Monthly Archives: April 2016

New kind of long-range particle interactions found by Massachusetts Institute of Technology (MIT) team

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A team from the Massachusetts Institute of Technology (MIT) found unexpected long-range interactions amongst particles in a liquid medium according to an April 12, 2016 news item on ScienceDaily,

Moving bodies can be attracted to each other, even when they’re quite far apart and separated by many other objects: That, in a nutshell, is the somewhat unexpected finding by a team of researchers at MIT.

Scientists have known for a long time that small particles of matter, from the size of dust to sand grains, can exert influences on each other through electrical, magnetic, or chemical effects. Now, this team has found a new kind of long-range interaction between particles, in a liquid medium, that is based entirely on their motions. And these interactions should apply to any kind of particles that move, whether they be living cells or metal particles whirled by magnetic fields.

An April 11, 2016 MIT news release (also on EurekAlert), which originated the news item, describes the work in more detail,

The discovery, which holds for both living and nonliving particles, is described in a paper by Alfredo Alexander-Katz, the Walter Henry Gale Associate Professor of Materials Science and Engineering at MIT, and his co-researchers, in the Proceedings of the National Academies of Sciences.

Alexander-Katz describes the kind of interactions his team found as being related to the research field of active matter. Example of active systems are the flocking behavior of birds or the schooling of fish. Each individual member of the system may be responding just to others in its vicinity, but the result is a coherent overall pattern of movement that can span a large region. Cells in a fluid medium, or even tiny structures moving within a cell, exhibit similar kinds of motion, he says.

The researchers studied magnetic particles a few micrometers (millionths of a meter) across, comparable to the size of some cells. A small number of these magnetic metal microparticles were interspersed with a much larger quantity of inert particles of comparable size, all suspended in water. When a rotating magnetic field was applied, the metal particles would begin to spin, simulating the movements of living cells in the midst of nonliving or relatively inert objects — such as when cells migrate through tissues or move in a crowded environment.

They found that the spinning particles, even when separated by distances tens of times their size, would ultimately migrate toward each other. Though that attraction progressed through a slow and apparently random series of motions, the particles would in the end almost always come together.

While there has been a lot of research on interactions among active particles, Alexander-Katz says, this is one of the few studies that has looked at the way such particles interact when they are surrounded by inactive particles. “In the absence of the inactive particles there are essentially no interactions,” he says.

The unexpected finding might ultimately lead to a better understanding of the behavior of some natural biological systems or new methods for creating synthetic active materials which could be useful for selectively delivering drugs into certain parts of the body, Alexander-Katz suggests. It could also end up finding applications in electronics or energy-harvesting systems, for example providing a way to flip a crystal structure between two different configurations.

“What we’re addressing is collective excitations of the system, or coherent excitations,” he explains. “What we’re looking at is, what are the interactions as a function of activity” of the individual particles.

The faster the particles spin, the greater the attraction between them, the team found. Below a certain speed the effect stops altogether. But the amount of inert matter also makes a difference, they found.

With no inert particles — if the moving particles are suspended in clear water — there is no motion-based attraction. But when the nonspinning particles are added and their concentration reaches a certain point, “there is attraction!” Alexander-Katz says.

One unexpected aspect of the findings was how far the effect extended. “What was really surprising was that the range of the interactions is gigantic,” he says. By way of comparison, he says, imagine you’re in a crowd, and you start to move a bit, and someone else also starts to move, while everyone else tries to stand still. “I would be able to sense, even 20 people away or more, that that person is also active — assuming that the other folks around us are not active.”

The attraction, he says, “is not chemical, it is not magnetic, it is not electrostatic, it’s just based on activity.” And because the range is so long, these interactions could not be modeled in simulations but required physical experiments to be uncovered. The tests by Alexander-Katz and his team used two-dimensional films, similar to particle sediments that form on a rock surface, he says.

He speculates that some biological organisms may use this phenomenon as a way of sensing parts of their environment, though this has not yet been tested.

There is an MIT video illustrating the work,

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

Emergent ultra–long-range interactions between active particles in hybrid active–inactive systems by Joshua P. Steimel, Juan L. Aragones, Helen Hu, Naser Qureshi, and Alfredo Alexander-Katz. Proceedings of the National Academy of Sciences,  2016; 201520481 doi: 10.1073/pnas.1520481113

This paper is behind a paywall.

