Tag Archives: Switzerland

Art project (autonomous bot purchases illegal goods) seized by Swiss law enforcement

Having just attended a talk on Robotics and Rehabilitation which included a segment on Robo Ethics, news of an art project where an autonomous bot (robot) is set loose on the darknet to purchase goods (not all of them illegal) was fascinating in itself (it was part of an art exhibition which also displayed the proceeds of the darknet activity). But things got more interesting when the exhibit attracted legal scrutiny in the UK and occasioned legal action in Switzerland.

Here’s more from a Jan. 23, 2015 article by Mike Masnick for Techdirt (Note: A link has been removed),

… some London-based Swiss artists, !Mediengruppe Bitnik [(Carmen Weisskopf and Domagoj Smoljo)], presented an exhibition in Zurich of The Darknet: From Memes to Onionland. Specifically, they had programmed a bot with some Bitcoin to randomly buy $100 worth of things each week via a darknet market, like Silk Road (in this case, it was actually Agora). The artists’ focus was more about the nature of dark markets, and whether or not it makes sense to make them illegal:

The pair see parallels between copyright law and drug laws: “You can enforce laws, but what does that mean for society? Trading is something people have always done without regulation, but today it is regulated,” says ays [sic] Weiskopff.

“There have always been darkmarkets in cities, online or offline. These questions need to be explored. But what systems do we have to explore them in? Post Snowden, space for free-thinking online has become limited, and offline is not a lot better.”

Interestingly the bot got excellent service as Mike Power wrote in his Dec. 5, 2014 review of the show. Power also highlights some of the legal, ethical, and moral implications,

The gallery is next door to a police station, but the artists say they are not afraid of legal repercussions of their bot buying illegal goods.

“We are the legal owner of the drugs [the bot purchased 10 ecstasy pills along with a baseball cap, a pair of sneaker/runners/trainers among other items] – we are responsible for everything the bot does, as we executed the code, says Smoljo. “But our lawyer and the Swiss constitution says art in the public interest is allowed to be free.”

The project also aims to explore the ways that trust is built between anonymous participants in a commercial transaction for possibly illegal goods. Perhaps most surprisingly, not one of the 12 deals the robot has made has ended in a scam.

“The markets copied procedures from Amazon and eBay – their rating and feedback system is so interesting,” adds Smojlo. “With such simple tools you can gain trust. The service level was impressive – we had 12 items and everything arrived.”

“There has been no scam, no rip-off, nothing,” says Weiskopff. “One guy could not deliver a handbag the bot ordered, but he then returned the bitcoins to us.”

The exhibition scheduled from Oct. 18, 2014 – Jan. 11, 2015 enjoyed an uninterrupted run but there were concerns in the UK (from the Power article),

A spokesman for the National Crime Agency, which incorporates the National Cyber Crime Unit, was less philosophical, acknowledging that the question of criminal culpability in the case of a randomised software agent making a purchase of an illegal drug was “very unusual”.

“If the purchase is made in Switzerland, then it’s of course potentially subject to Swiss law, on which we couldn’t comment,” said the NCA. “In the UK, it’s obviously illegal to purchase a prohibited drug (such as ecstasy), but any criminal liability would need to assessed on a case-by-case basis.”

Masnick describes the followup,

Apparently, that [case-by[case] assessment has concluded in this case, because right after the exhibit closed in Switzerland, law enforcement showed up to seize stuff …

!Mediengruppe Bitnik  issued a Jan. 15, 2015 press release (Note: Links have been removed),

«Can a robot, or a piece of software, be jailed if it commits a crime? Where does legal culpability lie if code is criminal by design or default? What if a robot buys drugs, weapons, or hacking equipment and has them sent to you, and police intercept the package?» These are some of the questions Mike Power asked when he reviewed the work «Random Darknet Shopper» in The Guardian. The work was part of the exhibition «The Darknet – From Memes to Onionland. An Exploration» in the Kunst Halle St. Gallen, which closed on Sunday, January 11, 2015. For the duration of the exhibition, !Mediengruppe Bitnik sent a software bot on a shopping spree in the Deepweb. Random Darknet Shopper had a budget of $100 in Bitcoins weekly, which it spent on a randomly chosen item from the deepweb shop Agora. The work and the exhibition received wide attention from the public and the press. The exhibition was well-attended and was discussed in a wide range of local and international press from Saiten to Vice, Arte, Libération, CNN, Forbes. «There’s just one problem», The Washington Post wrote in January about the work, «recently, it bought 10 ecstasy pills».

What does it mean for a society, when there are robots which act autonomously? Who is liable, when a robot breaks the law on its own initiative? These were some of the main questions the work Random Darknet Shopper posed. Global questions, which will now be negotiated locally.

On the morning of January 12, the day after the three-month exhibition was closed, the public prosecutor’s office of St. Gallen seized and sealed our work. It seems, the purpose of the confiscation is to impede an endangerment of third parties through the drugs exhibited by destroying them. This is what we know at present. We believe that the confiscation is an unjustified intervention into freedom of art. We’d also like to thank Kunst Halle St. Gallen for their ongoing support and the wonderful collaboration. Furthermore, we are convinced, that it is an objective of art to shed light on the fringes of society and to pose fundamental contemporary questions.

This project brings to mind Isaac Asimov’s three laws of robotics and a question (from the Wikipedia entry; Note: Links have been removed),

The Three Laws of Robotics (often shortened to The Three Laws or Three Laws, also known as Asimov’s Laws) are a set of rules devised by the science fiction author Isaac Asimov. The rules were introduced in his 1942 short story “Runaround”, although they had been foreshadowed in a few earlier stories. The Three Laws are:

A robot may not injure a human being or, through inaction, allow a human being to come to harm.
A robot must obey the orders given it by human beings, except where such orders would conflict with the First Law.
A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.

Here’s my question, how do you programme a robot to know what would injure a human being? For example, if a human ingests an ecstasy pill the bot purchased, would that be covered in the first law?

Getting back to the robot ethics talk I recently attended, it was given by Ajung Moon (Ph.D. student at the University of British Columbia [Vancouver, Canada] studying Human-Robot Interaction and Roboethics. Mechatronics engineer with a sprinkle of Philosophy background). She has a blog,  Roboethic info DataBase where you can read more on robots and ethics.

I strongly recommend reading both Masnick’s post (he positions this action in a larger context) and Power’s article (more details and images from the exhibit).

