up the hexagonal crystal lattice.

By applying a magnetic field perpendicular to the plane of graphene, the current-carrying electrons are forced to move in closed circular “cyclotron” orbits. In pure graphene, the only way in which an electron can escape from this orbit is by bouncing off a “phonon” in a scattering event. These phonons are particle-like bundles of energy and momentum and are the “quanta” of the sound waves associated with the vibrating carbon atom. The phonons are generated in increasing numbers when the graphene crystal is warmed up from very low temperatures.

By passing a small electrical current through the graphene sheet, the team were able to measure precisely the amount of energy and momentum that is transferred between an electron and a phonon during a scattering event.

A July 26, 2019 University of Manchester press release, which originated the news item, provides additional technical details,

Their experiment revealed that two types of phonon scatter the electrons: transverse acoustic (TA) phonons in which the carbon atoms vibrate perpendicular to the direction of phonon propagation and wave motion (somewhat analogous to surface waves on water) and longitudinal acoustic (LA) phonons in which the carbon atoms vibrate back and forth along the direction of the phonon and the wave motion; (this motion is somewhat analogous to the motion of sound waves through air).

The measurements provide a very accurate measure of the speed of both types of phonons, a measurement which is otherwise difficult to make for the case of a single atomic layer. An important outcome of the experiments is the discovery that TA phonon scattering dominates over LA phonon scattering.

The observed phenomena, commonly referred to as “magnetophonon oscillations”, was measured in many semiconductors years before the discovery of graphene. It is one of the oldest quantum transport phenomena that has been known for more than fifty years, predating the quantum Hall effect. Whereas graphene possesses a number of novel, exotic electronic properties, this rather fundamental phenomenon has remained hidden.

Laurence Eaves & Roshan Krishna Kumar, co-authors of the work said: “We were pleasantly surprised to find such prominent magnetophonon oscillations appearing in graphene. We were also puzzled why people had not seen them before, considering the extensive amount of literature on quantum transport in graphene.”

Their appearance requires two key ingredients. First, the team had to fabricate high quality graphene transistors with large areas at the National Graphene Institute. If the device dimensions are smaller than a few micrometres the phenomena could not be observed.

Piranavan Kumaravadivel from The University of Manchester, lead author of the paper said: “At the beginning of quantum transport experiments, people used to study macroscopic, millimetre sized crystals. In most of the work on quantum transport on graphene, the studied devices are typically only a few micrometres in size. It seems that making larger graphene devices is not only important for applications but now also for fundamental studies.”

The second ingredient is temperature. Most graphene quantum transport experiments are performed at ultra-cold temperatures in-order to slow down the vibrating carbon atoms and “freeze-out” the phonons that usually break quantum coherence. Therefore, the graphene is warmed up as the phonons need to be active to cause the effect.

Mark Greenaway, from Loughborough University, who worked on the quantum theory of this effect said: “This result is extremely exciting – it opens a new route to probe the properties of phonons in two-dimensional crystals and their heterostructures. This will allow us to better understand electron-phonon interactions in these promising materials, understanding which is vital to develop them for use in new devices and applications.”

Here’s a link to and a citation for the paper,

Strong magnetophonon oscillations in extra-large graphene by P. Kumaravadivel, M. T. Greenaway, D. Perello, A. Berdyugin, J. Birkbeck, J. Wengraf, S. Liu, J. H. Edgar, A. K. Geim, L. Eaves & R. Krishna Kumar. ature Communicationsvolume 10, Article number: 3334 (2019) DOI: https://doi.org/10.1038/s41467-019-11379-3 Published 26 July 2019

This paper is open access.

Sound-absorbing nanofoam

In these increasingly noisy days (there’s construction going on around me), news of a cheaper, easier way to dull the noise is very attractive. From a June 25, 2018 Far Eastern Federal University (Russia) press release on EurekAlert,

The breakthrough material reduces a noise level by 100% more efficient comparing to standard analogs, cutting the level of noise transmission by 20-22 dB. The new foam reacts to sound waves not only of high but also of low frequencies, which can damage human health. A young scientist from the Far Eastern Federal University (FEFU) took part in the development.

