Tag Archives: piezoelectricity

Harvesting energy from tires, streetlights, buildings, and more

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It seems to me that this year there’s been more interest than usual in harvesting energy from heretofore untapped resources, from an October 17, 2024 news item on ScienceDaily,

Imagine tires that charge a vehicle as it drives, streetlights powered by the rumble of traffic, or skyscrapers that generate electricity as the buildings naturally sway and shudder.

These energy innovations could be possible thanks to researchers at Rensselaer Polytechnic Institute developing environmentally friendly materials that produce electricity when compressed or exposed to vibrations.

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The RPI team developed a polymer film infused with a special chalcogenide perovskite compound that produces electricity when squeezed or stressed. The device could be used in consumer goods, such as a shoe that lights up when the user walks, though it has potential applications in transportation and infrastructure. Credit: Rensselaer Polytechnic Institute

An October 15, 2024 Rensselaer Polytechnic Institute news release (also on EurekAlert) by Samantha Murray, which originated the news item, provides a few technical details about the research, Note: Links have been removed,

In a recent study published in the journal Nature Communications, the team developed a polymer film infused with a special chalcogenide perovskite compound that produces electricity when squeezed or stressed, a phenomenon known as the piezoelectric effect. While other piezoelectric materials currently exist, this is one of the few high-performing ones that does not contain lead, making it an excellent candidate for use in machines, infrastructure as well as bio-medical applications.

“We are excited and encouraged by our findings and their potential to support the transition to green energy,” said Nikhil Koratkar, Ph.D., corresponding author of the study and the John A. Clark and Edward T. Crossan Professor in the Department of Mechanical, Aerospace, and Nuclear Engineering. “Lead is toxic and increasing being restricted and phased out of materials and devices. Our goal was to create a material that was lead-free and could be made inexpensively using elements commonly found in nature.”

The energy harvesting film, which is only 0.3 millimeters thick, could be integrated into a wide variety of devices, machines, and structures, Koratkar explained.

“Essentially, the material converts mechanical energy into electrical energy — the greater the applied pressure load and the greater the surface area over which the pressure is applied, the greater the effect,” Koratkar said. “For example, it could be used beneath highways to generate electricity when cars drive over them.  It could also be used in building materials, making electricity when buildings vibrate.”

The piezoelectric effect occurs in materials that lack structural symmetry. Under stress, piezoelectric materials deform in such a way that causes positive and negative ions within the material to separate. This “dipole moment,” as it is known scientifically, can be harnessed and turned into an electric current. In the chalcogenide perovskite material discovered by the RPI team, structural symmetry can be easily broken under stress leading to a pronounced piezoelectric response. 

Once they synthesized their new material, which contains barium, zirconium and sulfur, the researchers tested its ability to produce electricity by subjecting it to various bodily movements, such as walking, running, clapping, and tapping fingers.

The researchers found that the material generated electricity during these experiments, enough to even power banks of LED’s that spelled out RPI.

“These tests show this technology could be useful, for example, in a device worn by runners or bikers that lights up their shoes or helmets and makes them more visible. However, this is just a proof of concept, as we’d like to eventually see this kind of material implemented at scale, where it can really make a difference in energy production,” Koratkar said.

Moving forward, Koratkar’s lab will explore the entire family of chalcogenide perovskite compounds in the search for those that exhibit an even stronger piezoelectric effect. Artificial intelligence and machine learning could prove useful tools in this pursuit, Koratkar said.

“Sustainable energy production is vital to our future,” said Shekhar Garde, Ph.D., dean of the RPI School of Engineering. “Professor Koratkar’s work is a great example of how innovating approaches to materials discovery can help address a global problem.”

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

Piezoelectricity in chalcogenide perovskites by Sk Shamim Hasan Abir, Shyam Sharma, Prince Sharma, Surya Karla, Ganesh Balasubramanian, Johnson Samuel & Nikhil Koratkar. Nature Communications volume 15, Article number: 5768 (2024) DOI: https://doi.org/10.1038/s41467-024-50130-5 Published: 09 July 2024

This paper is open access.