The science behind a firefly’s glow

A Dec. 17, 2014 news item on Nanotechnology Now describes research into the phenomenon of bioluminescence and fireflies,

 Fireflies used rapid light flashes to communicate. This “bioluminescence” is an intriguing phenomenon that has many potential applications, from drug testing and monitoring water contamination, and even lighting up streets using glow-in-dark trees and plants. Fireflies emit light when a compound called luciferin breaks down. We know that this reaction needs oxygen, but what we don’t know is how fireflies actually supply oxygen to their light-emitting cells. Using state-of-the-art imaging techniques, scientists from Switzerland and Taiwan have determined how fireflies control oxygen distribution to light up their cells. The work is published in Physical Review Letters.

A Dec. 17, 2014 EPFL (Ecole Polytechnique Fédérale de Lausanne) news release on EurekAlert provides more description of the work,

The firefly’s light-producing organ is called the “lantern”, and it is located in the insect’s abdomen. It looks like a series of tubes progressing into smaller ones and so one, like a tree’s branches growing into twigs. The function of these tubes, called, is to supply oxygen to the cells of the lantern, which contain luciferase and can produce light. However, the complexity of the firefly’s lantern has made it difficult to study this mechanism in depth, and reproduce it for technological applications.

Giorgio Margaritondo at EPFL, Yeukuang Hwu at the Academia Sinica and their colleagues at the National Tsing Hua University in Taiwan have successfully used two sophisticated imaging techniques to overcome the complexity of the firefly lantern and map out how oxygen is supplied to light-emitting cells. The techniques are called synchrotron phase contrast microtomography and transmission x-ray microscopy. They can scan down to the level of a single cell, even allowing researchers to look inside it.

By applying these techniques on live fireflies, the scientists were able to see the entire structure of the lantern for the first time, and to also make quantitative evaluations of oxygen distribution.

The imaging showed that the firefly diverts oxygen from other cellular functions and puts it into the reaction that breaks up luciferin. Specifically, the researchers found that oxygen consumption in the cell decreased, slowing down energy production. At the same time, oxygen supply switched to light-emission.

The study is the first to ever show the firefly’s lantern in such detail, while also providing clear evidence that it is optimized for light emission thanks to the state-of-the-art techniques used by the scientists. But Margaritondo points out another innovation: “The techniques we used have an advantage over, say, conventional x-ray techniques, which cannot easily distinguish between soft tissues. By using an approach based on changes in light intensity (phase-contrast) as opposed to light absorption (x-rays), we were able to achieve high-resolution imaging of the delicate firefly lantern.”

Here’s an image illustrating the work,

Tomographic Reconstruction of Part of the Firefly Lantern;  This detailed microimage shows larger channels branching into smaller ones, supplying oxygen for the firefly's light emission. The smallest channels are ten thousand times smaller than a millimeter and therefore invisible to other experimental probes: this has prevented scientists so far to unlock the mystery of firefly light flashes. Credit: Giorgio Margaritondo/EPFL

Tomographic Reconstruction of Part of the Firefly Lantern; This detailed microimage shows larger channels branching into smaller ones, supplying oxygen for the firefly’s light emission. The smallest channels are ten thousand times smaller than a millimeter and therefore invisible to other experimental probes: this has prevented scientists so far to unlock the mystery of firefly light flashes. Credit: Giorgio Margaritondo/EPFL

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

Firefly Light Flashing: Oxygen Supply Mechanism by Yueh-Lin Tsai, Chia-Wei Li, Tzay-Ming Hong, Jen-Zon Ho, En-Cheng Yang, Wen-Yen Wu, G. Margaritondo, Su-Ting Hsu, Edwin B. L. Ong, and Y. Hwu. Phys. Rev. Lett. 113, 258103 – Published 17 December 2014 DOI:  http://dx.doi.org/10.1103/PhysRevLett.113.258103

This paper is behind a paywall.

Insurance companies, the future, and perceptions about nanotechnology risks

Michael Berger has written a Dec. 15, 2014 Nanowerk Spotlight about a study examining perceptions of nanotechnology risks amongst members of the insurance industry,

Insurance companies are major stakeholders capable of contributing to the safer and more sustainable development of nanotechnologies and nanomaterials. This is owed to the fact that the insurance industry is one of the bearers of potential losses that can arise from the production and use of nanomaterials and nanotechnology applications.

Researchers at the University of Limerick in Ireland have examined how the insurance market perception of nanotechnology can influence the sustainability of technological advances and insurers’ concern for nanotechnology risks. They claim that, despite its role in sustaining technology development in modern society, insurers’ perception on nanomaterials has been largely overlooked by researchers and regulators alike.

I encourage you to read Berger’s piece in its entirety as it includes nuggets such as this,

… Over 64 per cent of surveyed insurers said they were vaguely familiar with nanotechnology and nanomaterial terms, and over 25 per cent said they had a moderate working knowledge and were able to define the terms. The interview data, however, suggests that this knowledge is at a basic level and there is a need for more information in order to allow this group to differentiate between distinct nanomaterial risks.

For those of you who would like to read the researchers’ paper in its entirety, you can find it in the Geneva Association Newsletter: Risk Management, No. 54, June 2014 where you will find a very interesting set of prognostications in Walter R. Stahel’s editorial,

In the editorial of the Risk Management newsletter of May 2013, I was looking back at 25 years of Risk Management Research of The Geneva Association. Today, this editorial and newsletter will look at some specific risks of the next 25 years.

If we first look back 25 years, to 1988, the PC had just been invented, Internet was still an internal network at the site of its invention the CERN [European Particle Physics Laboratory] in Geneva, cars were driven by people and mobile phones weighed five kilos and cost $5000, to give but a few technical examples. Dying forests, air pollution and retreating glaciers were the main environmental topics in the news, unemployment and sovereign debt were high on the agenda of politicians—some topics change, others remain.

Looking forward to 2039, the impacts of climate change will have amplified: invasive species—both plants such as ambrosia and animals such as the tiger mosquito—will have advanced further northward in Europe, while intensive agriculture in Scotland and Scandinavia will have become the norm—the European Union (EU) expects a 75 per cent increase in agricultural yields in these regions.

Other topics, such as bacteria which are resistant to antibiotics, represent a formidable challenge both as an opportunity for science and a risk to society. The European Commission estimates that today, 25,000 people die annually as a result of an infection with multi-drug-resistant bacteria.

The ageing population is another major opportunity and risk in the hands of policymakers, a topic which The Geneva Association started analysing more than 25 years ago. Yet the multiple benefits of continued activity by the elderly—such as lower health costs—are only starting to be recognised by politicians. And most companies, organisations and administrations are still extremely hesitant to keep able employees beyond the legal age of retirement.

No easy predictions can be made on the outcome of societal changes. Trends such as a shift from science-based policymaking to policy-based science, from evidence-based advocacy to advocacy-based evidence and from fault-based liability to need-based compensation could lead society onto down the wrong path, which may be irreversible.

