Category Archives: health and safety

Concrete collapse and research into durability

I have two items about concrete buildings, one concerns the June 24, 2021 collapse of a 12-storey condominium building in Surfside, close to Miami Beach in Florida. There are at least 20 people dead and, I believe, over 120 are still unaccounted for (July 2, 2021 Associated Press news item on Canadian Broadcasting Corporation news online website).

Miami collapse

Nate Berg’s June 25, 2021 article for Fast Company provides an instructive overview of the building collapse (Note: A link has been removed),

Why the building collapsed is not yet known [emphasis mine]. David Darwin is a professor of civil engineering at the University of Kansas and an expert in reinforced concrete structures, and he says the eventual investigation of the Surfside collapse will explore all the potential causes, ranging from movement in the foundation before the collapse, corrosion in the debris, and excessive cracking in the part of the building that remains standing. “There are all sorts of potential causes of failure,” Darwin says. “At this point, speculation is not helpful for anybody.”

Sometimes I can access the entire article, and at other times, only a few paragraphs; I hope you get access to all of it as it provides a lot of information.

The Surfside news puts this research from Northwestern University (Chicago, Illinois) into much sharper relief than might otherwise be the case. (Further on I have some information about the difference between cement and concrete and how cement leads to concrete.)

Smart cement for more durable roads and cities

Coincidentally, just days before the Miami Beach building collapse, a June 21, 2021 Northwestern University news release (also on EurekAlert), announced research into improving water and fracture resistance in cement,

Forces of nature have been outsmarting the materials we use to build our infrastructure since we started producing them. Ice and snow turn major roads into rubble every year; foundations of houses crack and crumble, in spite of sturdy construction. In addition to the tons of waste produced by broken bits of concrete, each lane-mile of road costs the U.S. approximately $24,000 per year to keep it in good repair.

Engineers tackling this issue with smart materials typically enhance the function of materials by increasing the amount of carbon, but doing so makes materials lose some mechanical performance. By introducing nanoparticles into ordinary cement, Northwestern University researchers have formed a smarter, more durable and highly functional cement.

The research was published today (June 21 [2021]) in the journal Philosophical Transactions of the Royal Society A.

With cement being the most widely consumed material globally and the cement industry accounting for 8% of human-caused greenhouse gas emissions, civil and environmental engineering professor Ange-Therese Akono turned to nanoreinforced cement to look for a solution. Akono, the lead author on the study and an assistant professor in the McCormick School of Engineering, said nanomaterials reduce the carbon footprint of cement composites, but until now, little was known about its impact on fracture behavior.

“The role of nanoparticles in this application has not been understood before now, so this is a major breakthrough,” Akono said. “As a fracture mechanics expert by training, I wanted to understand how to change cement production to enhance the fracture response.”

Traditional fracture testing, in which a series of light beams is cast onto a large block of material, involves lots of time and materials and seldom leads to the discovery of new materials.

By using an innovative method called scratch testing, Akono’s lab efficiently formed predictions on the material’s properties in a fraction of the time. The method tests fracture response by applying a conical probe with increasing vertical force against the surface of microscopic bits of cement. Akono, who developed the novel method during her Ph.D. work, said it requires less material and accelerates the discovery of new ones.

“I was able to look at many different materials at the same time,” Akono said. “My method is applied directly at the micrometer and nanometer scales, which saves a considerable amount of time. And then based on this, we can understand how materials behave, how they crack and ultimately predict their resistance to fracture.”

Predictions formed through scratch tests also allow engineers to make changes to materials that enhance their performance at the larger scale. In the paper, graphene nanoplatelets, a material rapidly gaining popularity in forming smart materials, were used to improve the resistance to fracture of ordinary cement. Incorporating a small amount of the nanomaterial also was shown to improve water transport properties including pore structure and water penetration resistance, with reported relative decreases of 76% and 78%, respectively.

Implications of the study span many fields, including building construction, road maintenance, sensor and generator optimization and structural health monitoring.

By 2050, the United Nations predicts two-thirds of the world population will be concentrated in cities. Given the trend toward urbanization, cement production is expected to skyrocket.

Introducing green concrete that employs lighter, higher-performing cement will reduce its overall carbon footprint by extending maintenance schedules and reducing waste.

Alternately, smart materials allow cities to meet the needs of growing populations in terms of connectivity, energy and multifunctionality. Carbon-based nanomaterials including graphene nanoplatelets are already being considered in the design of smart cement-based sensors for structural health monitoring.

Akono said she’s excited for both follow-ups to the paper in her own lab and the ways her research will influence others. She’s already working on proposals that look into using construction waste to form new concrete and is considering “taking the paper further” by increasing the fraction of nanomaterial that cement contains.

“I want to look at other properties like understanding the long-term performance,” Akono said. “For instance, if you have a building made of carbon-based nanomaterials, how can you predict the resistance in 10, 20 even 40 years?”

The study, “Fracture toughness of one- and two-dimensional nanoreinforced cement via scratch testing,” was supported by the National Science Foundation Division of Civil, Mechanical and Manufacturing Innovation (award number 18929101).

Akono will give a talk on the paper at The Royal Society’s October [2021] meeting, “A Cracking Approach to Inventing Tough New Materials: Fracture Stranger Than Friction,” which will highlight major advances in fracture mechanics from the past century.

I don’t often include these kinds of photos (one or more of the researchers posing (sometimes holding something) for the camera but I love the professor’s first name, Ange-Therese (which means angel in French, I don’t know if she ever uses the French spelling for Thérèse),

Caption: Professor Ange-Therese Akono holds a sample of her smart cement. Credit: Northwestern University

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

Fracture toughness of one- and two-dimensional nanoreinforced cement via scratch testing by Ange-Therese Akono. Philosophical Transactions of the Royal Society A: Mathematical, Physical & Engineering Sciences 2021 379 (2203): 20200288 DOI: 10.1098/rsta.2020.0288 Published June 21, 2021

This paper appears to be open access.

Cement vs. concrete

Andrew Logan’s April 3, 2020 article for MIT (Massachusetts Institute of Technology) News is a very readable explanation of how cement and concrete differ and how they are related,

There’s a lot the average person doesn’t know about concrete. For example, it’s porous; it’s the world’s most-used material after water; and, perhaps most fundamentally, it’s not cement.

