Tag Archives: silver nanoparticles

Nanotechnology in the house; a guide to what you already have

A July 4, 2016 essay by Cameron Shearer of Flinders University (Australia) on The Conversation website describes how nanotechnology can be found in our homes (Note: Links have been removed),

All kitchens have a sink, most of which are fitted with a water filter. This filter removes microbes and compounds that can give water a bad taste.

Common filter materials are activated carbon and silver nanoparticles.

Activated carbon is a special kind of carbon that’s made to have a very high surface area. This is achieved by milling it down to a very small size. Its high surface area gives more room for unwanted compounds to stick to it, removing them from water.

The antimicrobial properties of silver makes it one of the most common nanomaterials today. Silver nanoparticles kill algae and bacteria by releasing silver ions (single silver atoms) that enter into the cell wall of the organisms and become toxic.

It is so effective and fashionable that silver nanoparticles are now used to coat cutlery, surfaces, fridges, door handles, pet bowls and almost anywhere else microorganisms are unwanted.

Other nanoparticles are used to prepare heat-resistant and self-cleaning surfaces, such as floors and benchtops. By applying a thin coating containing silicon dioxide or titanium dioxide nanoparticles, a surface can become water repelling, which prevents stains (similar to how scotch guard protects fabrics).

Nanoparticle films can be so thin that they can’t be seen. The materials also have very poor heat conductivity, which means they are heat resistant.

The kitchen sink (or dishwasher) is used for washing dishes with the aid of detergents. Detergents form nanoparticles called micelles.

A micelle is formed when detergent molecules self-assemble into a sphere. The centre of this sphere is chemically similar to grease, oils and fats, which are what you want to wash off. The detergent traps oils and fats within the cavity of the sphere to separate them from water and aid dish washing.

Your medicine cabinet may include nanotechnology similar to micelles, with many pharmaceuticals using liposomes.

A liposome is an extended micelle where there is an extra interior cavity within the sphere. Making liposomes from tailored molecules allows them to carry therapeutics inside; the outside of the nanoparticle can be made to target a specific area of the body.

Shearer’s essay goes on to cover the laundry, bathroom, closets, and garage. (h/t July 5, 2016 news item on phys.org)

Nano and food discussion for beginners

I try to make sure there are a range of posts here for various levels of ‘nanotechnology sophistication’ but over time I’ve given less attention to ‘beginner’ posts, i.e., pieces where nanotechnology basics are explained as best as possible. This is largely due to concerns about repetition; I mean, how many times do you want to read that nano means one billionth?

In that spirit, this June 22, 2016 news item on Nanowerk about food and nanotechnology provides a good entry piece that is not terribly repetitive,

Every mouthful of food we eat is teeming with chemical reactions. Adding ingredients and cooking helps us control these reactions and makes the food taste better and last longer. So what if we could target food at the molecular level, sending in specially designed particles to control reactions even more tightly? Well, this is exactly what scientists are trying to do and it has already produced some impressive results – from food that tastes salty without the health risks of adding salt, to bread that contains healthy fish oil but without any fishy aftertaste.

But while this nanotechnology could significantly enhance our food, it also raises big questions about safety. We only have to look at the strong reaction against genetically modified foods to see how important this issue is. How can we ensure that nanotechnology in food will be different? Will our food be safe? And will people accept these new foods?

Nanotechnology is an emerging technology that creates and uses materials and particles at the scale of a nanometre, one billionth of a metre. To get an understanding of just how small this is, if you imagine a nanoparticle was the size of a football then an animal like a sheep would be as big as our planet.

Working with such small particles allows us to create materials and products with improved properties, from lighter bicycles and more durable beer bottles to cosmetic creams with better absorption and toothpastes that stop bacteria from growing. Being able to change a material’s properties means nanotechnology can help create many innovative food products and applications that change the way we process, preserve and package foods.

For example, nanotechnology can be used for “smart” packaging that can monitor the condition of foods while they are stored and transported. When foods are contaminated or going off, the sensors on the packaging pick up gases produced by bacteria and change colour to alert anyone who wants to eat the food.

A June 22, 2016 essay by Seda Erdem (University of Stirling; UK) on The Conversation, which originated the news item, provides more information in this excerpt,

Silver is already used in healthcare products such as dental equipment for its antibacterial properties. Nano-sizing silver particles improves their ability to kill bacteria because it increases the surface area of silver the bacteria are exposed to. Israeli scientists found that also coating packaging paper with nano-sized silver particles [also known as silver nanoparticles] combats bacteria such as E. coli and extends product shelf life.

Another example of nanotechnology’s use in food manufacturing is nano-encapsulation. This technology has been used to mask the taste and odour of tuna fish oil so that it could be used to enrich bread with heart healthy Omega-3 fatty acids. Fish oil particles are packed into a film coating that prevents the fish oil from reacting with oxygen and releasing its smell. The nanocapsules break open only when they reach the stomach so you can receive the health benefits of eating them without experiencing the odour.

Meanwhile, researchers at Nottingham University are looking into nanoscale salt particles than can increase the saltiness of food without increasing the amount of salt.

As with silver, breaking salt into smaller nanosize increases its surface area. This means its flavour can be spread more efficiently. The researchers claim this can reduce the salt content of standard crisps by 90% while keeping the same flavour.

Despite all the opportunities nanotechnology offers the food industry, most developments remain at the research and development stage. This slow uptake is due to the lack of information about the health and environmental impacts of the technology. For example, there is a concern whether ingested nanomaterials migrate to different parts of the body and accumulate in certain organs, such as liver and kidneys. This may then affect the functionality of these organs in the medium to long term.

Unknown risks

However, our knowledge of the risks associated with the use of nanomaterials is incomplete. These issues need to be better understood and addressed for the public to accept nanotechnology in food. This will also depend on the public’s understanding of the technology and how much they trust the food industry and the regulatory process watching over it.

Research has shown, for example, that consumers are more likely to accept nanotechnology when it is used in food packaging rather than in food processing. But nanotechnology in food production was seen as more acceptable if it increased the food’s health benefits, although consumers weren’t necessarily willing to pay more for this.

In our recent research, we found no strong attitudes towards or resistance to nanotechnology in food packaging in the UK. But there was still concern among a small group of consumers about the safety of foods. This shows how important it will be for food producers and regulators to provide consumers with the best available information about nanotechnology, including any uncertainties about the technology.

There you have it.

First Canadian Governor-General’s innovation award goes to professor Robert Burrell (nanoscientist) at the University of Alberta

The first innovation award ever given by the Canadian Governor General* has gone to a nanomedicine pioneer at the University of Alberta. From a May 12, 2016 news article by Marc Montgomery for Radio Canada International*, Note: A link has been removed,

Professor Robert Burrell of the University of Alberta has won a prestigious Governor-General’s Innovation Award for the world’s first therapeutic use of nanotechnology.