Canadian science: a new writing guide and a new open access journal

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The book
The Scientist’s Guide to Writing: How to Write More Easily and Effectively Throughout Your Scientific Career by Stephen Heard (professor at the University of New Brunswick, Canada) was published today, April 12, 2016. Heard has written up his book and experiences in an April 12, 2016 posting on his blog, Scientist Sees Squirrel,

It’s been almost five years since I started work on what became The Scientist’s Guide to Writing. I’m absolutely thrilled to announce that as of today, the book is officially published!  The Scientist’s Guide is now available from your local or internet bookseller (links below) or, of course, from your local library. …

All scientists are writers – we have to be, or our work will be lost.  But many of us don’t find writing easy.  I wrote The Scientist’s Guide to tell you some of things I wish someone had told me when I was beginning to practice the craft.  Actually (and somewhat to my surprise), in writing it I learned new things that are helping me even this late in my career.  I think the book can help any writer; as of today, you can grab a copy and see whether I’m right.

I have taken a look at the Table of Contents, as usual with Amazon’s previews (thank you for the preview but sigh), I can’t copy and paste it here. Briefly, the book has 28 chapters and is split into seven parts: What Writing Is, Behavior, Content and Structure, Style, Revision, Some Loose Threads, and Final Thoughts. Should this whet your appetite, the paperback book is priced at $27.67 CAD.

The open access journal

An April 12, 2016 post by Dr. Jules Blais on the Canadian Science Publishing blog announces a new journal,

It is my distinct pleasure to introduce FACETS, an open access, multidisciplinary and interdisciplinary science journal that will offer new approaches to publishing original research and perspectives, with a focus on multidisciplinary and interdisciplinary science and engineering.

… It is widely recognized that multidisciplinary and interdisciplinary approaches will be increasingly required to face the challenges of the twenty-first century. Developments to improve and sustain essential aspects of modern society, such as health, energy, environment, and technology, will require a multidisciplinary and interdisciplinary perspective. Although the two terms are often used interchangeably, multidisciplinary approaches refer to independent research leading to a common goal, whereas interdisciplinary research refers to a sharing of methods or concepts among participants. FACETS intends to promote both of these approaches. We believe FACETS is timely because we anticipate that the major research breakthroughs in the coming decades will be made at the interfaces of traditional fields of inquiry. …

Blais goes on to discuss whys of the open access policy, the types of manuscripts they will be accepting, and the journal’s bilingual language policy,

… Open access is still a relatively new concept and online journals have only existed for 20 years. Before this time, research was printed on paper and hand delivered to libraries, making it an exclusive enterprise accessible to the privileged few. There has now been a seismic shift in the research landscape with open access becoming more prevalent in publishing spheres, and in a growing number of cases, a requirement of funding agencies. Open access can serve to expand the reach, influence, and openness of research, making research accessible to those whose public funds have largely paid for it. Funding agency requirements for publishing open access research are now being seen across much of the world, which should put to rest any questions about the future of open access publishing – it is here to stay.

… We will accept a wide variety of paper types that represent the full coverage of research communication, including Research Articles, Review Articles, Perspectives, Communications, Notes, Comments, Editorials, and Science Applications Forum articles focusing on sound science that advances knowledge. An exciting aspect of our journal will be its Integrative Sciences section, which will feature topics at the interface between science and the humanities, including Science Communication, Science and Policy, Science Education, Science and Society, Conservation and Sustainability, Science and Ethics, and Public Health. … Another novel feature of FACETS is that we will accept submissions in either English or French to serve the research landscape in Canada and other francophone countries. …

You can find FACETS here and there’s a special deal available until June 30, 2016 where you can submit your piece free-of-processing-charge until then.

With over 150 partners from over 20 countries, the European Union’s Graphene Flagship research initiative unveils its work package devoted to biomedical technologies

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An April 11, 2016 news item on Nanowerk announces the Graphene Flagship’s latest work package,

With a budget of €1 billion, the Graphene Flagship represents a new form of joint, coordinated research on an unprecedented scale, forming Europe’s biggest ever research initiative. It was launched in 2013 to bring together academic and industrial researchers to take graphene from the realm of academic laboratories into European society in the timeframe of 10 years. The initiative currently involves over 150 partners from more than 20 European countries. The Graphene Flagship, coordinated by Chalmers University of Technology (Sweden), is implemented around 15 scientific Work Packages on specific science and technology topics, such as fundamental science, materials, health and environment, energy, sensors, flexible electronics and spintronics.