The last paragraph from the excerpt is the most interesting to me as its puts some of the current machinations within Canadian public life into context within the European (and I suspect the international) political scene.

I do have a comment or two about the research but first here’s a citation for it,

Insurance Market Perception of Nanotechnology and Nanomaterials Risks By Lijana Baublyte, Martin Mullins, Finbarr Murphy and Syed A.M. Tofai. Geneva Association Newsletter: Risk Management, No. 54, June 2014.

No date is offered for when the research was conducted and there is no indication in the newsletter that it was published prior to its June 2014 publication.

As for the research itself, first, the respondents are self-assessing their knowledge about nanotechnology. That presents an interesting problem for researchers since self-assessment in any area is highly dependent on various attributes such as confidence, perceived intelligence, etc. For example, someone who’s more knowledgeable might self-assess as being less so than someone who has more confidence in themselves. As for this statistic from the report,

… Over 40 per cent of surveyed laypeople heard nothing at all about nanotechnologies and nanomaterials, 47.5 per cent said they were vaguely familiar with the technology and the remaining 11.7 per cent of respondents reported having moderate working knowledge.

Generally, people won’t tell you that they know about nanotechnologies and nanomaterials from a video game (Deux Ex) or a comic book (Iron Man’s Extremis story line) as they may not consider that to be knowledge or are embarrassed. In the case of the video game, the information about nanotechnology is based on reputable scientific research although it is somewhat massaged to fit into the game ethos. Nonetheless, information about emerging technologies is often conveyed through pop culture properties and/or advertising and most researchers don’t take that into account.

One more thing about layperson awareness, the researchers cite a meta-analysis conducted by Terre Satterfield, et. al. (full citation: Satterfield, T., Kandlikar, M., Beaudrie, C.E.H., Conti,J., and Herr Harthorn, B. [2009]. Anticipating the perceived risk of nanotechnologies. Nature Nanotechnology, 4[11]: 752–758),  which was published in 2009 (mentioned in my Sept. 22, 2009 post; scroll down about 35% of the way). As I recall, the meta-analysis fell a bit short as the researchers didn’t provide in-depth analysis of the research instruments (questionnaires) instead analysing only the results. That said, one can’t ‘reinvent the wheel’ every time one writes a paper or analyses data although I do wish just once I’d stumble across a study where researchers analysed the assumptions posed by the wording of the questions.

Solar cells and ‘tinkertoys’

A Nov. 3, 2014 news item on Nanowerk features a project researchers hope will improve photovoltaic efficiency and make solar cells competitive with other sources of energy,

 Researchers at Sandia National Laboratories have received a $1.2 million award from the U.S. Department of Energy’s SunShot Initiative to develop a technique that they believe will significantly improve the efficiencies of photovoltaic materials and help make solar electricity cost-competitive with other sources of energy.

The work builds on Sandia’s recent successes with metal-organic framework (MOF) materials by combining them with dye-sensitized solar cells (DSSC).

“A lot of people are working with DSSCs, but we think our expertise with MOFs gives us a tool that others don’t have,” said Sandia’s Erik Spoerke, a materials scientist with a long history of solar cell exploration at the labs.

A Nov. 3, 2014 Sandia National Laboratories news release, which originated the news item, describes the project and the technology in more detail,

Sandia’s project is funded through SunShot’s Next Generation Photovoltaic Technologies III program, which sponsors projects that apply promising basic materials science that has been proven at the materials properties level to demonstrate photovoltaic conversion improvements to address or exceed SunShot goals.

The SunShot Initiative is a collaborative national effort that aggressively drives innovation with the aim of making solar energy fully cost-competitive with traditional energy sources before the end of the decade. Through SunShot, the Energy Department supports efforts by private companies, universities and national laboratories to drive down the cost of solar electricity to 6 cents per kilowatt-hour.

DSSCs provide basis for future advancements in solar electricity production

Dye-sensitized solar cells, invented in the 1980s, use dyes designed to efficiently absorb light in the solar spectrum. The dye is mated with a semiconductor, typically titanium dioxide, that facilitates conversion of the energy in the optically excited dye into usable electrical current.

DSSCs are considered a significant advancement in photovoltaic technology since they separate the various processes of generating current from a solar cell. Michael Grätzel, a professor at the École Polytechnique Fédérale de Lausanne in Switzerland, was awarded the 2010 Millennium Technology Prize for inventing the first high-efficiency DSSC.

“If you don’t have everything in the DSSC dependent on everything else, it’s a lot easier to optimize your photovoltaic device in the most flexible and effective way,” explained Sandia senior scientist Mark Allendorf. DSSCs, for example, can capture more of the sun’s energy than silicon-based solar cells by using varied or multiple dyes and also can use different molecular systems, Allendorf said.

“It becomes almost modular in terms of the cell’s components, all of which contribute to making electricity out of sunlight more efficiently,” said Spoerke.

MOFs’ structure, versatility and porosity help overcome DSSC limitations

Though a source of optimism for the solar research community, DSSCs possess certain challenges that the Sandia research team thinks can be overcome by combining them with MOFs.

Allendorf said researchers hope to use the ordered structure and versatile chemistry of MOFs to help the dyes in DSSCs absorb more solar light, which he says is a fundamental limit on their efficiency.

“Our hypothesis is that we can put a thin layer of MOF on top of the titanium dioxide, thus enabling us to order the dye in exactly the way we want it,” Allendorf explained. That, he said, should avoid the efficiency-decreasing problem of dye aggregation, since the dye would then be locked into the MOF’s crystalline structure.

MOFs are highly-ordered materials that also offer high levels of porosity, said Allendorf, a MOF expert and 29-year veteran of Sandia. He calls the materials “Tinkertoys for chemists” because of the ease with which new structures can be envisioned and assembled. [emphasis mine]

Allendorf said the unique porosity of MOFs will allow researchers to add a second dye, placed into the pores of the MOF, that will cover additional parts of the solar spectrum that weren’t covered with the initial dye. Finally, he and Spoerke are convinced that MOFs can help improve the overall electron charge and flow of the solar cell, which currently faces instability issues.

“Essentially, we believe MOFs can help to more effectively organize the electronic and nano-structure of the molecules in the solar cell,” said Spoerke. “This can go a long way toward improving the efficiency and stability of these assembled devices.”

In addition to the Sandia team, the project includes researchers at the University of Colorado-Boulder, particularly Steve George, an expert in a thin film technology known as atomic layer deposition.

The technique, said Spoerke, is important in that it offers a pathway for highly controlled materials chemistry with potentially low-cost manufacturing of the DSSC/MOF process.