Though many use “cement” and “concrete” interchangeably, they actually refer to two different — but related — materials: Concrete is a composite made from several materials, one of which is cement. [emphasis mine]

Cement production begins with limestone, a sedimentary rock. Once quarried, it is mixed with a silica source, such as industrial byproducts slag or fly ash, and gets fired in a kiln at 2,700 degrees Fahrenheit. What comes out of the kiln is called clinker. Cement plants grind clinker down to an extremely fine powder and mix in a few additives. The final result is cement.

“Cement is then brought to sites where it is mixed with water, where it becomes cement paste,” explains Professor Franz-Josef Ulm, faculty director of the MIT Concrete Sustainability Hub (CSHub). “If you add sand to that paste it becomes mortar. And if you add to the mortar large aggregates — stones of a diameter of up to an inch — it becomes concrete.”

Final thoughts

I offer my sympathies to the folks affected by the building collapse and my hopes that research will lead the way to more durable cement and, ultimately, concrete buildings.

Edible nano-structured holograms could decorate food one day

Caption Nanostructures (yellowish-green images; scale bar, 5 μm) were patterned onto dried corn syrup films, producing edible, rainbow-colored holograms (scale bar, 2 mm). Credit Adapted from ACS Nano 2021, DOI: 10.1021/acsnano.0c02438

Where food safety is concerned, much of the research I’ve seen is focused on adding senors to the packaging rather than direct application to the foodstuff but this is different, from a February 17, 2021 news item on phys.org,

Holograms are everywhere, from driver’s licenses to credit cards to product packaging. And now, edible holograms could someday enhance foods. Researchers reporting in ACS [American Chemical Society] Nano have developed a laser-based method to print nanostructured holograms on dried corn syrup films. The edible holograms could also be used to ensure food safety, label a product or indicate sugar content, the researchers say.

A February 17, 2021American Chemical Society news release (also on EurekAlert), which originated the news item,

Most holograms are imprinted with lasers onto metal surfaces, such as aluminum, but the materials aren’t edible. For foods, holograms made with nanoparticles have been proposed, but the tiny particles can generate reactive oxygen species, which might be harmful for people to eat. In a different approach, food scientists have molded edible holograms onto chocolate, but the process only works for certain types of the confection, and a different mold is needed for each hologram design. Bader AlQattan, Haider Butt and colleagues wanted to find a safe, fast and versatile way to pattern edible holograms onto a variety of foods.

To develop their method, the researchers made a solution of corn syrup, vanilla and water and dried it into a thin film. They coated the film with a fine layer of non-toxic black dye. Then, they used a technique called direct laser interference patterning to etch off most of the dye, leaving behind raised, nanoscale lines that formed a diffraction grating. When struck by light, the nanostructure diffracted the light into a rainbow pattern, with different colors appearing at different angles of viewing. The team could control the intensity and range of colors by varying the spacing between lines in the grating or the sugar content of the corn syrup film. Before edible holograms are ready to hit store shelves, however, the researchers want to adapt the method to a food-grade dye that could replace the synthetic black dye used in these pilot experiments.

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

Direct Printing of Nanostructured Holograms on Consumable Substrates by Bader AlQattan, Joelle Doocey, Murad Ali, Israr Ahmed, Ahmed E. Salih, Fahad Alam, Magdalena Bajgrowicz-Cieslak, Ali K. Yetisen, Mohamed Elsherif, and Haider Butt. ACS Nano 2021, 15, 2, 2340–2349 DOI: https://doi.org/10.1021/acsnano.0c02438 Publication Date:February 1, 2021 Copyright © 2021 American Chemical Society

This paper appears to be open access.

It seems these scientists are also considering the aesthetic possibilities. Ffrom the paper, Note: Links have been removed,

The use of holograms in food could potentially improve sensory appeal [emphasis mine] and, through biosensing, could increase health and safety.(1,2) Holograms can even be used to store information as edible microtags.(3) They are also attractive to the eye as they produce rainbow patterns with light. Using edible holograms on foods, not only as decoration but also to sense harmful bacteria, could improve food quality/lifetime monitoring.(4,5) Food holograms which signify a qualitative information about the sugar contents could be of value in controlling the sugar consumption, that is challenging to be measured at the moment.(6)

As it is, I find food pretty attractive. So, I’m not sure why there’s a need to improve its sensory appeal. On the other hand, I can’t argue with increased food safety.

Should you be interested in more about holograms and their current applications, including chocolate decoration, you can check out Michael Berger’s February 17, 2021 Nanowerk Spotlight article.

Holographic chocolate surfaces. (Image: Morphotonix) [downloaded from https://www.nanowerk.com/spotlight/spotid=57310.php]

What do you think about decorating food with holograms? If you feel inclined, do let me know in the comments.

Health Canada advisory: Face masks that contain graphene may pose health risks

Since COVID-19, we’ve been advised to wear face masks. It seems some of them may not be as safe as we assumed. First, the Health Canada advisory that was issued today, April 2, 2021 and then excerpts from an in-depth posting by Dr. Andrew Maynard (associate dean in the Arizona State University College of Global Futures) about the advisory and the use of graphene in masks.

From the Health Canada Recalls & alerts: Face masks that contain graphene may pose health risks webpage,

Summary

  • Product: Face masks labelled to contain graphene or biomass graphene.
  • Issue: There is a potential that wearers could inhale graphene particles from some masks, which may pose health risks.
  • What to do: Do not use these face masks. Report any health product adverse events or complaints to Health Canada.

Issue

Health Canada is advising Canadians not to use face masks that contain graphene because there is a potential that they could inhale graphene particles, which may pose health risks.

Graphene is a novel nanomaterial (materials made of tiny particles) reported to have antiviral and antibacterial properties. Health Canada conducted a preliminary scientific assessment after being made aware that masks containing graphene have been sold with COVID-19 claims and used by adults and children in schools and daycares. Health Canada believes they may also have been distributed for use in health care settings.

