Category Archives: health and safety

Using carbon dots (organic nanosensors) to detect pesticides

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Before getting to the latest about carbon dots, there’s something to be clarified (and it was news to me), a carbon dot is not a quantum dot. So says this 2020 paper, “Advances in carbon dots: from the perspective of traditional quantum dots” by Yanhong Liu, Hui Huang, Weijing Cao, Baodong Mao, Yang Liu, and Zhenhui Kang. Mater. Chem. Front., 2020,4, 1586-1613 First published March 17, 2020.

Abstract

Quantum dots (QDs) have been the core concept of nanoscience and nanotechnology since their inception, and play a dominant role in the development of the nano-field. Carbon dots (CDots), defined by a feature size of <10 nm, have become a rising star in the crossover field of carbon materials and traditional QDs (TQDs). CDots possess many unique structural, physicochemical and photochemical properties that render them a promising platform for biology, devices, catalysis and other applications. …

This story is about carbon dots but you can find out more about quantum dots in my October 6, 2023 posting concerning the 2023 Nobel prizes; scroll down to the ‘Chemistry’ subhead.

An August 30, 2023 news item on phys.org describes work from Concordia University (Montréal, Canada) on carbon dots,

Researchers at Concordia have developed a new system using tiny nanosensors called carbon dots to detect the presence of the widely used chemical glyphosate. Their research, titled “Ratiometric Sensing of Glyphosate in Water Using Dual Fluorescent Carbon Dots,” is published in Sensors.

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An August 30, 2023 Concordia University news release (also on EurekAlert) by Patrick Lejtenyi, which originated the news item, explains the importance of the work and provides more technical details, Note: Links have been removed,

Glyphosate is a pesticide found in more than 750 agricultural, forestry, urban and home products, including Monsanto’s popular weed-killer Roundup. It is also controversial: studies have linked its overuse to environmental pollution and cancer in humans. Its sale is banned or restricted in dozens of countries and jurisdictions, including Canada.

The researchers’ system relies on the carbon dots’ chemical interaction with glyphosate to detect its presence. Carbon dots are exceedingly small fluorescent particles, usually no more than 10 or 15 nanometres in size (a human hair is between 80,000 and 100,000 nanometres). But when they are added to water solutions, these nanomaterials emit blue and red fluorescence.

The researchers employed an analysis technique called a ratiometric self-referencing assay to determine glyphosate levels in a solution. The red fluorescence emitted by the carbon dots when exposed to varying concentrations of the chemical and different pH levels is compared with a control in which no glyphosate is present. In all the tests, the blue fluorescence remained unchanged, giving the researchers a common reference point across the different tests.

They observed that higher levels of glyphosate quenched the red fluorescence, which they accredited to the interaction of the pesticide with the carbon dots’ surface.

“Our system differs from others because we are measuring the area between two peaks—two fluorescent signatures—on the visible spectrum,” says Adryanne Clermont-Paquette, a PhD candidate in biology and the paper’s lead author. “This is the integrated area between the two curves. Ratiometric measurement allows us to ignore variables such as temperature, pH levels or other environmental factors. That allows us to just only look at the levels of glyphosate and carbon dots that are in the system.”

“By understanding the chemistry at the surface of these very small dots and by knowing their optical properties, we can use them to our advantage for many different applications,” says Rafik Naccache, an associate professor of chemistry and biochemistry and the paper’s supervising author.

Research assistants Diego-Andrés Mendoza and Amir Sadeghi, along with associate professor of biology Alisa Piekny, are co-authors.

Starting small

Naccache says the technique is designed to detect minute amounts of the pesticide. The technique they developed is sensitive enough to be able to detect the presence of pesticide at levels as low as 0.03 parts per million.

“The challenge is always in the other direction, to see how low we can go in terms of sensitivity and selectivity,” he says.

There remains much work to be done before this technology can be used widely. But as Clermont-Paquette notes, this paper represents an important beginning.

“Understanding the interaction between glyphosate and carbon dots is a first step. If we are to move this along further, and develop it into a real-life application, we have to start with the fundamentals.”

The researchers are supported by funding from the Natural Sciences and Engineering Research Council of Canada.

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

Ratiometric Sensing of Glyphosate in Water Using Dual Fluorescent Carbon Dots
by Adryanne Clermont-Paquette, Diego-Andrés Mendoza, Amir Sadeghi, Alisa Piekny, and Rafik Naccache. Sensors 2023, 23(11), 5200; DOI: https://doi.org/10.3390/s23115200 Published: 30 May 2023

This paper is open access.

Biodegradable electronics: a seaweed biosensor

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By combining seaweed and graphene, scientists have been able to create sensors that can be worn like a ‘second skin’ and outperform other similar biosensors, according to a March 3, 2023 news item on ScienceDaily,

Scientists at the University of Sussex have successfully trialed new biodegradable health sensors that could change the way we experience personal healthcare and fitness monitoring technology.