“With the combination of MOFs, dye-sensitized solar cells and atomic layer deposition, we think we can figure out how to control all of the key cell interfaces and material elements in a way that’s never been done before,” said Spoerke. “That’s what makes this project exciting.”

Here’s a picture showing an early Tinkertoy set,

Original Tinkertoy, Giant Engineer #155. Questor Education Products Co., c.1950 [downloaded from http://en.wikipedia.org/wiki/Tinkertoy#mediaviewer/File:Tinkertoy_300126232168.JPG]

Original Tinkertoy, Giant Engineer #155. Questor Education Products Co., c.1950 [downloaded from http://en.wikipedia.org/wiki/Tinkertoy#mediaviewer/File:Tinkertoy_300126232168.JPG]

The Tinkertoy entry on Wikipedia has this,

The Tinkertoy Construction Set is a toy construction set for children. It was created in 1914—six years after the Frank Hornby’s Meccano sets—by Charles H. Pajeau and Robert Pettit and Gordon Tinker in Evanston, Illinois. Pajeau, a stonemason, designed the toy after seeing children play with sticks and empty spools of thread. He and Pettit set out to market a toy that would allow and inspire children to use their imaginations. At first, this did not go well, but after a year or two over a million were sold.

Shrinky Dinks, tinkertoys, Lego have all been mentioned here in conjunction with lab work. I’m always delighted to see scientists working with or using children’s toys as inspiration of one type or another.

Nanosafety research: a quality control issue

Toxicologist Dr. Harald Krug has published a review of several thousand studies on nanomaterials safety exposing problematic research methodologies and conclusions. From an Oct. 29, 2014 news item on Nanowerk (Note: A link has been removed),

Empa [Swiss Federal Laboratories for Materials Science and Technology] toxicologist Harald Krug has lambasted his colleagues in the journal Angewandte Chemie (“Nanosafety Research—Are We on the Right Track?”). He evaluated several thousand studies on the risks associated with nanoparticles and discovered no end of shortcomings: poorly prepared experiments and results that don’t carry any clout. Instead of merely leveling criticism, however, Empa is also developing new standards for such experiments within an international network.

An Oct. 29, 2014 Empa press release (also on EurekAlert), which originated the news item, describes the new enthusiasm for research into nanomaterials and safety,

Researching the safety of nanoparticles is all the rage. Thousands of scientists worldwide are conducting research on the topic, examining the question of whether titanium dioxide nanoparticles from sun creams can get through the skin and into the body, whether carbon nanotubes from electronic products are as hazardous for the lungs as asbestos used to be or whether nanoparticles in food can get into the blood via the intestinal flora, for instance. Public interest is great, research funds are flowing – and the number of scientific projects is skyrocketing: between 1980 and 2010, a total of 5,000 projects were published, followed by another 5,000 in just the last three years. However, the amount of new knowledge has only increased marginally. After all, according to Krug the majority of the projects are poorly executed and all but useless for risk assessments.

The press release goes on to describe various pathways into the body and problems with research methodologies,

How do nanoparticles get into the body?

Artificial nanoparticles measuring between one and 100 nanometers in size can theoretically enter the body in three ways: through the skin, via the lungs and via the digestive tract. Almost every study concludes that healthy, undamaged skin is an effective protective barrier against nanoparticles. When it comes to the route through the stomach and gut, however, the research community is at odds. But upon closer inspection the value of many alarmist reports is dubious – such as when nanoparticles made of soluble substances like zinc oxide or silver are being studied. Although the particles disintegrate and the ions drifting into the body are cytotoxic, this effect has nothing to do with the topic of nanoparticles but is merely linked to the toxicity of the (dissolved) substance and the ingested dose.

Laboratory animals die in vain – drastic overdoses and other errors

Krug also discovered that some researchers maltreat their laboratory animals with absurdly high amounts of nanoparticles. Chinese scientists, for instance, fed mice five grams of titanium oxide per kilogram of body weight, without detecting any effects. By way of comparison: half the amount of kitchen salt would already have killed the animals. A sloppy job is also being made of things in the study of lung exposure to nanoparticles: inhalation experiments are expensive and complex because a defined number of particles has to be swirled around in the air. Although it is easier to place the particles directly in the animal’s windpipe (“instillation”), some researchers overdo it to such an extent that the animals suffocate on the sheer mass of nanoparticles.

While others might well make do without animal testing and conduct in vitro experiments on cells, here, too, cell cultures are covered by layers of nanoparticles that are 500 nanometers thick, causing them to die from a lack of nutrients and oxygen alone – not from a real nano-effect. And even the most meticulous experiment is worthless if the particles used have not been characterized rigorously beforehand. Some researchers simply skip this preparatory work and use the particles “straight out of the box”. Such experiments are irreproducible, warns Krug.

As noted in the news item, the scientists at Empa have devised a solution to some to of the problems (from the press release),

The solution: inter-laboratory tests with standard materials
Empa is thus collaborating with research groups like EPFL’s Powder Technology Laboratory, with industrial partners and with Switzerland’s Federal Office of Public Health (FOPH) to find a solution to the problem: on 9 October the “NanoScreen” programme, one of the “CCMX Materials Challenges”, got underway, which is expected to yield a set of pre-validated methods for lab experiments over the next few years. It involves using test materials that have a closely defined particle size distribution, possess well-documented biological and chemical properties and can be altered in certain parameters – such as surface charge. “Thanks to these methods and test substances, international labs will be able to compare, verify and, if need be, improve their experiments,” explains Peter Wick, Head of Empa’s laboratory for Materials-Biology Interactions.

Instead of the all-too-familiar “fumbling around in the dark”, this would provide an opportunity for internationally coordinated research strategies to not only clarify the potential risks of new nanoparticles in retrospect but even be able to predict them. The Swiss scientists therefore coordinate their research activities with the National Institute of Standards and Technology (NIST) in the US, the European Commission’s Joint Research Center (JRC) and the Korean Institute of Standards and Science (KRISS).

Bravo! and thank you Dr. Krug and Empa for confirming something I’ve suspected due to hints from more informed commentators. Unfortunately my ignorance. about research protocols has not permitted me to undertake a better analysis of the research. ,

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

Nanosafety Research—Are We on the Right Track? by Prof. Dr. Harald F. Krug. Angewandte Chemie International Edition DOI: 10.1002/anie.201403367 Article first published online: 10 OCT 2014

This is an open access paper.