PARTNERSHIP DEVELOPMENT

Alexey Zavjalov, postdoc, researcher at the Academic Department of Nuclear Technologies School of Natural Science, FEFU, worked as a part of the international team of Russian and South Korean scientists under professor S.P. Bardakhanov. Alexey’s research performance led to the creation of nanofoam – the new noise-absorbing composite material. The results of the work are published in ‘Applied Acoustics’.

‘The problem of noise is the problem of modern technogenic civilization. In South Korea, cities are equipped with round-the-clock working stationary and mobile networks for noise levels monitoring. The urbanization level of such territorially small countries as South Korea is much higher than in Russia. However, in our country this problem is still crucial for big cities,’ – explained Alexey Zavjalov. – ‘The development of new noise-absorbing materials is especially interesting for the automotive industry. Modern people spend a lot of time driving cars and the noise level inside the vehicles’ directly determines the quality of life. For East Asian countries, the issue of noise control is relevant for high-speed rail lines.’ Porous materials are excellent sound absorbers but their noise-absorbing properties can be significantly enhanced by nanoporous grit injected into the foam structure and formed internal channels in it. Alexey Zavjalov has developed approaches for saturation of macroporous foam material with nanoporous grit.

HARMFULNESS OF THE LOW FREQUENCIES NOISES.

Along with the rapid development of nanotechnology, there have been many attempts to mix nano- and microsized materials to create a modified material with enhanced strength, elastic, dynamical and vibrational properties. The acoustic parameters of such materials could not be fundamentally enhanced thus far.

Foam materials are most often used for soundproofing purposes. They provide the proper quality at a reasonable cost, but until today have been effective against high-frequency noise only. At the same time, low frequencies can be much more harmful to human health.

Infra- and low-frequency vibrations and noise (less than 0.4 kHz) are most harmful and dangerous for human health and life. Especially unfavorable is their long-lasting impact, since leads to serious diseases and pathologies. Complaints on such oppressions exceed 35% of the sum total of complaints on harmful environmental conditions.

The foam material, developed by Russian and Korean scientists, demonstrated promising results at medium frequencies and, therefore, more specialized low-frequency noise tests are needed.

CHEAPER AND EASIER FOR APPLICATION THAN AEROGEL.

The improved acoustic characteristics of the newest hybrid nanofoam were obtained by additional impregnation of the standard off-the-shelf sound-absorbing foam with porous granules of silica and magnetite nanoparticles. The porous foam was immersed in nanopowder suspensions in the liquid, subjected to ultrasonic treatment and dried.

The nanoparticles granules formed in the result can be compared structurally to a widely known class of materials – aerogel. It has not only excellent thermal insulation properties but also has a good noise-proof. However, aerogels are quite expensive and complex when used in structures. The new material, created according to the scheme developed by the FEFU researcher, is structurally similar to aerogel but is free of such shortcomings as a high price and engineering problems.

COMPOSITE TECHNOLOGY

The mechanism of sound absorption of a new foam is based on the fact that its sound-absorbing surface is significantly scaled due to the presence of a large number of nanopores in the particles injected, as well as the location of these particles in the foam matrix in the form of distinct channels. Nanoparticles dissipate the energy of a sound wave transforming it into heat. The soundproof properties of the material increase.

Scientists found out that the composite structure is most effective for noise reduction. Thin layers of foam impregnated with nanoparticles are connected to each other in a “sandwich”-construction. This design significantly improves the soundproof properties of the resulting material. The outcome of the study also suggests that the more foamy material is impregnated with nanoparticles, the better it’s sound absorption is.

‘In some approximation, any material can be represented as a network of weights connected by springs. Such a mechanical system always has its own frequency bands, in which the oscillations propagate in the system relatively freely. There are also forbidden frequency bands in which the oscillations rapidly fade out in the system. To effectively extinguish the transmission of oscillations, including sound waves, the materials should be alternated in such a way that the fluctuations that propagate freely in the first material would be in the forbidden band for the second layer,’- commented Alexey Zavjalov. – ‘Of course, for our foam material, this idealization is too crude. However, it allows us to clearly illustrate the fundamentally conditioned necessity of creating a “sandwich” structure.’

