Tag Archives: Swiss Federal Laboratories for Materials Science and Technology (Empa)

Nanoplastics in the air we breathe

Most of the research I’ve seen about polluting nanoplastics it concerns the ocean; this time it concerns the air. This research dates from November 2021 but I didn’t stumble across it until this February 2, 2022 article by Talib Visram for Fast Company (Note: Links have been removed),

By some estimates, people have discarded 4,900 million tonnes of plastic have into the environment. Once in nature, that plastic starts to degrade, fragmenting into microplastics about the size of a sesame seed, which are inadvertently ingested by humans and animals through eating them in seafood and drinking them in water. Some reports suggest that we all consume five grams a week–about the weight of a bottle cap.

But, we may be taking more plastics into our systems through our respiratory systems. There’s been less investigation of nanoplastics: particles smaller than microplastics, so small that they can move huge distances in the air and be more easily inhaled into the bloodstream. A new study looks at the travel of those lighter particles, finding them abundant in the atmosphere, and carried, via aerosol transmission, even to remote areas. As far as the scientists know, it’s “the most accurate record of air pollution by nanoplastics ever made.”

A February 1, 2022 news item on SciTechDaily.com highlights some of the concerns raised by the research,

In a new study, Empa [Swiss Federal Laboratories for Materials Science and Technology] researcher Dominik Brunner, together with colleagues from Utrecht University and the Austrian Central Institute for Meteorology and Geophysics, is investigating how much plastic is trickling down on us from the atmosphere.

According to the study, some nanoplastics travel over 2000 kilometers through the air. According to the figures from the measurements about 43 trillion miniature plastic particles land in Switzerland every year. Researchers still disagree on the exact number. But according to estimates from the study, it could be as much as 3,000 tonnes of nanoplastics that cover Switzerland every year, from the remote Alps to the urban lowlands. These estimates are very high compared to other studies, and more research is needed to verify these numbers.

….

A January 25, 2022 EMPA [Swiss Federal Laboratories for Materials Science and Technology] press release by Noé Waldmann, which originated the news item, provides some technical details,

In a large-scale fundraising campaign, popular YouTubers like Mister Beast and Mark Rober are currently trying to rid the oceans of almost 14,000 tonnes of plastic waste. That’s about 0.15 per cent of the amount that ends up in the oceans every year. But it’s not just our waters that are full of plastic. A new study shows that the spread of nanoplastic through the air is a more widespread problem than previously thought.

….

Extreme conditions

The scientists studied a small area at an altitude of 3106 meters at the top of the mountain “Hoher Sonnenblick” in the “Hohe Tauern” National Park in Austria. An observatory of the Central Institute for Meteorology and Geodynamics has been located here since 1886. The observatory is run by meteorologist and Arctic researcher Elke Ludewig. Since research began here in the late 19th century, the observatory has only been non-operational on four days. The research station also served as a base for the study on the spread of nanoplastics in remote areas.

Every day, and in all weather conditions, scientists removed a part of the top layer of snow around a marker at 8 AM and carefully stored it. Contamination of the samples by nanoplastics in the air or on the scientists’ clothes was a particular challenge. In the laboratory, the researchers sometimes had to remain motionless when a colleague handled an open sample.

The origin of the tiny particles was traced with the help of European wind and weather data. The researchers could show that the greatest emission of nanoplastics into the atmosphere occurs in densely populated, urban areas. About 30% of the nanoplastic particles measured on the mountain top originate from a radius of 200 kilometers, mainly from cities. However, plastics from the world’s oceans apparently also get into the air via the spray of the waves. Around 10% of the particles measured in the study were blown onto the mountain by wind and weather over 2000 kilometers – some of them from the Atlantic.

Nanoparticles in the bloodstream

It is estimated that more than 8300 million tonnes of plastic have been produced worldwide to date, about 60% of which is now waste. This waste erodes through weathering effects and mechanical abrasion from macro- to micro- and nanoparticles. But discarded plastic is far from the only source. Everyday use of plastic products such as packaging and clothing releases nanoplastics. Particles in this size range are so light that their movement in the air can best be compared to gases.

Besides plastics, there are all kinds of other tiny particles. From Sahara sand to brake pads, the world is buzzing through the air as abrasion. It is as yet unclear whether this kind of air pollution poses a potential health threat to humans. Nanoparticles, unlike microparticles, do not just end up in the stomach. They are sucked deep into the lungs through respiration, where their size may allow them to cross the cell-blood barrier and enter the human bloodstream. Whether this is harmful or even dangerous, however, remains to be researched.

