Tag Archives: Jie Sun

Killer graphene spikes to kill bacteria on medical implants

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Implants of all kinds (hip replacements, knee replacements, etc.) seem to be on the rise and along with that an increasing number of infections. A Swedish research team announces a technology that could make implants safer in an April 16, 2018 news item on Nanowerk,

A tiny layer of graphene flakes becomes a deadly weapon and kills bacteria, stopping infections during procedures such as implant surgery. This is the findings of new research from Chalmers University of Technology, Sweden, recently published in the scientific journal Advanced Materials Interfaces (“Vertically Aligned Graphene Coating is Bactericidal and Prevents the Formation of Bacterial Biofilms”).

An April 16, 2018 Chalmers University of Technology press release (also on EurekAlert), which originated the news item, provides more detail about the scope of the problem and the proposed solution (Note: A link has been removed),

Operations for surgical implants, such as hip and knee replacements or dental implants, have increased in recent years. However, in such procedures, there is always a risk of bacterial infection. In the worst case scenario, this can cause the implant to not attach to the skeleton, meaning it must be removed.

Bacteria travel around in fluids, such as blood, looking for a surface to cling on to. Once in place, they start to grow and propagate, forming a protective layer, known as a biofilm.

A research team at Chalmers has now shown that a layer of vertical graphene flakes forms a protective surface that makes it impossible for bacteria to attach. Instead, bacteria are sliced apart by the sharp graphene flakes and killed. Coating implants with a layer of graphene flakes can therefore help protect the patient against infection, eliminate the need for antibiotic treatment, and reduce the risk of implant rejection. The osseointegration – the process by which the bone structure grow to attach the implant – is not disturbed. In fact, the graphene has been shown to benefit the bone cells.

Chalmers University is a leader in the area of graphene research, but the biological applications did not begin to materialise until a few years ago. The researchers saw conflicting results in earlier studies. Some showed that graphene damaged the bacteria, others that they were not affected.

“We discovered that the key parameter is to orient the graphene vertically. If it is horizontal, the bacteria are not harmed” says Ivan Mijakovic, Professor at the Department of Biology and Biological Engineering.

The sharp flakes do not damage human cells. The reason is simple: one bacterium is one micrometer – one thousandth of a millimeter – in diameter, while a human cell is 25 micrometers. So, what constitutes a deadly knife attack for a bacterium, is therefore only a tiny scratch for a human cell.

“Graphene has high potential for health applications. But more research is needed before we can claim it is entirely safe. Among other things, we know that graphene does not degrade easily” says Jie Sun, Associate Professor at the Department of Micro Technology and Nanoscience.

Good bacteria are also killed by the graphene. But that’s not a problem, as the effect is localised and the balance of microflora in the body remains undisturbed.

“We want to prevent bacteria from creating an infection. Otherwise, you may need antibiotics, which could disrupt the balance of normal bacteria and also enhance the risk of antimicrobial resistance by pathogens” says Santosh Pandit, postdoc at Biology and Biological Engineering.

Vertical flakes of graphene are not a new invention, having existed for a few years. But the Chalmers research teams are the first to use the vertical graphene in this way. The next step for the research team will be to test the graphene flakes further, by coating implant surfaces and studying the effect on animal cells.

Chalmers cooperated with Wellspect Healthcare, a company which makes catheters and other medical instruments, in this research. They will now continue with a second study.

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

Vertically Aligned Graphene Coating is Bactericidal and Prevents the Formation of Bacterial Biofilms by Santosh Pandit, Zhejian Cao, Venkata R. S. S. Mokkapati, Emanuele Celauro, Avgust Yurgens, Martin Lovmar, Fredrik Westerlund, Jie Sun, Ivan Mijakovic. Advanced Materials Interfaces Volume5, Issue7 April 9, 2018 Pages 1701331 [sic] https://doi.org/10.1002/admi.201701331 First published [online]: 2 February 2018

This paper is behind a paywall.

Finally, here’s a ‘killer spikes’ video made available by Chalmers University of Technology,

The volatile lithium-ion battery

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On the heels of Samsung’s Galaxy Note 7 recall due to fires (see Alex Fitzpatrick’s Sept. 9, 2016 article for Time magazine for a good description of lithium-ion batteries and why they catch fire; see my May 29, 2013 posting on lithium-ion batteries, fires [including the airplane fires], and nanotechnology risk assessments), there’s new research on lithium-ion batteries and fires from China. From an Oct. 21, 2016 news item on Nanotechnology Now,

Dozens of dangerous gases are produced by the batteries found in billions of consumer devices, like smartphones and tablets, according to a new study. The research, published in Nano Energy, identified more than 100 toxic gases released by lithium batteries, including carbon monoxide.

An Oct. 20, 2016 Elsevier Publishing press release (also on EurekAlert), which originated the news item, expands on the theme,

The gases are potentially fatal, they can cause strong irritations to the skin, eyes and nasal passages, and harm the wider environment. The researchers behind the study, from the Institute of NBC Defence and Tsinghua University in China, say many people may be unaware of the dangers of overheating, damaging or using a disreputable charger for their rechargeable devices.

In the new study, the researchers investigated a type of rechargeable battery, known as a “lithium-ion” battery, which is placed in two billion consumer devices every year.

“Nowadays, lithium-ion batteries are being actively promoted by many governments all over the world as a viable energy solution to power everything from electric vehicles to mobile devices. The lithium-ion battery is used by millions of families, so it is imperative that the general public understand the risks behind this energy source,” explained Dr. Jie Sun, lead author and professor at the Institute of NBC Defence.