RESEARCH OUTCOME

The study showed the effectiveness of the method of foams impregnation with nanosilica or nanomagnetite, which form granules up to several hundred micrometers (in accordance with the pore sizes of the modified foam material) and having pores about 15 nm. This small addition provided a more complex and branched 3D network of nanochannels which led to an additional absorption of noise energy.

Due to the method used, the noise absorption efficiency was achieved in the range of 2.0-6.3 kHz and at lower frequencies 0.5-1.6 kHz. The degree of absorption was increased by 60-100% and the sound transmission was reduced by 20-22 dB, regardless of the type of nanofiller.

‘There is room to further improve the sound absorbing properties of the new material for medium and low frequencies using the” active control” strategy’. – Alexey Zavjalov comments on the plans for further development of such an important scientific topic. – ‘First of all, this refers to the materials obtained by using a magnetite nanopowder. Active noise protection systems have long been used in the world. The main idea is to detect the noise acoustic fields “online” and to generate sound waves in antiphase by means of loudspeakers. That allows achieving a significant reduction of noise in a given area. Concerning the nanofoam, it’s proposed to adapt this approach and to actively exert on a material saturated with granules of magnetite nanoparticles by magnetic fields. This will achieve even better noise reduction.’

Here’s a link to and a citation for the paper,

Hybrid sound-absorbing foam materials with nanostructured grit-impregnated pores by S.P.Bardakhanov, C.M.Lee, V.N.Goverdovskiy, A.P.Zavjalov, K.V.Zobov, M.Chen, Z.H.Xu, I.K.Chakin, D.Yu.Trufanov. Applied Acoustics Volume 139, October 2018, Pages 69-74
https://doi.org/10.1016/j.apacoust.2018.04.024 Available online 23 April 2018.

This paper is behind a paywall.

If you have difficulty seeing the press release on EurekAlert, there is a June 26, 2018 news item on a Russian news site, RSF News and there is an edited version in a June 26, 2018 news item on Azonano.

Using sound to transfer quantum information

It seems sound is becoming more prominent as a means of science data communication (data sonification) and in this upcoming case, data transfer. From a June 5, 2018 news item on ScienceDaily,

Quantum physics is on the brink of a technological breakthrough: new types of sensors, secure data transmission methods and maybe even computers could be made possible thanks to quantum technologies. However, the main obstacle here is finding the right way to couple and precisely control a sufficient number of quantum systems (for example, individual atoms).

A team of researchers from TU Wien and Harvard University has found a new way to transfer the necessary quantum information. They propose using tiny mechanical vibrations. The atoms are coupled with each other by ‘phonons’ — the smallest quantum mechanical units of vibrations or sound waves.

A June 5, 2018 Technical University of Vienna (TU Wien) press release, which originated the news item, explains the work in greater detail,

“We are testing tiny diamonds with built-in silicon atoms – these quantum systems are particularly promising,” says Professor Peter Rabl from TU Wien. “Normally, diamonds are made exclusively of carbon, but adding silicon atoms in certain places creates defects in the crystal lattice where quantum information can be stored.” These microscopic flaws in the crystal lattice can be used like a tiny switch that can be switched between a state of higher energy and a state of lower energy using microwaves.

Together with a team from Harvard University, Peter Rabl’s research group has developed a new idea to achieve the targeted coupling of these quantum memories within the diamond. One by one they can be built into a tiny diamond rod measuring only a few micrometres in length, like individual pearls on a necklace. Just like a tuning fork, this rod can then be made to vibrate – however, these vibrations are so small that they can only be described using quantum theory. It is through these vibrations that the silicon atoms can form a quantum-mechanical link to each other.