Professor Burrell used nano-technology on a wound bandage that has already begun transforming treatment of wounds in situations around the world.

Robert Burrell,  Professor in the Faculty of Chemical and Mechanical Engineering at the University of Alberta, is also Canada Research Chair in Nanostructured Biomaterials, and Chair, Biomedical Engineering at the university.

Burrell’s development called Acticoat came from research into nano-forms of silver.  When silver is reduced to nano scale it’s properties and chemical activity change.

In his research prior to joining the University in 2002, Burrell created a coating of nano-crystals of silver which not only kills bacteria but also has anti-inflammatory properties.

A May 9, 2016 University of Alberta news release has a bit more information,

… The chair of the U of A Department of Biomedical Engineering has been awarded a new national innovation prize in recognition of an invention that transformed wound care around the world.

Rob Burrell PhD, FCAHS, who holds the Canada Research Chair in Nanostructure Biomaterials and leads the Department of Biomedical Engineering, is one of six Canadians to win the inaugural round of the Governor General’s Innovation Awards. The awards recognize “exceptional and transformative work” that has helped “shape our future and positively impact our quality of life.”

“It was a nice surprise,” Burrell says of receiving the award. “I got an email in April—and was wondering why the Secretary to the Governor General of Canada [David Johnston is the current Governor General] wanted to talk to me. When we had our phone call he congratulated me on winning the award.”

Burrell invented Acticoat, a new wound dressing that uses nanocrystalline silver to fight bacteria and inflammation in wounds, while working for Westaim Biomedical, later Nucryst Pharmaceuticals. He joined the Faculty of Engineering in 2002.

The dressing was the world’s first therapeutic use of nanotechnology and has saved thousands of lives and limbs, transforming the treatment of burns and wounds.

“We have three projects on the go now. We’ve developed a new dressing and applied for a patent on it for scar control and we’re looking at commercializing that,” he said. “I have two of my grad students—and this summer we will have three summer students—working on a diagnostic tool that will allow a surgeon in an operating room to assess a tumour in 10 to 15 minutes. The analysis of the tumour can determine the type of surgery and post-surgical care the patient receives.”

You can find out more about the Governor General awards, which include, in addition to the new innovation category, the arts,  the sciences and humanities, and more here.

* I have a couple of explanatory notes for those unfamiliar with the concept of a Governor General and/or those who may be curious about Radio Canada International.

The Governor General is the Queen’s or the British monarch’s representative in Canada. Here’s another more general definition from a Wikipedia entry,

Governor-general or governor general, in modern usage, is the title of an office-holder appointed to represent the monarch of a sovereign state in the governing of an independent realm. Governors-general have also previously been appointed in respect of major colonial states or other territories held by either a monarchy or republic, such as French Indochina.

Radio Canada International is a little complicated. Radio Canada is the French language arm of the Canadian Broadcasting Corporation (CBC) and the name ‘Radio Canada’ refers to its radio, television, and internet services.

Interestingly Radio Canada International is the global outreach for both Radio Canada and CBC, presumably, uniting the English and French language services under one banner.

Printing in midair

Dexter Johnson’s May 16, 2016 posting on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) was my first introduction to something wonder-inducing (Note: Links have been removed),

While the growth of 3-D printing has led us to believe we can produce just about any structure with it, the truth is that it still falls somewhat short.

Researchers at Harvard University are looking to realize a more complete range of capabilities for 3-D printing in fabricating both planar and freestanding 3-D structures and do it relatively quickly and on low-cost plastic substrates.

In research published in the journal Proceedings of the National Academy of Sciences (PNAS),  the researchers extruded a silver-nanoparticle ink and annealed it with a laser so quickly that the system let them easily “write” free-standing 3-D structures.

While this may sound humdrum, what really takes one’s breath away with this technique is that it can create 3-D structures seemingly suspended in air without any signs of support as though they were drawn there with a pen.

Laser-assisted direct ink writing allowed this delicate 3D butterfly to be printed without any auxiliary support structure (Image courtesy of the Lewis Lab/Harvard University)

Laser-assisted direct ink writing allowed this delicate 3D butterfly to be printed without any auxiliary support structure (Image courtesy of the Lewis Lab/Harvard University)

A May 16, 2016 Harvard University press release (also on EurekAlert) provides more detail about the work,

“Flat” and “rigid” are terms typically used to describe electronic devices. But the increasing demand for flexible, wearable electronics, sensors, antennas and biomedical devices has led a team at Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS) and Wyss Institute for Biologically Inspired Engineering to innovate an eye-popping new way of printing complex metallic architectures – as though they are seemingly suspended in midair.

“I am truly excited by this latest advance from our lab, which allows one to 3D print and anneal flexible metal electrodes and complex architectures ‘on-the-fly,’ ” said Lewis [Jennifer Lewis, the Hansjörg Wyss Professor of Biologically Inspired Engineering at SEAS and Wyss Core Faculty member].

Lewis’ team used an ink composed of silver nanoparticles, sending it through a printing nozzle and then annealing it using a precisely programmed laser that applies just the right amount of energy to drive the ink’s solidification. The printing nozzle moves along x, y, and z axes and is combined with a rotary print stage to enable freeform curvature. In this way, tiny hemispherical shapes, spiral motifs, even a butterfly made of silver wires less than the width of a hair can be printed in free space within seconds. The printed wires exhibit excellent electrical conductivity, almost matching that of bulk silver.

When compared to conventional 3D printing techniques used to fabricate conductive metallic features, laser-assisted direct ink writing is not only superior in its ability to produce curvilinear, complex wire patterns in one step, but also in the sense that localized laser heating enables electrically conductive silver wires to be printed directly on low-cost plastic substrates.

According to the study’s first author, Wyss Institute Postdoctoral Fellow Mark Skylar-Scott, Ph.D., the most challenging aspect of honing the technique was optimizing the nozzle-to-laser separation distance.

“If the laser gets too close to the nozzle during printing, heat is conducted upstream which clogs the nozzle with solidified ink,” said Skylar-Scott. “To address this, we devised a heat transfer model to account for temperature distribution along a given silver wire pattern, allowing us to modulate the printing speed and distance between the nozzle and laser to elegantly control the laser annealing process ‘on the fly.’ ”

The result is that the method can produce not only sweeping curves and spirals but also sharp angular turns and directional changes written into thin air with silver inks, opening up near limitless new potential applications in electronic and biomedical devices that rely on customized metallic architectures.

Seeing is believing, eh?