Health Canada’s preliminary assessment of available research identified that inhaled graphene particles had some potential to cause early lung toxicity in animals. However, the potential for people to inhale graphene particles from face masks and the related health risks are not yet known, and may vary based on mask design. The health risk to people of any age is not clear. Variables, such as the amount and duration of exposure, and the type and characteristics of the graphene material used, all affect the potential to inhale particles and the associated health risks. Health Canada has requested data from mask manufacturers to assess the potential health risks related to their masks that contain graphene.

Until the Department completes a thorough scientific assessment and has established the safety and effectiveness of graphene-containing face masks, it is taking the precautionary approach of removing them from the market while continuing to gather and assess information. Health Canada has directed all known distributors, importers and manufacturers to stop selling and to recall the affected products. Additionally, Health Canada has written to provinces and territories advising them to stop distribution and use of masks containing graphene. The Department will continue to take appropriate action to stop the import and sale of graphene face masks.

Products affected

Face masks labelled as containing graphene or biomass graphene.

What you should do

  • Do not use face masks labelled to contain graphene or biomass graphene.
  • Consult your health care provider if you have used graphene face masks and have health concerns, such as new or unexplained shortness of breath, discomfort or difficulty breathing.
  • Report any health product adverse events or complaints regarding graphene face masks to Health Canada.

Dr. Andrew Maynard’s Edge of Innovation series features a March 26, 2021 posting about the use of graphene in masks (Note: Links have been removed),

Face masks should protect you, not place you in greater danger. However, last Friday Radio Canada revealed that residents of Quebec and Ottawa were being advised not to use specific types of graphene-containing masks as they could potentially be harmful.

The offending material in the masks is graphene — a form of carbon that consists of nanoscopically thin flakes of hexagonally-arranged carbon atoms. It’s a material that has a number of potentially beneficial properties, including the ability to kill bacteria and viruses when they’re exposed to it.

Yet despite its many potential uses, the scientific jury is still out when it comes to how safe the material is.

As with all materials, the potential health risks associated with graphene depend on whether it can get into the body, where it goes if it can, what it does when it gets there, and how much of it is needed to cause enough damage to be of concern.

Unfortunately, even though these are pretty basic questions, there aren’t many answers forthcoming when it comes to the substance’s use in face masks.

Early concerns around graphene were sparked by previous research on another form of carbon — carbon nanotubes. It turns out that some forms of these fiber-like materials can cause serious harm if inhaled. And following on from research here, a natural next-question to ask is whether carbon nanotubes’ close cousin graphene comes with similar concerns.

Because graphene lacks many of the physical and chemical aspects of carbon nanotubes that make them harmful (such as being long, thin, and hard for the body to get rid of), the indications are that the material is safer than its nanotube cousins. But safer doesn’t mean safe. And current research indicates that this is not a material that should be used where it could potentially be inhaled, without a good amount of safety testing first.

[downloaded from https://medium.com/edge-of-innovation/how-safe-are-graphene-based-face-masks-b88740547e8c] Original source: Wikimedia

When it comes to inhaling graphene, the current state of the science indicates that if the material can get into the lower parts of the lungs (the respirable or alveolar region) it can lead to an inflammatory response at high enough concentrations.

There is some evidence that adverse responses are relatively short-lived, and that graphene particles can be broken down and disposed of by the lungs’ defenses.

This is good news as it means that there are less likely to be long-term health impacts from inhaling the material.

There’s also evidence that graphene, unlike some forms of thin, straight carbon nanotubes, does not migrate to the outside layers of the lungs where it could potentially do a lot more damage.

Again, this is encouraging as it suggests that graphene is unlikely to lead to serious long-term health impacts like mesothelioma.

However, research also shows that this is not a benign material. Despite being made of carbon — and it’s tempting to think of carbon as being safe, just because we’re familiar with it — there is some evidence that the jagged edges of some graphene particles can harm cells, leading to local damage as the body responds to any damage the material causes.

There are also concerns, although they are less well explored in the literature, that some forms of graphene may be carriers for nanometer-sized metal particles that can be quite destructive in the lungs. This is certainly the case with some carbon nanotubes, as the metallic catalyst particles used to manufacture them become embedded in the material, and contribute to its toxicity.

The long and short of this is that, while there are still plenty of gaps in our knowledge around how much graphene it’s safe to inhale, inhaling small graphene particles probably isn’t a great idea unless there’s been comprehensive testing to show otherwise.

And this brings us to graphene-containing face masks.

….

Here, it’s important to stress that we don’t yet know if graphene particles are being released and, if they are, whether they are being released in sufficient quantities to cause health effects. And there are indications that, if there are health risks, these may be relatively short-term — simply because graphene particles may be effectively degraded by the lungs’ defenses.

At the same time, it seems highly irresponsible to include a material with unknown inhalation risks in a product that is intimately associated with inhalation. Especially when there are a growing number of face masks available that claim to use graphene.

… There are millions of graphene face masks and respirators being sold and used around the world. And while the unfolding news focuses on Quebec and one particular type of face mask, this is casting uncertainty over the safety of any graphene-containing masks that are being sold.

And this uncertainty will persist until manufacturers and regulators provide data indicating that they have tested the products for the release and subsequent inhalation of fine graphene particles, and shown the risks to be negligible.

I strongly recommend reading, in its entirety , Dr. Maynard’s March 26, 2021 posting, Which he has updated twice since first posting the story.

In short. you may want to hold off before buying a mask with graphene until there’s more data about safety.

It’s about sound: (1) Earable computing? (2) The end of the cacophony in hospitals?

I have two items, both concerning sound but in very different ways.

Phones in your ears

Researchers at the University of Illinois are working on smartphones you can put in your ears like you do an earbud. The work is in its very earliest stages as they are trying to establish a new field of research. There is a proposed timeline,

Caption: Earable computing timeline, according to SyNRG. Credit: Romit Roy Choudhury, The Grainger College of Engineering

Here’s more from a December 2, 2020 University of Illinois Grainger College of Engineering news release (also on EurekAlert but published on December 15, 2020),

CSL’s [Coordinated Science Laboratory] Systems and Networking Research Group (SyNRG) is defining a new sub-area of mobile technology that they call “earable computing.” The team believes that earphones will be the next significant milestone in wearable devices, and that new hardware, software, and apps will all run on this platform.