Today [April 11, 2016], the Graphene Flagship announced in Barcelona the creation of a new Work Package devoted to Biomedical Technologies, one emerging application area for graphene and other 2D materials. This initiative is led by Professor Kostas Kostarelos, from the University of Manchester (United Kingdom), and ICREA Professor Jose Antonio Garrido, from the Catalan Institute of Nanoscience and Nanotechnology (ICN2, Spain). The Kick-off event, held in the Casa Convalescència of the Universitat Autònoma de Barcelona (UAB), is co-organised by ICN2 (ICREA Prof Jose Antonio Garrido), Centro Nacional de Microelectrónica (CNM-IMB-CSIC, CIBER-BBN; CSIC Tenured Scientist Dr Rosa Villa), and Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS; ICREA Prof Mavi Sánchez-Vives).

An April 11, 2016 ICN2 press release, which originated the news item, provides more detail about the Biomedical Technologies work package and other work packages,

The new Work Package will focus on the development of implants based on graphene and 2D-materials that have therapeutic functionalities for specific clinical outcomes, in disciplines such as neurology, ophthalmology and surgery. It will include research in three main areas: Materials Engineering; Implant Technology & Engineering; and Functionality and Therapeutic Efficacy. The objective is to explore novel implants with therapeutic capacity that will be further developed in the next phases of the Graphene Flagship.

The Materials Engineering area will be devoted to the production, characterisation, chemical modification and optimisation of graphene materials that will be adopted for the design of implants and therapeutic element technologies. Its results will be applied by the Implant Technology and Engineering area on the design of implant technologies. Several teams will work in parallel on retinal, cortical, and deep brain implants, as well as devices to be applied in the periphery nerve system. Finally, The Functionality and Therapeutic Efficacy area activities will centre on development of devices that, in addition to interfacing the nerve system for recording and stimulation of electrical activity, also have therapeutic functionality.

Stimulation therapies will focus on the adoption of graphene materials in implants with stimulation capabilities in Parkinson’s, blindness and epilepsy disease models. On the other hand, biological therapies will focus on the development of graphene materials as transport devices of biological molecules (nucleic acids, protein fragments, peptides) for modulation of neurophysiological processes. Both approaches involve a transversal innovation environment that brings together the efforts of different Work Packages within the Graphene Flagship.

A leading role for Barcelona in Graphene and 2D-Materials

The kick-off meeting of the new Graphene Flagship Work Package takes place in Barcelona because of the strong involvement of local institutions and the high international profile of Catalonia in 2D-materials and biomedical research. Institutions such as the Catalan Institute of Nanoscience and Nanotechnology (ICN2) develop frontier research in a supportive environment which attracts talented researchers from abroad, such as ICREA Research Prof Jose Antonio Garrido, Group Leader of the ICN2 Advanced Electronic Materials and Devices Group and now also Deputy Leader of the Biomedical Technologies Work Package. Until summer 2015 he was leading a research group at the Technische Universität München (Germany).

Further Graphene Flagship events in Barcelona are planned; in May 2016 ICN2 will also host a meeting of the Spintronics Work Package. ICREA Prof Stephan Roche, Group Leader of the ICN2 Theoretical and Computational Nanoscience Group, is the deputy leader of this Work Package led by Prof Bart van Wees, from the University of Groningen (The Netherlands). Another Work Package, on optoelectronics, is led by Prof Frank Koppens from the Institute of Photonic Sciences (ICFO, Spain), with Prof Andrea Ferrari from the University of Cambridge (United Kingdom) as deputy. Thus a number of prominent research institutes in Barcelona are deeply involved in the coordination of this European research initiative.

Kostas Kostarelos, the leader of the Biomedical Technologies Graphene Flagship work package, has been mentioned here before in the context of his blog posts for The Guardian science blog network (see my Aug. 7, 2014 post for a link to his post on metaphors used in medicine).

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

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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.

Drone fly larvae avoid bacterial contamination due to their nanopillars

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This is some fascinating bug research. From an April 6, 2016 news item on phys.org,

The immature stage of the drone fly (Eristalis tenax) is known as a “rat-tailed maggot” because it resembles a hairless baby rodent with a “tail” that is actually used as a breathing tube. Rat-tailed maggots are known to live in stagnant, fetid water that is rich in bacteria, fungi, and algae. However, despite this dirty environment, they are able to avoid infection by these microorganisms.