The dangers of exploding batteries have led manufacturers to recall millions of devices: Dell recalled four million laptops in 2006 and millions of Samsung Galaxy Note 7 devices were recalled this month after reports of battery fires. But the threats posed by toxic gas emissions and the source of these emissions are not well understood.

Dr. Sun and her colleagues identified several factors that can cause an increase in the concentration of the toxic gases emitted. A fully charged battery will release more toxic gases than a battery with 50 percent charge, for example. The chemicals contained in the batteries and their capacity to release charge also affected the concentrations and types of toxic gases released.

Identifying the gases produced and the reasons for their emission gives manufacturers a better understanding of how to reduce toxic emissions and protect the wider public, as lithium-ion batteries are used in a wide range of environments.

“Such dangerous substances, in particular carbon monoxide, have the potential to cause serious harm within a short period of time if they leak inside a small, sealed environment, such as the interior of a car or an airplane compartment,” Dr. Sun said.

Almost 20,000 lithium-ion batteries were heated to the point of combustion in the study, causing most devices to explode and all to emit a range of toxic gases. Batteries can be exposed to such temperature extremes in the real world, for example, if the battery overheats or is damaged in some way.

The researchers now plan to develop this detection technique to improve the safety of lithium-ion batteries so they can be used to power the electric vehicles of the future safely.

“We hope this research will allow the lithium-ion battery industry and electric vehicle sector to continue to expand and develop with a greater understanding of the potential hazards and ways to combat these issues,” Sun concluded.

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

Toxicity, a serious concern of thermal runaway from commercial Li-ion battery by Jie Sun, Jigang Li, Tian Zhou, Kai Yang, Shouping Wei, Na Tang, Nannan Dang, Hong Li, Xinping Qiu, Liquan Chend. Nano Energy Volume 27, September 2016, Pages 313–319  http://dx.doi.org/10.1016/j.nanoen.2016.06.031

This paper appears to be open access.

Chalmers University gears up to offer Graphene Science and Technology, an online, international course

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They’ll be offering a MOOC, massive open online course, at Chalmers University of Technology, Sweden, on the topic of graphene starting March 23, 2015 according a Nov. 21, 2014 news item on Nanowerk,

Starting in 2015, Chalmers University of Technology in Sweden will be a global disseminator of knowledge. The beginning of the year will mark the start of ChalmersX – the venture of Chalmers moocs on the platform edx.org.

Chalmers announces its membership in edx at the ongoing conference Edx Global Forum in Boston. Edx is the platform where Chalmers’ moocs will be accessible. Universities such as MIT, Harvard, UC Berkeley, the University of Tokyo and many more offer their moocs on the same platform.

“This is a new and different way for us to take on the role of knowledge disseminator in our society“, says Maria Knutson Wedel, vice president for undergraduate and master’s education at Chalmers.

With a computer and an Internet connection, course participants all over the world can watch video lectures, take part in discussions, do assignments and take exams.

“Previously, we have primarily shared knowledge on a local and national level. The technology today enables global knowledge sharing – we can reach people who need the knowledge in question no matter where they are located in the world,“ says Maria Knutson Wedel.

A Nov. 21, 2014 Chalmers University press release on mydesk.com, which seems to have originated the news item, notes that the university is the consortium lead on the European Union’s Graphene Flagship project,

The first ChalmersX mooc will be an introduction to the super-material graphene: Introduction to Graphene Science and Technology. The subject is at the forefront of research, and EU’s biggest research initiative ever – Graphene Flagship – is based at Chalmers.

The course is led by graphene researcher Jie Sun. He took the initiative to the mooc as he saw the need of large-scale education about graphene.

“I hope to give the participants of the course basic knowledge of graphene. At the end of the course, an engineer should be able to determine if graphene is suitable for the company’s products, and a student should be able to decide if the subject is of interest for continued studies”, says Jie Sun.

Moocs are a growing trend in higher education. There is a great deal of interest in the courses – each one typically attracts tens of thousands of participants.

Maria Knutson Wedel believes that moocs can be very useful as supplementary or continuing professional development for people who are already part of working life. She does not believe that the courses can completely replace a traditional campus education, however. Campus education are closely connected and designed to correspond to the expectations from industry, for example. This type of education also results in a degree and a title, something which companies consider when hiring.

“However, this probably depends in part on traditional thinking on the part of the people who do the hiring at companies. In the future, we may reach a point that knowledge, regardless of how it has been obtained, becomes more important than certificates and grades,“ says Maria Knutson Wedel.

The ChalmersX moocs will be specially adapted to their context – the recordings will not consist of traditional 45-minute lectures. The teachers who have developed the course have carefully analysed the concepts they want participants to come away with after the course. The content is then boiled down to short video clips of 5-7 minutes each.

The next mooc in line after the course on graphene will be on sustainability in everyday life, starting in May 2015.

More about: Moocs

Moocs, an abbreviation of massive open online courses, are online courses aimed at unlimited participation and open access via the web. The term mooc was coined in 2008. As opposed to traditional distance learning, moocs do not have any prerequisites for admission. Exams are conducted by machine and there are platforms on which participants can get in contact with each other and discuss. The courses do not generate higher education credits, but the participants do receive a certificate for completing the course.

They do have a course prerequisite, from the Introduction to Graphene Science and Technology course,

In order to benefit fully from this course you should have an adequate knowledge of general physics and university level mathematics.

Here’s a video of Jie Sun talking about graphene and his course,

Enjoy the course!