“The leap from today’s earphones to ‘earables’ would mimic the transformation that we had seen from basic phones to smartphones,” said Romit Roy Choudhury, professor in electrical and computer engineering (ECE). “Today’s smartphones are hardly a calling device anymore, much like how tomorrow’s earables will hardly be a smartphone accessory.”

Instead, the group believes tomorrow’s earphones will continuously sense human behavior, run acoustic augmented reality, have Alexa and Siri whisper just-in-time information, track user motion and health, and offer seamless security, among many other capabilities.

The research questions that underlie earable computing draw from a wide range of fields, including sensing, signal processing, embedded systems, communications, and machine learning. The SyNRG team is on the forefront of developing new algorithms while also experimenting with them on real earphone platforms with live users.

Computer science PhD student Zhijian Yang and other members of the SyNRG group, including his fellow students Yu-Lin Wei and Liz Li, are leading the way. They have published a series of papers in this area, starting with one on the topic of hollow noise cancellation that was published at ACM SIGCOMM 2018. Recently, the group had three papers published at the 26th Annual International Conference on Mobile Computing and Networking (ACM MobiCom) on three different aspects of earables research: facial motion sensing, acoustic augmented reality, and voice localization for earphones.

In Ear-AR: Indoor Acoustic Augmented Reality on Earphones, the group looks at how smart earphone sensors can track human movement, and, depending on the user’s location, play 3D sounds in the ear.

“If you want to find a store in a mall,” says Zhijian, “the earphone could estimate the relative location of the store and play a 3D voice that simply says ‘follow me.’ In your ears, the sound would appear to come from the direction in which you should walk, as if it’s a voice escort.”

The second paper, EarSense: Earphones as a Teeth Activity Sensor, looks at how earphones could sense facial and in-mouth activities such as teeth movements and taps, enabling a hands-free modality of communication to smartphones. Moreover, various medical conditions manifest in teeth chatter, and the proposed technology would make it possible to identify them by wearing earphones during the day. In the future, the team is planning to look into analyzing facial muscle movements and emotions with earphone sensors.

The third publication, Voice Localization Using Nearby Wall Reflections, investigates the use of algorithms to detect the direction of a sound. This means that if Alice and Bob are having a conversation, Bob’s earphones would be able to tune into the direction Alice’s voice is coming from.

“We’ve been working on mobile sensing and computing for 10 years,” said Wei. “We have a lot of experience to define this emerging landscape of earable computing.”

Haitham Hassanieh, assistant professor in ECE, is also involved in this research. The team has been funded by both NSF [US National Science Foundation] and NIH [National Institutes of Health], as well as companies like Nokia and Google. See more at the group’s Earable Computing website.

Noise hurts hospital caregivers and patients

A December 11, 2020 Canadian Broadcasting Corporation (CBC) article features one of the corporation’s Day 6 Radio programmes. This one was about proposed sound design in hospitals as imagined by musician Yoko Sen and, on a converging track, professor of applied psychology, Judy Edworthy,

As an ambient electronic musician, Yoko Sen spends much of her time building intricate, soothing soundscapes. 

But when she was hospitalized in 2012, she found herself immersed in a very different sound environment.

Already panicked by her health condition, she couldn’t tune out the harsh tones of the medical machinery in her hospital room.

Instead, she zeroed in on two machines — a patient monitor and a bed fall alarm. Their piercing tones had blended together to create a diminished fifth, a musical interval so offensive that it was banned in medieval churches.

Sen went on to start Sen Sound, a Washington, D.C.-based social enterprise dedicated to improving the sound of hospitals. 

‘Alarms are ignored, missed’

The volume of noise in today’s hospitals isn’t just unpleasant. It can also put patients’ health at risk.

According to Judy Edworthy, a professor of applied psychology at the University of Plymouth, the sheer number of alarms going off each day can spark a sort of auditory burnout among doctors and nurses.

“Alarms are ignored, missed, or generally just not paid attention to,” says Edworthy.

In a hospital environment that’s also inundated with announcements from overhead speakers, ringing phones, trolleys, and all other manner of insidious background sound, it can be difficult for staff to accurately locate and differentiate between the alarms.

Worse yet, in many hospitals, many of the alarms ringing out across the ward are false. Studies have shown that as many as 99 per cent of clinical alarms are inaccurate

The resulting problem has become so widespread that a term has been coined to describe it: alarm fatigue.

Raising the alarm

Sen’s company, launched in 2016, has partnered with hospitals and design incubators and even collaborates directly with medical device companies seeking to redesign their alarms.

Over the years, Sen has interviewed countless patients and hospital staff who share her frustration with noise. 

But when she first sat down with the engineers responsible for the devices’ design, she found that they tended to treat the sound of their devices as an “afterthought.” 

“When people first started to develop medical devices … people thought it was a good idea to have one or two sounds to demonstrate or to indicate when, let’s say for example, the patient’s temperature … exceeded some kind of range,” she [Edworthy] said.

“There wasn’t really any design put into this; it was just a sound that people thought would get your attention by being very loud and aversive and so on.”

Edworthy, who has spent decades studying medical alarm design, took things one step further this summer. In July, the International Standards Organization approved a new set of alarm designs, created by Edworthy, that mimic the natural hospital environment.

The standards, which are accepted by Health Canada, include an electronic heartbeat sound for alarms related to cardiac issues; and a rattling pillbox for drug administration. 

Her [Sen’s] team continues to work with companies to improve the sound of existing medical devices. But she has also begun to think more deeply about the long-term future of hospital sound — especially as it relates to the end-of-life experience.

“A study shows that hearing can be the last sense to go when we die,” says Sen. 

“It’s really beyond upsetting to think that many people end up dying in acute care hospitals and there are all these medical devices.”

As part of her interviews with patients, Sen has asked what sounds they would most like to hear at the end of their lives — and she discovered a common theme in their responses.

“I asked this question in many different countries, but they are all sounds that symbolize life,” said Sen. 

“Sounds of nature, sound of water, voices of loved ones. It’s all the sounds of life that people say they want to hear.”

As the pandemic continues to affect hospitals around the world, those efforts have taken on a new resonance — and Sen hopes the current crisis might serve as an opportunity to help usher in a more healing soundscape.

“My own health crisis almost gave me a new pathway in life,” she said.