Sound-suppressing silk

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I keep telling a friend that noise will be the ‘new smoking’; i.e., there will be more rules and people will demand enforcement. She doesn’t agree, vociferously so. With the mounting research into the effects that noise has on health and on longevity, it doesn’t matter if I win the ‘argument’, I’m just happy to see research dedicated to mitigating noise levels. From a May 7, 2024 news item on ScienceDaily,

We are living in a very noisy world. From the hum of traffic outside your window to the next-door neighbor’s blaring TV to sounds from a co-worker’s cubicle, unwanted noise remains a resounding problem. [nice bit of wordplay]

Caption: The fabric can suppress sound by generating sound waves that interfere with an unwanted noise to cancel it out (as seen in figure C) or by being held still to suppress vibrations that are key to the transmission of sound (as seen in figure D). Credit: Courtesy of Yoel Fink and Grace (Noel) Yang and Massachusetts Institute of Technology (MIT)

A May 7, 2024 Massachusetts Institute of Technology (MIT) news release (also on EurekAlert), which originated the news item, describes how a surprising material, silk, can be used for suppressing sound, Note: Links have been removed,

To cut through the din, an interdisciplinary collaboration of researchers from MIT and elsewhere developed a sound-suppressing silk fabric that could be used to create quiet spaces. 

The fabric, which is barely thicker than a human hair, contains a special fiber that vibrates when a voltage is applied to it. The researchers leveraged those vibrations to suppress sound in two different ways.

In one, the vibrating fabric generates sound waves that interfere with an unwanted noise to cancel it out, similar to noise-canceling headphones, which work well in a small space like your ears but do not work in large enclosures like rooms or planes. 

In the other, more surprising technique, the fabric is held still to suppress vibrations that are key to the transmission of sound. This prevents noise from being transmitted through the fabric and quiets the volume beyond. This second approach allows for noise reduction in much larger spaces like rooms or cars.

By using common materials like silk, canvas, and muslin, the researchers created noise-suppressing fabrics which would be practical to implement in real-world spaces. For instance, one could use such a fabric to make dividers in open workspaces or thin fabric walls that prevent sound from getting through. 

“Noise is a lot easier to create than quiet. In fact, to keep noise out we dedicate a lot of space to thick walls. [First author] Grace’s work provides a new mechanism for creating quiet spaces with a thin sheet of fabric,” says Yoel Fink, a professor in the departments of Materials Science and Engineering and Electrical Engineering and Computer Science, a Research Laboratory of Electronics principal investigator, and senior author of a paper on the fabric.

The study’s lead author is Grace (Noel) Yang SM ’21, PhD ’24. Co-authors include MIT graduate students Taigyu Joo, Hyunhee Lee, Henry Cheung, and Yongyi Zhao; Zachary Smith, the Robert N. Noyce Career Development Professor of Chemical Engineering at MIT; graduate student Guanchun Rui and professor Lei Zhu of Case Western [Reserve] University; graduate student Jinuan Lin and Assistant Professor Chu Ma of the University of Wisconsin at Madison; and Latika Balachander, a graduate student at the Rhode Island School of Design. The an open-access paper about the research appeared recently in Advanced Materials.

Silky silence

The sound-suppressing silk builds off the group’s prior work to create fabric microphones.

In that research, they sewed a single strand of piezoelectric fiber into fabric. Piezoelectric materials produce an electrical signal when squeezed or bent. When a nearby noise causes the fabric to vibrate, the piezoelectric fiber converts those vibrations into an electrical signal, which can capture the sound. 

In the new work, the researchers flipped that idea to create a fabric loudspeaker that can be used to cancel out soundwaves. 

“While we can use fabric to create sound, there is already so much noise in our world. We thought creating silence could be even more valuable,” Yang says.

Applying an electrical signal to the piezoelectric fiber causes it to vibrate, which generates sound. The researchers demonstrated this by playing Bach’s “Air” using a 130-micrometer sheet of silk mounted on a circular frame.