An April 6, 2016 Entomological Society of America news release on EurekAlert, which originated the news item, describes the findings,

Recently, Matthew Hayes, a cell biologist at the Institute of Ophthalmology at University College London in England, discovered never-before-seen structures that appear to keep the maggot mostly free of bacteria, despite living where microorganisms flourish. …

With scanning and transmission electron microscopes, Hayes carefully examined the larva and saw that much of its body is covered with thin spines, or “nanopillars,” that narrow to sharp points. Once he confirmed the spiky structures were indeed part of the maggot, he noticed a direct relationship between the presence of the spines and the absence of bacteria on the surface of the larva. He speculated that the carpet of spines simply makes it impossible for the bacteria to find enough room to adhere to the larva’s body surface.

Here’s an image of the nanopillars,

Caption: This electron-microscope image expose the spines, or "nanopillars," that poke up from the body of the rat-tailed maggot. The length and density of the spines vary as shown in this cross-section image of the cuticle. Credit: Matthew Hayes

Caption: This electron-microscope image expose the spines, or “nanopillars,” that poke up from the body of the rat-tailed maggot. The length and density of the spines vary as shown in this cross-section image of the cuticle. Credit: Matthew Hayes

Back to the news release,

“They’re much like anti-pigeon spikes that keep the birds away because they can’t find a nice surface to land on,” he said.

Hayes also ventured that the spines could possibly have superoleophobic properties (the ability to repel oils), which would also impede the bacteria from colonizing and forming a biofilm that could ultimately harm or kill the maggot. The composition of the spines is as unique as the structures themselves, Hayes said. Each spine appears to consist of a stack of hollow-cored disks, the largest at the bottom and the smallest at the top.

“What I really think they look like is the baby’s toy with the stack of rings of decreasing size, but on a very small scale,” he said. “I’ve worked in many different fields and looked at lots of different things, and I’ve never seen anything that looks like it.”

This work with the rat-tailed maggot is leading him to examine other insects as well, including the ability of another aquatic invertebrate — the mosquito larva — to thwart bacteria. Such antibacterial properties have applications in many different fields, including ophthalmology and other medical fields where biofilms can foul surgical instruments or implanted devices.

For now, though, he’s thrilled about shedding light on the underappreciated rat-tailed maggot and revealing its spiny armor.

“I’ve loved insects since I was a child, when I would breed butterflies and moths,” he said. “I’m just so chuffed to have discovered something a bit new about insects!”

I am charmed by Hayes’s admission of being “chuffed.”

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

Identification of Nanopillars on the Cuticle of the Aquatic Larvae of the Drone Fly (Diptera: Syrphidae) by Matthew J. Hayes, Timothy P. Levine, Roger H. Wilson. DOI: http://dx.doi.org/10.1093/jisesa/iew019 36 First published online: 30 March 2016

This is an open access paper.

2-D boron as a superconductor

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A March 31, 2016 news item on ScienceDaily highlights some research into 2D (two-dimensional) boron at Rice University (Texas, US),

Rice University scientists have determined that two-dimensional boron is a natural low-temperature superconductor. In fact, it may be the only 2-D material with such potential.

Rice theoretical physicist Boris Yakobson and his co-workers published their calculations that show atomically flat boron is metallic and will transmit electrons with no resistance. …

The hitch, as with most superconducting materials, is that it loses its resistivity only when very cold, in this case between 10 and 20 kelvins (roughly, minus-430 degrees Fahrenheit). But for making very small superconducting circuits, it might be the only game in town.

A March 30, 2016 Rice University news release (also on EurekAlert but dated March 31, 2016), which originated the news item, expands on the theme,

The basic phenomenon of superconductivity has been known for more than 100 years, said Evgeni Penev, a research scientist in the Yakobson group, but had not been tested for its presence in atomically flat boron.

“It’s well-known that the material is pretty light because the atomic mass is small,” Penev said. “If it’s metallic too, these are two major prerequisites for superconductivity. That means at low temperatures, electrons can pair up in a kind of dance in the crystal.”

“Lower dimensionality is also helpful,” Yakobson said. “It may be the only, or one of very few, two-dimensional metals. So there are three factors that gave the initial motivation for us to pursue the research. Then we just got more and more excited as we got into it.”

Electrons with opposite momenta and spins effectively become Cooper pairs; they attract each other at low temperatures with the help of lattice vibrations, the so-called “phonons,” and give the material its superconducting properties, Penev said. “Superconductivity becomes a manifestation of the macroscopic wave function that describes the whole sample. It’s an amazing phenomenon,” he said.

