Category Archives: health and safety

Using sugar for a better way to clean nanoparticles from organisms

Researchers at the US National Institute of Standards and Technology (NIST) have found that a laboratory technique used for over 60 years is the best way to date to clean nanoparticles from organisms. From a Jan. 26, 2017 news item on ScienceDaily,

Sometimes old-school methods provide the best ways of studying cutting-edge tech and its effects on the modern world.

Giving a 65-year-old laboratory technique a new role, researchers at the National Institute of Standards and Technology (NIST) have performed the cleanest separation to date of synthetic nanoparticles from a living organism. The new NIST method is expected to significantly improve experiments looking at the potential environmental and health impacts of these manufactured entities. It will allow scientists to more accurately count how many nanoparticles have actually been ingested by organisms exposed to them.

A Jan. 26, 2017 NIST news release (also on EurekAlert), which originated the news item, offers more detail,

The common roundworm Caenorhabditis elegans has been used in recent years as a living model for laboratory studies of how biological and chemical compounds may affect multicellular organisms. These compounds include engineered nanoparticles (ENPs), bits of material between 1 and 100 nanometers (billionths of a meter, or about 1/10,000 the diameter of a red blood cell). Previous research has often focused on quantifying the amount and size of engineered nanoparticles ingested by C. elegans. Measuring the nanoparticles that actually make it into an organism is considered a more relevant indicator of potential toxicity than just the amount of ENPs to which the worms are exposed.

Traditional methods for counting ingested ENPs have produced questionable results. Currently, researchers expose C. elegans to metal ENPs such as silver or gold in solution, then rinse the excess particles away with water followed by centrifugation and freeze-drying. A portion of the “cleaned” sample produced is then typically examined by a technique that determines the amount of metal present, known as inductively coupled plasma mass spectrometry (ICP-MS). It often yields ENP counts in the tens of thousands per worm; however, those numbers always seem too high to NIST researchers working with C. elegans.

“Since ICP-MS will detect all of the nanoparticles associated with the worms, both those ingested and those that remain attached externally, we suspect that the latter is what makes the ‘ENPs’ per-worm counts so high,” said NIST analytical chemist Monique Johnson (link sends e-mail), the lead author on the ACS Nano paper. “Since we only wanted to quantify the ingested ENPs, a more robust and reliable separation method was needed.”

Luckily, the solution to the problem was already in the lab.

Cross section of the roundworm C. elegans

Scanning electron micrograph showing a cross section of the roundworm C. elegans with two ingested engineered nanoparticles (red dots just right of center). Images such as this provided NIST researchers with visual confirmation that nanoparticle consumption actually occurred. Credit: K. Scott/NIST

In the course of culturing C. elegans for ENP-exposure experiments, Johnson and her colleagues had used sucrose density gradient centrifugation, a decades-old and established system for cleanly separating cellular components, to isolate the worms from debris and bacteria. “We wondered if the same process would allow us to perform an organism-from-ENP separation as well, so I designed a study to find out,” Johnson said.

In their experiment, the NIST researchers first exposed separate samples of C. elegans to low and high concentrations of two sizes of gold nanospheres, 30 and 60 nanometers in diameter. The researchers put each of the samples into a centrifuge and removed the supernatant (liquid portion), leaving the worms and ENPs in the remaining pellets. These were centrifuged twice in a salt solution (rather than just water as in previous separation methods), and then centrifuged again, but this time, through a uniquely designed sucrose density gradient.

“From top to bottom, our gradient consisted of a salt solution layer to trap excess ENPs and three increasingly dense layers of sucrose [20, 40 and 50 percent] to isolate the C. elegans,” Johnson explained. “We followed up the gradient with three water rinses and with centrifugations to ensure that only worms with ingested ENPs, and not the sucrose separation medium with any excess ENPs, would make it into the final pellet.”

Analyzing the range of masses in the ultrapurified samples indicated gold levels more in line with what the researchers expected would be found as ingested ENPs. Experimental validation of the NIST separation method’s success came when the worms were examined in detail under a scanning electron microscope (SEM).

“For me, the eureka moment was when I first saw gold ENPs in the cross section images taken from the C. elegans samples that had been processed through the sucrose density gradient,” Johnson said. “I had been dreaming about finding ENPs in the worm’s digestive tract and now they were really there!”

The high-resolution SEM images also provided visual evidence that only ingested ENPs were counted. “No ENPs were attached to the cuticle, the exoskeleton of C. elegans, in any of the sucrose density gradient samples,” Johnson said. “When we examined worms from our control experiments [processed using the traditional no-gradient, water-rinse-only separation method], there were a number of nanospheres found attached to the cuticle.

Now that it has been successfully demonstrated, the NIST researchers plan to refine and further validate their system for evaluating the uptake of ENPs by C. elegans. “Hopefully, our method will become a useful and valuable tool for reducing the measurement variability and sampling bias that can plague environmental nanotoxicology studies,” Johnson said.

They’ve tested this technique on gold nanoparticles, which begs the question, What kinds of nanoparticles can this technique be used for? Metal nanoparticles only or all nanoparticles?

