Tag Archives: Maurizio Prato

Neuronal regenerative-interfaces made of cross-linked carbon nanotube films

If I understand this research rightly, they are creating a film made of carbon nanotubes that can stimulate the growth of nerve cells (neurons) thus creating a ‘living/nonliving’ hybrid or as they call it in the press release a ‘biosynthetic hybrid’.

An August 2, 2019 news item on Nanowerk introduces the research (Note 1: There seem to be some translation issues; Note 2: Links have been removed),

Carbon nanotubes able to take on the desired shapes thanks to a special chemical treatment, called crosslinking and, at the same time, able to function as substrata for the growth of nerve cells, finely tuning their growth and activity.

The research published in ACS Nano (“Chemically Cross-Linked Carbon Nanotube Films Engineered to Control Neuronal Signaling”), is a new and important step towards the construction of neuronal regenerative-interfaces to repair spinal injuries.

The study is the new achievement of a long-term and, in terms of results, successful collaboration between the scientists Laura Ballerini of SISSA (Scuola Internazionale Superiore di Studi Avanzati), Trieste, and Maurizio Prato of the University of Trieste. The work team has also been assisted by CIC biomaGUNE of San Sebastián, Spain.

Caption: Carbon nanotubes able to take on the desired shapes thanks to a special chemical treatment, called crosslinking and, at the same time, able to function as substrata for the growth of nerve cells, finely tuning their growth and activity. Credit: Rossana Rauti

An August 2, 2019 SISSA press release (also on EurekAlert), which originated the news item, adds detail,

The carbon nanotubes used in the research have been modified by appropriate chemical treatments: “For many years, in our laboratories we have been working on the chemical reactivity of carbon nanotubes, a fascinating but very difficult material to work. Thanks to our experience, we have crosslinked them or, to say it more clearly, we have treated the nanotubes so they could link themselves to one another thanks to specific chemical reactions. We have discovered that this procedure gives the material very interesting characteristics. For example, the material organises itself in a stable manner according to a precise shape, we choose: a tissue where nerve cells need to be planted, for example. Or around some electrodes” explains Professor Prato. “We know from previous research that nerve cells grow well on carbon nanotubes so they could be used as a surface to build hybrid devices to regenerate nerve tissues. It was necessary to ensure that this chemical modification did not compromise this process and study whether the interaction with neurons was altered”.

Towards biosynthetic hybrids

Professor Ballerini continues: “We have discovered that the chemical process has important effects because through this treatment we can modulate the activity of neurons, in terms of growth, adhesion and survival. These materials can also regulate the communication between neurons. We can say that the carpet of crosslinked carbon nanotubes interacts intensely and constructively with the nerve cells”. This interaction depends on how much the different carbon nanotubes are linked to each other, or rather crosslinked. The lower the link number among the nanotubes the higher the activity of neurons that grow on their surface. Through the chemical control of their properties, and of the links between them, it is possible to regulate the response of the neurons. Ballerini and Prato explain: “This is an intriguing result that emerges from the important and fruitful collaboration between our research groups involving advanced research in chemistry, nanoscience and neurobiology . This study provides a further step in the design of future biosynthetic hybrids to recover injured nerve tissues functions”.

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

Chemically Cross-Linked Carbon Nanotube Films Engineered to Control Neuronal Signaling by Myriam Barrejón, Rossana Rauti, Laura Ballerini, Maurizio Prato. ACS Nano2019 XXXXXXXXXX-XXX Publication Date:July 22, 2019 DOI: https://doi.org/10.1021/acsnano.9b02429 Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Human lung enzyme can degrade graphene

Caption: A human lung enzyme can biodegrade graphene. Credit: Fotolia Courtesy: Graphene Flagship

The big European Commission research programme, Grahene Flagship, has announced some new work with widespread implications if graphene is to be used in biomedical implants. From a August 23, 2018 news item on ScienceDaily,

Myeloperoxidase — an enzyme naturally found in our lungs — can biodegrade pristine graphene, according to the latest discovery of Graphene Flagship partners in CNRS, University of Strasbourg (France), Karolinska Institute (Sweden) and University of Castilla-La Mancha (Spain). Among other projects, the Graphene Flagship designs based like flexible biomedical electronic devices that will interfaced with the human body. Such applications require graphene to be biodegradable, so our body can be expelled from the body.