“Light is made from photons, the quantum of light. In the same way, mechanical vibrations or sound waves can also be described in a quantum-mechanical manner. They are comprised of phonons – the smallest possible units of mechanical vibration,” explains Peter Rabl. As the research team has now been able to show using simulation calculations, any number of these quantum memories can be linked together in the diamond rod thanks to these phonons. The individual silicon atoms are “switched on and off” using microwaves. During this process, they emit or absorb phonons. This creates a quantum entanglement of different silicon defects, thus allowing quantum information to be transferred.

The road to a scalable quantum network
Until now it was not clear whether something like this was even possible: “Usually you would expect the phonons to be absorbed somewhere, or to come into contact with the environment and thus lose their quantum mechanical properties,” says Peter Rabl. “Phonons are the enemy of quantum information, so to speak. But with our calculations, we were able to show that, when controlled appropriately using microwaves, the phonons are in fact useable for technical applications.”

The main advantage of this new technology lies in its scalability: “There are many ideas for quantum systems that, in principle, can be used for technological applications. The biggest problem is that it is very difficult to connect enough of them to be able to carry out complicated computing operations,” says Peter Rabl. The new strategy of using phonons for this purpose could pave the way to a scalable quantum technology.

Here’s a link to and a citation for the paper,

Phonon Networks with Silicon-Vacancy Centers in Diamond Waveguides by M.-A. Lemonde, S. Meesala, A. Sipahigil, M. J. A. Schuetz, M. D. Lukin, M. Loncar, and P. Rabl. Phys. Rev. Lett. 120 (21), 213603 DOI:https://doi.org/10.1103/PhysRevLett.120.213603 Published 25 May 2018

This paper is behind a paywall.

Using acoustic waves to move fluids at the nanoscale

A Nov. 14, 2016 news item on ScienceDaily describes research that could lead to applications useful for ‘lab-on-a-chip’ operations,

A team of mechanical engineers at the University of California San Diego [UCSD] has successfully used acoustic waves to move fluids through small channels at the nanoscale. The breakthrough is a first step toward the manufacturing of small, portable devices that could be used for drug discovery and microrobotics applications. The devices could be integrated in a lab on a chip to sort cells, move liquids, manipulate particles and sense other biological components. For example, it could be used to filter a wide range of particles, such as bacteria, to conduct rapid diagnosis.

A Nov. 14, 2016 UCSD news release (also on EurrekAlert), which originated the news item, provides more information,

The researchers detail their findings in the Nov. 14 issue of Advanced Functional Materials. This is the first time that surface acoustic waves have been used at the nanoscale.

The field of nanofluidics has long struggled with moving fluids within channels that are 1000 times smaller than the width of a hair, said James Friend, a professor and materials science expert at the Jacobs School of Engineering at UC San Diego. Current methods require bulky and expensive equipment as well as high temperatures. Moving fluid out of a channel that’s just a few nanometers high requires pressures of 1 megaPascal, or the equivalent of 10 atmospheres.

Researchers led by Friend had tried to use acoustic waves to move the fluids along at the nano scale for several years. They also wanted to do this with a device that could be manufactured at room temperature.

After a year of experimenting, post-doctoral researcher Morteza Miansari, now at Stanford, was able to build a device made of lithium niobate with nanoscale channels where fluids can be moved by surface acoustic waves. This was made possible by a new method Miansari developed to bond the material to itself at room temperature.  The fabrication method can be easily scaled up, which would lower manufacturing costs. Building one device would cost $1000 but building 100,000 would drive the price down to $1 each.

The device is compatible with biological materials, cells and molecules.

Researchers used acoustic waves with a frequency of 20 megaHertz to manipulate fluids, droplets and particles in nanoslits that are 50 to 250 nanometers tall. To fill the channels, researchers applied the acoustic waves in the same direction as the fluid moving into the channels. To drain the channels, the sound waves were applied in the opposite direction.

By changing the height of the channels, the device could be used to filter a wide range of particles, down to large biomolecules such as siRNA, which would not fit in the slits. Essentially, the acoustic waves would drive fluids containing the particles into these channels. But while the fluid would go through, the particles would be left behind and form a dry mass. This could be used for rapid diagnosis in the field.