I’m sure the researchers have already asked these questions and started researching the answers. While the rest of us wait, here’s a link to and a citation for the paper about this promising new technique,

Separation, Sizing, and Quantitation of Engineered Nanoparticles in an Organism Model Using Inductively Coupled Plasma Mass Spectrometry and Image Analysis by Monique E. Johnson, Shannon K. Hanna, Antonio R. Montoro Bustos, Christopher M. Sims, Lindsay C. C. Elliott, Akshay Lingayat, Adrian C. Johnston, Babak Nikoobakht, John T. Elliott, R. David Holbrook, Keana C. K. Scott, Karen E. Murphy, Elijah J. Petersen, Lee L. Yu, and Bryant C. Nelson. ACS Nano, 2017, 11 (1), pp 526–540 DOI: 10.1021/acsnano.6b06582 Publication Date (Web): December 16, 2016

Copyright This article not subject to U.S. Copyright. Published 2016 by the American Chemical Society

This paper is behind a paywall.

Nanoparticles can activate viruses lying dormant in lung cells

The nanoparticles in question are from combustion engines, which means that we are exposed to them. One other note, the testing has not been done on humans but rather on cells. From a Jan. 16, 2017 news item on ScienceDaily,

Nanoparticles from combustion engines can activate viruses that are dormant in in lung tissue cells. This is the result of a study by researchers of Helmholtz Zentrum München, a partner in the German Center for Lung Research (DZL), which has now been published in the journal Particle and Fibre Toxicology.

To evade the immune system, some viruses hide in cells of their host and persist there. In medical terminology, this state is referred to as a latent infection. If the immune system becomes weakened or if certain conditions change, the viruses become active again, begin to proliferate and destroy the host cell. A team of scientists led by Dr. Tobias Stöger of the Institute of Lung Biology and Prof. Dr. Heiko Adler, deputy head of the research unit Lung Repair and Regeneration at Helmholtz Zentrum München, now report that nanoparticles can also trigger this process.

A Jan. 16, 2017 Helmholtz Zentrum München press release (also on EurekAlert), which originated the news item, provides more detail,

“From previous model studies we already knew that the inhalation of nanoparticles has an inflammatory effect and alters the immune system,” said study leader Stöger. Together with his colleagues Heiko Adler and Prof. Dr. Philippe Schmitt-Kopplin, he showed that “an exposure to nanoparticles can reactivate latent herpes viruses in the lung.”

Specifically, the scientists tested the influence of nanoparticles typically generated by fossil fuel combustion in an experimental model for a particular herpes virus infection. They detected a significant increase in viral proteins, which are only produced with active virus proliferation. “Metabolic and gene expression analyses also revealed patterns resembling acute infection,” said Philippe Schmitt-Kopplin, head of the research unit Analytical BioGeoChemistry (BGC). Moreover, further experiments with human cells demonstrated that Epstein-Barr viruses are also ‘awakened’ when they come into contact with the nanoparticles.

Potential approach for chronic lung diseases

In further studies, the research team would like to test whether the results can also be transferred to humans. “Many people carry herpes viruses, and patients with idiopathic pulmonary fibrosis are particularly affected,” said Heiko Adler. “If the results are confirmed in humans, it would be important to investigate the molecular process of the reactivation of latent herpes viruses induced by particle inhalation. Then we could try to influence this pathway therapeutically.”

Special cell culture models shall therefore elucidate the exact mechanism of virus reactivation by nanoparticles. “In addition,” Stöger said, ”in long-term studies we would like to investigate to what extent  repeated nanoparticle exposure with corresponding virus reactivation leads to chronic inflammatory and remodeling processes in the lung.”

Further Information

In 2015 another group at the Helmholtz Zentrum München demonstrated how the Epstein-Barr virus  hides in human cells. In March 2016 researchers also showed that microRNAs silence immune alarm signals of cells infected with the Epstein-Barr virus.

Original Publication:
Sattler, C. et al. (2016): Nanoparticle exposure reactivates latent herpesvirus and restores a signature of acute infection. Particle and Fibre Toxicology, DOI 10.1186/s12989-016-0181-1

Here’s a link to and a citation for the paper on investigating latent herpes virus,

Nanoparticle exposure reactivates latent herpesvirus and restores a signature of acute infection by Christine Sattler, Franco Moritz, Shanze Chen, Beatrix Steer, David Kutschke, Martin Irmler, Johannes Beckers, Oliver Eickelberg, Philippe Schmitt-Kopplin, Heiko Adler. Particle and Fibre Toxicology201714:2 DOI: 10.1186/s12989-016-0181-1 Published: 10 January 2017

©  The Author(s). 2017

This paper is open access and, so too, is the 2016 paper.

XSEDE: the most advanced, powerful integrated digital resources in the world and nanomaterials

The University of Iowa does not jump to mind when considering powerhouse nanomaterial research; it seems that’s a mistake. An Oct. 19, 2016 news item on Nanowerk sets the record straight,

Chemists at the University of Iowa will research the effects of nanomaterials on the environment and human health using a network of supercomputers funded by the U.S. National Science Foundation.

Sara E. Mason, assistant professor in the Department of Chemistry, won an NSF award that grants her team access to the Extreme Science and Engineering Discovery Environment (XSEDE). The XSEDE project links computers, data, and people from around the world to establish a single, virtual system that scientists can interactively use to conduct research. It was started in 2011 and was renewed by the NSF last August.