Included here because of its compelling story is Utrecht University’s November 1, 2021 press release conveying the researchers’ excitement, (Note: Links have been removed)

Nanoplastics found in the Alps, transported by air from Frankfurt, Paris and London

A team of researchers have found nanoplastics at the pristine high-altitude Sonnblick Observatory in the Alps. This is the first time that nanoplastics were found in this area. The researchers were originally looking for certain organic particles, but found nanoplastics by chance, discovering a new analysis method for detecting nanoplastics in the process. …

The researchers were looking for organic particles by taking samples of snow or ice, evaporating them, and then burning the residue to detect and analyse the vapours. “Our detection method is a bit like a mechanical nose. And unexpectedly, it smelled burning plastics in our snow samples,” lead researcher Dušan Materić explains. The detector found the smell of several types of plastic, mostly polypropylene (PP) and polyethylene terephthalate (PET).

The detected plastic particles turned out to be less than 200 nm in size, about one hundredth the width of a human hair. That is significantly smaller than plastic particles detected in previous studies. “With this detection method, we are the first group to quantify nanoplastics in the environment,” says Materić. “Since the high Alps are a very remote and pristine area, we were quite shocked and surprised to find such a high concentration of nanoplastics there.” The results suggest that in addition to microplastics, there might be as much nanoplastics present in these remote places.

Transported by air

“We were quite gripped by these findings,” Materić continues. “It’s highly unlikely that these nanoplastics originated from local pristine Alpine areas. So where did they come from? We completely turned around our research project to study this further.”

The researchers found a striking correlation between high concentrations of nanoplastics and winds coming from the direction of major European cities, most notably Frankfurt and the industrial Ruhr area (Germany), but also the Netherlands, Paris, and even London.

“Advanced modelling supported the idea that nanoplastics are indeed transported by air from these urban places,” says Materić. “That’s potentially alarming, because that could mean that there are hotspots of nanoplastics in our cities, and indeed in the very air we’re breathing. We are currently studying this in more detail.” Since working on the current publication, Materić has already received an additional NWO [Dutch Research Council] grant of 50,000 Euros to study the size distribution of nanoplastics in indoor, urban and rural air.

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

Nanoplastics transport to the remote, high-altitude Alps by Dušan Materić,
Elke Ludewig, Dominik Brunner, Thomas Röckmann, Rupert Holzinger. Environmental Pollution Volume 288, 1 November 2021, 117697 DOI: https://doi.org/10.1016/j.envpol.2021.117697

This paper is open access.

Nanocellulose sensors: 3D printed and biocompatible

I do like to keep up with nanocellulose doings, especially when there’s some Canadian involvement, and an October 8, 2019 news item on Nanowerk alerted me to a newish application for the product,

Physiological parameters in our blood can be determined without painful punctures. Empa researchers are currently working with a Canadian team to develop flexible, biocompatible nanocellulose sensors that can be attached to the skin. The 3D-printed analytic chips made of renewable raw materials will even be biodegradable in future.

The idea of measuring parameters that are relevant for our health via the skin has already taken hold in medical diagnostics. Diabetics, for example, can painlessly determine their blood sugar level with a sensor instead of having to prick their fingers.

An October 8, 2019 Empa (Swiss Federal Laboratories for Materials Science and Technology) press release, which originated the news item, provides more detail,

A transparent foil made of wood

Nanocellulose is an inexpensive, renewable raw material, which can be obtained in form of crystals and fibers, for example from wood. However, the original appearance of a tree no longer has anything to do with the gelatinous substance, which can consist of cellulose nanocrystals and cellulose nanofibers. Other sources of the material are bacteria, algae or residues from agricultural production. Thus, nanocellulose is not only relatively easy and sustainable to obtain. Its mechanical properties also make the “super pudding” an interesting product. For instance, new composite materials based on nanocellulose can be developed that could be used as surface coatings, transparent packaging films or even to produce everyday objects like beverage bottles.

Researchers at Empa’s Cellulose & Wood Materials lab and Woo Soo Kim from the Simon Fraser University [SFU] in Burnaby, Canada, are also focusing on another feature of nanocellulose: biocompatibility. Since the material is obtained from natural resources, it is particularly suitable for biomedical research.

With the aim of producing biocompatible sensors that can measure important metabolic values, the researchers used nanocellulose as an “ink” in 3D printing processes. To make the sensors electrically conductive, the ink was mixed with silver nanowires. The researchers determined the exact ratio of nanocellulose and silver threads so that a three-dimensional network could form.