An August 23, 2018 Grapehene Flagship press release (mildly edited version on EurekAlert), which originated the news item, provides more detail,

To test how graphene behaves within the body, researchers analysed how it was broken down with the addition of a common human enzyme – myeloperoxidase or MPO. If a foreign body or bacteria is detected, neutrophils surround it and secrete MPO, thereby destroying the threat. Previous work by Graphene Flagship partners found that MPO could successfully biodegrade graphene oxide.

However, the structure of non-functionalized graphene was thought to be more resistant to degradation. To test this, the team looked at the effects of MPO ex vivo on two graphene forms; single- and few-layer.

Alberto Bianco, researcher at Graphene Flagship Partner CNRS, explains: “We used two forms of graphene, single- and few-layer, prepared by two different methods in water. They were then taken and put in contact with myeloperoxidase in the presence of hydrogen peroxide. This peroxidase was able to degrade and oxidise them. This was really unexpected, because we thought that non-functionalized graphene was more resistant than graphene oxide.”

Rajendra Kurapati, first author on the study and researcher at Graphene Flagship Partner CNRS, remarks how “the results emphasize that highly dispersible graphene could be degraded in the body by the action of neutrophils. This would open the new avenue for developing graphene-based materials.”

With successful ex-vivo testing, in-vivo testing is the next stage. Bengt Fadeel, professor at Graphene Flagship Partner Karolinska Institute believes that “understanding whether graphene is biodegradable or not is important for biomedical and other applications of this material. The fact that cells of the immune system are capable of handling graphene is very promising.”

Prof. Maurizio Prato, the Graphene Flagship leader for its Health and Environment Work Package said that “the enzymatic degradation of graphene is a very important topic, because in principle, graphene dispersed in the atmosphere could produce some harm. Instead, if there are microorganisms able to degrade graphene and related materials, the persistence of these materials in our environment will be strongly decreased. These types of studies are needed.” “What is also needed is to investigate the nature of degradation products,” adds Prato. “Once graphene is digested by enzymes, it could produce harmful derivatives. We need to know the structure of these derivatives and study their impact on health and environment,” he concludes.

Prof. Andrea C. Ferrari, Science and Technology Officer of the Graphene Flagship, and chair of its management panel added: “The report of a successful avenue for graphene biodegradation is a very important step forward to ensure the safe use of this material in applications. The Graphene Flagship has put the investigation of the health and environment effects of graphene at the centre of its programme since the start. These results strengthen our innovation and technology roadmap.”

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

Degradation of Single‐Layer and Few‐Layer Graphene by Neutrophil Myeloperoxidase by Dr. Rajendra Kurapati, Dr. Sourav P. Mukherjee, Dr. Cristina Martín, Dr. George Bepete, Prof. Ester Vázquez, Dr. Alain Pénicaud, Prof. Dr. Bengt Fadeel, Dr. Alberto Bianco. Angewandte Chemie https://doi.org/10.1002/anie.201806906 First published: 13 July 2018

This paper is behind a paywall.

Neurons and graphene carpets

I don’t entirely grasp the carpet analogy. Actually, I have no why they used a carpet analogy but here’s the June 12, 2018 ScienceDaily news item about the research,

A work led by SISSA [Scuola Internazionale Superiore di Studi Avanzati] and published on Nature Nanotechnology reports for the first time experimentally the phenomenon of ion ‘trapping’ by graphene carpets and its effect on the communication between neurons. The researchers have observed an increase in the activity of nerve cells grown on a single layer of graphene. Combining theoretical and experimental approaches they have shown that the phenomenon is due to the ability of the material to ‘trap’ several ions present in the surrounding environment on its surface, modulating its composition. Graphene is the thinnest bi-dimensional material available today, characterised by incredible properties of conductivity, flexibility and transparency. Although there are great expectations for its applications in the biomedical field, only very few works have analysed its interactions with neuronal tissue.