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

Laser-assisted direct ink writing of planar and 3D metal architectures by Mark A. Skylar-Scott, Suman Gunasekaran, and Jennifer A. Lewis. PNAS [Proceedings of the National Academy of Sciences] 2016 doi: 10.1073/pnas.1525131113

I believe this paper is open access.

A question: I wonder what conditions are necessary before you can 3D print something in midair? Much as I’m dying to try this at home, I’m pretty that’s not possible.

New model to track flow of nanomaterials through our air, earth, and water

Just how many tons of nanoparticles are making their way through the environment? Scientists at the Swiss Federal Laboratories for Materials Science and Technology (Empa) have devised a new model which could help answer that question. From a May 12, 2016 news item on phys.org,

Carbon nanotubes remain attached to materials for years while titanium dioxide and nanozinc are rapidly washed out of cosmetics and accumulate in the ground. Within the National Research Program “Opportunities and Risks of Nanomaterials” (NRP 64) a team led by Empa scientist Bernd Nowack has developed a new model to track the flow of the most important nanomaterials in the environment.

A May 12, 2016 Empa press release by Michael Hagmann, which also originated the news item, provides more detail such as an estimated tonnage for titanium dioxide nanoparticles produced annually in Europe,

How many man-made nanoparticles make their way into the air, earth or water? In order to assess these amounts, a group of researchers led by Bernd Nowack from Empa, the Swiss Federal Laboratories for Materials Science and Technology, has developed a computer model as part of the National Research Program “Opportunities and Risks of Nanomaterials” (NRP 64). “Our estimates offer the best available data at present about the environmental accumulation of nanosilver, nanozinc, nano-tinanium dioxide and carbon nanotubes”, says Nowack.

In contrast to the static calculations hitherto in use, their new, dynamic model does not just take into account the significant growth in the production and use of nanomaterials, but also makes provision for the fact that different nanomaterials are used in different applications. For example, nanozinc and nano-titanium dioxide are found primarily in cosmetics. Roughly half of these nanoparticles find their way into our waste water within the space of a year, and from there they enter into sewage sludge. Carbon nanotubes, however, are integrated into composite materials and are bound in products such as which are immobilized and are thus found for example in tennis racquets and bicycle frames. It can take over ten years before they are released, when these products end up in waste incineration or are recycled.

39,000 metric tons of nanoparticles

The researchers involved in this study come from Empa, ETH Zurich and the University of Zurich. They use an estimated annual production of nano-titanium dioxide across Europe of 39,000 metric tons – considerably more than the total for all other nanomaterials. Their model calculates how much of this enters the atmosphere, surface waters, sediments and the earth, and accumulates there. In the EU, the use of sewage sludge as fertilizer (a practice forbidden in Switzerland) means that nano-titanium dioxide today reaches an average concentration of 61 micrograms per kilo in affected soils.

Knowing the degree of accumulation in the environment is only the first step in the risk assessment of nanomaterials, however. Now this data has to be compared with results of eco-toxicological tests and the statutory thresholds, says Nowack. A risk assessment has not been carried out with his new model so far. Earlier work with data from a static model showed, however, that the concentrations determined for all four nanomaterials investigated are not expected to have any impact on the environment.

But in the case of nanozinc at least, its concentration in the environment is approaching the critical level. This is why this particular nanomaterial has to be given priority in future eco-toxicological studies – even though nanozinc is produced in smaller quantities than nano-titanium dioxide. Furthermore, eco-toxicological tests have until now been carried out primarily with freshwater organisms. The researchers conclude that additional investigations using soil-dwelling organisms are a priority.

Here are links to and citations for papers featuring the work,

Dynamic Probabilistic Modeling of Environmental Emissions of Engineered Nanomaterials by Tian Yin Sun†, Nikolaus A. Bornhöft, Konrad Hungerbühler, and Bernd Nowack. Environ. Sci. Technol., 2016, 50 (9), pp 4701–4711 DOI: 10.1021/acs.est.5b05828 Publication Date (Web): April 04, 2016

Copyright © 2016 American Chemical Society

Probabilistic environmental risk assessment of five nanomaterials (nano-TiO2, nano-Ag, nano-ZnO, CNT, and fullerenes) by Claudia Coll, Dominic Notter, Fadri Gottschalk, Tianyin Sun, Claudia Som, & Bernd Nowack. Nanotoxicology Volume 10, Issue 4, 2016 pages 436-444 DOI: 10.3109/17435390.2015.1073812 Published online: 10 Nov 2015

The first paper, which is listed in Environmental Science & Technology, appears to be open access while the second paper is behind a paywall.

Nanosafety Cluster newsletter—excerpts from the Spring 2016 issue

The European Commission’s NanoSafety Cluster Newsletter (no.7) Spring 2016 edition is some 50 pp. long and it provides a roundup of activities and forthcoming events. Here are a few excerpts,

“Closer to the Market” Roadmap (CTTM) now finalised

Hot off the press! the Cluster’s “Closer to the Market” Roadmap (CTTM)  is  a  multi-dimensional,  stepwise  plan  targeting  a framework to deliver safe nano-enabled products to the market. After some years of discussions, several consultations of a huge number of experts in the nanosafety-field, conferences at which the issue of market implementation of nanotechnologies was talked  about,  writing  hours/days,  and  finally  two public consultation rounds, the CTTM is now finalized.

As stated in the Executive Summary: “Nano-products and nano-enabled applications need a clear and easy-to-follow human and environmental safety framework for the development along the innovation chain from initial idea to market and beyond that facilitates  navigation  through  the  complex  regulatory and approval processes under which different product categories fall.

Download it here, and get involved in its implementation through the Cluster!
Authors: Andreas Falk* 1, Christa Schimpel1, Andrea Haase3, Benoît Hazebrouck4, Carlos Fito López5, Adriele Prina-Mello6, Kai Savolainen7, Adriënne Sips8, Jesús M. Lopez de Ipiña10, Iseult Lynch11, Costas Charitidis12, Visser Germ13

NanoDefine hosts Synergy Workshop with NSC projects

NanoDefine  organised  the  2nd Nanosafety  Cluster  (NSC)  Synergy Workshop  at  the  Netherlands  House  for Education  and  Research  in Brussels  on  2nd  February  2016. The  aim  was  to  identify  overlaps and synergies existing between different projects that could develop into
outstanding cooperation opportunities.

One central issue was the building of a common ontology and a European framework for data management and analysis, as planned within eNanoMapper, to facilitate a closer interdisciplinary collaboration between  NSC projects and to better address the need for proper data storage, analysis and sharing (Open Access).