The NSF says it “will be the most advanced, powerful, and robust collection of integrated advanced digital resources and services in the world.”

An Oct. 12, 2016 University of Iowa (UI) news release by Richard C. Lewis, which originated the news item, provides a little more detail,

The UI grant, valued at $72,503, essentially gives Mason’s team time on the supercomputer network, which they can access from their desktops. The researchers will use that time to study nanoparticles—matter far too small to be seen by the naked eye and present in a range of products, from sunscreen to advanced batteries for hybrid and electric vehicles.

The team hopes to better define the atom-to-atom interactions of various nanoparticles. Mason says the grant will “super charge” her computational research.

“To me, having four concurrent NSF research grants is a big deal, and now, having the boost of the computer time allows us to do even more,” Mason says. “XSEDE allows us to run simulations using quantum mechanics and highly parallelized computers. The outcome is new chemical insight into natural or widely used nanoparticles. We can then connect the chemistry to broader issues, such as human health and the behavior of nanomaterials in the environment.”

Mason’s group aims to find and design nanomaterials that are more benign to the environment and human health. Part of the search means trying out new elements in computational designs to find out how they interact, as well as their side effects, good or bad.

The XSEDE computers will give them far more computing horsepower to carry out those computational experiments.

“We can collectively get a lot more done in a shorter period of time,” says Joseph Bennett, co-principal investigator on the grant and a post-doctoral researcher in Mason’s group.

The UI is one of 15 institutions affiliated with the NSF-funded Center for Sustainable Nanotechnology, devoted to investigating the fundamental molecular mechanisms by which nanoparticles interact with biological systems.

I wish them good luck.

Mimicking rain and sun to test plastic for nanoparticle release

One of Canada’s nanotechnology experts once informed a House of Commons Committee on Health that nanoparticles encased in plastic (he was talking about cell phones) weren’t likely to harm you except in two circumstances (when workers were using them in the manufacturing process and when the product was being disposed of). Apparently, under some circumstances, that isn’t true any more. From a Sept. 30, 2016 news item on Nanowerk,

If the 1967 film “The Graduate” were remade today, Mr. McGuire’s famous advice to young Benjamin Braddock would probably be updated to “Plastics … with nanoparticles.” These days, the mechanical, electrical and durability properties of polymers—the class of materials that includes plastics—are often enhanced by adding miniature particles (smaller than 100 nanometers or billionths of a meter) made of elements such as silicon or silver. But could those nanoparticles be released into the environment after the polymers are exposed to years of sun and water—and if so, what might be the health and ecological consequences?

A Sept. 30, 2016 US National Institute of Standards and Technology (NIST) news release, which originated the news item, describes how the research was conducted and its results (Note: Links have been removed),

In a recently published paper (link is external), researchers from the National Institute of Standards and Technology (NIST) describe how they subjected a commercial nanoparticle-infused coating to NIST-developed methods for accelerating the effects of weathering from ultraviolet (UV) radiation and simulated washings of rainwater. Their results indicate that humidity and exposure time are contributing factors for nanoparticle release, findings that may be useful in designing future studies to determine potential impacts.

In their recent experiment, the researchers exposed multiple samples of a commercially available polyurethane coating containing silicon dioxide nanoparticles to intense UV radiation for 100 days inside the NIST SPHERE (Simulated Photodegradation via High-Energy Radiant Exposure), a hollow, 2-meter (7-foot) diameter black aluminum chamber lined with highly UV reflective material that bears a casual resemblance to the Death Star in the film “Star Wars.” For this study, one day in the SPHERE was equivalent to 10 to 15 days outdoors. All samples were weathered at a constant temperature of 50 degrees Celsius (122 degrees Fahrenheit) with one group done in extremely dry conditions (approximately 0 percent humidity) and the other in humid conditions (75 percent humidity).

To determine if any nanoparticles were released from the polymer coating during UV exposure, the researchers used a technique they created and dubbed “NIST simulated rain.” Filtered water was converted into tiny droplets, sprayed under pressure onto the individual samples, and then the runoff—with any loose nanoparticles—was collected in a bottle. This procedure was conducted at the beginning of the UV exposure, at every two weeks during the weathering run and at the end. All of the runoff fluids were then analyzed by NIST chemists for the presence of silicon and in what amounts. Additionally, the weathered coatings were examined with atomic force microscopy (AFM) and scanning electron microscopy (SEM) to reveal surface changes resulting from UV exposure.

Both sets of coating samples—those weathered in very low humidity and the others in very humid conditions—degraded but released only small amounts of nanoparticles. The researchers found that more silicon was recovered from the samples weathered in humid conditions and that nanoparticle release increased as the UV exposure time increased. Microscopic examination showed that deformations in the coating surface became more numerous with longer exposure time, and that nanoparticles left behind after the coating degraded often bound together in clusters.

“These data, and the data from future experiments of this type, are valuable for developing computer models to predict the long-term release of nanoparticles from commercial coatings used outdoors, and in turn, help manufacturers, regulatory officials and others assess any health and environmental impacts from them,” said NIST research chemist Deborah Jacobs, lead author on the study published in the Journal of Coatings Technology and Research (link is external).