The team at Sussex have developed the new health sensors — such as those worn by runners or patients to monitor heart rate and temperature — using natural elements like rock salt, water and seaweed, combined with graphene. Because they are solely made with ingredients found in nature, the sensors are fully biodegradable, making them more environmentally friendly than commonly used rubber and plastic-based alternatives. Their natural composition also places them within the emerging scientific field of edible electronics — electronic devices that are safe for a person to consume.

Better still, the researchers found that their sustainable seaweed-based sensors actually outperform existing synthetic based hydrogels and nanomaterials, used in wearable health monitors, in terms of sensitivity. Therefore, improving the accuracy, as the more sensitive a sensor, the more accurately it will record a person’s vital signs.

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A March 2, 2023 University of Sussex press release (also on EurekAlert) by Poppy Luckett, which originated the news item, describes the inspiration for the research,

Dr Conor Boland, a materials physics lecturer in the School of Mathematical and Physical Sciences, said:  “I was first inspired to use seaweed in the lab after watching MasterChef during lockdown. Seaweed, when used to thicken deserts, gives them a soft and bouncy structure – favored by vegans and vegetarians as an alternative to gelatin. It got me thinking: “what if we could do that with sensing technology?”.

“For me, one of the most exciting aspects to this development is that we have a sensor that is both fully biodegradable and highly effective. The mass production of unsustainable rubber and plastic based health technology could, ironically, pose a risk to human health through microplastics leeching into water sources as they degrade.  

“As a new parent, I see it as my responsibility to ensure my research enables the realisation of a cleaner world for all our children.” 

Seaweed is first and foremost an insulator, but by adding a critical amount of graphene to a seaweed mixture the scientists were able to create an electrically conductive film. When soaked in a salt bath, the film rapidly absorbs water, resulting in a soft, spongy, electrically conductive hydrogel.  

The development has the potential to revolutionise health monitoring technology, as future applications of the clinical grade wearable sensors would look something like a second skin or a temporary tattoo: lightweight, easy to apply, and safe, as they are made with all natural ingredients. This would significantly improve the overall patient experience, without the need for more commonly used and potentially invasive hospital instruments, wires and leads.  

Dr Sue Baxter, Director of Innovation and Business Partnerships at the University of Sussex, is excited about the potential benefits of this technology:  “At the University of Sussex, we are committed to protecting the future of the planet through sustainability research, expertise and innovation. What’s so exciting about this development from Dr Conor Boland and his team is that it manages to be all at once truly sustainable, affordable, and highly effective – out-performing synthetic alternatives.  

“What’s also remarkable for this stage of research – and I think this speaks to the meticulous ground-work that Dr Boland and his team put in when they created their blueprint – is that it’s more than a proof of principle development. Our Sussex scientists have created a device that has real potential for industry development into a product from which you or I could benefit in the relatively near future.” 

This latest  research breakthrough follows the publication of a blueprint for nanomaterial development from the Sussex scientists in 2019, which presented a method for researchers to follow in order to optimise the development of nanomaterial sensors.  

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Kevin Doty, a Masters student in the School of Mathematical and Physical Sciences, at the University of Sussex, said:  “I taught chemistry previously, but decided I wanted to learn more about nanoscience. My gamble paid off, and not only did I enjoy it more than I expected, but I also ended up with an opportunity to utilize the information I had learned to work on a novel idea that has evolved into a first author publication as an MSc student. Learning about nanoscience showed me just how varied and multidisciplinary the field is. Any science background can bring knowledge that can be applied to this field in a unique way. This has led to further studies in a PhD studentship, opening up an all new career path I could not have previously considered.” 

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

Food-Inspired, High-Sensitivity Piezoresistive Graphene Hydrogels by Adel A. K. Aljarid, Kevin L. Doty, Cencen Wei, Jonathan P. Salvage, and Conor S. Boland. ACS Sustainable Chem. Eng. 2023, 11, 5, 1820–1827 DOI: https://doi.org/10.1021/acssuschemeng.2c06101 Publication Date:January 25, 2023 Copyright © 2023 The Authors. Published by American Chemical Society

This paper appears to be open access.

A roly-poly (woodlouse) gold rush

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This environmental monitoring story focused on the roly-poly was announced in an April 18, 2023 news item on Statnano,

The woodlouse goes by many names: roly-poly, pill bug, potato bug, tomato bug, butchy boy, cheesy bob, and chiggy pig, to name just a few. It is best known for contracting into a ball when agitated. This crustacean (yes, it’s a crustacean, not an insect) thrives in heavily metal-contaminated areas due to its specialized digestive organ, called a hepatopancreas, that stores and expels unwanted metals.

Metal nanoparticles are common in industrial and research plants. However, they can leach into the surrounding environment. Currently, little is known about the toxicity of metal nanoparticles for nearby organisms because detecting metal nanoparticles, particularly gold, requires microscopic, 3D imaging that cannot be done in the field

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Caption: (a) Cartoon of a woodlouse depicting the hepatopancreas (HP) and the hind gut (HG). (b) Transmission overview of a single HP tubule, showing the helical structure. (c) Section from a HP tubule with the nuclei fluorescently labeled in blue. Credit: Iestyn Pope, Nuno G.C. Ferreira, Peter Kille, Wolfgang Langbein, and Paola Borri

An April 11, 2023 American Institute of Physics (AIP) news release (also on EurekAlert), which originated the news item, describes a new approach to detecting gold nanoparticles in roly-polys,

In Applied Physics Letters, by AIP Publishing, researchers from Cardiff University in the U.K. introduce a novel imaging method to detect gold nanoparticles in woodlice. With information about the quantity, location, and impact of gold nanoparticles within the organism, scientists can better understand the potential harm other metals may have on nature.