Unexpectedly, there’s a Canadian connection,

Discovering protocols for nanoparticles: the soils case
NanoFASE WP7 & NanoSafety Cluster WG3 Exposure

In NanoFASE, of course, we focus on the exposure to nanomaterials. Having consistent and meaningful protocols to characterize the fate of nanomaterials in different environments is therefore of great interest to us. Soils and sediments are in this respect very cumbersome. Also in the case of conventional chemicals has the development of  protocols for fate description in terrestrial systems been a long route.

The special considerations of nanomaterials make this job even harder. For instance, how does one handle the fact that the interaction between soils and nanoparticles is always out of equilibrium? How does one distinguish between the nanoparticles that are still mobile and those that are attached to soil?

In the case of conventional chemicals, a single measurement of a filtered soil suspension often suffices to find the mobile fraction, as long one is sure that equilibrium has been attained. Equilibrium never occurs in the case of  nanoparticles, and the distinction between attached/suspended particles is analytically less clear to do.

Current activity in NanoFASE is focusing at finding protocols to characterize this interaction. Not only does the protocol have to provide meaningful parameters that can be used, e.g. in modelling, but also the method itself should be fast and cheap enough so that a lot of data can be collected in a reasonable amount of time. NanoFASE is  in a good position to do this, because of its focus on fate and because of the many international collaborators.

For  instance,  the Swedish  Agricultural  University (Uppsala)  is  collaborating  with  McGill  University (Montreal, Canada [emphasis mine]), an advisory partner to NanoFASE, in developing the OECD [Organization for Economic Cooperation and Development] protocol for column tests (OECD test nr 312:  “Leaching in soil columns”). The effort is led by Yasir Sultan from Environment Canada and by Karlheinz Weinfurtner from the Frauenhofer institute in Germany. Initial results show the transport of nanomaterials in soil columns to be very limited.

The OECD protocol therefore does not often lead to measurable breakthrough curves that can be modelled to provide information about  nanomaterial  mobility  in  soils  and  most  likely  requires adaptations  to  account  for  the  relatively  low mobility  of  typical pristine nanomaterials.

OECD 312 prescribes to use 40 cm columns, which is most likely too long to show a breakthrough in the case of nanoparticles. Testing in NanoFASE will therefore focus on working with shorter columns and also investigating the effect of the flow speed.

The progress and the results of this action will be reported on our website (www.nanofase.eu).

ENM [engineered nanomaterial] Transformation in and Release from Managed Waste Streams (WP5): The NanoFASE pilot Wastewater Treatment Plant is up and running and producing sludge – soon we’ll be dosing with nanoparticles to test “real world” aging.

Now, wastewater,

ENM [engineered nanomaterial] Transformation in and Release from Managed Waste Streams (WP5): The NanoFASE pilot Wastewater Treatment Plant is up and running and producing sludge – soon we’ll be dosing with nanoparticles to test “real world” aging.

WP5 led by Ralf Kaegi of EAWAG [Swiss Federal Institute of Aquatic Science and Technology] (Switzerland) will establish transformation and release rates of ENM during their passage through different reactors. We are focusing on wastewater treatment plants (WWTPs), solid waste and dedicated sewage sludge incinerators as well as landfills (see figure below). Additionally, lab-scale experiments using pristine and well characterized materials, representing the realistic fate relevant forms at each stage, will allow us to obtain a mechanistic understanding of the transformation processes in waste treatment reactors. Our experimental results will feed directly into the development of a mathematical model describing the transformation and transfer of ENMs through the investigated reactors.

I’m including this since I’ve been following the ‘silver nanoparticle story’ for some time,

NanoMILE publication update: NanoMILE on the air and on the cover

Dramatic  differences  in  behavior  of  nano-silver during  the  initial  wash  cycle  and  for  its  further dissolution/transformation potential over time depending on detergent composition and form.

In an effort to better relate nanomaterial aging procedures to those which they are most likely to undergo during the life cycle of nano-enhanced products, in this paper we describe the various transformations which are possible when exposing Ag engineered nanoparticles (ENPs) to a suite of commercially available washing detergents (Figure 1). While Ag ENP transformation and washing of textiles has received considerable attention in recent years, our study is novel in that we (1) used several commercially available detergents allowing us to estimate the various changes possible in individual homes and commercial washing settings; (2) we have continued  method  development  of  state  of  the  art nanometrology techniques, including single particle ICP-MS, for the detection and characterization of ENPs in complex media; and (3) we were able to provide novel additions to the knowledge base of the environmental nanotechnology research community both in terms of the analytical methods (e.g. the first time ENP aggregates have been definitively analyzed via single particle ICP-MS) and broadening the scope of “real world” conditions that should be considered when understanding AgENP through their life cycle.

Our findings, which were recently published in Environmental Science and Toxicology (2015, 49: 9665), indicate that the washing detergent chemistry causes dramatic differences in ENP behavior during the initial wash cycle and has ramifications for the dissolution/transformation potential of the Ag ENPs over time (see Figure 2). The use of silver as an  antimicrobial  treatment  in  textiles  continues  to garner  considerable  attention.  Last  year  we  published  a manuscript in ACS Nano that considered how various silver treatments to textiles (conventional and nano) both release  nano-sized  material  after  the  wash  cycle  with  similar chemical  characteristics.  That  study  essentially conveyed that multiple silver treatments would become more similar through the product life cycle. Our newest  work expands this by investigating one silver ENP under various washing conditions thereby creating more varied silver products as an end result.

Fascinating stuff if you’ve been following the issues around nanotechnology and safety.

Towards the end of the newsletter on pp. 46-48, they list opportunities for partnerships, collaboration, and research posts and they list websites where you can check out job opportunities. Good Luck!

The Canadian nano scene as seen by the OECD (Organization for Economic Cooperation and Development)

I’ve grumbled more than once or twice about the seemingly secret society that is Canada’s nanotechnology effort (especially health, safety, and environment issues) and the fact that I get most my information from Organization for Economic Cooperation and Development (OECD) documents. That said, thank you to Lynne Bergeson’s April 8, 2016 post on Nanotechnology Now for directions to the latest OECD nano document,

The Organization for Economic Cooperation and Development recently posted a March 29, 2016, report entitled Developments in Delegations on the Safety of Manufactured Nanomaterials — Tour de Table. … The report compiles information, provided by Working Party on Manufactured Nanomaterials (WPMN) participating delegations, before and after the November 2015 WPMN meeting, on current developments on the safety of manufactured nanomaterials.

It’s an international roundup that includes: Australia, Austria, Belgium, Canada, Germany, Japan, Korea, the Netherlands, Switzerland, Turkey, United Kingdom, U.S., and the European Commission (EC), as well as the Business and Industry Advisory Committee to the OECD (BIAC) and International Council on Animal Protection in OECD Programs (ICAPO).