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

Surface degradation and nanoparticle release of a commercial nanosilica/polyurethane coating under UV exposure by Deborah S. Jacobs, Sin-Ru Huang, Yu-Lun Cheng, Savelas A. Rabb, Justin M. Gorham, Peter J. Krommenhoek, Lee L. Yu, Tinh Nguyen, Lipiin Sung. J Coat Technol Res (2016) 13: 735. doi:10.1007/s11998-016-9796-2 First published online 13 July 2016

This paper is behind a paywall.

For anyone interested in the details about the House of Commons nano story I told at the start of this post, here’s the June 23, 2010 posting where I summarized the hearing on nanotechnology. If you scroll down about 50% of the way, you’ll find Dr. Nils Petersen’s (then director of Canada’s National Institute of Nanotechnology) comments about nanoparticles being encased. The topic had been nanosunscreens and he was describing the conditions under which he believed nanoparticles could be dangerous.

Germany has released a review of their research strategy for nanomaterials

A Sept. 24, 2016 posting by Lynn L. Bergeson and Carla N. Hutton on The National Law Review blog features a new report from German authorities (Note: A link has been removed),

On September 19, 2016, the Federal Institute for Occupational Safety and Health (BAuA) published a report entitled Review of the joint research strategy of the higher federal authorities — Nanomaterials and other advanced materials:  Application safety and environmental compatibility.  The report states that in a long-term research strategy, the higher federal authorities responsible for human and environmental safety — the German Environment Agency (UBA), the Federal Institute for Risk Assessment (BfR), BAuA, the Federal Institute for Materials Research and Testing (BAM), and the National Metrology Institute (PTB) — are accompanying the rapid pace of development of new materials from the points of view of occupational safety and health, consumer protection, and environmental protection.

Here’s a link to Review of the joint research strategy of the higher federal authorities — Nanomaterials and other advanced materials:  Application safety and environmental compatibility (PDF) and excerpts from the foreword (Note: There are some differences in formatting between what you see here and what you’ll see in the report),

The research strategy builds on the outcomes so far of the joint research strategy of the higher federal authorities launched in 2008 and first evaluated in 2013, “Nanotechnology: Health and Environmental Risks of Nanomaterials”1, while additionally covering other advanced materials where these pose similar risks to humans and the environment or where such risks need to be studied. It also takes up the idea of application safety of chemical products 2 from the New Quality of Work (INQA) initiative of the Federal Ministry of Labour and Social Affairs (BMAS) and the concept of sustainable
chemistry 3 endorsed by the Federal  Ministry  for  the  Environment, Nature Conservation, Building  and Nuclear Safety (BMUB). Application safety and environmental compatibility are aimed for advanced materials and derived products in order to largely rule out unacceptable risks to humans and the environment. This can be achieved by:

Using safe materials without hazardous properties for humans and the environment (direct application safety); or

Product design for low emissions and environmental compatibility over the entire product lifecycle (integrated application safety); or

Product stewardship, where producers support users in taking technical, organizational, and personal safety measures for the safe use and disposal of products (supported application safety).

As a comprising part of the Federal Government’s Nanotechnology Action Plan 2020, the update of the joint research strategy aims to contribute to governmental research in the following main areas:

 characterising and assessing the human and environmental risks of advanced materials
 Supporting research institutions and business enterprises
 Science-based revision of legal requirements and recommendations
 Public acceptance

The research strategy is to be implemented in projects and other research-related activities. These  include  governmental  research,  tendering  and  extramural  research  funding, and participation in mostly publicly supported projects with third-party funding. Additional activities will take place as part of policy advice and the ongoing work of the sovereign tasks of agencies involved. Interdisciplinary and transdisciplinary approaches will be used to better connect risk and safety research with innovation research and material development. In keeping up with the rapid pace of development, the time horizon for the research strategy is up to 2020. The research objectives address the research approaches likely to be actionable in this period. The research strategy will be supported by a working group and be evaluated and revised by the end of the Nanotechnology Action Plan 2020. tegy will be implemented in projects and other research-related activities, including governmental research, tendering and extramural research funding, and participation in mostly publicly supported projects with third-party funding.  Agencies will use interdisciplinary and transdisciplinary approaches to connect better risk and safety research with innovation research and material development. To keep up with the pace of development, the time horizon for the research strategy extends to 2020.  The research objectives in the report address the research approaches likely to be actionable in this period.  The research strategy will be supported by a working group and be evaluated and revised by the end of the Nanotechnology Action Plan 2020.

It’s always interesting to find out what’s happening elsewhere.

Walgreens (US-based pharmacy), As You Sow (civil society), and engineered hydroxyapatite (HA) nanoparticles

As You Sow has graced this blog before, notably in a March 13, 2015 posting about their success getting the corporate giant, Dunkin’ Donuts, to stop its practice of making powdered sugar whiter by adding nanoscale (and other scales) of titanium dioxide. What’s notable about As You Sow is that it files shareholder resolutions (in other words, the society owns shares of their corporate target) as one of its protest tactics.