A June 12, 2018 SISSA press release (also on EurekAlert), which originated the news item, provides more detail,

A study conducted by SISSA – Scuola Internazionale Superiore di Studi Avanzati, in association with the University of Antwerp (Belgium), the University of Trieste and the Institute of Science and Technology of Barcelona (Spain), has analysed the behaviour of neurons grown on a single layer of graphene, observing a strengthening in their activity. Through theoretical and experimental approaches the researchers have shown that such behaviour is due to reduced ion mobility, in particular of potassium, to the neuron-graphene interface. This phenomenon is commonly called ‘ion trapping’, already known at theoretical level, but observed experimentally for the first time only now. “It is as if graphene behaves as an ultra-thin magnet on whose surface some of the potassium ions present in the extra cellular solution between the cells and the graphene remain trapped. It is this small variation that determines the increase in neuronal excitability” comments Denis Scaini, researcher at SISSA who has led the research alongside Laura Ballerini.

The study has also shown that this strengthening occurs when the graphene itself is supported by an insulator, like glass, or suspended in solution, while it disappears when lying on a conductor. “Graphene is a highly conductive material which could potentially be used to coat any surface. Understanding how its behaviour varies according to the substratum on which it is laid is essential for its future applications, above all in the neurological field” continues Scaini, “considering the unique properties of graphene it is natural to think for example about the development of innovative electrodes of cerebral stimulation or visual devices”.

It is a study with a double outcome. Laura Ballerini comments as follows: “This ‘ion trap’ effect was described only in theory. Studying the impact of the ‘technology of materials’ on biological systems, we have documented a mechanism to regulate membrane excitability, but at the same time we have also experimentally described a property of the material through the biology of neurons.”

Dexter Johnson in a June 13, 2018 posting, on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website), provides more context for the work (Note: Links have been removed),

While graphene has been tapped to deliver on everything from electronics to optoelectronics, it’s a bit harder to picture how it may offer a key tool for addressing neurological damage and disorders. But that’s exactly what researchers have been looking at lately because of the wonder material’s conductivity and transparency.

In the most recent development, a team from Europe has offered a deeper understanding of how graphene can be combined with neurological tissue and, in so doing, may have not only given us an additional tool for neurological medicine, but also provided a tool for gaining insights into other biological processes.

“The results demonstrate that, depending on how the interface with [single-layer graphene] is engineered, the material may tune neuronal activities by altering the ion mobility, in particular potassium, at the cell/substrate interface,” said Laura Ballerini, a researcher in neurons and nanomaterials at SISSA.

Ballerini provided some context for this most recent development by explaining that graphene-based nanomaterials have come to represent potential tools in neurology and neurosurgery.

“These materials are increasingly engineered as components of a variety of applications such as biosensors, interfaces, or drug-delivery platforms,” said Ballerini. “In particular, in neural electrode or interfaces, a precise requirement is the stable device/neuronal electrical coupling, which requires governing the interactions between the electrode surface and the cell membrane.”

This neuro-electrode hybrid is at the core of numerous studies, she explained, and graphene, thanks to its electrical properties, transparency, and flexibility represents an ideal material candidate.

In all of this work, the real challenge has been to investigate the ability of a single atomic layer to tune neuronal excitability and to demonstrate unequivocally that graphene selectively modifies membrane-associated neuronal functions.

I encourage you to read Dexter’s posting as it clarifies the work described in the SISSA press release for those of us (me) who may fail to grasp the implications.

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

Single-layer graphene modulates neuronal communication and augments membrane ion currents by Niccolò Paolo Pampaloni, Martin Lottner, Michele Giugliano, Alessia Matruglio, Francesco D’Amico, Maurizio Prato, Josè Antonio Garrido, Laura Ballerini, & Denis Scaini. Nature Nanotechnology (2018) DOI: https://doi.org/10.1038/s41565-018-0163-6 Published online June 13, 2018

This paper is behind a paywall.

All this brings to mind a prediction made about the Graphene Flagship and the Human Brain Project shortly after the European Commission announced in January 2013 that each project had won funding of 1B Euros to be paid out over a period of 10 years. The prediction was that scientists would work on graphene/human brain research.

Carbon nanotubes to repair nerve fibres (cyborg brains?)