“Gold nanoparticles are used extensively for biological research applications owing to their biocompatibility and photostability and are available in a large range of shapes and sizes,” said author Wolfgang Langbein. “By using gold nanoparticles, which would not normally be present in the woodlice diet, we can study the journey of nanoparticles inside complex biological systems.”

The researchers developed an imaging method known as four-wave mixing microscopy, which flashes light that the gold nanoparticles absorb. The light flashes again and the subsequent scattering reveals the nanoparticles’ locations. Using this state-of-the-art technique, they locate the individual gold nanoparticles in the 3D cellular environment.

“By precisely pinpointing the fate of individual gold nanoparticles in the hepatopancreas of woodlice, we can gain a better understanding of how these organisms sequester and respond to metals ingested from the environment,” said Langbein. “Tracking this metal within these organisms is the first step enabling further study to determine, for example, if gold is collected within specific cells, or if it can interfere with the metabolisms in high doses.”

The use of gold nanoparticles in medical devices is increasing and with it, their abundance in the environment. This imaging technique will provide clarity into the little-understood mechanisms in the woodlice hepatopancreas and will also provide helpful environmental monitoring.

In the future, background-free four-wave mixing microscopy could be used to detect other metal nanoparticles and may be applied to organisms like fish larvae and even human cell cultures.

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

Background-free four-wave mixing microscopy of small gold nanoparticles inside a multi-cellular organ by Iestyn Pope, Nuno G.C. Ferreira, Peter Kille, Wolfgang Langbein, and Paola Borri. Appl. Phys. Lett. 122, 153701 (2023) DOI: https://doi.org/10.1063/5.0140651Published online April 11, 2023

This paper is open access.

Future firefighters and wearable technology

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I imagine this wearable technology would also be useful for the military too. However, the focus for these researchers from China is firefighting. (Given the situation with the Canadian wildfires in June 2023, we have 10x more than the average at this time in the season over the last 10 years, it’s good to see some work focused on safety for firefighters.) From a January 17, 2023 news item on phys.org,

Firefighting may look vastly different in the future thanks to intelligent fire suits and masks developed by multiple research institutions in China.

Researchers published results showing breathable electrodes woven into fabric used in fire suits have proven to be stable at temperatures over 520ºC. At these temperatures, the fabric is found to be essentially non-combustible with high rates of thermal protection time.

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Caption: Scientists from multiple institutions address the challenges and limitations of current fire-fighting gear by introducing wearable, breathable sensors and electrodes to better serve firefighters. Credit: Nano Research, Tsinghua University Press

A January 17, 2023 Tsinghua University Press press release on EurekAlert, which originated the news item, provides more technical details,

The results show the efficacy and practicality of Janus graphene/poly(p-phenylene benzobisoxazole), or PBO, woven fabric in making firefighting “smarter” with the main goal being to manufacture products on an industrial scale that are flame-retardant but also intelligent enough to warn the firefighter of increased risks while traversing the flames.

“Conventional firefighting clothing and fire masks can ensure firemen’s safety to a certain extent,” said Wei Fan, professor at the School of Textile Science and Engineering at Xi’an Polytechnic University. “However, the fire scene often changes quickly, sometimes making firefighters trapped in the fire for failing to judge the risks in time. At this situation, firefighters also need to be rescued.”

The key here is the use of Janus graphene/PBO, woven fabrics. While not the first of its kind, the introduction of PBO fibers offers better strength and fire protection than other similar fibers, such as Kevlar. The PBO fibers are first woven into a fabric that is then irradiated using a CO2 infrared laser. From here, the fabric becomes the Janus graphene/PBO hybrid that is the focus of the study.   

The mask also utilizes a top and bottom layer of Janus graphene/PBO with a piezoelectric layer in between that acts as a way to convert mechanical pressures to electricity.

“The mask has a good smoke particle filtration effect, and the filtration efficiency of PM2.5 and PM3.0 reaches 95% and 100%, respectively. Meanwhile, the mask has good wearing comfort as its respiratory resistance (46.8 Pa) is lower than 49 Pa of commercial masks. Besides, the mask is sensitive to the speed and intensity of human breathing, which can dynamically monitor the health of the firemen” said Fan.

Flame-retardant electronics featured in these fire suits are flexible, heat resistant, quick to make and low-cost which makes scaling for industrial production a tangible achievement. This makes it more likely that the future of firefighting suits and masks will be able to effectively use this technology. Quick, effective responses can also reduce economic losses attributed to fires.