The Innovation Society’s Nanorama Car Workshop

Thanks to a Sept. 23, 2014 news item on Nanowerk, I’ve come across this education initiative for workers in the automotive industry,

Nanomaterials and ultra-fine particles in car workshops – learn how to handle them safely by exploring the “Nanorama Car Workshop”, which is now available (in German) at http://nano.dguv.de/nanorama/bghm/. A “Nanorama” is a virtual classroom that allows its users to gather important information on safe handling of nanomaterials in a 360° work environment.

The emphasis of the “Nanorama Car Workshop” is on the handling of products containing nanomaterials and on work processes that can lead to the formation of ultra-fine particles. In the “Nanorama Car Workshop”, the user receives useful information about hazard evaluation assessment, the occupational exposure to nanomaterials and necessary protective measures.

An Aug. 25, 2014 DGUV (Deutsche Gesetzliche Unfallversicherung; German Social Accident Insurance Institution) press release, (summary available here) provides more details,

The ‘Nanorama Lab’ (http://nano.dguv.de/nanorama/bgrci/) represents the second interactive educational tool on the Nano-Platform ‘Safe Handling of Nanomaterials’ (http://nano.dguv.de) (both currently only available in German). They were developed by the Innovation Society, St. Gallen, in close collaboration with the German Social Accident Insurance Institution for the raw materials and chemical industry (BG RCI). The ‘Nanorama Lab’ offers in-depth insights into the safe handling of nanomaterials and installations used to manufacture or process nanomaterials in laboratories. Complementary to hazard evaluation assessments, it enables users to assess the occupational exposure to nanomaterials and to identify necessary protective measures when handling said materials in laboratories.

«Due to the attractive visual implementation and the interactive contents, the ‘Nanorama Lab’ offers a great introduction to protective measures in laboratories », says Dr. Thomas H. Brock, Head of the Expert Committee on Hazardous Substances of the BG RCI. The ‘Nanorama Lab’ inspires curiosity in users and instigates them to reflect on the conditions in their respective workplaces. «By exploring the ‘Nanorama Lab’, laboratory staff actively deals with occupational health and safety in laboratories and its practical implementation with regard to nanomaterials.»

The press release goes on to describe the ‘nanorama’ concept,

Presenting the ‘Nanorama Lab’, the DGUV again harnesses the interactive E-Learning tool ‘Nanorama’ developed by The Innovation Society, St. Gallen. A ‘Nanorama’ – a lexical blend of ‘Nano’ and ‘Panorama’, – is a novel 360°-E-learning module in which the user enters a virtual space and moves around in it. By completing a ‘Nanorama’, users acquire knowledge in an entertaining manner. ‘Nanoramas’ can be applied in many areas of education and communication.

The first module of the Nano-Platform, the ‘Nanorama Construction’, can be visited on http://nano.dguv.de/nanorama/bgbau/. It offers insights into the use and applications of nanomaterials in the construction industry and will soon be followed by the ‘Nanorama
Metal’. Additionally, the Nano-Platform c an be expanded with further ‘Nanorama’-modules on any given sector or trade thanks to its modular design.

There is no word as to when an English-language version may be available but you can visit the Nanomara car workshop, regardless.

You can also check out the Nano-Portal for more information about this car Nanorama and other such inititiatives.

Here’s an image from the Nanorama car workshop,

Nanorama car workshop [downloaded from http://nano.dguv.de/]

Nanorama car workshop [downloaded from http://nano.dguv.de/]

Malaria vaccine with self-assembling nanoparticles

This research was published in April 2013 so I’m not sure what has occasioned a Sept. 2014 push for publicity. Still, it’s interesting work which may lead to a more effective vaccine for malaria than some of the other solutions being tested.  From a Sept. 4, 2014 news item on Nanowerk,

A self-assembling nanoparticle designed by a University of Connecticut (UConn) professor is the key component of a potent new malaria vaccine that is showing promise in early tests.

For years, scientists trying to develop a malaria vaccine have been stymied by the malaria parasite’s ability to transform itself and “hide” in the liver and red blood cells of an infected person to avoid detection by the immune system.

But a novel protein nanoparticle developed by Peter Burkhard, a professor in the Department of Molecular & Cell Biology, in collaboration with David Lanar, an infectious disease specialist with the Walter Reed Army Institute of Research, has shown to be effective at getting the immune system to attack the most lethal species of malaria parasite, Plasmodium falciparum, after it enters the body and before it has a chance to hide and aggressively spread.

Sept. 3, 2014 University of Connecticut news release by Colin Poitras, which originated the news item, describes the particle and the research in greater detail,

The key to the vaccine’s success lies in the nanoparticle’s perfect icosahedral symmetry (think of the pattern on a soccer ball) and ability to carry on its surface up to 60 copies of the parasite’s protein. The proteins are arranged in a dense, carefully constructed cluster that the immune system perceives as a threat, prompting it to release large amounts of antibodies that can attack and kill the parasite.

In tests with mice, the vaccine was 90-100 percent effective in eradicating the Plasmodium falciparum parasite and maintaining long-term immunity over 15 months. That success rate is considerably higher than the reported success rate for RTS,S, the world’s most advanced malaria vaccine candidate currently undergoing phase 3 clinical trials, which is the last stage of testing before licensing.

“Both vaccines are similar, it’s just that the density of the RTS,S protein displays is much lower than ours,” says Burkhard. “The homogeneity of our vaccine is much higher, which produces a stronger immune system response. That is why we are confident that ours will be an improvement.

“Every single protein chain that forms our particle displays one of the pathogen’s protein molecules that are recognized by the immune system,” adds Burkhard, an expert in structural biology affiliated with UConn’s Institute of Materials Science. “With RTS,S, only about 14 percent of the vaccine’s protein is from the malaria parasite. We are able to achieve our high density because of the design of the nanoparticle, which we control.”

Here’s an image illustrating the nanoparticle,

This self-assembling protein nanoparticle relies on rigid protein structures called ‘coiled coils’ (blue and green in the image) to create a stable framework upon which scientists can attach malaria parasite antigens. Early tests show that injecting the nanoparticles into the body as a vaccine initiates a strong immune system response that destroys a malarial parasite when it enters the body and before it has time to spread. (Image courtesy of Peter Burkhard)

This self-assembling protein nanoparticle relies on rigid protein structures called ‘coiled coils’ (blue and green in the image) to create a stable framework upon which scientists can attach malaria parasite antigens. Early tests show that injecting the nanoparticles into the body as a vaccine initiates a strong immune system response that destroys a malarial parasite when it enters the body and before it has time to spread. (Image courtesy of Peter Burkhard)

The news release goes on to explain why malaria is considered a major, global health problem and how the researchers approached the problem with developing a malaria vaccine for humans,

The search for a malaria vaccine is one of the most important research projects in global public health. The disease is commonly transported through the bites of nighttime mosquitoes. Those infected suffer from severe fevers, chills, and a flu-like illness. In severe cases, malaria causes seizures, severe anemia, respiratory distress, and kidney failure. Each year, more than 200 million cases of malaria are reported worldwide. The World Health Organization estimated that 627,000 people died from malaria in 2012, many of them children living in sub-Saharan Africa.