This time, As You Sow has focused on Walgreens, a US pharmacy giant. This company has chosen a response that differs from Dunkin’ Donuts’ according to a Sept. 21, 2016 news item on Nanotechnology Now,

Rather than respond to shareholder concerns that Walgreens’ store-brand infant formula may contain harmful, “needle-like” nanomaterials, Walgreens filed a motion with the SEC [US Securities and Regulatory Commission] to block the inquiry.

A Sept. 21, 2016 As You Sow press release, which originated the news item, fills in a few details,

Walgreen’s Well Beginnings™ Advantage® infant formula has been reported to contain engineered hydroxyapatite (HA) nanoparticles, according to independent laboratory testing commissioned by nonprofit group Friends of the Earth. The E.U. Scientific Committee on Consumer Safety (SCCS) has determined that nano-HA may be toxic to humans and that the needle-form of nano-HA should not be used in products.

Walgreens’ “no-action letter” to the SEC argues that the company can exclude the shareholder proposal because “the use of nanomaterials in products … does not involve a significant social policy issue.” The company also claims its infant formula does not contain engineered nanomaterials, contrary to the independent laboratory testing.

“Walgreens is effectively silencing shareholder discussion of this subject,” said Austin Wilson, Environmental Health Program Manager of shareholder advocacy group As You Sow. “If Walgreens had responded to consumers’ and investors’ concerns, there would be no need for shareholders to file a proposal.”

“Shareholders will ultimately bear the burden of litigation if infants are harmed,” said Danielle Fugere, President and Chief Counsel of As You Sow. “Walgreens’ attempt to silence, rather than address, shareholder concerns raises red flags. To be successful, Walgreens must remain a trusted name for consumers and it can’t do that by sweeping new health studies under the rug.”

Nanoparticles are extremely small particles that can permeate cell membranes and travel throughout the body, including into organs, in ways that larger ingredients cannot. The extremely small size of nanoparticles may result in greater toxicity for human health and the environment.

The shareholder proposal asks the company to issue a report about actions the company is taking to reduce or eliminate the risk of nanoparticles.

In 2014, Dunkin’ Donuts reached an agreement with As You Sow to remove the nanoparticle titanium dioxide from its donuts. Starbucks plans to remove it from all products by 2017, and Krispy Kreme is reformulating its products to exclude titanium dioxide and other nanoparticles.

To seemingly dismiss concerns about their brand infant formula appears to be an odd tactic for Walgreens. After all this is infant safety and it’s the kind of thing that makes people very, very angry. On the other hand, Friends of the Earth has not always been scrupulous in its presentation of ‘facts’ (see my Feb. 9, 2012 posting).

2016 hasn’t been a good year for Walgreens. In June they ended their high profile partnership with blood testing startup, Theranos. From a June 13, 2016 article by Abigail Tracy for Vanity Fair,

After months of getting pummeled at the hands of regulators and the media over its questionable blood-testing technology, Theranos may have just been dealt its final blow. Walgreens, the main source of Theranos’s customers, has officially ended its partnership with the embattled biotech company, cutting off a critical revenue stream for founder Elizabeth Holmes’s once-promising start-up.

In a statement issued Sunday [June 12, 2016], the drugstore chain announced that it was terminating its nearly three-year-long relationship with the once $9 billion company and would immediately close all 40 Theranos-testing locations in its Arizona stores, The Wall Street Journal reports. Like so many in Silicon Valley, Walgreens fell victim to Holmes’s claims that Theranos’s technology, and its proprietary diagnostic product, Edison, would revolutionize blood testing and put its rivals, Laboratory Corporation of America and Quest Diagnostics, out of business. When it inked its deal with Holmes in 2013, Walgreens failed to properly vet the Edison technology, which was billed as being capable of conducting hundreds of diagnostics tests with just a few drops of blood.

You can read more about the Theranos situation in Tracy’s June 13, 2016 article and I have some details in a Sept. 2, 2016 posting where I feature the scandal and the proposed movie about Theranos (and other ‘science’ movies).

Getting back to Walgreens, you can find the As You Sow resolution here.

‘Potalyzer’ for roadside sobriety tests

Given the drive to legalize marijuana in Canada and in the US and the current crop of marijuana dispensaries in Vancouver (if nowhere else), this new ‘potalyzer’ test from Stanford University (California, US) seems quite timely and destined for popularity in police departments everywhere. From a Sept. 13, 2016 news item on Nanowerk,

This November [2016], several states will vote whether to legalize marijuana use, joining more than 20 states that already allow some form of cannabis use. This has prompted a need for effective tools for police to determine on the spot whether people are driving under the influence. Cars stopped while police interview drivers

Stanford researchers have devised a potential solution, applying magnetic nanotechnology, previously used as a cancer screen, to create what could be the first practical roadside test for marijuana intoxication.

While police are trying out potential tools, no device currently on the market has been shown to quickly provide a precise measurement of a driver’s marijuana intoxication as effectively as a breathalyzer gauges alcohol intoxication. THC, the drug’s most potent psychoactive agent, is commonly screened for in laboratory blood or urine tests – not very helpful for an officer in the field.

The Stanford device might function as a practical “potalyzer” because it can quickly detect not just the presence of THC in a person’s saliva, but also measure its concentration.