“The graphene/PBO woven fabrics-based sensors exhibit good repeatability and stability in human motion monitoring and NO2 gas detection, the main toxic gas in fires, which can be applied to firefighting suits to help firefighters effectively avoiding danger” Fan said. Being able to detect sharp increases in NO2 gas can help firefighters change course in an instant if needed and could be a lifesaving addition to firefighter gear.

Major improvements can be made in the firefighting field to better protect the firefighters by taking advantage of graphene/PBO woven and nonwoven fabrics. Widescale use of this technology can help the researchers reach their ultimate goal of reducing mortality and injury to those who risk their lives fighting fires.

Yu Luo and Yaping Miao of the School of Textile Science and Engineering at Xi’an Polytechnic University contributed equally to this work. Professor Wei Fan is the corresponding author. Yingying Zhang and Huimin Wang of the Department of Chemistry at Tsinghua University, Kai Dong of the Beijing Institute of Nanoenergy and Nanosystems at the Chinese Academy of Sciences, and Lin Hou and Yanyan Xu of Shaanxi Textile Research Institute Co., LTD, Weichun Chen and Yao Zhang of the School of Textile Science and Engineering at Xi’an Polytechnic University contributed to this research. 

This work was supported by the National Natural Science Foundation of China, Textile Vision Basic Research Program of China, Key Research and Development Program of Xianyang Science and Technology Bureau, Key Research and Development Program of Shaanxi Province, Natural Science Foundation of Shaanxi Province, and Scientific Research Project of Shaanxi Provincial Education Department.

Here are two links and a citation for the same paper,

Laser-induced Janus graphene/poly(p-phenylene benzobisoxazole) fabrics with intrinsic flame retardancy as flexible sensors and breathable electrodes for fire-fighting field by Yu Luo, Yaping Miao, Huimin Wang, Kai Dong, Lin Hou, Yanyan Xu, Weichun Chen, Yao Zhang, Yingying Zhang & Wei Fan. Nano Research (2023) DOI: https://doi.org/10.1007/s12274-023-5382-y Published12 January 2023

This link leads to a paywall.

Here’s the second link (to SciOpen)

Laser-induced Janus graphene/poly(p-phenylene benzobisoxazole) fabrics with intrinsic flame retardancy as flexible sensors and breathable electrodes for fire-fighting field. SciOpen Published January 12, 2023

This link leads to an open access journal published by Tsinghua University Press.

Combat yellow fever mosquito with carbon black nanoparticles?

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This April 19, 2022 news item on Nanowerk announces mosquito research from Ohio State University (OSU), Note: A link has been removed,

Before being accidentally introduced to the New World by the 16th century slave trade, the yellow fever mosquito was a species native only to Africa. Highly adaptable, it has since become an invasive species in North America, but researchers at The Ohio State University may have found a way to squash the pesky population in its juvenile stages.

Recently published in the journal Insects (“Larvicidal Activity of Carbon Black against the Yellow Fever Mosquito Aedes aegypti”), a new paper describes how mosquitoes have evolved a natural resistance to some chemical insecticides, and offers an alternative called carbon black, a type of carbon-based nanoparticles, or CNPs [when it’s specifically carbon black nanoparticles, it may sometimes be abbreviated to CBNPs; more about that at the end of this post].

An April 18, 2022 OSU news release (also on EurekAlert), which originated the news item, describes the work in more detail,

Study co-author and an associate professor of entomology at Ohio State, Peter Piermarini described CNPs as “microscopic” materials made out of organic elements. The study used a modified version of carbon black called Emperor 1800, which is often used to coat automobiles black. While CNPs are a relatively new scientific development, they have been considered as new tools to control various insect and pest infestations, he said.

“If we can learn more about how carbon black works and how to use it safely, we could design a commercially available nanoparticle that is highly effective against insecticide-resistant mosquitoes,” Piermarini said.

The yellow fever mosquito, or Aedes aegypti, is a species of mosquito known for spreading not just yellow fever, but also diseases like the Zika virus, dengue fever and chikungunya fever. Adults rarely fly more than a few hundred meters from where they emerge, but their abundance leads to steady transmission of diseases – enough to claim tens of thousands of lives every year and hospitalize hundreds of thousands more people.

Because of this, the mosquito is considered to be one of the deadliest animals on the planet. For this study, the researchers’ goal was to figure out how toxic these nanomaterials could be to mosquito larvae, or the immature form of the insect.

Contrary to popular belief, not all mosquitoes set their sights on turning our blood into their latest meal. Male mosquitoes subsist only on flower nectar; it’s the females that will consume both flower nectar and blood in a bid to provide their eggs with enough protein to grow.

When female mosquitoes are ready to lay their eggs, they return to standing pools of water, like lakes or birdbaths, to release them. After they hatch, these larvae will stay in the water for about a week until they reach adulthood, and take wing.

To test whether Emperor 1800 would be effective in stopping that process, researchers worked with two different strains of the yellow fever mosquito inside the lab, one extremely susceptible to typical chemical insecticides, and the other, extremely resistant to them.

By applying the carbon black nanomaterials to the water during the earliest stages of the mosquito’s life cycle and checking in 48 hours later, they were able to determine that CNPs kill mosquito larvae both quickly and efficiently.