It took the researchers more than 10 years to finalize the precise assembly of the nanoparticle as the critical carrier of the vaccine and find the right parts of the malaria protein to trigger an effective immune response. The research was further complicated by the fact that the malaria parasite that impacts mice used in lab tests is structurally different from the one infecting humans.

The scientists used a creative approach to get around the problem.

“Testing the vaccine’s efficacy was difficult because the parasite that causes malaria in humans only grows in humans,” Lanar says. “But we developed a little trick. We took a mouse malaria parasite and put in its DNA a piece of DNA from the human malaria parasite that we wanted our vaccine to attack. That allowed us to conduct inexpensive mouse studies to test the vaccine before going to expensive human trials.”

The pair’s research has been supported by a $2 million grant from the National Institutes of Health and $2 million from the U.S. Military Infectious Disease Research Program. A request for an additional $7 million in funding from the U.S. Army to conduct the next phase of vaccine development, including manufacturing and human trials, is pending.

“We are on schedule to manufacture the vaccine for human use early next year,” says Lanar. “It will take about six months to finish quality control and toxicology studies on the final product and get permission from the FDA to do human trials.”

Lanar says the team hopes to begin early testing in humans in 2016 and, if the results are promising, field trials in malaria endemic areas will follow in 2017. The required field trial testing could last five years or more before the vaccine is available for licensure and public use, Lanar says.

Martin Edlund, CEO of Malaria No More, a New York-based nonprofit focused on fighting deaths from malaria, says, “This research presents a promising new approach to developing a malaria vaccine. Innovative work such as what’s being done at the University of Connecticut puts us closer than we’ve ever been to ending one of the world’s oldest, costliest, and deadliest diseases.”

A Switzerland-based company, Alpha-O-Peptides, founded by Burkhard, holds the patent on the self-assembling nanoparticle used in the malaria vaccine. Burkhard is also exploring other potential uses for the nanoparticle, including a vaccine that will fight animal flu and one that will help people with nicotine addiction. Professor Mazhar Khan from UConn’s Department of Pathobiology is collaborating with Burkhard on the animal flu vaccine.

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

Mechanisms of protective immune responses induced by the Plasmodium falciparum circumsporozoite protein-based, self-assembling protein nanoparticle vaccine by Margaret E McCoy, Hannah E Golden, Tais APF Doll, Yongkun Yang, Stephen A Kaba, Peter Burkhard, and David E Lanar. Malaria Journal 2013, 12:136 doi:10.1186/1475-2875-12-136

This is an open access article.

Batteryfree cardiac pacemaker

This particular energy-havesting pacemaker has been tested ‘in vivo’ or, as some like to say, ‘on animal models’. From an Aug. 31, 2014 European Society of Cardiology news release (also on EurekAlert),

A new batteryless cardiac pacemaker based on an automatic wristwatch and powered by heart motion was presented at ESC Congress 2014 today by Adrian Zurbuchen from Switzerland. The prototype device does not require battery replacement.

Mr Zurbuchen, a PhD candidate in the Cardiovascular Engineering Group at ARTORG, University of Bern, Switzerland, said: “Batteries are a limiting factor in today’s medical implants. Once they reach a critically low energy level, physicians see themselves forced to replace a correctly functioning medical device in a surgical intervention. This is an unpleasant scenario which increases costs and the risk of complications for patients.”

Four years ago Professor Rolf Vogel, a cardiologist and engineer at the University of Bern, had the idea of using an automatic wristwatch mechanism to harvest the energy of heart motion. Mr Zurbuchen said: “The heart seems to be a very promising energy source because its contractions are repetitive and present for 24 hours a day, 7 days a week. Furthermore the automatic clockwork, invented in the year 1777, has a good reputation as a reliable technology to scavenge energy from motion.”

The researchers’ first prototype is based on a commercially available automatic wristwatch. All unnecessary parts were removed to reduce weight and size. In addition, they developed a custom-made housing with eyelets that allows suturing the device directly onto the myocardium (photo 1).

The prototype works the same way it would on a person’s wrist. When it is exposed to an external acceleration, the eccentric mass of the clockwork starts rotating. This rotation progressively winds a mechanical spring. After the spring is fully charged it unwinds and thereby spins an electrical micro-generator.

To test the prototype, the researchers developed an electronic circuit to transform and store the signal into a small buffer capacity. They then connected the system to a custom-made cardiac pacemaker (photo 2). The system worked in three steps. First, the harvesting prototype acquired energy from the heart. Second, the energy was temporarily stored in the buffer capacity. And finally, the buffered energy was used by the pacemaker to apply minute stimuli to the heart.

The researchers successfully tested the system in in vivo experiments with domestic pigs. The newly developed system allowed them for the first time to perform batteryless overdrive-pacing at 130 beats per minute.

Mr Zurbuchen said: “We have shown that it is possible to pace the heart using the power of its own motion. The next step in our prototype is to integrate both the electronic circuit for energy storage and the custom-made pacemaker directly into the harvesting device. This will eliminate the need for leads.”

He concluded: “Our new pacemaker tackles the two major disadvantages of today’s pacemakers. First, pacemaker leads are prone to fracture and can pose an imminent threat to the patient. And second, the lifetime of a pacemaker battery is limited. Our energy harvesting system is located directly on the heart and has the potential to avoid both disadvantages by providing the world with a batteryless and leadless pacemaker.”

This project seems the furthest along with regard to its prospects for replacing batteries in pacemakers (with leadlessness being a definite plus) but there are other projects such as Korea’s Professor Keon Jae Lee of KAIST and Professor Boyoung Joung, M.D. at Severance Hospital of Yonsei University who are working on a piezoelectric nanogenerator according to a June 26, 2014 article by Colin Jeffrey for Gizmodo.com,

… Unfortunately, the battery technology used to power these devices [cardiac pacemakers] has not kept pace and the batteries need to be replaced on average every seven years, which requires further surgery. To address this problem, a group of researchers from Korea Advanced Institute of Science and Technology (KAIST) has developed a cardiac pacemaker that is powered semi-permanently by harnessing energy from the body’s own muscles.

The research team, headed by Professor Keon Jae Lee of KAIST and Professor Boyoung Joung, M.D. at Severance Hospital of Yonsei University, has created a flexible piezoelectric nanogenerator that has been used to directly stimulate the heart of a live rat using electrical energy produced from small body movements of the animal.