As usual, I’m focusing on Canada. From the DEVELOPMENTS IN DELEGATIONS ON THE SAFETY OF MANUFACTURED NANOMATERIALS – TOUR DE TABLE Series on the Safety of Manufactured Nanomaterials No. 67,

CANADA
National  developments  on  human  health  and  environmental  safety  including  recommendations, definitions, or discussions related to adapting or applying existing regulatory systems or the drafting of new laws/ regulations/amendments/guidance materials A consultation document on a Proposed Approach to Address Nanoscale Forms of Substances on the Domestic  Substances  List was  published  with  a  public  comment  period  ending on  May  17,  2015. The proposed approach outlines the Government’s plan to address nanomaterials considered in commerce in Canada (on  Canada’s  public inventory).  The  proposal is a stepwise  approach to  acquire  and  evaluate information,  followed  by  any  necessary  action. A  follow-up  stakeholder  workshop  is  being  planned  to discuss  next  steps  and  possible  approaches  to prioritize  future  activities. The  consultation document  is available at: http://www.ec.gc.ca/lcpe-cepa/default.asp?lang=En&n=1D804F45-1

A mandatory information gathering survey was published on July 25, 2015. The purpose of the survey is to collect information to determine the commercialstatus of certain nanomaterials in Canada. The survey targets  206  substances  considered  to  be  potentially  in commerce  at  the  nanoscale. The  list  of  206 substances was developed using outcomes from the Canada-United States Regulatory Cooperation Council (RCC)  Nanotechnology  Initiative  to  identify nanomaterial  types. These  nanomaterial  types  were  cross-referenced  with  the Domestic  Substances  List to  develop  a  preliminary  list  of  substances  which are potentially intentionally manufactured at the nanoscale. The focus of the survey aligns with the Proposed Approach to  Address  Nanoscale  Forms  of  Substances  on  the Domestic  Substances  List (see  above)  and certain  types  of  nanomaterials  were  excluded  during the  development  of  the  list  of  substances. The information  being  requested  by  the  survey  includes substance  identification,  volumes,  and  uses.  This information will feed into the Government’s proposed approach to address nanomaterials on the Domestic Substances List. Available at: http://gazette.gc.ca/rp-pr/p1/2015/2015-07-25/html/notice-avis-eng.php

Information on:

a.risk  assessment  decisions, including  the  type  of:  (a)  nanomaterials  assessed; (b) testing recommended; and (c) outcomes of the assessment;

Four substances were notified to the program since the WPMN14 – three surface modified substances and  one  inorganic  substance.  No  actions,  including  additional  data requests,  were  taken  due  to  low expected  exposures  in  accordance  with  the New  Substances  Notifications  Regulations  (Chemicals and Polymers) (NSNR) for two of the substances.  Two of the substances notified were subject to a Significant New Activity Notice. A Significant New Activity notice is an information gathering tool used to require submission  of  additional  information  if  it  is suspected  that  a  significant  new  activity  may  result in  the substance becoming toxic under the Canadian Environmental Protection Act, 1999.

b.Proposals, or modifications to previous regulatory decisions

As  part  of  the  Government’s  Chemicals  Management Plan,  a  review  is  being  undertaken  for  all substances  which  have  been  controlled through  Significant  New  Activity  (SNAc)  notices (see  above).  As part  of  this  activity,  the  Government  is  reviewing past  nanomaterials  SNAc  notices  to  see  if  new information  is  available  to  refine  the  scope  and information  requirements.    As  a  result  of  this  review, 9 SNAc  notices  previously  in  place  for  nanomaterials have  been  rescinded.    This  work  is  ongoing,  and  a complete review of all nanomaterial SNAcs is currently planned to be completed in 2016.

Information related to good practice documents

The Canada-led,  ISO  standards project, ISO/DTR  19716 Nanotechnologies — Characterization  of cellulose  nanocrystals, [emphasis mine] initiated  in  April 2014, is  now at Committee  Draft  (CD)  3-month  ISO ballot, closing    Aug 31, 2015. Ballot comments will be addressed during JWG2 Measurement and Characterization working  group meetings  at  the 18th Plenary  of  ISO/TC229, Nanotechnologies,  being held in Edmonton, Alberta, Sep. 28 – Oct. 2, 2015.

Research   programmes   or   strategies   designed   to  address   human   health   and/   or environmental safety aspects of nanomaterials

Scientific research

Environment Canada continues to support various academic and departmental research projects. This research has to date included studying fate and effects of nanomaterials in the aquatic, sediment, soil, and air  compartments. Funding  in  fiscal  2015-16  continues  to  support  such  projects,  including  sub-surface transportation, determining key physical-chemical parameters to predict ecotoxicity, and impacts of nano-silver [silver nanoparticles]  addition  to  a  whole  lake  ecosystem [Experimental Lakes Area?]. Environment  Canada  has  also  partnered  with  the National Research  Council  of  Canada  recently  to  initiate  a project  on  the  development  of  test  methods  to identify surfaces of nanomaterials for the purposes of regulatory identification and to support risk assessments. In addition,  Environment  Canada  is  working  with  academic laboratories in  Canada  and  Germany  to  prepare guidance to support testing of nanoparticles using the OECD Test Guideline for soil column leaching.

Health  Canada  continues  its  research  efforts  to  investigate  the  effects  of  surface-modified  silica nanoparticles. The   aims   of   these   projects   are  to:   (1) study the importance of size and surface functionalization;  and  (2)  provide a genotoxic profile and  to  identify  mechanistic  relationships  of  particle properties  to  elicited  toxic  responses.  A manuscript reporting  the in  vitro genotoxic,  cytotoxic and transcriptomic  responses  following  exposure  to  silica  nanoparticles  has  recently  been  submitted to  a  peer reviewed journal and is currently undergoing review. Additional manuscripts reporting the toxicity results obtained to date are in preparation.

Information on public/stakeholder consultations;

A consultation document on a Proposed Approach to Address Nanoscale Forms of Substances on the Domestic  Substances  List was  published  with a  public  comment  period ending  on May  17,  2015  (see Question  1).  Comments  were  received  from approximately  20  stakeholders  representing  industry and industry  associations,  as  well  as  non-governmental  organizations. These  comments  will  inform  decision making to address nanomaterials in commerce in Canada.

Information on research or strategies on life cycle aspects of nanomaterials

Canada, along with Government agencies in the United States, Non-Governmental Organizations and Industry,  is  engaged  in  a  project  to  look  at releases  of  nanomaterials  from  industrial  consumer  matrices (e.g., coatings). The objectives of the NanoRelease Consumer Products project are to develop protocols or
methods (validated  through  interlaboratory  testing) to  measure  releases  of  nanomaterials  from  solid matrices as a result of expected uses along the material life cycle for consumer products that contain the nanomaterials. The  project  is  currently  in  the  advanced  stages  of Phase  3  (Interlaboratory  Studies).  The objectives of Phase 3 of the project are to develop robust methods for producing and collecting samples of CNT-epoxy  and  CNT-rubber  materials  under  abrasion  and  weathering scenarios,  and  to  detect  and quantify, to the extent possible, CNT release fractions. Selected laboratories in the US, Canada, Korea and the European Community are finalising the generation and analysis of sanding and weathering samples and the    results    are    being    collected    in    a   data    hub    for    further    interpretation    and    analysis.