It wasn’t entirely by chance that the first theoretical paper establishing conductivity in a 2-D material appeared at roughly the same time the first samples of the material were made by laboratories in the United States and China. In fact, an earlier paper by the Yakobson group had offered a road map for doing so.

That 2-D boron has now been produced is a good thing, according to Yakobson and lead authors Penev and Alex Kutana, a postdoctoral researcher at Rice. “We’ve been working to characterize boron for years, from cage clusters to nanotubes to planer sheets, but the fact that these papers appeared so close together means these labs can now test our theories,” Yakobson said.

“In principle, this work could have been done three years ago as well,” he said. “So why didn’t we? Because the material remained hypothetical; okay, theoretically possible, but we didn’t have a good reason to carry it too far.

“But then last fall it became clear from professional meetings and interactions that it can be made. Now those papers are published. When you think it’s coming for real, the next level of exploration becomes more justifiable,” Yakobson said.

Boron atoms can make more than one pattern when coming together as a 2-D material, another characteristic predicted by Yakobson and his team that has now come to fruition. These patterns, known as polymorphs, may allow researchers to tune the material’s conductivity “just by picking a selective arrangement of the hexagonal holes,” Penev said.

He also noted boron’s qualities were hinted at when researchers discovered more than a decade ago that magnesium diborite is a high-temperature electron-phonon superconductor. “People realized a long time ago the superconductivity is due to the boron layer,” Penev said. “The magnesium acts to dope the material by spilling some electrons into the boron layer. In this case, we don’t need them because the 2-D boron is already metallic.”

Penev suggested that isolating 2-D boron between layers of inert hexagonal boron nitride (aka “white graphene”) might help stabilize its superconducting nature.

Without the availability of a block of time on several large government supercomputers, the study would have taken a lot longer, Yakobson said. “Alex did the heavy lifting on the computational work,” he said. “To turn it from a lunchtime discussion into a real quantitative research result took a very big effort.”

The paper is the first by Yakobson’s group on the topic of superconductivity, though Penev is a published author on the subject. “I started working on superconductivity in 1993, but it was always kind of a hobby, and I hadn’t done anything on the topic in 10 years,” Penev said. “So this paper brings it full circle.”

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

Can Two-Dimensional Boron Superconduct? by Evgeni S. Penev, Alex Kutana, and Boris I. Yakobson. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.6b00070 Publication Date (Web): March 22, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Dexter Johnson has published an April 5, 2016 post on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) about this latest Rice University work on 2D boron that includes comments from his email interview with Penev.

Nature celebrates some nanotechnology anniversaries

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An April 5, 2016 editorial in Nature magazine celebrates some nanotechnology milestones (Note: Links have been removed),

In March 1986, the atomic force microscope (AFM) was introduced by Gerd Binnig, Calvin Quate and Christoph Gerber with a paper in the journal Physical Review Letters titled simply ‘Atomic force microscope’1. This was 5 years (to the month) after the precursor to the AFM, the scanning tunnelling microscope (STM), had first been successfully tested at IBM’s Zurich Research Laboratory by Binnig and the late Heinrich Rohrer, and 7 months before Binnig and Rohrer were awarded a share of the Nobel Prize in Physics for the design of the STM (the prize was shared with Ernst Ruska, the inventor of the electron microscope). Achieving atomic resolution with the AFM proved more difficult than with the STM. It was, for example, only two years after its invention that the STM provided atomic-resolution images of an icon of surface science, the 7 × 7 surface reconstruction of Si(111) (ref. 2), whereas it took 8 years to achieve a similar feat with the AFM3, 4.

…

The editorial also provides an explanation of how the AFM works,

The AFM works by scanning a sharp tip attached to a flexible cantilever across a sample while measuring the interaction between the tip and the sample surface. The technique can operate in a range of environments, including in liquid and in air, and unlike the STM, it can be used with insulating materials; in their original paper, Binnig and colleagues used the instrument to analyse an aluminium oxide sample.

Then, the editorial touches on DNA (deoxyribonucleic acid) nanotechnology (Note: Links have been removed),

The history of structural DNA nanotechnology can, like the AFM, be traced back to the early 1980s, when Nadrian Seeman suggested that the exquisite base-pairing rules of DNA could be exploited to build artificial self-assembled structures11. But the founding experiment of the field came later. In April 1991, Seeman and Junghuei Chen reported building a cube-like molecular complex from DNA using a combination of branched junctions and single-stranded ‘sticky’ ends12. A range of significant advances soon followed, from 2D DNA arrays to DNA-based nanomechanical devices.