“Given the properties of carbon black, it has the most potential for killing larvae because it can be suspended in water,” Piermarini said. Their findings showed that the material seemed to accumulate on the mosquito larvae’s head, abdomen, and even in its gut, meaning that at some point, the larvae were ingesting smaller particles of carbon black.

“Our hypothesis is that these materials may be physically obstructing their ability to perform basic biological functions. It could be blocking their digestion, or might be interfering with their ability to breathe,” said Piermarini.

However, there was one thing that Piermarini found particularly surprising.

When first suspended in water, carbon black appeared equally toxic to larvae of insecticide-resistant and insecticide-susceptible mosquitoes, but the longer the carbon black was suspended in water before treating them. it became more toxic to the insecticide-resistant larvae.

“When you first apply the CNP solution it has similar toxicity against both strains,” Piermarini said. “But when you let the suspension age for a few weeks, it tends to become more potent against the resistant strain of mosquitoes.”

Although they couldn’t determine the reason behind the time-lapsed deaths, the study concluded that these new nanomaterials could be extremely beneficial to controlling the species when applied as a preventive treatment to mosquito breeding grounds.

But before it can be utilized by the public, Piermarini said, carbon black needs to undergo rigorous testing to ensure it won’t harm humans and the environment as a whole.

Co-authors were Erick Martinez Rodriguez, a visiting scholar currently in the Ohio State Entomology Graduate program, Parker Evans, a previous PhD student in the Ohio State Translational Plant Sciences Graduate program, and Megha Kalsi, a previous postdoctoral researcher in entomology. This research was supported by Ohio State’s College of Food, Agricultural, and Environmental Sciences and Vaylenx LLC.

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

Larvicidal Activity of Carbon Black against the Yellow Fever Mosquito Aedes aegypti by Erick J. Martínez Rodríguez, Parker Evans, Megha Kalsi, Noah Rosenblatt, Morgan Stanley, and Peter M. Piermarini. Insects 2022, 13(3), 307 DOI: https://doi.org/10.3390/insects13030307 Published: 20 March 2022

The paper appears to be open access.

The naming of things

The nomenclature for carbon at the nanoscale is a little confusing to me. As best as I can determine all of the elements have multiple names at the nanoscale but it’s only with carbon that subcategories function as categories themselves. For example, fullerenes (C60s), single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs), and mulit-walled carbon nanotubes (MWCNTs) are subcategories that stand on their own but, sometimes, are referred to as carbon nanoparticles, which is the main category. I checked carbon black nanoparticles online and found a number of instances where it was abbreviated to CBNP and it can also be a CNP since it is found under the carbon nanoparticle category as per this Wikipedia entry.

Nanotechnology-enabled pain relief for tooth sensitivity

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A November 23, 2021 news item on phys.org announces research from Australia that may lead to pain relief for anyone with sensitive teeth,

In an Australian first, researchers from the University of Queensland have used nanotechnology to develop effective ways to manage tooth sensitivity.

Dr. Chun Xu from UQ’s [University of Queensland] School of Dentistry said the approach might provide more effective long-term pain relief for people with sensitive teeth, compared to current options.

A November 23, 2021 University of Queensland press release, which originated the news item, describes the condition leading to tooth sensitivity and how the proposed solution works (Note: Links have been removed),

“Dentin tubules are located in the dentin, one of the layers below the enamel surface of your teeth,” Dr Xu said.

“When tooth enamel has been worn down, and the dentin are exposed, eating or drinking something cold or hot can cause a sudden sharp flash of pain.

“The nanomaterials used in this preclinical study can rapidly block the exposed dentin tubules and prevent the unpleasant pain.

“Our approach acts faster and lasts longer than current treatment options.

“The materials could be developed into a paste, so people who have sensitive teeth could simply apply this paste to the tooth and massage for one to three minutes.

“The next step is clinical trials.”

Tooth sensitivity affects up to 74 per cent of the population, at times severely impacting quality of life and requiring expensive treatment.

“If clinical trials are successful people will benefit from this new method that can be used at home, without the need to go to a dentist in the near future,” Dr Xu said.

“We hope this study encourages more research using nanotechnology to address dental problems.”

The team also included researchers from UQ’s Australian Institute for Bioengineering and Nanotechnology (AIBN.

…

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

Calcium-Doped Silica Nanoparticles Mixed with Phosphate-Doped Silica Nanoparticles for Rapid and Stable Occlusion of Dentin Tubules by Yuxue Cao, Chun Xu, Patricia P. Wright, Jingyu Liu, Yueqi Kong, Yue Wang, Xiaodan Huang, Hao Song, Jianye Fu, Fang Gao, Yang Liu, Laurence J. Walsh, and Chang Lei. ACS Appl. Nano Mater. 2021, 4, 9, 8761–8769 DOI: https://doi.org/10.1021/acsanm.1c01365 Publication Date:August 25, 2021 Copyright © 2021 American Chemical Society

This paper is behind a paywall.