Additional details about the project can be found at the project website: http://www.ilsi.org/ResearchFoundation/RSIA/Pages/NanoRelease1.aspx

Under the OECD Working Party on Resource Productivity and Waste (WPRPW), the expert group on waste containing nanomaterials has developed four reflection papers on the fate of nanomaterials in waste treatment  operations.  Canada  prepared the  paper  on  the  fate  of  nanomaterials in  landfills;  Switzerland on the  recycling  of  waste  containing  nanomaterials;  Germany  on  the  incineration  of  waste  containing nanomaterials;  and  France  on  nanomaterials  in wastewater  treatment.  The  purpose  of  these  papers is to provide  an  overview  of  the  existing  knowledge  on the  behaviour  of  nanomaterials  during  disposal operations and identify the information gaps. At the fourth meeting of the WPRPW that took place on 12-14 November 2013, three of the four reflection papers were considered by members. Canada’s paper was presented and discussed at the fifth meeting of the WPRPRW that took place on 8-10 December 2014. The four  papers  were  declassified  by  EPOC  in  June  2015, and  an  introductory  chapter  was  prepared  to  draw these  papers  together. The introductory  chapter  and accompanying  papers  will  be  published in  Fall  2015. At  the sixth  meeting  of  the  WPRPW  in  June – July  2015,  the  Secretariat  presented  a  proposal  for an information-sharing  platform  that  would  allow  delegates  to  share research  and  documents  related  to nanomaterials. During a trial phase, delegates will be asked to use the platform and provide feedback on its use at the next meeting of the WPRPW in December 2015. This information-sharing platform will also be accessible to delegates of the WPMN.

Information related to exposure measurement and exposure mitigation.

Canada and the Netherlands are co-leading a project on metal impurities in carbon nanotubes. A final version  of  the  report  is  expected  to  be ready for WPMN16. All  research has  been completed (e.g. all components are published or in press and there was a presentation by Pat Rasmussen to SG-08 at the Face-to-Face Meeting in Seoul June 2015). The first draft will be submitted to the SG-08 secretariat in autumn 2015. Revisions  will  be  based  on  early  feedback  from  SG-08  participants.  The  next  steps  depend  on  this feedback and amount of revision required.

Information on past, current or future activities on nanotechnologies that are being done in co-operation with non-OECD countries.

A webinar between ECHA [European Chemicals Agency], the US EPA [Environmental Protection Agency] and Canada was hosted by Canada on April 16, 2015. These are  regularly  scheduled  trilateral  discussions  to keep  each  other  informed  of  activities  in  respective jurisdictions.

In  March 2015, Health  Canada  hosted  3  nanotechnology knowledge  transfer sessions  targeting Canadian  government  research  and  regulatory  communities  working  in  nanotechnology.  These  sessions were  an  opportunity  to  share  information  and perspectives  on  the  current  state  of  science supporting  the regulatory  oversight  of  nanomaterials with  Government.  Presenters  provided  detailed  outputs  from  the OECD WPMN including: updates on OECD test methods and guidance documents; overviews of physical-chemical properties, as well as their relevance to toxicological testing and risk assessment; ecotoxicity and fate   test   methods;   human   health   risk   assessment   and   alternative   testing   strategies;   and exposure measurement  and  mitigation.  Guest  speakers  included  Dr  Richard  C.  Pleus  Managing  Director  and  Director of Intertox, Inc and Dr. Vladimir Murashov Special Assistant on Nanotechnology to the Director of National Institute for Occupational Safety and Health (NIOSH).

On   March   4-5, 2015, Industry   Canada   and   NanoCanada co-sponsored  “Commercializing Nanotechnology  in  Canada”,  a  national  workshop  that brought  together  representatives  from  industry, academia and government to better align Canada’s efforts in nanotechnology.  This workshop was the first of  its  kind  in  Canada. It  also  marked  the  official  launch  of  NanoCanada (http://nanocanada.com/),  a national  initiative  that  is  bringing  together stakeholders  from  across  Canada  to  bridge  the  innovation  gap and stimulates emerging technology solutions.

It’s nice to get an update about what’s going on. Despite the fact this report was published in 2016 the future tense is used in many of the verbs depicting actions long since accomplished. Maybe this was a cut-and-paste job?

Moving on, I note the mention of the Canada-led,  ISO  standards project, ISO/DTR  19716 Nanotechnologies — Characterization  of cellulose  nanocrystals (CNC). For those not familiar with CNC, the Canadian government has invested hugely in this material derived mainly from trees, in Canada. Other countries and jurisdictions have researched nanocellulose derived from carrots, bananas, pineapples, etc.

Finally, it was interesting to find out about the existence of  NanoCanada. In looking up the Contact Us page, I noticed Marie D’Iorio’s name. D’Iorio, as far as I’m aware, is still the Executive Director for Canada’s National Institute of Nanotechnology (NINT) or here (one of the National Research Council of Canada’s institutes). I have tried many times to interview someone from the NINT (Nils Petersen, the first NINT ED and Martha Piper, a member of the advisory board) and more recently D’Iorio herself only to be be met with a resounding silence. However, there’s a new government in place, so I will try again to find out more about the NINT, and, this time, NanoCanada.

US National Institute of Occupational Heath and Safety (NIOSH) issues a draft bulletin about silver nanoparticles

The US National Institute of Occupational Health and Safety (NIOSH) is requesting comments on a draft version of the NIOSH Current Intelligence Bulletin: Health Effects of Occupational Exposure to Silver Nanoparticles (PDF of 321 pp.) according to a Jan. 21, 2016 notice on the US Federal Register,

On December 19, 2012, the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention announced in the Federal Registerhttp://www.gpo.gov/fdsys/pkg/FR-2012-12-19/pdf/2012-30515.pdf plans to evaluate the scientific data on silver nanomaterials and to issue its findings on the potential health risks. A draft document entitled, Health Effects of Occupational Exposure to Silver Nanomaterials, has been developed which contains a review and assessment of the currently available scientific literature on the toxicological effects of exposure to silver nanoparticles in experimental animal and cellular systems, and on the occupational exposures to silver dust and fume and the associated health effects. An emphasis area of this review is evaluating the scientific evidence on the role of particle size on the toxicological effects of silver, including the evidence basis to evaluate the adequacy of the current NIOSH recommended exposure limit (REL) for silver (metal dust and soluble compounds, as Ag) [available at: http://www.cdc.gov/niosh/npg/npgd0557.html].