Then, in March 2006, the field of structural DNA nanotechnology experienced another decisive moment: Paul Rothemund reported the development of DNA origami13. This technique involves folding a long single strand of DNA into a predetermined shape with the help of short ‘staple’ strands. Used at first to create 2D structures, which were incidentally characterized using the AFM, the approach was quickly expanded to the building of intricate 3D structures and the organization of other species such as nanoparticles and proteins. …

Happy reading!

Unraveling carbyne (one-dimensional carbon)

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An international group of researchers has developed a technique for producing a record-breaking length of one-dimensional carbon (carbon chain) according to an April 4, 2016 news item on Nanowerk,

Elemental carbon appears in many different modifications, including diamond, fullerenes and graphene. Their unique structural, electronic, mechanical, transport and optical properties have a broad range of applications in physics, chemistry and materials science, including composite materials, nanoscale light emitting devices and energy harvesting materials. Within the “carbon family”, only carbyne, the truly one-dimensional form of carbon, has not yet been synthesized despite having been studied for more than 50 years. Its extreme instability in ambient conditions rendered the final experimental proof of its existence elusive.

An international collaboration of researchers now succeeded in developing a novel route for the bulk production of carbon chains composed of more than 6,400 carbon atoms by using thin double-walled carbon nanotubes as protective hosts for the chains.

An April 4, 2016 University of Vienna press release (also on EurekAlert) provides another perspective on the research,

Even in its elemental form, the high bond versatility of carbon allows for many different well-known materials, including diamond and graphite. A single layer of graphite, termed graphene, can then be rolled or folded into carbon nanotubes or fullerenes, respectively. To date, Nobel prizes have been awarded for both graphene (2010) and fullerenes (1996). Although the existence of carbyne, an infinitely long carbon chain, was proposed in 1885 by Adolf von Baeyer (Nobel laureate for his overall contributions in organic chemistry, 1905), scientists have not yet been able to synthesize this material. Von Baeyer even suggested that carbyne would remain elusive as its high reactivity would always lead to its immediate destruction. Nevertheless, carbon chains of increasing length have been successfully synthesized over the last 50 years, with a record of around 100 carbon atoms (2003). This record has now been broken by more than one order of magnitude, with the demonstration of micrometer length-scale chains.

The new record

Researchers from the University of Vienna, led by Thomas Pichler, have presented a novel approach to grow and stabilize carbon chains with a record length of 6,000 carbon atoms, improving the previous record by more than one order of magnitude. They use the confined space inside a double-walled carbon nanotube as a nano-reactor to grow ultra-long carbon chains on a bulk scale. In collaboration with the groups of Kazu Suenaga at the AIST Tsukuba [National Institute of Advanced Industrial Science and Technology] in Japan, Lukas Novotny at the ETH Zürich [Swiss Federal Institute of Technology] in Switzerland and Angel Rubio at the MPI [Max Planck Institute] Hamburg in Germany and UPV/EHU [University of the Basque Country] San Sebastian in Spain, the existence of the chains has been unambiguously confirmed by using a multitude of sophisticated, complementary methods. These are temperature dependent near- and far-field Raman spectroscopy with different lasers (for the investigation of electronic and vibrational properties), high resolution transmission electron spectroscopy (for the direct observation of carbyne inside the carbon nanotubes) and x-ray scattering (for the confirmation of bulk chain growth).

The researchers present their study in the latest edition of Nature Materials. “The direct experimental proof of confined ultra-long linear carbon chains, which are more than an order of magnitude longer than the longest proven chains so far, can be seen as a promising step towards the final goal of unraveling the “holy grail” of carbon allotropes, carbyne”, explains the lead author, Lei Shi.

Application potential

Carbyne is very stable inside double-walled carbon nanotubes. This property is crucial for its eventual application in future materials and devices. According to theoretical models, carbyne’s mechanical properties exceed all known materials, outperforming both graphene and diamond. Carbyne’s electrical properties suggest novel nanoelectronic applications in quantum spin transport and magnetic semiconductors.