Nanoparticles for prolonged anti-lice protection

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Caption Graphical abstract [the animal is a capybara, world’s largest rodent] Credit: Kazan Federal University, Louisiana Tech University, Gubkin University

A September 28, 2021Kazan Federal University (Russia) press release (also on EurekAlert; Source text: Larisa Busil Photo: Rawil Fakhrullin) announces news that could lead to relief for anyone who owns animals,

An international researcher team of Louisiana Tech University, Gubkin University [also known as, Gubkin Russian State University of Oil and Gas] and Kazan Federal University reported the fabrication of nanoscale insecticidal hair coating for prolonged anti-lice protection. The study was supported by the Russian Science Foundation.

“Treating agricultural and domestic animals infected with ectoparasites (such as lice, fleas, chewing lice, etc.) is among the primary challenges of veterinary medicine and agriculture. In case of mass infestation, regular measures, such as isolation of infected animals or repeated reapplication of insecticides, are not always effective. These methods are time-limited and provide a short-term therapeutic effect,” explains co-author Rawil Fakhrullin, Head of Kazan University’s Bionanotechnology Lab. “Using an inorganic nanoscale carrier as a component of a therapeutic formulation for topical application of insecticides might be the optimal way to address this challenge.”

Halloysite, a natural nanosized tubular mineral, was used as a drug carrier capable of forming a durable and uniform coating on the surface of animal hair.

“Loading an insecticidal drug, permethrin, into halloysite nanotubes reduces the release rate, leading to fewer re-treatments and fewer side effects,” continues Dr. Fakhrullin.

The paper shows that after goat hair samples were treated with halloysite-based nanocontainers, a stable 2-3 micron waterproof coating was formed on the surface of the hair, suitable for long-term antiparasitic protection.

“Long-term insecticidal activity is the result of the gradual release of the drug from the nanotubes. A formulation based on halloysite retains its protective antiparasitic properties after washing the animal’s hair with water. This stable and water-resistant composite coating provides a drug dose effective for long-term protection of animals,” says the interviewee.

The authors also examined the hair structure of the capybara, world’s largest rodent native to South America. They found that the wax-like layer present on the hair surface of this semi-aquatic animal facilitates the formation of a denser and more durable coating of halloysite than in terrestrial animals (guinea pigs and goats). The wax helps retaining nanoclay particles on the surface of the animal’s hair.

Dr. Fakhrullin comments about the test subjects, “We studied the suppressive effects of nanocontainers on goat ectoparasites Damalinia caprae from the Trichodectidae family. At the same time, our technique can be effective towards other types of lice, since these parasites live in hair and maintain close contact with hair cuticles, regardless of the animal’s dietary preferences. We believe that this approach can be used for long-term and sustainable antiparasitic protection of farm animals, especially if other insecticidal preparations are encapsulated in addition to permethrin. In addition, similar drugs can be used for the prevention or treatment of head lice in humans.”

Furthermore, the described material can also be helpful in treating fur in zoological collections.

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

Clay Nanotube Immobilization on Animal Hair for Sustained Anti-Lice Protection by Naureen Rahman, Faith Hannah Scott, Yuri Lvov, Anna Stavitskaya, Farida Akhatova, Svetlana Konnova, Gӧlnur Fakhrullina and Rawil Fakhrullin. Pharmaceutics 2021, 13(9), 1477; DOI: https://doi.org/10.3390/pharmaceutics13091477 Published: 15 September 2021

This paper is open access.

Methylene Blue-based sunscreen—anti-aging and coral reef safe

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In any event, it’s time to start thinking about sunscreens (for those of us in the Northern Hemisphere.) One other thing, this is informational; it is not an endorsement. A March 1, 2022 Mblue Labs product announcement on EurekAlert (also on EIN Presswire) describes some of the research that went into this new sunscreen,

(Bethesda, MD – March 1, 2022) Mblue Labs releases the first sunscreen based on a recent study that found Methylene Blue, a century old medicine, to be  a highly effective, broad-spectrum UV irradiation protector that absorbs UVA and UVB, repairs ROS (Free Radicals) and UV irradiation induced DNA damages, and is safe for coral reefs. The research paper, “Ultraviolet radiation protection potentials of Methylene Blue for human skin and coral reef health ” was published in Nature’s Scientific Reports (5/28/2021) https://www.nature.com/articles/s41598-021-89970-2 [open access].

80% of today’s sunscreens use Oxybenzone as a chemical UV blocker, despite multiple studies that have shown it expedites the destruction of coral reefs. Several states and countries have now banned the use of Oxybenzone and its derivatives to stop the devastating effects on the world’s marine ecosystem. In addition, consumers focus primarily on the Sun Protection Factor (SPF) to prevent sunburns and potentially dangerous long-term health issues. However, SPF only measures UVB exposure, leaving sunscreen users vulnerable to UVA-triggered oxidative stress and photo-aging.