Can cyborg brains be far behind now that researchers are looking at ways to repair nerve fibers with carbon nanotubes (CNTs)? A June 26, 2017 news item on ScienceDaily describes the scheme using carbon nanotubes as a material for repairing nerve fibers,

Carbon nanotubes exhibit interesting characteristics rendering them particularly suited to the construction of special hybrid devices — consisting of biological issue and synthetic material — planned to re-establish connections between nerve cells, for instance at spinal level, lost on account of lesions or trauma. This is the result of a piece of research published on the scientific journal Nanomedicine: Nanotechnology, Biology, and Medicine conducted by a multi-disciplinary team comprising SISSA (International School for Advanced Studies), the University of Trieste, ELETTRA Sincrotrone and two Spanish institutions, Basque Foundation for Science and CIC BiomaGUNE. More specifically, researchers have investigated the possible effects on neurons of the interaction with carbon nanotubes. Scientists have proven that these nanomaterials may regulate the formation of synapses, specialized structures through which the nerve cells communicate, and modulate biological mechanisms, such as the growth of neurons, as part of a self-regulating process. This result, which shows the extent to which the integration between nerve cells and these synthetic structures is stable and efficient, highlights the great potentialities of carbon nanotubes as innovative materials capable of facilitating neuronal regeneration or in order to create a kind of artificial bridge between groups of neurons whose connection has been interrupted. In vivo testing has actually already begun.

The researchers have included a gorgeous image to illustrate their work,

Caption: Scientists have proven that these nanomaterials may regulate the formation of synapses, specialized structures through which the nerve cells communicate, and modulate biological mechanisms, such as the growth of neurons, as part of a self-regulating process. Credit: Pixabay

A June 26, 2017 SISSA press release (also on EurekAlert), which originated the news item, describes the work in more detail while explaining future research needs,

“Interface systems, or, more in general, neuronal prostheses, that enable an effective re-establishment of these connections are under active investigation” explain Laura Ballerini (SISSA) and Maurizio Prato (UniTS-CIC BiomaGUNE), coordinating the research project. “The perfect material to build these neural interfaces does not exist, yet the carbon nanotubes we are working on have already proved to have great potentialities. After all, nanomaterials currently represent our best hope for developing innovative strategies in the treatment of spinal cord injuries”. These nanomaterials are used both as scaffolds, a supportive framework for nerve cells, and as means of interfaces releasing those signals that empower nerve cells to communicate with each other.

Many aspects, however, still need to be addressed. Among them, the impact on neuronal physiology of the integration of these nanometric structures with the cell membrane. “Studying the interaction between these two elements is crucial, as it might also lead to some undesired effects, which we ought to exclude”. Laura Ballerini explains: “If, for example, the mere contact provoked a vertiginous rise in the number of synapses, these materials would be essentially unusable”. “This”, Maurizio Prato adds, “is precisely what we have investigated in this study where we used pure carbon nanotubes”.

The results of the research are extremely encouraging: “First of all we have proved that nanotubes do not interfere with the composition of lipids, of cholesterol in particular, which make up the cellular membrane in neurons. Membrane lipids play a very important role in the transmission of signals through the synapses. Nanotubes do not seem to influence this process, which is very important”.

There is more, however. The research has also highlighted the fact that the nerve cells growing on the substratum of nanotubes, thanks to this interaction, develop and reach maturity very quickly, eventually reaching a condition of biological homeostasis. “Nanotubes facilitate the full growth of neurons and the formation of new synapses. This growth, however, is not indiscriminate and unlimited since, as we proved, after a few weeks a physiological balance is attained. Having established the fact that this interaction is stable and efficient is an aspect of fundamental importance”. Maurizio Prato and Laura Ballerini conclude as follows: “We are proving that carbon nanotubes perform excellently in terms of duration, adaptability and mechanical compatibility with the tissue. Now we know that their interaction with the biological material, too, is efficient. Based on this evidence, we are already studying the in vivo application, and preliminary results appear to be quite promising also in terms of recovery of the lost neurological functions”.