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

Confined linear carbon chains as a route to bulk carbyne by Lei Shi, Philip Rohringer, Kazu Suenaga, Yoshiko Niimi, Jani Kotakoski, Jannik C. Meyer, Herwig Peterlik, Marius Wanko, Seymur Cahangirov, Angel Rubio, Zachary J. Lapin, Lukas Novotny, Paola Ayala, & Thomas Pichler. Nature Materials (2016) doi:10.1038/nmat4617 Published online 04 April 2016

This paper is behind a paywall.

But, there is this earlier and open access version on arXiv.org,

Confined linear carbon chains: A route to bulk carbyne
Lei Shi, Philip Rohringer, Kazu Suenaga, Yoshiko Niimi, Jani Kotakoski, Jannik C. Meyer, Herwig Peterlik, Paola Ayala, Thomas Pichler (Submitted on 17 Jul 2015 (v1), last revised 20 Jul 2015 (this version, v2))

Changing the colour of single photons in a diamond quantum memory

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An artist’s impression of quantum frequency conversion in a diamond quantum memory. (Credit: Dr. Khabat Heshami, National Research Council Canada)

An artist’s impression of quantum frequency conversion in a diamond quantum memory. (Credit: Dr. Khabat Heshami, National Research Council Canada)

An April 5, 2016 University of Waterloo news release (also on EurekAlert) describes the research,

Researchers from the Institute for Quantum Computing at the University of Waterloo and the National Research Council of Canada (NRC) have, for the first time, converted the colour and bandwidth of ultrafast single photons using a room-temperature quantum memory in diamond.

Shifting the colour of a photon, or changing its frequency, is necessary to optimally link components in a quantum network. For example, in optical quantum communication, the best transmission through an optical fibre is near infrared, but many of the sensors that measure them work much better for visible light, which is a higher frequency. Being able to shift the colour of the photon between the fibre and the sensor enables higher performance operation, including bigger data rates.

The research, published in Nature Communications, demonstrated small frequency shifts that are useful for a communication protocol known as wavelength division multiplexing. This is used today when a sender needs to transmit large amounts of information through a transmission so the signal is broken into smaller packets of slightly different frequencies and sent through together. The information is then organized at the other end based on those frequencies.

In the experiments conducted at NRC, the researchers demonstrated the conversion of both the frequency and bandwidth of single photons using a room-temperature diamond quantum memory.

“Originally there was this thought that you just stop the photon, store it for a little while and get it back out. The fact that we can manipulate it at the same time is exciting,” said Kent Fisher a PhD student at the Institute for Quantum Computing and with the Department of Physics and Astronomy at Waterloo. “These findings could open the door for other uses of quantum memory as well.”

The diamond quantum memory works by converting the photon into a particular vibration of the carbon atoms in the diamond, called a phonon. This conversion works for many different colours of light allowing for the manipulation of a broad spectrum of light. The energy structure of diamond allows for this to occur at room temperature with very low noise. Researchers used strong laser pulses to store and retrieve the photon. By controlling the colours of these laser pulses, researchers controlled the colour of the retrieved photon.

“The fragility of quantum systems means that you are always working against the clock,” remarked Duncan England, researcher at NRC. “The interesting step that we’ve shown here is that by using extremely short pulses of light, we are able to beat the clock and maintain quantum performance.”

The integrated platform for photon storage and spectral conversion could be used for frequency multiplexing in quantum communication, as well as build up a very large entangled state – something called a cluster state. Researchers are interested in exploiting cluster states as the resource for quantum computing driven entirely by measurements.

…

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

Frequency and bandwidth conversion of single photons in a room-temperature diamond quantum memory by Kent A. G. Fisher, Duncan G. England, Jean-Philippe W. MacLean, Philip J. Bustard, Kevin J. Resch, & Benjamin J. Sussman. Nature Communications 7, Article number: 11200  doi:10.1038/ncomms11200 Published 05 April 2016

This paper is open access.

The world’s smallest diode is made from a single molecule

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Both the University of Georgia (US) and the American Associates Ben-Gurion University of the Negev (Israel) have issued press releases about a joint research project resulting in the world’s smallest diode.

I stumbled across the April 4, 2016 University of Georgia news release on EurekAlert first,

Researchers at the University of Georgia and at Ben-Gurion University in Israel have demonstrated for the first time that nanoscale electronic components can be made from single DNA molecules. Their study, published in the journal Nature Chemistry, represents a promising advance in the search for a replacement for the silicon chip.