A Sept, 8, 2016 Stanford University news release by Carrie Kirby, which originated the news item, describes the technology in a little more detail,

Led by Shan Wang, a professor of materials science and engineering and of electrical engineering, the Stanford team created a mobile device that uses magnetic biosensors to detect tiny THC molecules in saliva. Officers could collect a spit sample with a cotton swab and read the results on a smartphone or laptop in as little as three minutes.

Researchers tackling the “potalyzer” problem have zeroed in on saliva because testing it is less invasive and because THC in saliva may correlate with impairment better than THC in urine or blood. The big challenge is that these spit tests may be called upon to detect superlatively tiny concentrations of THC. Some states have no set limit of THC in the body for drivers, while others set a limit of 0 or 5 nanograms (a billionth of a gram) per milliliter of blood.

Wang’s device can detect concentrations of THC in the range of 0 to 50 nanograms per milliliter of saliva. While there’s still no consensus on how much THC in a driver’s system is too much, previous studies have suggested a cutoff between 2 and 25 ng/mL, well within the capability of Wang’s device.

Repurposing biomedical tools

The researchers achieved such precision by harnessing the behavior of magnetism in nanoparticles, which measure just a few tens of billionths of a meter.

The Wang Group has been exploring magnetic nanotechnology for years, using it to attack such diverse problems as in vitro cancer diagnostics and magnetic information storage. In this case, they’re combining magnetic nanotechnology with the time-tested biochemical technique of the immunoassay. Immunoassays detect a certain molecule in a solution by introducing an antibody that will bind only to that molecule.

In the test, saliva is mixed with THC antibodies, which bind to any THC molecules in the sample. Then the sample is placed on a disposable chip cartridge, which contains magnetoresistive (GMR) sensors pre-coated with THC, and inserted into the handheld reader.

This sets in motion a “competition” between the THC pre-coated on the sensor and THC in the saliva to bind with the antibodies; the more THC in the saliva, the fewer antibodies will be available to bind to the THC on the sensor surface.

The number of antibodies bound to THC molecules on the sensor tells the device how many antibodies the THC in the sample used up, and therefore how many THC molecules were present in the sample.

Next, magnetic nanoparticles, specially made to bind only to the antibodies, are introduced to the sample. Each nanoparticle binds onto a THC-antibody pair like a sticky beacon, but only the molecules on the sensor surface will be close enough to trip the GMR biosensors in the reader. The device then uses Bluetooth to communicate results to the screen of a smartphone or laptop.

“To the best of our knowledge, this is the first demonstration that GMR biosensors are capable of detecting small molecules,” Wang wrote in a paper describing the device, published in Analytical Chemistry.

Beyond marijuana

The platform has potential usefulness beyond THC. Just as they do with THC, the GMR biosensors in the device could detect any small molecule, meaning that the platform could also test for morphine, heroin, cocaine or other drugs.

In fact, with 80 sensors built into it, the GMR biosensor chip could screen a single sample for multiple substances. The team has already tried screening for morphine with promising results.

Students are currently working on creating a user-friendly form factor for the device, which would need to go through field tests and be approved by regulators before it can be deployed by police.

Another thing that would have to happen before the device would be useful to law enforcement: State laws must set limits for the concentration of THC allowed in a driver’s saliva.

Here too, the Wang Group’s device could be helpful. For example, the next generation of the device could screen both the blood and saliva of a subject to establish an understanding of the correlation between blood THC level and saliva THC level at the same degree of intoxication.

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

Small Molecule Detection in Saliva Facilitates Portable Tests of Marijuana Abuse by Jung-Rok Lee, Joohong Choi, Tyler O. Shultz, and Shan X. Wang. Anal. Chem., 2016, 88 (15), pp 7457–7461 DOI: 10.1021/acs.analchem.6b01688 Publication Date (Web): July 19, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Nanoscale elements that govern the behaviour of our teeth

Are we going to be adopting atomically correct dental hygiene practices in the future? It’s certainly a possibility given the latest Australian research announced in a Sept. 7, 2016 news item on Nanowerk (Note: A link has been removed),

With one in two Australian children reported to have tooth decay in their permanent teeth by age 12, researchers from the University of Sydney believe they have identified some nanoscale elements that govern the behaviour of our teeth.

Material and structures engineers worked with dentists and bioengineers to map the exact composition and structure of tooth enamel at the atomic scale.

Using a relatively new microscopy technique called atom probe tomography, their work produced the first-ever three-dimensional maps showing the positions of atoms critical in the decay process.

The new knowledge on atom composition at the nanolevel has the potential to aid oral health hygiene and caries prevention, and has been published today in the journal Science Advances(“Atomic-scale compositional mapping reveals Mg-rich amorphous calcium phosphate in human dental enamel”).

A Sept. 8, 2016 University of Sydney press release, which originated the news item, expands on the theme (Note: A link has been removed),

Professor Julie Cairney, Material and Structures Engineer in the Faculty of Engineering and Information Technologies, said:

“The dental professionals have known that certain trace ions are important in the tough structure of tooth enamel but until now it had been impossible to map the ions in detail.