To enable direct sound suppression, the researchers use a silk fabric loudspeaker to emit sound waves that destructively interfere with unwanted sound waves. They control the vibrations of the piezoelectric fiber so that sound waves emitted by the fabric are opposite of unwanted sound waves that strike the fabric, which can cancel out the noise.

However, this technique is only effective over a small area. So, the researchers built off this idea to develop a technique that uses fabric vibrations to suppress sound in much larger areas, like a bedroom.

Let’s say your next-door neighbors are playing foosball in the middle of the night. You hear noise in your bedroom because the sound in their apartment causes your shared wall to vibrate, which forms sound waves on your side.

To suppress that sound, the researchers could place the silk fabric onto your side of the shared wall, controlling the vibrations in the fiber to force the fabric to remain still. This vibration-mediated suppression prevents sound from being transmitted through the fabric.

“If we can control those vibrations and stop them from happening, we can stop the noise that is generated, as well,” Yang says.

A mirror for sound

Surprisingly, the researchers found that holding the fabric still causes sound to be reflected by the fabric, resulting in a thin piece of silk that reflects sound like a mirror does with light. 

Their experiments also revealed that both the mechanical properties of a fabric and the size of its pores affect the efficiency of sound generation. While silk and muslin have similar mechanical properties, the smaller pore sizes of silk make it a better fabric loudspeaker. 

But the effective pore size also depends on the frequency of sound waves. If the frequency is low enough, even a fabric with relatively large pores could function effectively, Yang says.

When they tested the silk fabric in direct suppression mode, the researchers found that it could significantly reduce the volume of sounds up to 65 decibels (about as loud as enthusiastic human conversation). In vibration-mediated suppression mode, the fabric could reduce sound transmission up to 75 percent.

These results were only possible due to a robust group of collaborators, Fink says. Graduate students at the Rhode Island School of Design helped the researchers understand the details of constructing fabrics; scientists at the University of Wisconsin at Madison conducted simulations; researchers at Case Western Reserve University characterized materials; and chemical engineers in the Smith Group at MIT used their expertise in gas membrane separation to measure airflow through the fabric.

Moving forward, the researchers want to explore the use of their fabric to block sound of multiple frequencies. This would likely require complex signal processing and additional electronics. 

In addition, they want to further study the architecture of the fabric to see how changing things like the number of piezoelectric fibers, the direction in which they are sewn, or the applied voltages could improve performance.

“There are a lot of knobs we can turn to make this sound-suppressing fabric really effective. We want to get people thinking about controlling structural vibrations to suppress sound. This is just the beginning,” says Yang.

This work is funded, in part, by the National Science Foundation (NSF), the Army Research Office (ARO), the Defense Threat Reduction Agency (DTRA), and the Wisconsin Alumni Research Foundation.

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

Single Layer Silk and Cotton Woven Fabrics for Acoustic Emission and Active Sound Suppression by Grace H. Yang, Jinuan Lin, Henry Cheung, Guanchun Rui, Yongyi Zhao, Latika Balachander, Taigyu Joo, Hyunhee Lee, Zachary P. Smith, Lei Zhu, Chu Ma, Yoel Fink. Advanced Materials DOI: https://doi.org/10.1002/adma.202313328 First published: 01 April 2024

This paper is open access.

Sound waves for wearable patches that deliver drugs painlessly

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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.

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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.

Smart dental implant resists bacterial growth and generates own electricity

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A “smart” dental implant could improve upon current devices by employing biofilm-resisting nanoparticles and a light powered by biomechanical forces to promote health of the surrounding gum tissue. (Image: Courtesy of Albert Kim)

A September 9, 2021 news item on ScienceDaily announces research into ‘smart’ dental implants,

More than 3 million people in America have dental implants, used to replace a tooth lost to decay, gum disease, or injury. Implants represent a leap of progress over dentures or bridges, fitting much more securely and designed to last 20 years or more.

But often implants fall short of that expectation, instead needing replacement in five to 10 years due to local inflammation or gum disease, necessitating a repeat of a costly and invasive procedure for patients.

“We wanted to address this issue, and so we came up with an innovative new implant,” says Geelsu Hwang, an assistant professor in the University of Pennsylvania School of Dental Medicine, who has a background in engineering that he brings to his research on oral health issues.