There’s an embedded audio file from the Day 6 radio programme featuring this material on sound design and hospitals and there’s an embedded video of Sen delivery a talk about her work in the December 11, 2020 Canadian Broadcasting Corporation (CBC) article.

Sen and Edworthy give hope for a less noisy future and better care in hospitals for the living and the dying. Here’s a link to Sen Sound.

Living plants detect arsenic by way of embedded nanosensors

There’s a lot of arsenic in the world and it’s often a factor in making water undrinkable. When that water is used in farming It also pollutes soil and enters food-producing plants. A December 11, 2020 news item on Nanowerk announces research into arsenic detectors in plants,

Researchers have developed a living plant-based sensor that can in real-time detect and monitor levels of arsenic, a highly toxic heavy metal, in the soil. Arsenic pollution is a major threat to humans and ecosystems in many Asia Pacific countries.

Caption: Non-destructive plant nanobionic sensor embedded within leaves to report arsenic levels within plants to portable electronics, enabling real-time monitoring of arsenic uptake in living plants. Credit: Dr. Tedrick Thomas Salim Lew

I was not able to find the source for the news item but I did locate something close. From a December 13, 2020 Singapore-Massachusetts Institute of Technology (MIT) Alliance for Research and Technology (SMART), also on EurekAlert,

Scientists from the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) research group at the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, have engineered a novel type of plant nanobionic optical sensor that can detect and monitor, in real time, levels of the highly toxic heavy metal arsenic in the underground environment. This development provides significant advantages over conventional methods used to measure arsenic in the environment and will be important for both environmental monitoring and agricultural applications to safeguard food safety, as arsenic is a contaminant in many common agricultural products such as rice, vegetables, and tea leaves.

Arsenic and its compounds are a serious threat to humans and ecosystems. Long-term exposure to arsenic in humans can cause a wide range of detrimental health effects, including cardiovascular disease such as heart attack, diabetes, birth defects, severe skin lesions, and numerous cancers including those of the skin, bladder, and lung. Elevated levels of soil arsenic as a result of anthropogenic activities such as mining and smelting are also harmful to plants, inhibiting growth and resulting in substantial crop losses.

Food crops can absorb arsenic from the soil, leading to contamination of food and produce consumed by humans. Arsenic in underground environments can also contaminate groundwater and other underground water sources, the long-term consumption of which can cause severe health issues. As such, developing accurate, effective, and easy-to-deploy arsenic sensors is important to protect both the agriculture industry and wider environmental safety.

The novel optical nanosensors exhibit changes in their fluorescence intensity upon detecting arsenic. Embedded in plant tissues, with no detrimental effects on the plant, these sensors provide a nondestructive way to monitor the internal dynamics of arsenic taken up by plants from the soil. This integration of optical nanosensors within living plants enables the conversion of plants into self-powered detectors of arsenic from their natural environment, marking a significant upgrade from the time- and equipment-intensive arsenic sampling methods of current conventional methods.

“Our plant-based nanosensor is notable not only for being the first of its kind, but also for the significant advantages it confers over conventional methods of measuring arsenic levels in the below-ground environment, requiring less time, equipment, and manpower,” says Lew. “We envision that this innovation will eventually see wide use in the agriculture industry and beyond. I am grateful to SMART DiSTAP and the Temasek Life Sciences Laboratory (TLL), both of which were instrumental in idea generation and scientific discussion as well as research funding for this work.”

Besides detecting arsenic in rice and spinach, the team also used a species of fern, Pteris cretica, which can hyperaccumulate arsenic. This fern species can absorb and tolerate high levels of arsenic with no detrimental effect — engineering an ultrasensitive plant-based arsenic detector, capable of detecting very low concentrations of arsenic, as low as 0.2 parts per billion. In contrast, the regulatory limit for arsenic detectors is 10 parts per billion. Notably, the novel nanosensors can also be integrated into other species of plants. The researchers say this is the first successful demonstration of living plant-based sensors for arsenic and represents a groundbreaking advancement that could prove highly useful in both agricultural research (e.g., to monitor arsenic taken up by edible crops for food safety) and general environmental monitoring.

Previously, conventional methods of measuring arsenic levels included regular field sampling, plant tissue digestion, extraction, and analysis using mass spectrometry. These methods are time-consuming, require extensive sample treatment, and often involve the use of bulky and expensive instrumentation. The new approach couples nanoparticle sensors with plants’ natural ability to efficiently extract analytes via the roots and transport them. This allows for the detection of arsenic uptake in living plants in real time, with portable, inexpensive electronics such as a portable Raspberry Pi platform equipped with a charge-coupled device camera akin to a smartphone camera.

Co-author, DiSTAP co-lead principal investigator, and MIT Professor Michael Strano adds, “This is a hugely exciting development, as, for the first time, we have developed a nanobionic sensor that can detect arsenic — a serious environmental contaminant and potential public health threat. With its myriad advantages over older methods of arsenic detection, this novel sensor could be a game-changer, as it is not only more time-efficient, but also more accurate and easier to deploy than older methods. It will also help plant scientists in organizations such as TLL to further produce crops that resist uptake of toxic elements. Inspired by TLL’s recent efforts to create rice crops which take up less arsenic, this work is a parallel effort to further support SMART DiSTAP’s efforts in food security research, constantly innovating and developing new technological capabilities to improve Singapore’s food quality and safety.”

The research is carried out by SMART and supported by the National Research Foundation (NRF) Singapore under its Campus for Research Excellence And Technological Enterprise (CREATE) program.

Led by MIT’s Strano and Singapore co-lead principal investigator Professor Chua Nam Hai, DiSTAP is one of the five Interdisciplinary Research Groups (IRGs) in SMART. The DiSTAP program addresses deep problems in food production in Singapore and the world by developing a suite of impactful and novel analytical genetic and biosynthetic technologies. The goal is to fundamentally change how plant biosynthetic pathways are discovered, monitored, engineered, and ultimately translated to meet the global demand for food and nutrients. Scientists from MIT, TTL, Nanyang Technological University, and National University of Singapore are collaboratively developing new tools for the continuous measurement of important plant metabolites and hormones for novel discovery, deeper understanding and control of plant biosynthetic pathways in ways not yet possible, especially in the context of green leafy vegetables; leveraging these new techniques to engineer plants with highly desirable properties for global food security, including high yield density production, drought and pathogen resistance and biosynthesis of high-value commercial products; developing tools for producing hydrophobic food components in industry-relevant microbes; developing novel microbial and enzymatic technologies to produce volatile organic compounds that can protect and/or promote growth of leafy vegetables; and applying these technologies to improve urban farming.