“Our peer-reviewed study demonstrates that Methylene Blue is an effective UV blocker with a number of highly desired characteristics as a novel ingredient to be included in sunscreens. It shows a broad spectrum absorption of both UVA and UVB rays, promotes DNA damage repair, combats reactive oxygen species (ROS) induced by UVA, and most importantly, poses no harm to coral reefs.” says the study’s senior author Dr. Kan Cao, Founder of Mblue Labs, Bluelene Skincare and a Professor at the University of Maryland Department of Cell Biology and Molecular Genetics.

Mblue Labs and the University of Maryland have a pending patent on the property of Methylene Blue as an effective UV blocking agent that also delays skin aging and promotes DNA damage repair. The company’s first anti-aging sunscreen called “Bluevado SunFix”, contains the FDA approved, safe active ingredients Zinc Oxide and Titanium Dioxide, together with an optimized dosage of Methylene Blue. 

“Our Vision for this novel multifunctionsunscreen is deeply rooted in our concern for coral reefs – the rainforest of the ocean. We look forward to working with the industry and the FDA to get Methylene Blue included in the sunscreen monograph. We are confident that Bluevado SunFix not only delivers broad spectrum UVB/UVA protection and post sun repair, but also provides the full anti-aging benefits of our Bluelene Moisturizer with the same cosmetic elegance.”  says Jasmin EL Kordi, CEO Mblue Labs.

This research was supported by a National Science Foundation (NSF) Small Business Technology Transfer Grant (Grant: 1842745). This press release does not necessarily represent the views of the NSF. This study was conducted jointly by researchers at Mblue Labs and the University of Maryland.

About Mblue Labs + Bluelene: 

MBlue Labs provides revolutionary anti-aging technology to consumers around the world.  The company’s clinical skincare brand Bluelene uses patented ingredient Methylene Blue to repair and protect skin on the mitochondrial level. Mblue Labs’ recent research demonstrates Methylene Blue as the new retinol challenger for anti-aging treatments, in addition to its exciting properties as a new UV sunscreen.

I went looking for the new sunscreen (Bluevado SunFix) and found this,

$58.00

…

Bluevado SunFix is the first FDA-approved anti-aging sunscreen with Methylene Blue. Methylene Blue’s unique ability to promote skin cell health, repair/delay skin aging and protect against UVA and UVB radiation, is now captured in the bravado of this revolutionary SPF Day Cream.

Our innovative formulation blends Methylene Blue with proven minerals to outperform Oxybenzone, deliver cosmetic elegance, and protect our precious coral reefs from harmful substances. 

Methylene Blue is a preferred alternative to retinol for sensitive skin sufferers and with SunFix there is no retinol sun sensitivity.

Bluevado SunFix is proudly made in the USA and is formulated for ALL skin types.

Preorder now to reserve your SunFix. First shipments are available in mid-March [2022].

Application:

Use as a daily SPF Moisturizer. For sun protection apply 15mins before sun exposure and reapply after 40 minutes of swimming or sweating.

Benefits:

Broad-spectrum UVA/UVB sun protection 

Prevents pre-mature aging 

Repairs photo-aging DNA damage caused by UVA exposure

Reduces fine lines, crows feet, and wrinkles

Improves skin elasticity & firmness

Provides all-day skin hydration

Protects coral reefs

Free USPS shipping for all domestic orders over $34!

Ingredients:

Active Ingredients: Zinc Oxide 8.2%, Titanium Dioxide 2.8%   

Inactive Ingredients: Water (Aqua), Caprylic/Capric Triglyceride, C13-15 Alkane, Cetearyl Alcohol, Glycerin, Oryza Sativa (Rice) Bran Oil, Heptyl Undecylenate, Cetyl Alcohol, Argania Spinosa (Argan) Kernel Oil, Tocopheryl Acetate, Glyceryl Stearate, PEG-100 Stearate, Capryloyl Glycerin/Sebacic Acid Copolymer, Sorbitan Laurate, Butyrospermum Parkii (Shea) Butter, Cocos Nucifera (Coconut) Oil, Bisabolol, Xanthan Gum, Polyhydroxystearic Acid, Jojoba Esters, Polysorbate 60, Ascorbyl Palmitate, Citrus Aurantium Bergamia (Bergamot) Peel Oil, Pelargonium Graveolens (Geranium) Leaf Oil, Citrus Grandis (Grapefruit) Peel Oil, Lavandula Angustifolia (Lavender) Oil, Phenoxyethanol, Caprylyl Glycol, Methylene Blue. [emphasis mine]

Caution: For external use only. Keep out of reach of children. In case of irritation or allergic reaction, discontinue use and consult your physician.

There’s 3 fl oz or 90 mL of product in the tube and it’s SPF 21. (If memory serves, Methylene Blue’s placement at the end of the list ingredients means that it’s the ingredient that weighs the least.)

Again, I am not endorsing this product. That said, it does look interesting.

Caption: Corals exposed to Methylene Blue remain healthy. Credit: Mblue Labs

BTW, Finding a product announcement on EurekAlert (online science news service sponsored by the American Association for the Advancement of Science [AAAS]) was a little unexpected but only because I was ignorant of their Content Eligibility Guidelines (scroll down to Business Announcements). Duly noted.

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.

…

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.