Here’s a link to and a citation for the paper,

Acoustic Nanofluidics via Room-Temperature Lithium Niobate Bonding: A Platform for Actuation and Manipulation of Nanoconfined Fluids and Particles by Morteza Miansari and James R. Friend. Advanced Functional Materials DOI: 10.1002/adfm.201602425 Version of Record online: 20 SEP 2016
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

They do have an animation sequence illustrating the work but it could be considered suggestive and is, weirdly, silent,

 

 

Swallow your technology and wear it inside (wearable tech: 2 of 3)

While there are a number of wearable and fashionable pieces of technology that monitor heart rate and breathing, they are all worn on the outside of your body. Researchers are working on an alternative that can be swallowed and will monitor vital signs from within the gastrointestinal tract. I believe this is a prototype of the device,

This ingestible electronic device invented at MIT can measure heart rate and respiratory rate from inside the gastrointestinal tract. Courtesy: MIT

This ingestible electronic device invented at MIT can measure heart rate and respiratory rate from inside the gastrointestinal tract. Image: Albert Swiston/MIT Lincoln Laboratory Courtesy: MIT

From a Nov. 18, 2015 news item on phys.org,

This type of sensor could make it easier to assess trauma patients, monitor soldiers in battle, perform long-term evaluation of patients with chronic illnesses, or improve training for professional and amateur athletes, the researchers say.

The new sensor calculates heart and breathing rates from the distinctive sound waves produced by the beating of the heart and the inhalation and exhalation of the lungs.

“Through characterization of the acoustic wave, recorded from different parts of the GI tract, we found that we could measure both heart rate and respiratory rate with good accuracy,” says Giovanni Traverso, a research affiliate at MIT’s Koch Institute for Integrative Cancer Research, a gastroenterologist at Massachusetts General Hospital, and one of the lead authors of a paper describing the device in the Nov. 18 issue of the journal PLOS One.

A Nov. 18, 2015 Massachusetts Institute of Technology (MIT) news release by Anne Trafton, which originated the news item, further explains the research,

Doctors currently measure vital signs such as heart and respiratory rate using techniques including electrocardiograms (ECG) and pulse oximetry, which require contact with the patient’s skin. These vital signs can also be measured with wearable monitors, but those are often uncomfortable to wear.

Inspired by existing ingestible devices that can measure body temperature, and others that take internal digestive-tract images, the researchers set out to design a sensor that would measure heart and respiratory rate, as well as temperature, from inside the digestive tract.

The simplest way to achieve this, they decided, would be to listen to the body using a small microphone. Listening to the sounds of the chest is one of the oldest medical diagnostic techniques, practiced by Hippocrates in ancient Greece. Since the 1800s, doctors have used stethoscopes to listen to these sounds.

The researchers essentially created “an extremely tiny stethoscope that you can swallow,” Swiston says. “Using the same sensor, we can collect both your heart sounds and your lung sounds. That’s one of the advantages of our approach — we can use one sensor to get two pieces of information.”

To translate these acoustic data into heart and breathing rates, the researchers had to devise signal processing systems that distinguish the sounds produced by the heart and lungs from each other, as well as from background noise produced by the digestive tract and other parts of the body.

The entire sensor is about the size of a multivitamin pill and consists of a tiny microphone packaged in a silicone capsule, along with electronics that process the sound and wirelessly send radio signals to an external receiver, with a range of about 3 meters.

In tests along the GI tract of pigs, the researchers found that the device could accurately pick up heart rate and respiratory rate, even when conditions such as the amount of food being digested were varied.

“The authors introduce some interesting and radically different approaches to wearable physiological status monitors, in which the devices are not worn on the skin or on clothing, but instead reside, in a transient fashion, inside the gastrointestinal tract. The resulting capabilities provide a powerful complement to those found in wearable technologies as traditionally conceived,” says John Rogers, a professor of materials science and engineering at the University of Illinois who was not part of the research team.

Better diagnosis

The researchers expect that the device would remain in the digestive tract for only a day or two, so for longer-term monitoring, patients would swallow new capsules as needed.