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

Sculpting neurotransmission during synaptic development by 2D nanostructured interfaces by Niccolò Paolo Pampaloni, Denis Scaini, Fabio Perissinotto, Susanna Bosi, Maurizio Prato, Laura Ballerini. Nanomedicine: Nanotechnology, Biology and Medicine, DOI: http://dx.doi.org/10.1016/j.nano.2017.01.020 Published online: May 25, 2017

This paper is open access.

A carbon nanotube ‘bridge’ for nerves

Italian researchers have developed a three-dimensional carbon nanotube sponge (or bridge) that could be used in conjunction with neural explants according to a July 15, 2016 SISSA press release (also on EurekAlert), which describes the work,

A complex study, lasting several years and involving work groups with specialties in various fields, has shown that a new material (a three-dimensional sponge made of carbon nanotubes) supports the growth of nerve fibers, bridging segregated neural explants and providing a functional re-connection. The study, which was coordinated by the International School for Advanced Studies (SISSA) in Trieste, in collaboration with the University of Rome Tor Vergata and the University of Trieste, also observed biocompatibility in vivo of the material, demonstrating that implanting it into  the brain of small rodents does not cause large scars or a marked immune response.

“Under the microscope, it looks like a knotted tangle of tubes. It was initially studied by Maurizio De Crescenzi’s team at the University of Rome Tor Vergata for cleaning up spilled hydrocarbons in the sea,” explains Laura Ballerini, SISSA Professor and coordinator of the recently-published study. It was Maurizio Prato’s intuition, however, that pushed them to investigate the possibility of applying such a material to nerve tissue. The idea of developing the hybrids of neurons and nano-materials was the result of a long-term project and collaboration between Prato (University of Trieste) and Ballerini’s (SISSA) groups.

In the present study, Ballerini and her team first investigated the material’s reaction to nerve tissue in vitro. “We explanted two spinal cord segments and cultured them together but separated by 300 microns,” says Sadaf Usmani, a PhD student at the School and first author of the study. “In those conditions, without any scaffolds reconstructing the space between the two explants, we observed growth of nerve fibers which extended in a straight bundles in any direction, but not necessarily towards the other tissue. If we insert a small piece of the carbon sponge into the space between the two, however, we see dense growth of nerve fibers that fill the structure and intertwine with the other sample.”

“Observing fiber reaching the contralateral explant is not enough, however,” points out University of Trieste researcher and one of the authors of the study, Denis Scaini. “You have to show that there is a functional connection between the two populations of neurons.” For this, SISSA Professor, David Zoccolan and his team’s contribution was crucial. “With signal analysis techniques they had already developed, we were able to demonstrate two things: first, that spontaneous nervous activity in the two samples was actually correlated, indicating a connection, that was not there when the sponge was absent, and second,, that by applying an electrical signal to one of the samples, the activity of the second sample could be triggered, but only when the nanotubes were present.”

Tests for Biocompatibility

The results in the lab were extremely positive. But this was not sufficient for Ballerini and her colleagues. “In order to continue to invest additional energy and resources to the study for potential applications, is crucial to test if the material is accepted by living organisms without negative consequences,” says Ballerini.

To perform these tests, Ballerini’s team worked closely with SISSA Post-Doc researcher, and member of Zoccolan’s team, Federica Rosselli. “We implanted small portions of the material into the brain of healthy rodents. After four weeks, we observed that the material was well tolerated. There were limited scars, as well as low immune responses, some biological indicators even showed that there could be positive implications. There was also a progressive invasion of neurons within the sponge. The rats were vital and healthy during the entire four weeks,” says Usmani.

“In conclusion,” says Ballerini, “the excellent results at the structural and functional level in vitro and in vivo showed biocompatibility are encouraging us to continue this line of research. These materials could be useful for covering electrodes used for treating movement disorders like Parkinson’s because they are well accepted by tissue, while the implants being used today become less effective over time because of scar tissue. We hope this encourages other research teams with multidisciplinary expertise to expand this type of study even further.”

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

3D meshes of carbon nanotubes guide functional reconnection of segregated spinal explants by Sadaf Usmani, Emily Rose Aurand, Manuela Medelin, Alessandra Fabbro, Denis Scaini, Jummi Laishram, Federica B. Rosselli, Alessio Ansuini, Davide Zoccola1, Manuela Scarselli, Maurizio De Crescenzi, Susanna Bosi, Maurizio Prato, and Laura Ballerini. Science Advances  15 Jul 2016: Vol. 2, no. 7, e1600087 DOI: 10.1126/sciadv.1600087 Published 01 July 2016

This paper is open access.