“The structure of human tooth enamel is extremely intricate and while we have known that magnesium, carbonate and fluoride ions influence enamel properties scientists have never been able to capture its structure at a high enough resolution or definition.”

“What we have found are the magnesium-rich regions between the hydroxyapatite nanorods that make up the enamel.”

“This means we have the first direct evidence of the existence of a proposed amorphous magnesium-rich calcium phosphate phase that plays an essential role in governing the behaviour of teeth. “

Co-lead researcher on the study, Dr Alexandre La Fontaine from the University’s Australian Centre for Microscopy and Microanalysis, said:

“We were also able to see nanoscale ‘clumps’ of organic material, which indicates that proteins and peptides are heterogeneously distributed within the enamel rather than present along all the nanorod interfaces, which was what was previously suggested.

“The mapping has the potential for new treatments designed around protecting against the dissolution of this specific amorphous phase.

“The new understanding of how enamel forms will also help in tooth remineralisation research.”

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

Atomic-scale compositional mapping reveals Mg-rich amorphous calcium phosphate in human dental enamel by Alexandre La Fontaine, Alexander Zavgorodniy, Howgwei Liu, Rongkun Zheng, Michael Swain, and Julie Cairney. Science Advances  07 Sep 2016: Vol. 2, no. 9, e1601145 DOI: 10.1126/sciadv.1601145

This paper is open access.

Breathing nanoparticles into your brain

Thanks to Dexter Johnson and his Sept. 8, 2016 posting (on the Nanoclast blog on the IEEE [Institute for Electrical and Electronics Engineers]) for bringing this news about nanoparticles in the brain to my attention (Note: Links have been removed),

An international team of researchers, led by Barbara Maher, a professor at Lancaster University, in England, has found evidence that suggests that the nanoparticles that were first detected in the human brain over 20 years ago may have an external rather an internal source.

These magnetite nanoparticles are an airborne particulate that are abundant in urban environments and formed by combustion or friction-derived heating. In other words, they have been part of the pollution in the air of our cities since the dawn of the Industrial Revolution.

However, according to Andrew Maynard, a professor at Arizona State University, and a noted expert on the risks associated with nanomaterials,  the research indicates that this finding extends beyond magnetite to any airborne nanoscale particles—including those deliberately manufactured.

“The findings further support the possibility of these particles entering the brain via the olfactory nerve if inhaled.  In this respect, they are certainly relevant to our understanding of the possible risks presented by engineered nanomaterials—especially those that are iron-based and have magnetic properties,” said Maynard in an e-mail interview with IEEE Spectrum. “However, ambient exposures to airborne nanoparticles will typically be much higher than those associated with engineered nanoparticles, simply because engineered nanoparticles will usually be manufactured and handled under conditions designed to avoid release and exposure.”

A Sept. 5, 2016 University of Lancaster press release made the research announcement,

Researchers at Lancaster University found abundant magnetite nanoparticles in the brain tissue from 37 individuals aged three to 92-years-old who lived in Mexico City and Manchester. This strongly magnetic mineral is toxic and has been implicated in the production of reactive oxygen species (free radicals) in the human brain, which are associated with neurodegenerative diseases including Alzheimer’s disease.

Professor Barbara Maher, from Lancaster Environment Centre, and colleagues (from Oxford, Glasgow, Manchester and Mexico City) used spectroscopic analysis to identify the particles as magnetite. Unlike angular magnetite particles that are believed to form naturally within the brain, most of the observed particles were spherical, with diameters up to 150 nm, some with fused surfaces, all characteristic of high-temperature formation – such as from vehicle (particularly diesel) engines or open fires.

The spherical particles are often accompanied by nanoparticles containing other metals, such as platinum, nickel, and cobalt.

Professor Maher said: “The particles we found are strikingly similar to the magnetite nanospheres that are abundant in the airborne pollution found in urban settings, especially next to busy roads, and which are formed by combustion or frictional heating from vehicle engines or brakes.”

Other sources of magnetite nanoparticles include open fires and poorly sealed stoves within homes. Particles smaller than 200 nm are small enough to enter the brain directly through the olfactory nerve after breathing air pollution through the nose.

“Our results indicate that magnetite nanoparticles in the atmosphere can enter the human brain, where they might pose a risk to human health, including conditions such as Alzheimer’s disease,” added Professor Maher.

Leading Alzheimer’s researcher Professor David Allsop, of Lancaster University’s Faculty of Health and Medicine, said: “This finding opens up a whole new avenue for research into a possible environmental risk factor for a range of different brain diseases.”

Damian Carrington’s Sept. 5, 2016 article for the Guardian provides a few more details,

“They [the troubling magnetite particles] are abundant,” she [Maher] said. “For every one of [the crystal shaped particles] we saw about 100 of the pollution particles. The thing about magnetite is it is everywhere.” An analysis of roadside air in Lancaster found 200m magnetite particles per cubic metre.

Other scientists told the Guardian the new work provided strong evidence that most of the magnetite in the brain samples come from air pollution but that the link to Alzheimer’s disease remained speculative.

For anyone who might be concerned about health risks, there’s this from Andrew Maynard’s comments in Dexter Johnson’s Sept. 8, 2016 posting,

“In most workplaces, exposure to intentionally made nanoparticles is likely be small compared to ambient nanoparticles, and so it’s reasonable to assume—at least without further data—that this isn’t a priority concern for engineered nanomaterial production,” said Maynard.