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

Plant Nanobionic Sensors for Arsenic Detection by Tedrick Thomas Salim Lew, Minkyung Park, Jianqiao Cui, Michael S. Strano. Advanced Materials DOI: https://doi.org/10.1002/adma.202005683 First published: 26 November 2020

This paper is behind a paywall.

Longer lasting N95 masks thanks to a synchrotron in Saskatchewan (Canada)

A Nov. 3, 2020 Canadian Light Sources (CLS; also known as a synchrotron) news release by Erin Matthews (also on the University of Saskatchewan website), received via email, announces a technique that may make N95 masks last longer,

Through a collaboration between the Canadian Light Source (CLS) and the Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac)—both national research facilities at the University of Saskatchewan (USask) —scientists hope to understand the structural changes happening inside N95 respirator masks after being sterilized for reuse.  

Cutting-edge techniques unique to the CLS enable the team to analyze minute details in the masks that would be impossible to see with other methods. CLS Industrial Scientist Toby Bond is using X-rays produced by the synchrotron to see the tightly woven, microscopic fibres that are crucial to the filtering power of N95 respirators.  

N95 respirators get their name from their ability to filter at least 95 per cent of particles circulating in the air. These particular masks are used by frontline health-care workers for protection against COVID-19.  

However, N95 masks that were intended for one-time use were in short supply globally during the height of the pandemic this spring, and continue to be chronically unavailable in most parts of the world. As a result, health-care agencies and researchers have been looking for ways to sterilize masks for reuse to help ensure an emergency supply. 

While previous research has found that certain methods work better at maintaining the integrity of the masks following decontamination, Bond and colleagues want to understand why this happens and how to extend the lifespan of these critical masks. 

“We want to use the unique tools we have at the CLS to look at the fibres that actually do the filtering,” Bond said. “We use a specialized X-ray microscope to take tiny CT scans before and after exposing the N95 masks to different decontamination protocols. Previous research has shown that certain methods work better than others, but we don’t currently know what’s going on inside the mask at a microscopic level.”  

Bond is working to determine why the N95 mask fibres degrade. This information would enable manufacturers to design more resilient masks and help the medical industry move towards personal protective equipment that is designed to be reusable. 

“One thing that’s unique about a synchrotron CT scan is that we can scan a tiny fraction of the mask at high magnification without having to cut small pieces out of it. This is what allows us to do before-and-after imaging, since we can decontaminate the mask in its real-world environment without altering it,” Bond added. 

One method for decontaminating N95 masks, called vaporized hydrogen peroxide (VHP), is used to sterilize rooms and equipment in VIDO-InterVac.  

“With the outbreak of the pandemic and the recognized potential worldwide shortage of respirators, we were approached by the Saskatchewan Health Authority (SHA) to investigate the possibility of using VHP decontamination on N95 respirators to mitigate a potential shortage,” said VIDO-InterVac Biosafety Officer Tracey Thue.  

To date, VIDO-InterVac has sterilized more than 13,000 masks. Studies have demonstrated that N95 masks can undergo multiple VHP decontamination cycles without affecting mask integrity. 

When CLS Laboratory Co-ordinator Burke Barlow suggested that the two groups collaborate, Thue offered to run three styles of N95 respirators through their VHP system for Bond’s research. Bond compared the VHP-treated masks to others that he had treated with Moist Heat Incubation (MHI) and autoclaving. 

Autoclaving is a common decontamination method that uses hot pressurized steam to sterilize medical devices, however it is the most damaging method and certain masks do not survive even one autoclave sterilization cycle. MHI is gentler than the autoclave, but the masks still become less effective after repeated cycles. VHP is considered to be the best method for decontamination of N95s, but it requires specialized equipment that is not widely available in hospitals. 

Bond and his colleagues are using the BMIT beamline at the CLS, a one-of-a-kind tool in North America, to image the inside of the masks in three dimensions without damaging them. The researchers can then look at the structure of individual fibres in the masks to see how they change during decontamination. They can identify shifts in mask fibres as small as a few microns, which is a measurement much smaller than the width of a human hair.  

Analyses over the next few weeks will help clarify what effect these shifts have on the performance of the mask. Aerodynamic and fluid simulations conducted at the CLS will help show how the changes in mask fibre structure affect air flow.   

“Preliminary results show there is a gradual unravelling of the fibres during repeated exposure to MHI in some masks,” said Bond. “This is in contrast to autoclaving the masks, which immediately causes a very significant unravelling after a single decontamination.” 

“In some cases, this unravelling doesn’t affect the filtration, but it does affect the overall structure of the mask, causing it to fit poorly and no longer seal properly to the user’s face,” he added. “This indicates that manufacturers could potentially make an autoclavable mask by changing the structural parts of the mask and leaving the filtration layer as it is.” 

“In terms of Toby’s research at the CLS, being able to go down to the microscopic level and visualize changes in the material or lack there-of is another valuable piece of information,” Thue said. 

Bond emphasized that it’s not just tools and equipment that makes this kind of research possible at the CLS, but also the access to the vast research network at USask.  

“The CLS is a fantastic place to do research like this, since we’re a national facility with a broad network of researchers,” said Bond. “We’ve been able to work with our colleagues at VIDO-InterVac (which is just down the road on the USask campus), and we also have contacts in industry and academia who work in this sector that have helped us with the experiments.” 

Oddly, there is no reference to a published paper for this work or mention of future research into how manufacturers might make use of this information.

Adding nanofiber membranes results in cloth masks’ with 99% efficacy

An Oct. 22, 2020 news item on Nanowerk heralds a simple, inexpensive method for making your mask more protective,

The cloth masks many are sporting these days offer some protection against COVID-19. However, they typically provide much less than the professional N95 masks used by healthcare workers.

That may soon change. Recently, students from BYU’s [Brigham Young University; Utah, US] College of Engineering teamed up with Nanos Foundation [emphasis mine] to develop a nanofiber membrane that can be sandwiched between the cloth pieces in a homemade mask.