The novel implant would implement two key technologies, Hwang says. One is a nanoparticle-infused material that resists bacterial colonization. And the second is an embedded light source to conduct phototherapy, powered by the natural motions of the mouth, such as chewing or toothbrushing. In a paper in the journal ACS Applied Materials & Interfaces and a 2020 paper in the journal Advanced Healthcare Materials, Hwang and colleagues lay out their platform, which could one day be integrated not only into dental implants but other technologies, such as joint replacements, as well.

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A September 9, 2021 University of Pennsylvania news release (also on EurekAlert), which originated the news item, provides more technical details about the proposed technology,

“Phototherapy can address a diverse set of health issues,” says Hwang. “But once a biomaterial is implanted, it’s not practical to replace or recharge a battery. We are using a piezoelectric material, which can generate electrical power from natural oral motions to supply a light that can conduct phototherapy, and we find that it can successfully protect gingival tissue from bacterial challenge.”

In the paper, the material the researchers explored was barium titanate (BTO), which has piezoelectric properties that are leveraged in applications such as capacitators and transistors, but has not yet been explored as a foundation for anti-infectious implantable biomaterials. To test its potential as the foundation for a dental implant, the team first used discs embedded with nanoparticles of BTO and exposed them to Streptococcus mutans, a primary component of the bacterial biofilm responsible for tooth decay commonly known as dental plaque. They found that the discs resisted biofilm formation in a dose-dependent manner. Discs with higher concentrations of BTO were better at preventing biofilms from binding.

While earlier studies had suggested that BTO might kill bacteria outright using reactive oxygen species generated by light-catalyzed or electric polarization reactions, Hwang and colleagues did not find this to be the case due to the short-lived efficacy and off-target effects of these approaches. Instead, the material generates enhanced negative surface charge that repels the negatively charged cell walls of bacteria. It’s likely that this repulsion effect would be long-lasting, the researchers say.

“We wanted an implant material that could resist bacterial growth for a long time because bacterial challenges are not a one-time threat,” Hwang says.

The power-generating property of the material was sustained and in tests over time the material did not leach. It also demonstrated a level of mechanical strength comparable to other materials used in dental applications.

Finally, the material did not harm normal gingival tissue in the researchers’ experiments, supporting the idea that this could be used without ill effect in the mouth.

The technology is a finalist in the Science Center’s research accelerator program, the QED Proof-of-Concept program. As one of 12 finalists, Hwang and colleagues will receive guidance from experts in commercialization. If the project advances to be one of three finalists, the group has the potential to receive up to $200,000 in funding.

In future work, the team hopes to continue to refine the “smart” dental implant system, testing new material types and perhaps even using assymetric properties on each side of the implant components, one that encourages tissue integration on the side facing the gums and one that resists bacterial formation on the side facing the rest of the mouth.

“We hope to further develop the implant system and eventually see it commercialized so it can be used in the dental field,” Hwang says.

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

Bimodal Nanocomposite Platform with Antibiofilm and Self-Powering Functionalities for Biomedical Applications by Atul Dhall, Sayemul Islam, Moonchul Park, Yu Zhang, Albert Kim, and Geelsu Hwang. ACS Appl. Mater. Interfaces 2021, 13, 34, 40379–40391 DOI: https://doi.org/10.1021/acsami.1c11791 Publication Date:August 18, 2021 Copyright © 2021 American Chemical Society

This paper is behind a paywall.

The work from 2020, mentioned in the news release, laid groundwork for the latest paper.

Human Oral Motion-Powered Smart Dental Implant (SDI) for In Situ Ambulatory Photo-biomodulation Therapy by Moonchul Park, Sayemul Islam, Hye-Eun Kim, Jonathan Korosto, Markus B. Blatz, Geelsu Hwang, and Albert Kim. Adv. Healthcare Mater. 2020, 9, 2000658 DOI: 10.1002/adhm.202000658 First published: 01 July 2020 © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimHuman

This paper is behind a paywall.

Tracks of my tears could power smartphone?