… the team created their new high-performance flexible nanogenerator from a thin film semiconductor material. In this case, lead magnesium niobate-lead titanate (PMN-PT) was used rather than the graphene oxide and carbon nanotubes of previous versions. As a result, the new device was able to harvest up to 8.2 V and 0.22 mA of electrical energy as a result of small flexing motions of the nanogenerator. The resultant voltage and current generated in this way were of sufficient levels to stimulate the rat’s heart directly.

I gather this project too was tested on animal models, in this case, rats.

Gaining some attention at roughly the same time as the Korean researchers, a French team’s work with a ‘living battery’ is mentioned in a June 17, 2014 news item on the Open Knowledge website,

Philippe Cinquin, Serge Cosnier and their team at Joseph Fourier University in France have invented a ‘living battery.’ The device – a fuel cell and conductive wires modified with reactive enzymes – has the power to tap into the body’s endless supply of glucose and convert simple sugar, which constitutes the energy source of living cells, into electricity.

Visions of implantable biofuel cells that use the body’s natural energy sources to power pacemakers or artificial hearts have been around since the 1960s, but the French team’s innovations represents the closest anyone has ever come to harnessing this energy.

The French team was a finalist for the 2014 European Inventor Award. Here’s a description of how their invention works, from their 2014 European Inventor Award’s webpage,

Biofuel cells that harvest energy from glucose in the body function much like every-day batteries that conduct electricity through positive and negative terminals called anodes and cathodes and a medium conducive to electric charge known as the electrolyte. Electricity is produced via a series of electrochemical reactions between these three components. These reactions are catalysed using enzymes that react with glucose stored in the blood.

Bodily fluids, which contain glucose and oxygen, serve as the electrolyte. To create an anode, two enzymes are used. The first enzyme breaks down the sugar glucose, which is produced every time the animal or person consumes food. The second enzyme oxidises the simpler sugars to release electrons. A current then flows as the electrons are drawn to the cathode. A capacitor that is hooked up to the biofuel cell stores the electric charge produced.

I wish all the researchers good luck as they race towards a new means of powering pacemakers, deep brain stimulators, and other implantable devices that now rely on batteries which need to be changed thus forcing the patient to undergo major surgery.

Self-powered batteries for pacemakers, etc. have been mentioned here before:

April 3, 2009 posting

July 12, 2010 posting

March 8, 2013 posting

Bespoke (custom made) carbon nanotubes

Researchers have found a way to create single-walled carbon nanotubes (SWCNTs) that  are consistent and, hopefully, designed for specific applications if I’m reading the research rightly, (I have an embedded video in a March 15, 2013 posting which illustrates some of the issues with producing carbon nanotubes.) Getting back to this latest research, it suggests that we could order SWCNTs-on-demand. An Aug. 14, 2014 news item on Azonano provides more insight,

In future, it will be possible to specifically equip carbon nanotubes with properties which they need for electronic applications, for example. Researchers at Empa in Dübendorf/Switzerland and the Max Planck Institute for Solid State Research in Stuttgart [Germany] have succeeded for the first time in growing single-walled carbon nanotubes (CNTs) with only a single, prespecified structure.

The nanotubes thereby have identical electronic properties. The decisive trick here: The team has taken up an idea which originated from the Stuttgart-based Max Planck researchers and produced the CNT from custom-made organic precursor molecules. The researchers started with these precursor molecules and have built up the nanotubes on a platinum surface, as they report in the latest issue of the scientific journal Nature. Such CNTs could be used in future, for instance, in ultra-sensitive light detectors and very tiny transistors.

An Aug. 13, 2014 Max Planck Institute press release, which originated the news item, provides more detail,

For 20 years, material scientists working on the development of carbon nanotubes for a range of applications have been battling a problem – now an elegant solution is at hand. With their unusual mechanical, thermal and electronic properties, the tiny tubes with their honeycomb lattice of graphitic carbon have become the embodiment of nanomaterials. They could be used to manufacture the next generation of electronic and electro-optical components so that they are even smaller and with even faster switching times than before. But to achieve this, the material scientists must specifically equip the nanotubes with desired properties, and these depend on their structure. The production methods used to date, however, always result in a mixture of different CNTs. The team from Empa  and the Max Planck Institute for Solid State Research has now remedied the situation with a new production path for single-walled nanotubes.

Carbon nanotubes with the best possible varietal purity are in demand

With a diameter of around one nanometre, single-walled CNTs (SWCNTs) are deemed to be quantum structures; very tiny structural differences, in the diameter, for example, or in the orientation of the atomic lattice, can dramatically change the electronic properties: one SWCNT can be a metal, while one with a slightly different structure is semi-conducting. Correspondingly great is the interest in reliable methods for producing SWCNTs with the best possible varietal purity. Researchers working with Martin Jansen, Director Emeritus at the Max Planck Institute for Solid State Research, have been pursuing suitable concepts for the synthesis for ten years. But it is only now that the surface physicists at Empa and the chemists at the Stuttgart-based Max Planck Institute have succeeded in implementing one of these ideas in the laboratory. The researchers allowed structurally identical SWCNTs to grow on a platinum surface in a self-organised process and were able to unambiguously define their electronic properties.

The Max Planck research team headed by Martin Jansen had the idea of starting with small precursor molecules to synthesise carbon nanotubes. They felt it should be possible to achieve controlled conversion of the precursor molecules into a cap which acts as the seed for a SWCNT and thus unambiguously specify the structure of the nanotube. With this concept, they approached the Empa team working with Roman Fasel, head of Empa’s «nanotech@surfaces» department and titular professor at the Department of Chemistry and Biochemistry of the University of Bern. This group has already been working for some time on how molecules on a surface can be converted or combined into complex nanostructures according to the principle of molecular self-organisation. “The challenge now consists in finding the right precursor molecule which would actually grow on a smooth surface,” says Roman Fasel. This was ultimately achieved by Andreas Mueller and Konstantin Amsharov from the Max Planck Institute in Stuttgart with the synthesis of a hydrocarbon molecule from a not-inconsiderable 150 atoms.

Molecular origami on the platinum surface

What exactly is the process in which the carbon nanotube forms? In the first step, the flat precursor molecule must – as is the case in origami – convert into a three-dimensional object, the seed. This takes place on a hot platinum surface with the aid of a catalytic reaction, whereby hydrogen atoms split off from the precursor molecule and form new carbon-carbon bonds at very specific positions. The seed folds up from the flat molecule: a tiny, domed shape with open rim, which sits on the platinum surface. This so-called end cap forms the top of the growing SWCNT.