While deliberate nanoscale manufacturing may not carry much risk, Maynard does believe that the research raises serious questions about other manufacturing processes where exposure to high concentrations of airborne nanoscale iron particles is common—such as welding, gouging, or working with molten ore and steel.

It seems everyone is agreed that the findings are concerning but I think it might be good to remember that the percentage of people who develop Alzheimer’s Disease is much smaller than the population of people who have crystals in their brains. In other words, these crystals might (they don’t know) be a factor and likely there would have to be one or more factors to create the condition for developing Alzheimer’s.

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

Magnetite pollution nanoparticles in the human brain by Barbara A. Maher, Imad A. M. Ahmed, Vassil Karloukovski, Donald A. MacLaren, Penelope G. Fouldsd, David Allsop, David M. A. Mann, Ricardo Torres-Jardón, and Lilian Calderon-Garciduenas. PNAS [Proceedings of the National Academy of Sciences] doi: 10.1073/pnas.1605941113

This paper is behind a paywall but Dexter’s posting offers more detail for those who are still curious.

Reliable findings on the presence of synthetic (engineered) nanoparticles in bodies of water

An Aug. 29, 2016 news item on Nanowerk announces research into determining the presence of engineered (synthetic) nanoparticles in bodies of water,

For a number of years now, an increasing number of synthetic nanoparticles have been manufactured and incorporated into various products, such as cosmetics. For the first time, a research project at the Technical University of Munich and the Bavarian Ministry of the Environment provides reliable findings on their presence in water bodies.

An Aug. 29, 2016 Technical University of Munich (TUM) press release, which originated the news item, provides more information,

Nanoparticles can improve the properties of materials and products. That is the reason why an increasing number of nanoparticles have been manufactured over the past several years. The worldwide consumption of silver nanoparticles is currently estimated at over 300 metric tons. These nanoparticles have the positive effect of killing bacteria and viruses. Products that are coated with these particles include refrigerators and surgical instruments. Silver nanoparticles can even be found in sportswear. This is because the silver particles can prevent the smell of sweat by killing the bacteria that cause it.

Previously, it was unknown whether and in what concentration these nanoparticles enter the environment and e.g. enter bodies of water. If they do, this poses a problem. That is because the silver nanoparticles are toxic to numerous aquatic organisms, and can upset sensitive ecological balances.

Analytical challenge

In the past, however, nanoparticles have not been easy to detect. That is because they measure only 1 to 100 nanometers across [nanoparticles may be larger than 100nm or smaller than 1nm but the official definitions usually specify up to 100nm although some definitions go up to 1000nm] – a nanometer is a millionth of a millimeter. “In order to know if a toxicological hazard exists, we need to know how many of these particles enter the environment, and in particular bodies of water”, explains Michael Schuster, Professor for Analytical Chemistry at the TU Munich.

This was an analytical challenge for the researchers charged with solving the problem on behalf of the Bavarian Ministry of the Environment. In order to overcome this issue, they used a well-known principle that utilizes the effect of surfactants to separate and concentrate the particles. “Surfactants are also found in washing and cleaning detergents”, explains Schuster. “Basically, what they do is envelop grease and dirt particles in what are called micelles, making it possible for them to float in water.” One side of the surfactant is water-soluble, the other fat-soluble. The fat-soluble ends collect around non-polar, non-water soluble compounds such as grease or around particles, and “trap” them in a micelle. The water-soluble, polar ends of the surfactants, on the other hand, point towards the water molecules, allowing the microscopically small micelle to float in water.

A box of sugar cubes in the Walchensee lake

The researchers applied this principle to the nanoparticles. “When the micelles surrounding the particles are warmed slightly, they start to clump”, explains Schuster. This turns the water cloudy. Using a centrifuge, the surfactants and the nanoparticles trapped in them can then be separated from the water. This procedure is called cloud point extraction. The researchers then use the surfactants that have been separated out in this manner – which contain the particles in an unmodified, but highly concentrated form – to measure how many silver nanoparticles are present. To do this, they use a highly sensitive atomic spectrometer configured to only detect silver. In this manner, concentrations in a range of less than one nanogram per liter can be detected. To put this in perspective, this would be like detecting a box of sugar cubes that had dissolved in the Walchensee lake.

With the help of this analysis procedure, it is possible to gain new insight into the concentration of nanoparticles in drinking and waste water, sewage sludge, rivers, and lakes. In Bavaria, the measurements yielded good news: The concentrations measured in the water bodies were extremely low. In was only in four of the 13 Upper Bavarian lakes examined that the concentration even exceeded the minimum detection limit of 0.2 nanograms per liter. No measured value exceeded 1.3 nanograms per liter. So far, no permissible values have been established for silver nanoparticles.

Representative for watercourses, the Isar river was examined from its source to its mouth at around 30 locations. The concentration of silver nanoparticles was also measured in the inflow and outflow of sewage treatment plants. The findings showed that at least 94 percent of silver nanoparticles are filtered out by the sewage treatment plants.

Unfortunately, the researchers have not published their results.