Recommendations are provided for the safe handling of silver nanoparticles, and research needs are proposed to fill important data gaps in the current scientific literature on the potential adverse health effects of occupational exposure to silver nanoparticles. NIOSH is seeking comments on the draft document and plans to have a public meeting to discuss the document. To view the notice and related materials, visit www.regulations.gov and enter CDC-2016-0001 in the field and click “Search.” This draft document does not have the force or effect of the law.

As of a Feb. 10, 2016 NIOSH notice on the US Federal Register (H/T Lynn Bergeson in a Feb. 11, 2016 post on Nanotechnology Now), the public comment period has been extended,

DATES:
NIOSH is extending the comment period on the document published January 21, 2016 (81 FR 3425). Electronic or written comments must be received by April 22, 2016.

ADDRESSES:
You may submit comments, identified by CDC-2016-0001 and docket number NIOSH-260-A, by any of the following methods:

Federal eRulemaking Portal: www.regulations.gov Follow the instructions for submitting comments.
Mail: National Institute for Occupational Safety and Health, NIOSH Docket Office, 1090 Tusculum Avenue, MS C-34, Cincinnati, Ohio 45226-1998.

There will a public meeting about this draft bulletin to be held in Ohio (from the US Federal Register Jan. 21, 2016 notice , Note: Given the recent extension for comments, it might be prudent to check periodically for a change of date)

The public meeting will be held on March 23, 2016, 9:00 a.m.-3:00 p.m. Eastern Time, or after the last public commenter has spoken, whichever occurs first. Comments must be received on or before March 21, 2016.

ADDRESSES:
The public meeting will be held at the NIOSH/CDC Robert A. Taft Laboratories, Auditorium, 1150 Tusculum Avenue, Cincinnati, Ohio 45226.

FOR FURTHER INFORMATION CONTACT:
Charles Geraci, NIOSH, Education and Information Division, Nanotechnology Research Center, Robert A. Taft Laboratories, 1090 Tusculum Avenue, Cincinnati, OH 45226, (513) 533-8339 (not a toll free number).

SUPPLEMENTARY INFORMATION:
I. Background: To discuss and obtain comments on the draft document, “NIOSH Current Intelligence Bulletin: Health Effects of Occupational Exposure to Silver Nanomaterials”. Special emphasis will be placed on discussion of the following:

Whether the health hazard identification, risk estimation, and discussion of health effects of silver and silver nanomaterials are a reasonable reflection of the current understanding of the scientific literature;
Workplaces and occupations where exposure to silver and silver nanomaterials may occur; and studies on health effects associated with occupational exposure to silver dust and fume;
Current strategies for controlling or preventing exposure to silver and silver nanomaterials (e.g., engineering controls, work practices, personal protective equipment);
Current exposure measurement methods and challenges in measuring workplace exposures to silver nanomaterials; and
Areas for future collaborative efforts (e.g., research, communication, development of exposure measurement and control strategies).

II. Public Meeting: NIOSH will hold a public meeting on the NIOSH Draft Current Intelligence Bulletin: Health Effects of Occupational Exposure to Silver Nanomaterials to allow commenters to provide oral comments on the draft document, to inform NIOSH about additional relevant data or information, and to ask questions on the draft document and NIOSH recommendations.

The forum will include scientists and representatives from various government agencies, industry, labor, and other stakeholders, and is open to the public. Attendance is limited only by the space available. The meeting room accommodates 100 people. The meeting will be open to limited number of participants through a conference call phone number and Webcast live on the Internet. Due to the limited spaces, notification of intent to attend the meeting must be made to the NIOSH Docket Office, at nioshdocket@cdc.gov, (513) 533-8611, or fax (513) 533-8285, no later than March 9, 2016. Priority for attendance will be given to those providing oral comments. Other requests to attend the meeting will then be accommodated on a first-come, first-served basis.

Registration is required. Because this meeting is being held at a Federal site, pre-registration is required on or before March 9, 2016 and a government-issued photo ID (driver’s license, military ID or passport) will be required to obtain entrance to the facility. There will be an airport type security check. Non‐US citizens need to register by February 12, 2016 to allow sufficient time for mandatory facility security clearance procedures to be completed. Additional personal information will be required. This information will be transmitted to the CDC Security Office for approval. An email confirming registration will be sent from NIOSH for both in-person participation and audio conferencing participation.

Oral presentations will be limited to 15 minutes per presenter. If additional time becomes available, presenters will be notified. All requests to present should contain the name, address, telephone number, and relevant business affiliations of the presenter, topic of the presentation, and the approximate time requested for the presentation. An email confirming registration will be sent from the NIOSH Docket Office and will include details needed to participate. Oral comments given at the meeting will be recorded and included in the NIOSH Docket 260-A.

After reviewing the requests for presentations, NIOSH will notify the presenter that his/her presentation is scheduled. If a participant is not in attendance when his/her presentation is scheduled to begin, the remaining participants will be heard in order. After the last scheduled speaker is heard, participants who missed their assigned times may be allowed to speak, limited by time available.

Attendees who wish to speak but did not submit a request for the opportunity to make a presentation may be given this opportunity after the scheduled speakers are heard, at the discretion of the presiding officer and limited by time available.

You may submit comments, identified by CDC-2016-0001 and NIOSH 260-A, by either of the following methods:

Federal eRulemaking Portal: www.regulations.gov. Follow the instructions for submitting comments.
Mail: National Institute for Occupational Safety and Health, NIOSH Docket Office, 1090 Tusculum Avenue, MS C-34, Cincinnati, Ohio 45226-1998.

Instructions: All information received in response to this notice must include the agency name and docket number [CDC-2016-0001; NIOSH 260-A]. All relevant comments received will be posted without change to www.regulations.gov including any personal information provided. All information will be available for public examination and copying at the NIOSH Docket Office, 1150 Tusculum Avenue, Room 155, Cincinnati, Ohio 45226.

Non-U.S. Citizens: Because of CDC Security Regulations, any non-U.S. citizen wishing to attend this meeting must provide the following information in writing to the NIOSH Docket Officer at the address below no later than February 12, 2016 [emphasis mine].

Name:

Gender:

Date of Birth:

Place of Birth (city, province, state, country):

Citizenship:

Passport Number:

Date of Passport Issue:

Date of Passport Expiration:

Type of Visa:

U.S. Naturalization Number (if a naturalized citizen):

U.S. Naturalization Date (if a naturalized citizen):

Visitor’s Organization:

Organization Address:

Organization Telephone Number:

Visitor’s Position/Title within the Organization:

This information will be transmitted to the CDC Security Office for approval. Visitors will be notified as soon as approval has been obtained.