In a second chemical process, further carbon atoms, which are formed during the catalytic decomposition of ethanol on the platinum surface, are taken up. They deposit on the open rim between end cap and platinum surface and lift the cap higher and higher; the tube slowly grows upwards. The atomic structure of the nanotube is determined solely by the shape of the seed. The researchers proved this by analysing the vibrational modes of the SWCNTs and taking measurements with the scanning tunnelling microscope. Further investigations at Empa showed that the SWCNTs produced were over 300 nanometres in length.

Different nanotubes are formed from suitable precursor molecules

The researchers have thus proved that they can unambiguously specify the growth and thus the structure of long SWCNTs using custom-made molecular seeds. The SWCNTs synthesised in this study can exist in two forms, which correspond to an object and its mirror image. By choosing the precursor molecule appropriately, the researchers were able to influence which of the two variants forms. Depending on how the honeycomb atomic lattice is derived from the original molecule – straight or oblique with respect to the CNT axis – it is also possible for helically wound tubes, i.e. with right- or left-handed rotation, and with non-mirror symmetry to form. And it is precisely this structure that then determines which electronic, thermo-electric and optical properties of the material. In principle, the researchers can therefore specifically produce materials with different properties through their choice of precursor molecule.

In further steps, Roman Fasel and his colleagues want to gain an even better understanding of how SWCNTs establish themselves on a surface. Even if well in excess of 100 million nanotubes per square centimetre already grow on the platinum surface, only a relatively small fraction of the seeds actually develop into «mature» nanotubes. The question remains as to which processes are responsible for this, and how the yield can be increased.

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

Controlled synthesis of single-chirality carbon nanotubes by Juan Ramon Sanchez-Valencia, Thomas Dienel, Oliver Gröning, Ivan Shorubalko, Andreas Mueller, Martin Jansen, Konstantin Amsharov, Pascal Ruffieux, & Roman Fasel. Nature 512, 61–64 (07 August 2014) doi:10.1038/nature13607

Published online 06 August 2014

This paper is behind a paywall.

Gold on the brain, a possible nanoparticle delivery system for drugs

A July 21, 2014 news item on Nanowerk describes special gold nanoparticles that could make drug delivery to cells easier,

A special class of tiny gold particles can easily slip through cell membranes, making them good candidates to deliver drugs directly to target cells.

A new study from MIT materials scientists reveals that these nanoparticles enter cells by taking advantage of a route normally used in vesicle-vesicle fusion, a crucial process that allows signal transmission between neurons.

A July 21, 2014 MIT (Massachusetts Institute of Technology) news release (also on EurekAlert), which originated the news item, provides more details,

The findings suggest possible strategies for designing nanoparticles — made from gold or other materials — that could get into cells even more easily.

“We’ve identified a type of mechanism that might be more prevalent than is currently known,” says Reid Van Lehn, an MIT graduate student in materials science and engineering and one of the paper’s lead authors. “By identifying this pathway for the first time it also suggests not only how to engineer this particular class of nanoparticles, but that this pathway might be active in other systems as well.”

The paper’s other lead author is Maria Ricci of École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland. The research team, led by Alfredo Alexander-Katz, an associate professor of materials science and engineering, and Francesco Stellacci from EPFL, also included scientists from the Carlos Besta Institute of Neurology in Italy and Durham University in the United Kingdom.

Most nanoparticles enter cells through endocytosis, a process that traps the particles in intracellular compartments, which can damage the cell membrane and cause cell contents to leak out. However, in 2008, Stellacci, who was then at MIT, and Darrell Irvine, a professor of materials science and engineering and of biological engineering, found that a special class of gold nanoparticles coated with a mix of molecules could enter cells without any disruption.

“Why this was happening, or how this was happening, was a complete mystery,” Van Lehn says.

Last year, Alexander-Katz, Van Lehn, Stellacci, and others discovered that the particles were somehow fusing with cell membranes and being absorbed into the cells. In their new study, they created detailed atomistic simulations to model how this happens, and performed experiments that confirmed the model’s predictions.

Gold nanoparticles used for drug delivery are usually coated with a thin layer of molecules that help tune their chemical properties. Some of these molecules, or ligands, are negatively charged and hydrophilic, while the rest are hydrophobic. The researchers found that the particles’ ability to enter cells depends on interactions between hydrophobic ligands and lipids found in the cell membrane.

Cell membranes consist of a double layer of phospholipid molecules, which have hydrophobic lipid tails and hydrophilic heads. The lipid tails face in toward each other, while the hydrophilic heads face out.

In their computer simulations, the researchers first created what they call a “perfect bilayer,” in which all of the lipid tails stay in place within the membrane. Under these conditions, the researchers found that the gold nanoparticles could not fuse with the cell membrane.

However, if the model membrane includes a “defect” — an opening through which lipid tails can slip out — nanoparticles begin to enter the membrane. When these lipid protrusions occur, the lipids and particles cling to each other because they are both hydrophobic, and the particles are engulfed by the membrane without damaging it.

In real cell membranes, these protrusions occur randomly, especially near sites where proteins are embedded in the membrane. They also occur more often in curved sections of membrane, because it’s harder for the hydrophilic heads to fully cover a curved area than a flat one, leaving gaps for the lipid tails to protrude.

“It’s a packing problem,” Alexander-Katz says. “There’s open space where tails can come out, and there will be water contact. It just makes it 100 times more probable to have one of these protrusions come out in highly curved regions of the membrane.”

This phenomenon appears to mimic a process that occurs naturally in cells — the fusion of vesicles with the cell membrane. Vesicles are small spheres of membrane-like material that carry cargo such as neurotransmitters or hormones.

The similarity between absorption of vesicles and nanoparticle entry suggests that cells where a lot of vesicle fusion naturally occurs could be good targets for drug delivery by gold nanoparticles. The researchers plan to further analyze how the composition of the membranes and the proteins embedded in them influence the absorption process in different cell types. “We want to really understand all the constraints and determine how we can best design nanoparticles to target particular cell types, or regions of a cell,” Van Lehn says.

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

Lipid tail protrusions mediate the insertion of nanoparticles into model cell membranes by Reid C. Van Lehn, Maria Ricci, Paulo H.J. Silva, Patrizia Andreozzi, Javier Reguera, Kislon Voïtchovsky, Francesco Stellacci, & Alfredo Alexander-Katz. Nature Communications 5, Article number: 4482 doi:10.1038/ncomms5482 Published 21 July 2014

This article is behind a paywall but there is a free preview available via ReadCube Access.

I last featured this multi-country team’s work on gold nanoparticles in an Aug. 23, 2013 posting.