A few questions and a video

There is a video but you might find it helpful to know that when one of the students refers to OSHA she means the US Occupational Safety and Health Agency (OSHA). As for the ‘electrospinning’ I’m not sure how accessible that kind of equipment is, which calls into question how inexpensive and easy it would be to adopt this new mask insert. Fingers crossed that this will be as easy and effective as they seem to be suggesting,

The rest of the news

An October 21, 2020 BYU news release by Christie Allen, which originated the news item, delves into the technical details,

While today’s typical cloth mask might block fewer than 50% of virus particles, the membrane — which can be made using simple, inexpensive materials — will be able to block 90 to 99% of particles, increasing effectiveness [emphasis mine] while preserving breathability.

The membranes are made through a process called “electrospinning,” which involves dissolving a polymer plastic in a solution and then using an electrical current to move a droplet of the polymer downward through a needle. As the droplet accelerates, it stretches into a very small fiber that retains a static charge.

“Those nanofibers randomly land on a collector to create a sort of non-woven mesh,” said Katie Varela, a BYU mechanical engineering senior on the project team.

The remaining charge in the fibers is beneficial, she explained, because virus particles also have a static charge. “When they come close to your mask, they will be statically attracted to the mask and will not be able to go through it, and so it prevents you from inhaling viruses.”

In addition to the dramatic improvement in efficacy [emphasis mine], another key benefit of the nanofiber masks is that unlike traditional N95 masks, which have a reputation for being hot and stuffy, they allow for the circulation of (filtered) air, water and heat.

“Not only is it hard to find an N95 mask these days, but the best mask is useless if you won’t wear it,” said Will Vahle, director at Nanos Foundation. “Our nanofiber membranes are six times easier to breathe through than existing N95 masks, making them cooler, drier, and more comfortable.”

The group plans to make the instructions for creating the membranes open source. They hope that non-profit organizations will use the instructions to set up local sites where people can bring in their masks to be fitted with a membrane. They also hope other engineers will use their work as a springboard to produce more effective filters.

“We had our own proprietary nanofiber production process,” said Vahle of the project’s origins, “but we realized, hey, we have some expertise in this — why don’t we get this together and release a version that anybody can do?”

When Vahle and his colleagues approached BYU to collaborate on the project, BYU “jumped at the opportunity,” Vahle said. In addition to providing funding and facilities, the university connected the company with “fantastic students, who’ve really demonstrated an incredible work ethic and a drive to help people in need.”

Using cutting-edge science to make an immediate positive impact has also been highly valuable for the BYU students on the project.

“This experience makes things very real,” said Varela. “I’m really glad that I’m able to help with this fight against COVID-19 to help people all around the world and in my community.”

I’ve highlighted ‘effectiveness’ and ‘efficacy’, which are not synonyms although they’re often used that way. I can recall being quite surprised on discovering they were not, since I had, up to that point, confused them for many, many years. There’s a good description of the differences in a November 17, 2018 posting on the Public Health Notes website,

[downloaded from https://www.publichealthnotes.com/efficiency-vs-effectiveness-how-do-they-differ/]

So, the difference is between controlled environments for efficacy and real life for effectiveness, in this case, a mask.

Can you get one of these improved masks?

The Nanos Foundation has a dedicated 95+ Mask webpage answering that question,

Worldwide Accessibility

Current technology has not been updated since the 1970s. The Nanos technology is inexpensive, portable and accessible.

Our Open-Source process turns common plastics into highly effective respiratory PPE [personal protective equipment].

‘Electrospinning’ nanofibers onto common cloth turns the cloth into a filter → sew the cloth into a mask to produce an effective top notch respirator.

You can use our designs, or bring your own design – 95+ is about the nanofiber membrane that turns the ‘cloth face covering’ into a respirator. Just make sure to use a design that creates a good seal or fit against the face.

The 95+ Process Requires Only A Few Simple Things

The kinds of things that can be easily found, like an old television, paint thinner & recycled plastics

I didn’t find any instructions for how to ‘electrospin’ with an old television, paint thinner, and plastics to make the nanofiber membrane. Perhaps one is required to donate before receiving instructions.

Interestingly, Nanos Foundation has three locations:

  • Greenville, AL, USA
  • Providence, RI, USA
  • Montreal, Canada

I was not expecting a Canadian connection.

Efficectiveness?

While this ‘easy to produce’ plastic insert seems very useful, it’s not clear to me what happens when the mask has to be washed or cleaned in some fashion. How long these nanofiber membranes active? Do we have to keep replacing the nanofiber membranes thereby adding more plastic to the environment?

Printing wearable circuits onto skin

It seems that this new technique for creating wearable electronics will be more like getting a permanent tattoo where the circuits are applied directly to your skin as opposed to being like a temporary tattoo where the circuits are printed onto a substrate and then applied to then, worn on your skin.

Caption: On-body sensors, such as electrodes and temperature sensors, were directly printed and sintered on the skin surface. Credit: Adapted from ACS Applied Materials & Interfaces 2020, DOI: 10.1021/acsami.0c11479

An Oct. 14, 2020 American Chemical Society (ACS) news release (also on EurekAlert) announced this latest development in wearable electronics,

Wearable electronics are getting smaller, more comfortable and increasingly capable of interfacing with the human body. To achieve a truly seamless integration, electronics could someday be printed directly on people’s skin. As a step toward this goal, researchers reporting in ACS Applied Materials & Interfaces have safely placed wearable circuits directly onto the surface of human skin to monitor health indicators, such as temperature, blood oxygen, heart rate and blood pressure.

The latest generation of wearable electronics for health monitoring combines soft on-body sensors with flexible printed circuit boards (FPCBs) for signal readout and wireless transmission to health care workers. However, before the sensor is attached to the body, it must be printed or lithographed onto a carrier material, which can involve sophisticated fabrication approaches. To simplify the process and improve the performance of the devices, Peng He, Weiwei Zhao, Huanyu Cheng and colleagues wanted to develop a room-temperature method to sinter metal nanoparticles onto paper or fabric for FPCBs and directly onto human skin for on-body sensors. Sintering — the process of fusing metal or other particles together — usually requires heat, which wouldn’t be suitable for attaching circuits directly to skin.