H/t July 15, 2016 news item on phys.org.

Calming a synapse (part of a neuron) with graphene flakes

As we continue to colonize our own brains, there’s more news of graphene and neurons (see my Feb. 1, 2016 post featuring research from the same team in Italy featured in this post). A May 10, 2016 news item on ScienceDaily highlights work that could be used for epilepsy,

Innovative graphene technology to buffer the activity of synapses– this is the idea behind a recently-published study in the journal ACS Nano coordinated by the International School for Advanced Studies in Trieste (SISSA) and the University of Trieste. In particular, the study showed how effective graphene oxide flakes are at interfering with excitatory synapses, an effect that could prove useful in new treatments for diseases like epilepsy.

I guess the press release took a while to make its way through translation, here’s more from the April 10, 2016 SISSA (International School for Advanced Studies) press release (also on EurekAlert),

The laboratory of SISSA’s Laura Ballerini in collaboration with the University of Trieste, the University of Manchester and the University of Castilla -la Mancha, has discovered a new approach to modulating synapses. This methodology could be useful for treating diseases in which electrical nerve activity is altered. Ballerini and Maurizio Prato (University of Trieste) are the principal investigators of the project within the European flagship on graphene, a far-reaching 10-year international collaboration (one billion euros in funding) that studies innovative uses of the material.

Traditional treatments for neurological diseases generally include drugs that act on the brain or neurosurgery. Today however, graphene technology is showing promise for these types of applications, and is receiving increased attention from the scientific community. The method studied by Ballerini and colleagues uses “graphene nano-ribbons” (flakes) which buffer activity of synapses simply by being present.

“We administered aqueous solutions of graphene flakes to cultured neurons in ‘chronic’ exposure conditions, repeating the operation every day for a week. Analyzing functional neuronal electrical activity, we then traced the effect on synapses” says Rossana Rauti, SISSA researcher and first author of the study.

In the experiments, size of the flakes varied (10 microns or 80 nanometers) as well as the type of graphene: in one condition graphene was used, in another, graphene oxide. “The ‘buffering’ effect on synaptic activity happens only with smaller flakes of graphene oxide and not in other conditions,” says Ballerini. “The effect, in the system we tested, is selective for the excitatory synapses, while it is absent in inhibitory ones”

A Matter of Size

What is the origin of this selectivity? “We know that in principle graphene does not interact chemically with synapses in a significant way- its effect is likely due to the mere presence of synapses,” explains SISSA researcher and one of the study’s authors, Denis Scaini. “We do not yet have direct evidence, but our hypothesis is that there is a link with the sub-cellular organization of the synaptic space.”

A synapse is a contact point between one neuron and another where the nervous electrical signal “jumps” between a pre and post-synaptic unit. [emphasis mine] There is a small gap or discontinuity where the electrical signal is “translated” by a neurotransmitter and released by pre-synaptic termination into the extracellular space and reabsorbed by the postsynaptic space, to be translated again into an electrical signal. The access to this space varies depending on the type of synapses: “For the excitatory synapses, the structure’s organization allows higher exposure for the graphene flakes interaction, unlike inhibitory synapses, which are less physically accessible in this experimental model,” says Scaini.

Another clue that distance and size could be crucial in the process is found in the observation that graphene performs its function only in the oxidized form. “Normal graphene looks like a stretched and stiff sheet while graphene oxide appears crumpled, and thus possibly favoring interface with the synaptic space, ” adds Rauti.

Administering graphene flake solutions leaves the neurons alive and intact. For this reason the team thinks they could be used in biomedical applications for treating certain diseases. “We may imagine to target a drug by exploiting the apparent flakes’ selectivity for synapses, thus targeting directly the basic functional unit of neurons”concludes Ballerini.

That’s a nice description of neurons, synapses, and neurotransmitters.