For the military, this kind of ingestible device could be useful for monitoring soldiers for fatigue, dehydration, tachycardia, or shock, the researchers say. When combined with a temperature sensor, it could also detect hypothermia, hyperthermia, or fever from infections.

In the future, the researchers plan to design sensors that could diagnose heart conditions such as abnormal heart rhythms (arrhythmias), or breathing problems including emphysema or asthma. Currently doctors require patients to wear a harness (Holter) monitor for up to a week to detect such problems, but these often fail to produce a diagnosis because patients are uncomfortable wearing them 24 hours a day.

“If you could ingest a device that would listen for those pathological sounds, rather than wearing an electrical monitor, that would improve patient compliance,” Swiston says.

The researchers also hope to create sensors that would not only diagnose a problem but also deliver a drug to treat it.

“We hope that one day we’re able to detect certain molecules or a pathogen and then deliver an antibiotic, for example,” Traverso says. “This development provides the foundation for that kind of system down the line.”

MIT has provided a video with two of the researchers describing their work and and plans for its future development,

Here’s a link to and a citation for the paper,

Physiologic Status Monitoring via the Gastrointestinal Tract by G. Traverso, G. Ciccarelli, S. Schwartz, T. Hughes, T. Boettcher, R. Barman, R. Langer, & A. Swiston. PLOS DOI: 10.1371/journal.pone.0141666 Published: November 18, 2015

This paper is open access.

Note added Nov. 25, 2015 at 1625 hours PDT: US National Public Radio (NPR) has a story on this research. You can find Nov. 23, 2015 podcast (about six minutes) and a series of textual excerpts featuring Albert Swiston, biomaterials scientist at MIT, and Stephen Shankland, senior writer for CNET covering digital technology, from the podcast here.

The sound of moving data

In fact, scientists from the University of Sheffield (UK) and the University of Leeds (UK) have found a way to move data easily and quickly by using sound waves. From a Nov. 3, 2015 news item on ScienceDaily,

Nothing is more frustrating that watching that circle spinning in the centre of your screen, while you wait for your computer to load a programme or access the data you need. Now a team from the Universities of Sheffield and Leeds may have found the answer to faster computing: sound.

The research — published in Applied Physics Letters — has shown that certain types of sound waves can move data quickly, using minimal power.

A Nov. 3, 2015 University of Sheffield news release on EurekAlert, which originated the news item, explains some of the issues with data and memory before briefly describing how sound waves could provide a solution,

The world’s 2.7 zettabytes (2.7 followed by 21 zeros) of data are mostly held on hard disk drives: magnetic disks that work like miniaturised record players, with the data read by sensors that scan over the disk’s surface as it spins. But because this involves moving parts, there are limits on how fast it can operate.

For computers to run faster, we need to create “solid-state” drives that eliminate the need for moving parts – essentially making the data move, not the device on which it’s stored. Flash-based solid-state disk drives have achieved this, and store information electrically rather than magnetically. However, while they operate much faster than normal hard disks, they last much less time before becoming unreliable, are much more expensive and still run much slower than other parts of a modern computer – limiting total speed.

Creating a magnetic solid-state drive could overcome all of these problems. One solution being developed is ‘racetrack memory’, which uses tiny magnetic wires, each one hundreds of times thinner than a human hair, down which magnetic “bits” of data run like racing cars around a track. Existing research into racetrack memory has focused on using magnetic fields or electric currents to move the data bits down the wires. However, both these options create heat and reduce power efficiency, which will limit battery life, increase energy bills and CO2 emissions.

Dr Tom Hayward from the University of Sheffield and Professor John Cunningham from the University of Leeds have together come up with a completely new solution: passing sound waves across the surface on which the wires are fixed. They also found that the direction of data flow depends on the pitch of the sound generated – in effect they “sang” to the data to move it.

The sound used is in the form of surface acoustic waves – the same as the most destructive wave that can emanate from an earthquake. Although already harnessed for use in electronics and other areas of engineering, this is the first time surface acoustic waves have been applied to a data storage system.