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So far the researchers aren’t trying to power anything with tears but they have discovered that tears could be used to generate electricity (from an Oct. 2, 2017 news item on phys.org),

A team of Irish scientists has discovered that applying pressure to a protein found in egg whites and tears can generate electricity. The researchers from the Bernal Institute, University of Limerick (UL), Ireland, observed that crystals of lysozyme, a model protein that is abundant in egg whites of birds as well as in the tears, saliva and milk of mammals can generate electricity when pressed. Their report is published today (October 2) in the journal, Applied Physics Letters.

An Oct. 2, 2017 University of Limerick press release (also on EurekAlert), which originated the news item, offers additional detail,

The ability to generate electricity by applying pressure, known as direct piezoelectricity, is a property of materials such as quartz that can convert mechanical energy into electrical energy and vice versa. Such materials are used in a variety of applications ranging from resonators and vibrators in mobile phones to deep ocean sonars and ultrasound imaging. Bone, tendon and wood are long known to possess piezoelectricity.

“While piezoelectricity is used all around us, the capacity to generate electricity from this particular protein had not been explored. The extent of the piezoelectricity in lysozyme crystals is significant. It is of the same order of magnitude found in quartz. However, because it is a biological material, it is non toxic so it could have many innovative applications such as electroactive anti-microbial coatings for medical implants,” explained Aimee Stapleton, the lead author and an Irish Research Council EMBARK Postgraduate Fellow in the Department of Physics and Bernal Institute of UL.

Crystals of lysozyme are easy to make from natural sources. “The high precision structure of lysozyme crystals has been known since 1965,” said structural biologist at UL and co-author Professor Tewfik Soulimane.
“In fact, it is the second protein structure and the first enzyme structure that was ever solved,” he added, “but we are the first to use these crystals to show the evidence of piezoelectricity”.

According to team leader Professor Tofail Syed of UL’s Department of Physics, “Crystals are the gold-standard for measuring piezoelectricity in non-biological materials. Our team has shown that the same approach can be taken in understanding this effect in biology. This is a new approach as scientists so far have tried to understand piezoelectricity in biology using complex hierarchical structures such as tissues, cells or polypeptides rather than investigating simpler fundamental building blocks”.

The discovery may have wide reaching applications and could lead to further research in the area of energy harvesting and flexible electronics for biomedical devices. Future applications of the discovery may include controlling the release of drugs in the body by using lysozyme as a physiologically mediated pump that scavenges energy from its surroundings. Being naturally biocompatible and piezoelectric, lysozyme may present an alternative to conventional piezoelectric energy harvesters, many of which contain toxic elements such as lead.

Professor Luuk van der Wielen, Director of Bernal Institute and Bernal Professor of Biosystems Engineering and Design expressed his delight at this breakthrough by UL scientists.

“The €109-million Bernal Institute has the ambition to impact the world on the basis of top science in an increasingly international context. The impact of this discovery in the field of biological piezoelectricity will be huge and Bernal scientists are leading from the front the progress in this field,” he said.

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

The direct piezoelectric effect in the globular protein lysozyme featured by A. Stapleton, M. R. Noor, J. Sweeney, V. Casey, A. L. Kholkin, C. Silien, A. A. Gandhi, T. Soulimane, and S. A. M. Tofail. Appl. Phys. Lett. 111, 142902 (2017); doi: http://dx.doi.org/10.1063/1.4997446

This paper is open access.

As for Tracks of My Tears,

2D-nanocellulose and electricity

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The 2D trend seems to have swept into the world of nanocellulose materials. An Oct. 13, 2016 news item on Nanowerk describes work in the field piezoelectronics as driven by 2D nanocellulose materials (Note: A link has been removed),

Researchers from ICN2 [Catalan Institute of Nanoscience and Nanotechnology] Phononic and Photonic Nanostructures Group publish in Scientific Reports (“Orthotropic Piezoelectricity in 2D Nanocellulose”) findings providing the basis for new electromechanical designs using 2D-nanocellulose. In a longer-term perspective, the reinterpretation of electrical features for hydrogen bonds here introduced could pave the way in the understanding of life-essential molecules and events.