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

Graphene Oxide Nanosheets Reshape Synaptic Function in Cultured Brain Networks by Rossana Rauti, Neus Lozano, Veronica León, Denis Scaini†, Mattia Musto, Ilaria Rago, Francesco P. Ulloa Severino, Alessandra Fabbro, Loredana Casalis, Ester Vázquez, Kostas Kostarelos, Maurizio Prato, and Laura Ballerini. ACS Nano, 2016, 10 (4), pp 4459–4471
DOI: 10.1021/acsnano.6b00130 Publication Date (Web): March 31, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Graphene and neurons in a UK-Italy-Spain collaboration

There’s been a lot of talk about using graphene-based implants in the brain due to the material’s flexibility along with its other properties. A step forward has been taking according to a Jan. 29, 2016 news item on phys.org,

Researchers have successfully demonstrated how it is possible to interface graphene – a two-dimensional form of carbon – with neurons, or nerve cells, while maintaining the integrity of these vital cells. The work may be used to build graphene-based electrodes that can safely be implanted in the brain, offering promise for the restoration of sensory functions for amputee or paralysed patients, or for individuals with motor disorders such as epilepsy or Parkinson’s disease.

A Jan. 29, 2016 Cambridge University press release (also on EurekAlert), which originated the news item, provides more detail,

Previously, other groups had shown that it is possible to use treated graphene to interact with neurons. However the signal to noise ratio from this interface was very low. By developing methods of working with untreated graphene, the researchers retained the material’s electrical conductivity, making it a significantly better electrode.

“For the first time we interfaced graphene to neurons directly,” said Professor Laura Ballerini of the University of Trieste in Italy. “We then tested the ability of neurons to generate electrical signals known to represent brain activities, and found that the neurons retained their neuronal signalling properties unaltered. This is the first functional study of neuronal synaptic activity using uncoated graphene based materials.”

Our understanding of the brain has increased to such a degree that by interfacing directly between the brain and the outside world we can now harness and control some of its functions. For instance, by measuring the brain’s electrical impulses, sensory functions can be recovered. This can be used to control robotic arms for amputee patients or any number of basic processes for paralysed patients – from speech to movement of objects in the world around them. Alternatively, by interfering with these electrical impulses, motor disorders (such as epilepsy or Parkinson’s) can start to be controlled.

Scientists have made this possible by developing electrodes that can be placed deep within the brain. These electrodes connect directly to neurons and transmit their electrical signals away from the body, allowing their meaning to be decoded.

However, the interface between neurons and electrodes has often been problematic: not only do the electrodes need to be highly sensitive to electrical impulses, but they need to be stable in the body without altering the tissue they measure.

Too often the modern electrodes used for this interface (based on tungsten or silicon) suffer from partial or complete loss of signal over time. This is often caused by the formation of scar tissue from the electrode insertion, which prevents the electrode from moving with the natural movements of the brain due to its rigid nature.

Graphene has been shown to be a promising material to solve these problems, because of its excellent conductivity, flexibility, biocompatibility and stability within the body.

Based on experiments conducted in rat brain cell cultures, the researchers found that untreated graphene electrodes interfaced well with neurons. By studying the neurons with electron microscopy and immunofluorescence the researchers found that they remained healthy, transmitting normal electric impulses and, importantly, none of the adverse reactions which lead to the damaging scar tissue were seen.

According to the researchers, this is the first step towards using pristine graphene-based materials as an electrode for a neuro-interface. In future, the researchers will investigate how different forms of graphene, from multiple layers to monolayers, are able to affect neurons, and whether tuning the material properties of graphene might alter the synapses and neuronal excitability in new and unique ways. “Hopefully this will pave the way for better deep brain implants to both harness and control the brain, with higher sensitivity and fewer unwanted side effects,” said Ballerini.

“We are currently involved in frontline research in graphene technology towards biomedical applications,” said Professor Maurizio Prato from the University of Trieste. “In this scenario, the development and translation in neurology of graphene-based high-performance biodevices requires the exploration of the interactions between graphene nano- and micro-sheets with the sophisticated signalling machinery of nerve cells. Our work is only a first step in that direction.”