Just like spaghetti – only a wee bit smaller

It turned out that cellulose nanofibers are better suited than cellulose nanocrystals to produce a cross-linked matrix with the tiny silver wires. “Cellulose nanofibers are flexible similar to cooked spaghetti, but with a diameter of only about 20 nanometers and a length of just a few micrometers,” explains Empa researcher Gilberto Siqueira.

The team finally succeeded in developing sensors that measure medically relevant metabolic parameters such as the concentration of calcium, potassium and ammonium ions. The electrochemical skin sensor sends its results wirelessly to a computer for further data processing. The tiny biochemistry lab on the skin is only half a millimeter thin.

While the tiny biochemistry lab on the skin – which is only half a millimeter thin – is capable of determining ion concentrations specifically and reliably, the researchers are already working on an updated version. “In the future, we want to replace the silver [nano] particles with another conductive material, for example on the basis of carbon compounds,” Siqueira explains. This would make the medical nanocellulose sensor not only biocompatible, but also completely biodegradable.

I like the images from Empa better than the ones from SFU,

Using a 3D printer, the nanocellulose “ink” is applied to a carrier plate. Silver particles provide the electrical conductivity of the material. Image: Empa
Empa researcher Gilberto Siqueira demonstrates the newly printed nanocellulose circuit. After a subsequent drying, the material can be further processed. Image: Empa

SFU produced a news release about this work back in February 2019. Again, I prefer what the Swiss have done because they’re explaining/communicating the science, as well as , communicating benefits. From a February 13, 2019 SFU news release (Note: Links have been removed),

Simon Fraser University and Swiss researchers are developing an eco-friendly, 3D printable solution for producing wireless Internet-of-Things (IoT) sensors that can be used and disposed of without contaminating the environment. Their research has been published as the cover story in the February issue of the journal Advanced Electronic Materials.

SFU professor Woo Soo Kim is leading the research team’s discovery, which uses a wood-derived cellulose material to replace the plastics and polymeric materials currently used in electronics.

Additionally, 3D printing can give flexibility to add or embed functions onto 3D shapes or textiles, creating greater functionality.

“Our eco-friendly, 3D-printed cellulose sensors can wirelessly transmit data during their life, and then can be disposed without concern of environmental contamination,” says Kim, a professor in the School of Mechatronic Systems Engineering. The SFU research is being carried out at PowerTech Labs in Surrey, which houses several state-of-the-art 3D printers used to advance the research.

“This development will help to advance green electronics. For example, the waste from printed circuit boards is a hazardous source of contamination to the environment. If we are able to change the plastics in PCB to cellulose composite materials, recycling of metal components on the board could be collected in a much easier way.”

Kim’s research program spans two international collaborative projects, including the latest focusing on the eco-friendly cellulose material-based chemical sensors with collaborators from the Swiss Federal Laboratories for Materials Science.

He is also collaborating with a team of South Korean researchers from the Daegu Gyeongbuk Institute of Science and Technology’s (DGIST)’s department of Robotics Engineering, and PROTEM Co Inc, a technology-based company, for the development of printable conductive ink materials.

In this second project, researchers have developed a new breakthrough in the embossing process technology, one that can freely imprint fine circuit patterns on flexible polymer substrate, a necessary component of electronic products.

Embossing technology is applied for the mass imprinting of precise patterns at a low unit cost. However, Kim says it can only imprint circuit patterns that are imprinted beforehand on the pattern stamp, and the entire, costly stamp must be changed to put in different patterns.

The team succeeded in developing a precise location control system that can imprint patterns directly resulting in a new process technology. The result will have widespread implications for use in semiconductor processes, wearable devices and the display industry.

This paper was made available online back in December 2018 and then published in print in February 2019. As to why there’d be such large gaps between the paper’s publication dates and the two institution’s news/press releases, it’s a mystery to me. In any event, here’s a link to and a citation for the paper,

3D Printed Disposable Wireless Ion Sensors with Biocompatible Cellulose Composites by Taeil Kim, Chao Bao, Michael Hausmann, Gilberto Siqueira, Tanja Zimmermann, Woo Soo Kim. Advanced Electronic Materials DOI: https://doi.org/10.1002/aelm.201970007 First published online December 19, 2018. First published in print: 08 February 2019 (Adv. Electron. Mater. 2/2109) Volume 5, Issue 2 February 2019 1970007

This paper is behind a paywall.