The finding may eventually lead to smaller, more powerful and more advanced electronic devices, according to the study’s lead author, Bingqian Xu.

“For 50 years, we have been able to place more and more computing power onto smaller and smaller chips, but we are now pushing the physical limits of silicon,” said Xu, an associate professor in the UGA College of Engineering and an adjunct professor in chemistry and physics. “If silicon-based chips become much smaller, their performance will become unstable and unpredictable.”

To find a solution to this challenge, Xu turned to DNA. He says DNA’s predictability, diversity and programmability make it a leading candidate for the design of functional electronic devices using single molecules.

In the Nature Chemistry paper, Xu and collaborators at Ben-Gurion University of the Negev describe using a single molecule of DNA to create the world’s smallest diode. A diode is a component vital to electronic devices that allows current to flow in one direction but prevents its flow in the other direction.

Xu and a team of graduate research assistants at UGA isolated a specifically designed single duplex DNA of 11 base pairs and connected it to an electronic circuit only a few nanometers in size. After the measured current showed no special behavior, the team site-specifically intercalated a small molecule named coralyne into the DNA. They found the current flowing through the DNA was 15 times stronger for negative voltages than for positive voltages, a necessary feature of a diode.

“This finding is quite counterintuitive because the molecular structure is still seemingly symmetrical after coralyne intercalation,” Xu said.

A theoretical model developed by Yanantan Dubi of Ben-Gurion University indicated the diode-like behavior of DNA originates from the bias voltage-induced breaking of spatial symmetry inside the DNA molecule after the coralyne is inserted.

“Our discovery can lead to progress in the design and construction of nanoscale electronic elements that are at least 1,000 times smaller than current components,” Xu said.

The research team plans to continue its work, with the goal of constructing additional molecular devices and enhancing the performance of the molecular diode.

The April 4, 2016 American Associates Ben-Gurion University of the Negev press release on EurekAlert covers much of the same ground while providing some new details,

The world’s smallest diode, the size of a single molecule, has been developed collaboratively by U.S. and Israeli researchers from the University of Georgia and Ben-Gurion University of the Negev (BGU).

…

“Creating and characterizing the world’s smallest diode is a significant milestone in the development of molecular electronic devices,” explains Dr. Yoni Dubi, a researcher in the BGU Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology. “It gives us new insights into the electronic transport mechanism.”

Continuous demand for more computing power is pushing the limitations of present day methods. This need is driving researchers to look for molecules with interesting properties and find ways to establish reliable contacts between molecular components and bulk materials in an electrode, in order to mimic conventional electronic elements at the molecular scale.

An example for such an element is the nanoscale diode (or molecular rectifier), which operates like a valve to facilitate electronic current flow in one direction. A collection of these nanoscale diodes, or molecules, has properties that resemble traditional electronic components such as a wire, transistor or rectifier. The emerging field of single molecule electronics may provide a way to overcome Moore’s Law– the observation that over the history of computing hardware the number of transistors in a dense integrated circuit has doubled approximately every two years – beyond the limits of conventional silicon integrated circuits.

Prof. Bingqian Xu’s group at the College of Engineering at the University of Georgia took a single DNA molecule constructed from 11 base pairs and connected it to an electronic circuit only a few nanometers in size. When they measured the current through the molecule, it did not show any special behavior. However, when layers of a molecule called “coralyne,” were inserted (or intercalated) between layers of DNA, the behavior of the circuit changed drastically. The current jumped to 15 times larger negative vs. positive voltages–a necessary feature for a nano diode. “In summary, we have constructed a molecular rectifier by intercalating specific, small molecules into designed DNA strands,” explains Prof. Xu.

Dr. Dubi and his student, Elinor Zerah-Harush, constructed a theoretical model of the DNA molecule inside the electric circuit to better understand the results of the experiment. “The model allowed us to identify the source of the diode-like feature, which originates from breaking spatial symmetry inside the DNA molecule after coralyne is inserted.”

There’s an April 4, 2016 posting on the Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) which provides a brief overview and a link to a previous essay, Whatever Happened to the Molecular Computer?

Here’s a link and citation for the paper,

Molecular rectifier composed of DNA with high rectification ratio enabled by intercalation by Cunlan Guo, Kun Wang, Elinor Zerah-Harush, Joseph Hamill, Bin Wang, Yonatan Dubi, & Bingqian Xu. Nature Chemistry (2016) doi:10.1038/nchem.2480 Published online 04 April 2016

This paper is behind a paywall.