H/T Safety + Health; The Official Magazine of the NSC Congress & Expo, Feb. 10, 2016 news item for the information about the original January 2016 notice.

Pomegranates, silver nanoparticles, and Persian carpets

One of the issues with adding silver nanoparticles to textiles is that they wash off and eventually enter our water supply. According to a Dec. 14. 2015 news item on Nanotechnology Now, Iranian scientists has devised a technique for affixing silver nanoparticles,

Iranian researchers produced laboratorial samples of antibacterial woolen fabrics by using nanoparticles which are able to preserve their properties even after five times of washing.

A Dec. 12, 2015 Iran Nanotechnology Initiative Council (INIC) press release, which originated the news item, provides more detail,

Nanoparticles used in the production of fabrics have been produced through a cost-effective method and by using environmentally-friendly materials.

The aim of the research was to obtain an eco-friendly method for the production and application of silver nanoparticles in carpet weaving industry to create antibacterial properties in the final product. The interesting point in this research is the application of pomegranate skin as the reducer in the process to produce nanoparticles.

Results showed that pigment extracted from pomegranate skin is able to be used in the production of silver nanoparticles. Therefore, this method decreases the application of chemical reducers in the synthesis of these nanoparticles, and it also decreases the environmental pollution. In addition, the synthesized nanoparticles preserve their antibacterial properties after being loaded on woolen fiber samples. Therefore, carpets woven by these fibers have antibacterial properties and no bacteria will grow on them.

After carrying out complementary tests and producing the fabrics and fibers at a large scale, the products can be used in carpet weaving industries and also in production of medical devices.

Based on the results, fabrics completed with silver nanoparticles synthesized at low ratio of pigment have antibacterial properties and they do not affect the color of samples. Fabric samples also conserve their antibacterial properties even after five times of washing. The decrease in pH value and increase in temperature improves exhaustion of silver nanoparticles on the wool.

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

Novel method for synthesis of silver nanoparticles and their application on wool by Majid Nasiri Boroumand, Majid Montazer, Frank Simon, Jolanta Liesiene, Zoran Šaponjic, Victoria Dutschk. Applied Surface Science Volume 346, 15 August 2015, Pages 477–483 doi:10.1016/j.apsusc.2015.04.047

This paper is behind a paywall.

Smaller (20nm vs 110nm) silver nanoparticles are more likely to absorbed by fish

An Oct. 8, 2015 news item on Nanowerk offers some context for why researchers at the University of California at Los Angeles (UCLA) are studying silver nanoparticles and their entry into the water system,

More than 2,000 consumer products today contain nanoparticles — particles so small that they are measured in billionths of a meter.

Manufacturers use nanoparticles to help sunscreen work better against the sun’s rays and to make athletic apparel better at wicking moisture away from the body, among many other purposes.

Of those products, 462 — ranging from toothpaste to yoga mats — contain nanoparticles made from silver, which are used for their ability to kill bacteria. But that benefit might be coming at a cost to the environment. In many cases, simply using the products as intended causes silver nanoparticles to wind up in rivers and other bodies of water, where they can be ingested by fish and interact with other marine life.

For scientists, a key question has been to what extent organisms retain those particles and what effects they might have.

I’d like to know where they got those numbers “… 2,000 consumer products …” and “… 462 — ranging from toothpaste to yoga mats — contain nanoparticles made from silver… .”

Getting back to the research, an Oct. 7, 2015 UCLA news release, which originated the news item, describes the work in more detail,

A new study by the University of California Center for Environmental Implications of Nanotechnology has found that smaller silver nanoparticles were more likely to enter fish’s bodies, and that they persisted longer than larger silver nanoparticles or fluid silver nitrate. The study, published online in the journal ACS Nano, was led by UCLA postdoctoral scholars Olivia Osborne and Sijie Lin, and Andre Nel, director of UCLA’s Center for Environmental Implications of Nanotechnology and associate director of the California NanoSystems Institute at UCLA.

Nel said that although it is not yet known whether silver nanoparticles are harmful, the research team wanted to first identify whether they were even being absorbed by fish. CEIN, which is funded by the National Science Foundation, is focused on studying the effects of nanotechnology on the environment.

In the study, researchers placed zebrafish in water that contained fluid silver nitrate and two sizes of silver nanoparticles — some measuring 20 nanometers in diameter and others 110 nanometers. Although the difference in size between these two particles is so minute that it can only be seen using high-powered transmission electron microscopes, the researchers found that the two sizes of particles affected the fish very differently.

The researchers used zebrafish in the study because they have some genetic similarities to humans, their embryos and larvae are transparent (which makes them easier to observe). In addition, they tend to absorb chemicals and other substances from water.

Osborne said the team focused its research on the fish’s gills and intestines because they are the organs most susceptible to silver exposure.

“The gills showed a significantly higher silver content for the 20-nanometer than the 110-nanometer particles, while the values were more similar in the intestines,” she said, adding that both sizes of the silver particles were retained in the intestines even after the fish spent seven days in clean water. “The most interesting revelation was that the difference in size of only 90 nanometers made such a striking difference in the particles’ demeanor in the gills and intestines.”

The experiment was one of the most comprehensive in vivo studies to date on silver nanoparticles, as well as the first to compare silver nanoparticle toxicity by extent of organ penetration and duration with different-sized particles, and the first to demonstrate a mechanism for the differences.

Osborne said the results seem to indicate that smaller particles penetrated deeper into the fishes’ organs and stayed there longer because they dissolve faster than the larger particles and are more readily absorbed by the fish.

Lin said the results indicate that companies using silver nanoparticles have to strike a balance that recognizes their benefits and their potential as a pollutant. Using slightly larger nanoparticles might help make them somewhat safer, for example, but it also might make the products in which they’re used less effective.

He added that data from the study could be translated to understand how other nanoparticles could be used in more environmentally sustainable ways.

Nel said the team’s next step is to determine whether silver particles are potentially harmful. “Our research will continue in earnest to determine what the long-term effects of this exposure can be,” he said.

Here’s an image illustrating the findings,

Courtesy ACS Nano

Courtesy ACS Nano

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

Organ-Specific and Size-Dependent Ag Nanoparticle Toxicity in Gills and Intestines of Adult Zebrafish by Olivia J. Osborne, Sijie Lin, Chong Hyun Chang, Zhaoxia Ji, Xuechen Yu, Xiang Wang, Shuo Lin, Tian Xia, and André E. Nel. ACS Nano, Article ASAP DOI: 10.1021/acsnano.5b04583 Publication Date (Web): September 1, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.