The researchers designed an electronic health monitoring system that consisted of sensor circuits printed directly on the back of a human hand, as well as a paper-based FPCB attached to the inside of a shirt sleeve. To make the FPCB part of the system, the researchers coated a piece of paper with a novel sintering aid and used an inkjet printer with silver nanoparticle ink to print circuits onto the coating. As solvent evaporated from the ink, the silver nanoparticles sintered at room temperature to form circuits. A commercially available chip was added to wirelessly transmit the data, and the resulting FPCB was attached to a volunteer’s sleeve. The team used the same process to sinter circuits on the volunteer’s hand, except printing was done with a polymer stamp. As a proof of concept, the researchers made a full electronic health monitoring system that sensed temperature, humidity, blood oxygen, heart rate, blood pressure and electrophysiological signals and analyzed its performance. The signals obtained by these sensors were comparable to or better than those measured by conventional commercial devices. 

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

Wearable Circuits Sintered at Room Temperature Directly on the Skin Surface for Health Monitoring by Ling Zhang, Hongjun Ji, Houbing Huang, Ning Yi, Xiaoming Shi, Senpei Xie, Yaoyin Li, Ziheng Ye, Pengdong Feng, Tiesong Lin, Xiangli Liu, Xuesong Leng, Mingyu Li, Jiaheng Zhang, Xing Ma, Peng He, Weiwei Zhao, and Huanyu Cheng. ACS Appl. Mater. Interfaces 2020, 12, 40, 45504–45515 Publication Date:September 11, 2020 DOI: https://doi.org/10.1021/acsami.0c11479 Copyright © 2020 American Chemical Society

This paper is behind a paywall.

Could synergistic action of engineered nanoparticles have a health impact?

Synergistic action can be difficult to study especially when you’re looking at nanoparticles which could be naturally occurring and/or engineered. I believe this study is focused on engineered nanoparticles (ENPs) and I think it’s the first one I’ve seen that examines synergistic action of any kind. So, bravo to the scientists for tackling a very ambitious project.

An October 1, 2020 news item on phys.org describes this work from Denmark,

Nanoparticles are used in a wide range of products and manufacturing processes because the properties of a material can change dramatically when the material comes in nano-form.

They can be used, for example, to purify wastewater and to transport medicine around the body. They are also added to, for example, socks, pillows, mattresses, phone covers and refrigerators to supply the items with an antibacterial surface.

Much research has been done on how nanoparticles affect humans and the environment and a number of studies have shown that nanoparticles can disrupt or damage our cells.

This is confirmed by a new study that has also looked at how cells react when exposed to more than one kind of nano particle at the same time.

An October 1, 2020 University of Southern Denmark press release (also on EurekAlert) by Birgitte Svennevig, which originated the news item, provides more insight into the research,

The lead author of the study is Barbara Korzeniowska from the Department of Biochemistry and Molecular Biology at SDU. The head of research is Professor Frank Kjeldsen from the same department.

His research into metal nanoparticles is supported by a European Research Grant of DKK 14 million.

“Throughout a lifetime, we are exposed to many different kinds of nano-particles, and we should investigate how the combination of different nano-particles affects us and also whether an accumulation through life can harm us,” says Barbara Korzeniowska.

She herself became interested in the subject when her little daughter one day was going in the bathtub and got a rubber duck as a toy.

– It turned out that it had been treated with nano-silver, probably to keep it free of bacteria, but small children put their toys in their mouths, and she could thus ingest nano-silver. That is highly worrying when research shows that nano-silver can damage human cells, she says.

In her new study, she looked at nano-silver and nano-platinum. She has investigated their individual effect and whether exposure of both types of nanoparticles results in a synergy effect in two types of brain cells.

– There are almost no studies of the synergy effect of nano particles, so it is important to get started with these studies, she says.

She chose nano-silver because it is already known to be able to damage cells and nano-platinum, because nano-platinum is considered to be so-called bio-inert; i.e. has a minimal interaction with human tissue.

The nanoparticles were tested on two types of brain cells: astrocytes and endothelial cells. Astrocytes are supporter cells in the central nervous system, which i.a. helps to supply the nervous system with nutrients and repair damage to the brain. Endothelial cells sit on the inside of the blood vessels and transport substances from the bloodstream to the brain.

When the endothelial cells were exposed to nano-platinum, nothing happened. When exposed to nano-silver, their ability to divide deteriorated. When exposed to both nano-silver and nano-platinum, the effect was amplified, and they died in large numbers. Furthermore, their defense mechanisms decreased, and they had difficulty communicating with each other.

– So even though nano-platinum alone does not do harm, something drastic happens when they are combined with a different kind of nano-particle, says Frank Kjeldsen.

The astrocytes were more hardy and reacted “only” with impaired ability to divide when exposed to both types of nano-particles.

An earlier study, conducted by Frank Kjeldsen, has shown a dramatic synergy effect of silver nanoparticles and cadmium ions, which are found naturally all around us on Earth.

In that study, 72 % of the cells died (in this study it was intestinal cells) as they were exposed to both nano-silver and cadmium ions. When they were only exposed to nano-silver, 25% died. When exposed to cadmium ions only, 12% died.

We are involuntarily exposed

– Little is known about how large concentrations of nano-particles are used in industrial products. We also do not know what size particles they use – size also has an effect on whether they can enter a cell, says Barbara Korzeniowska and continues:

– But we know that a lot of people are involuntarily exposed to nano-particles, and that there can be lifelong exposure.

There are virtually no restrictions on adding nanoparticles to products. In the EU, however, manufacturers must have an approval if they want to use nanoparticles in products with antibacterial properties. In Denmark, they must also declare nano-content in such products on the label.

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

The Cytotoxicity of Metal Nanoparticles Depends on Their Synergistic Interactions by Barbara Korzeniowska, Micaella P. Fonseca, Vladimir Gorshkov, Lilian Skytte, Kaare L. Rasmussen, Henrik D. Schrøder, Frank Kjeldsen. Particle Volume 37, Issue 8, August 2020,. 2000135 DOI: https://doi.org/10.1002/ppsc.202000135 First published: 06 July 2020

This paper is behind a paywall.