Dr Hayward, from Sheffield’s Faculty of Engineering, said: “The key advantage of surface acoustic waves in this application is their ability to travel up to several centimetres without decaying, which at the nano-scale is a huge distance. Because of this, we think a single sound wave could be used to “sing” to large numbers of nanowires simultaneously, enabling us to move a lot of data using very little power. We’re now aiming to create prototype devices in which this concept can be fully tested.”

Here’s a link to and a citation for the paper,

A sound idea: Manipulating domain walls in magnetic nanowires using surface acoustic waves by J. Dean, M. T. Bryan, J. D. Cooper, A. Virbule, J. E. Cunningham, and T. J. Hayward. Appl. Phys. Lett. 107, 142405 (2015); http://dx.doi.org/10.1063/1.4932057

This is an open access paper.

Dexter Johnson in a Nov. 5, 2015 posting on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) provides a few additional details about the work such as a brief mention of IBM’s work developing racetrack memory, also known as, a non-volatile memory device.

High frequency sound waves enable precision micro- and nanomanufacturing

I have finally moved this item to the top of my playlist: researchers from RMIT University (formerly the Royal Melbourne Institute of Technology) in Australia have developed a technique employing sound waves for greater precision in manufacturing chips at the micro- and nanoscales. From a June 24, 2014 news item on ScienceDaily,

In a breakthrough discovery, researchers at RMIT University in Melbourne, Australia, have harnessed the power of sound waves to enable precision micro- and nano-manufacturing.

The researchers have demonstrated how high-frequency sound waves can be used to precisely control the spread of thin film fluid along a specially-designed chip, in a paper published today in Proceedings of the Royal Society A.

With thin film technology the bedrock of microchip and microstructure manufacturing, the pioneering research offers a significant advance — potential applications range from thin film coatings for paint and wound care to 3D printing, micro-casting and micro-fluidics.

A June 30, 2014 RMIT university news release, which originated the news item (despite the date discrepancy), offers more details (Note: Links have been removed),

Professor James Friend, Director of the MicroNano Research Facility at RMIT, said the researchers had developed a portable system for precise, fast and unconventional micro- and nano-fabrication.

“By tuning the sound waves, we can create any pattern we want on the surface of a microchip,” Professor Friend said.

“Manufacturing using thin film technology currently lacks precision – structures are physically spun around to disperse the liquid and coat components with thin film.

“We’ve found that thin film liquid either flows towards or away from high-frequency sound waves, depending on its thickness.

“We not only discovered this phenomenon but have also unravelled the complex physics behind the process, enabling us to precisely control and direct the application of thin film liquid at a micro and nano-scale.”

Professor Friend led the research team behind the breakthrough, which included Dr Amgad Rezk, from the School of Civil, Environmental and Chemical Engineering, Professor Leslie Yeo, co-Director of the Micro Nanophysics Research Laboratory, and Ofer Manor, from the Israel Institute of Technology.

The research was part of Dr Rezk’s recently completed PhD, in the School of Electrical and Computer Engineering.

The new process, which the researchers have called “acoustowetting”, works on a chip made of lithium niobate – a piezoelectric material capable of converting electrical energy into mechanical pressure.

The surface of the chip is covered with microelectrodes and the chip is connected to a power source, with the power converted to high-frequency sound waves. Thin film liquid is added to the surface of the chip, and the sound waves are then used to control its flow.

The research shows that when the liquid is ultra-thin – at nano and sub-micro depths – it flows away from the high-frequency sound waves.

The flow reverses at slightly thicker dimensions, moving towards the sound waves. But at a millimetre or more in depth, the flow reverses again, moving away.

Here’s a link to and a citation for the paper,

Double flow reversal in thin liquid films driven by megahertz-order surface vibration by Amgad R. Rezk, Ofer Manor, Leslie Y. Yeo, and James R. Friend. Proc. R. Soc. A 8 September 2014 vol. 470 no. 2169 20130765 Published 25 June 2014 doi: 10.1098/rspa.2013.0765

This paper is open access.

The researchers have produced this video illustrating the action of the sound waves,