An Oct. 11, 2016 ICN2 press release, which originated the news item, provides more information about this area of research,

In the next coming years nanocellulose (NC) would attract lot of attention from industrial researchers (market value is estimated to be 530 M$ worldwide by 2020)(1). The process of development and functionalization of NC materials is being promising because of their well-known unique optomechanical features and green nature. However, there is still a niche for applications based on NC electric-response. In this scenario, the results published in Scientific Reports with the participation of ICN2 researchers, would set up foundations for new strategies intended to drive novel applications based on 2D-NC with a predicted piezoelectric-response ~ pm V-1. This result could rank NC at the level of currently used bulk piezoelectrics like α-quartz and most recent 2D materials like MoSe2 or doped graphene. The first author of the article is Dr Yamila García, and the last one ICREA Research prof. Dr Clivia M. Sotomayor-Torres, Group leader of the ICN2 Phononic and Photonic Nanostructures Group.

“We are too big” (2). It is one of the main limitations to do nanotechnology as Richard Feynman pointed out in 1959. As a contribution in paving the way to overcome this restriction, it is introduced a theoretical framework for the investigation of electric field profiles with interatomic resolution and thus to understand the fundamentals of the electromechanical coupling at the nanoscale. Remarkably, the mean-field descriptor obtained with the methodology described in the manuscript would also complete the latest definition of hydrogen bonds stated by IUPAC since it is the first effective approach in quantifying the electrical nature of such interactions.

An “atom by atom” (2) understanding of electrical forces managing directional bonds is needed if we plan to engineer materials by means of highly selected nanoscale oriented mechanisms. So then, deepening on the understanding of 2D-NC as a piezoelectric system managed by electroactive and well-distinguishable HB  could facilitate new openings for nanotechnologies  community intended to progress on NC applications, i.e. straightforwardly introducing electronic-base sensing and actuating applications. Looking to the future, areas like molecular biology or genetic engineering would be benefited by the new contributions on the understanding of electrical forces within life-essential hydrogen bonds.

(1) Nanocellulose (Nano-crystalline Cellulose, Nano-fibrillated Cellulose and Bacterial Nanocellulose) Market for Composites, Oil & Gas, Paper Processing, Paints & Coatings, and Other Applications: Global Industry Perspective, Comprehensive Analysis, Size, Share, Growth, Segment, Trends and Forecast, 2015 – 2021.

(2) “The principles of physics, as far as I can see, do not speak against the possibility of manoeuvring things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big.” Richard Feynman, 1959

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

Orthotropic Piezoelectricity in 2D Nanocellulose by Y. García, Yasser B. Ruiz-Blanco, Yovani Marrero-Ponce & C. M. Sotomayor-Torres. Scientific Reports 6, Article number: 34616 (2016) doi:10.1038/srep34616 Published online: 06 October 2016

This paper is open access.

Using fish ‘biowaste’ for self-powered electronics

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Researchers in India have found a way to make use of fish ‘biowaste’ according to a Sept. 6, 2016 news item on Nanowerk,

Large quantities of fish are consumed in India on a daily basis, which generates a huge amount of fish “biowaste” materials. In an attempt to do something positive with this biowaste, a team of researchers at Jadavpur University in Koltata, India explored recycling the fish byproducts into an energy harvester for self-powered electronics.

Caption: Waste fish scales (upper left corner) are used to fabricate flexible nanogenerator (lower left) that power up more than 50 blue LEDs (lower right). An enlarged microscopic view of a fish scale shows the well-aligned collagen fibrils (upper right). The possibility of making a fish scale transparent (middle) and rollable (extreme left lower corner) is also illustrated. Credit: Sujoy Kuman Ghosh and Dipankar Mandal/Jadavpur University

Caption: Waste fish scales (upper left corner) are used to fabricate flexible nanogenerator (lower left) that power up more than 50 blue LEDs (lower right). An enlarged microscopic view of a fish scale shows the well-aligned collagen fibrils (upper right). The possibility of making a fish scale transparent (middle) and rollable (extreme left lower corner) is also illustrated. Credit: Sujoy Kuman Ghosh and Dipankar Mandal/Jadavpur University

A Sept. 6, 2016 American Institute of Physics news release on EurekAlert, which originated the news item, describes the research in more detail,

The basic premise behind the researchers’ work is simple: Fish scales contain collagen fibers that possess a piezoelectric property, which means that an electric charge is generated in response to applying a mechanical stress. As the team reports this week in Applied Physics Letters, from AIP Publishing, they were able to harness this property to fabricate a bio-piezoelectric nanogenerator.