Nanomaterial shapes and forms affect passage through blood brain barrier (BBB)

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I meant to get this published a lot sooner.

There seems to be a lot of excitement about this research. I got an embargoed press release further in advance than usual and now the embargo is lifted, it’s everywhere except, at the time of this writing (0920 PDT July 6, 2021), on the publisher’s (Proceedings of the National Academy of Sciences [PNAS]) website.

A July 5, 2021 news item on Medical Express announces the news,

Nanomaterials found in consumer and health-care products can pass from the bloodstream to the brain side of a blood-brain barrier model with varying ease depending on their shape—creating potential neurological impacts that could be both positive and negative, a new study reveals.

A July 5, 2021 University of Birmingham press release (also on EurekAlert), which originated the news item, delves into the details,

Scientists found that metal-based nanomaterials such as silver and zinc oxide can cross an in vitro model of the ‘blood brain barrier’ (BBB) as both particles and dissolved ions – adversely affecting the health of astrocyte cells, which control neurological responses.

But the researchers also believe that their discovery will help to design safer nanomaterials and could open up new ways of targeting hard-to-reach locations when treating brain disease.

Publishing its findings today in PNAS, an international team of researchers discovered that the physiochemical properties of metallic nanomaterials influence how effective they are at penetrating the in vitro model of the blood brain barrier and their potential levels of toxicity in the brain.

Higher concentration of certain shapes of silver nanomaterials and zinc oxide may impair cell growth and cause increased permeability of the BBB, which can lead to the BBB allowing easier brain access to these compounds.

The BBB plays a vital role in brain health by restricting the passage of various chemical substances and foreign molecules into the brain from surrounding blood vessels.

Impaired BBB integrity compromises the health of the central nervous system and increased permeability to foreign substances may eventually cause damage to the brain (neurotoxicity).

Study co-author Iseult Lynch, Professor of Environmental Nanosciences at the University of Birmingham, commented: “We found that silver and zinc oxide nanomaterials, which are widely used in various daily consumer and health-care products, passed through our in vitro BBB model, in the form of both particles and dissolved ions.

“Variation in shape, size and chemical composition can dramatically influence nanomaterials penetration through the (in vitro) blood brain barrier. This is of paramount importance for tailored medical application of nanomaterials – for example targeted delivery systems, bioimaging and assessing possible risks associated with each type of metallic nanomaterial.”

The BBB is a physical barrier composed of a tightly packed layer of endothelial cells surrounding the brain which separates the blood from the cerebrospinal fluid allowing the transfer of oxygen and essential nutrients but preventing the access of most molecules.

Recent studies found nanomaterials such as zinc oxide can accumulate on the brain side of the in vitro BBB in altered states which can affect neurological activity and brain health. Inhaled, ingested, and dermally-applied nanomaterials can reach the blood stream and a small fraction of these may cross the BBB – impacting on the central nervous system.

The researchers synthesised a library of metallic nanomaterials with different particle compositions, sizes, and shapes – evaluating their ability to penetrate the BBB using an in vitro BBB model, followed by assessment of their behaviour and fate in and beyond the model BBB.

Co-author Zhiling Guo, a Research Fellow at the University of Birmingham, commented: “”Understanding these materials’ behaviour once past the blood brain barrier is vital for evaluating the neurological effects arising from their unintentional entry into the brain. Neurotoxicity potential is greater in some materials than others, due to the different ways their shapes allow them to move and be transported.”

The research team tested varied sizes of cerium oxide and iron oxide, along with zinc oxide and four different shapes of silver – spherical (Ag NS), disc-like (Ag ND), rod-shaped (Ag NR) and nanowires (Ag NW).

Zinc oxide slipped through the in vitro BBB with the greatest ease. The researchers found spherical and disc-like silver nanomaterials underwent different dissolution regimes – gradually transforming to silver-sulfur compounds within the BBB, creating ‘easier’ entry pathways.

Zinc oxide is used as a bulking agent and a colorant. In over-the-counter drug products, it is used as a skin protectant and a sunscreen – reflecting and scattering UV radiation to help reduce or prevent sunburn and premature aging of the skin. Silver is used in cosmetic and skincare products such as anti-aging creams.

There’s still a long way to go with this research. For anyone who’s unfamiliar with the term ‘in vitro’, the rough translation is ‘in glass’ meaning test tubes, petri dishes, etc. are used. Even though the research paper has been peer-reviewed (not a perfect process), once it becomes available there will be added scrutiny from scientists with regard to how the research was conducted and whether or not the conclusions drawn are reasonable. One more question should also be asked, are the results reproducible by other scientists?

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

Biotransformation modulates the penetration of metallic nanomaterials across an artificial blood–brain barrier model by Zhiling Guo, Peng Zhang, Swaroop Chakraborty, Andrew J Chetwynd, Fazel Abdolahpur Monikh, Christopher Stark, Hanene Ali-Boucetta, Sandra Wilson, Iseult Lynch, and Eugenia Valsami-Jones. PNAS 118 (28) e2105245118 DOI: https://doi.org/10.1073/pnas.2105245118 Published: July 13, 2021

This paper appears to be open access.