To do this, the researchers first “collected biowaste in the form of hard, raw fish scales from a fish processing market, and then used a demineralization process to make them transparent and flexible,” explained Dipankar Mandal, assistant professor, Organic Nano-Piezoelectric Device Laboratory, Department of Physics, at Jadavpur University.

The collagens within the processed fish scales serve as an active piezoelectric element.

“We were able to make a bio-piezoelectric nanogenerator — a.k.a. energy harvester — with electrodes on both sides, and then laminated it,” Mandal said.

While it’s well known that a single collagen nanofiber exhibits piezoelectricity, until now no one had attempted to focus on hierarchically organizing the collagen nanofibrils within the natural fish scales.

“We wanted to explore what happens to the piezoelectric yield when a bunch of collagen nanofibrils are hierarchically well aligned and self-assembled in the fish scales,” he added. “And we discovered that the piezoelectricity of the fish scale collagen is quite large (~5 pC/N), which we were able to confirm via direct measurement.”

Beyond that, the polarization-electric field hysteresis loop and resulting strain-electric field hysteresis loop — proof of a converse piezoelectric effect — caused by the “nonlinear” electrostriction effect backed up their findings.

The team’s work is the first known demonstration of the direct piezoelectric effect of fish scales from electricity generated by a bio-piezoelectric nanogenerator under mechanical stimuli — without the need for any post-electrical poling treatments.

“We’re well aware of the disadvantages of the post-processing treatments of piezoelectric materials,” Mandal noted.

To explore the fish scale collagen’s self-alignment phenomena, the researchers used near-edge X-ray absorption fine-structure spectroscopy, measured at the Raja Ramanna Centre for Advanced Technology in Indore, India.

Experimental and theoretical tests helped them clarify the energy scavenging performance of the bio-piezoelectric nanogenerator. It’s capable of scavenging several types of ambient mechanical energies — including body movements, machine and sound vibrations, and wind flow. Even repeatedly touching the bio-piezoelectric nanogenerator with a finger can turn on more than 50 blue LEDs.

“We expect our work to greatly impact the field of self-powered flexible electronics,” Mandal said. “To date, despite several extraordinary efforts, no one else has been able to make a biodegradable energy harvester in a cost-effective, single-step process.”

The group’s work could potentially be for use in transparent electronics, biocompatible and biodegradable electronics, edible electronics, self-powered implantable medical devices, surgeries, e-healthcare monitoring, as well as in vitro and in vivo diagnostics, apart from its myriad uses for portable electronics.

“In the future, our goal is to implant a bio-piezoelectric nanogenerator into a heart for pacemaker devices, where it will continuously generate power from heartbeats for the device’s operation,” Mandal said. “Then it will degrade when no longer needed. Since heart tissue is also composed of collagen, our bio-piezoelectric nanogenerator is expected to be very compatible with the heart.”

The group’s bio-piezoelectric nanogenerator may also help with targeted drug delivery, which is currently generating interest as a way of recovering in vivo cancer cells and also to stimulate different types of damaged tissues.

“So we expect our work to have enormous importance for next-generation implantable medical devices,” he added.

“Our end goal is to design and engineer sophisticated ingestible electronics composed of nontoxic materials that are useful for a wide range of diagnostic and therapeutic applications,” said Mandal.

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

High-performance bio-piezoelectric nanogenerator made with fish scale by Sujoy Kumar Ghosh and Dipankar Mandal. Appl. Phys. Lett. 109, 103701 (2016); http://dx.doi.org/10.1063/1.4961623

This paper appears to be open access.