“These initial results show how we are just at the tip of the iceberg when it comes to the potential of graphene and related materials in bio-applications and medicine,” said Professor Andrea Ferrari, Director of the Cambridge Graphene Centre. “The expertise developed at the Cambridge Graphene Centre allows us to produce large quantities of pristine material in solution, and this study proves the compatibility of our process with neuro-interfaces.”

The research was funded by the Graphene Flagship [emphasis mine],  a European initiative which promotes a collaborative approach to research with an aim of helping to translate graphene out of the academic laboratory, through local industry and into society.

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

Graphene-Based Interfaces Do Not Alter Target Nerve Cells by Alessandra Fabbro, Denis Scaini, Verónica León, Ester Vázquez, Giada Cellot, Giulia Privitera, Lucia Lombardi, Felice Torrisi, Flavia Tomarchio, Francesco Bonaccorso, Susanna Bosi, Andrea C. Ferrari, Laura Ballerini, and Maurizio Prato. ACS Nano, 2016, 10 (1), pp 615–623 DOI: 10.1021/acsnano.5b05647 Publication Date (Web): December 23, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

There are a couple things I found a bit odd about this project. First, all of the funding is from the Graphene Flagship initiative. I was expecting to see at least some funding from the European Union’s other mega-sized science initiative, the Human Brain Project. Second, there was no mention of Spain nor were there any quotes from the Spanish researchers. For the record, the Spanish institutions represented were: University of Castilla-La Mancha, Carbon Nanobiotechnology Laboratory, and the Basque Foundation for Science.

A 2nd European roadmap for graphene

About 2.5 years ago there was an article titled, “A roadmap for graphene” (behind a paywall) which Nature magazine published online in Oct. 2012. I see at least two of the 2012 authors, Konstantin (Kostya) Novoselov and Vladimir Fal’ko,, are party to this second, more comprehensive roadmap featured in a Feb. 24, 2015 news item on Nanowerk,

In October 2013, academia and industry came together to form the Graphene Flagship. Now with 142 partners in 23 countries, and a growing number of associate members, the Graphene Flagship was established following a call from the European Commission to address big science and technology challenges of the day through long-term, multidisciplinary R&D efforts.

A Feb.  24, 2015 University of Cambridge news release, which originated the news item, describes the roadmap in more detail,

In an open-access paper published in the Royal Society of Chemistry journal Nanoscale, more than 60 academics and industrialists lay out a science and technology roadmap for graphene, related two-dimensional crystals, other 2D materials, and hybrid systems based on a combination of different 2D crystals and other nanomaterials. The roadmap covers the next ten years and beyond, and its objective is to guide the research community and industry toward the development of products based on graphene and related materials.

The roadmap highlights three broad areas of activity. The first task is to identify new layered materials, assess their potential, and develop reliable, reproducible and safe means of producing them on an industrial scale. Identification of new device concepts enabled by 2D materials is also called for, along with the development of component technologies. The ultimate goal is to integrate components and structures based on 2D materials into systems capable of providing new functionalities and application areas.

Eleven science and technology themes are identified in the roadmap. These are: fundamental science, health and environment, production, electronic devices, spintronics, photonics and optoelectronics, sensors, flexible electronics, energy conversion and storage, composite materials, and biomedical devices. The roadmap addresses each of these areas in turn, with timelines.

Research areas outlined in the roadmap correspond broadly with current flagship work packages, with the addition of a work package devoted to the growing area of biomedical applications, to be included in the next phase of the flagship. A recent independent assessment has confirmed that the Graphene Flagship is firmly on course, with hundreds of research papers, numerous patents and marketable products to its name.

Roadmap timelines predict that, before the end of the ten-year period of the flagship, products will be close to market in the areas of flexible electronics, composites, and energy, as well as advanced prototypes of silicon-integrated photonic devices, sensors, high-speed electronics, and biomedical devices.

“This publication concludes a four-year effort to collect and coordinate state-of-the-art science and technology of graphene and related materials,” says Andrea Ferrari, director of the Cambridge Graphene Centre, and chairman of the Executive Board of the Graphene Flagship. “We hope that this open-access roadmap will serve as the starting point for academia and industry in their efforts to take layered materials and composites from laboratory to market.” Ferrari led the roadmap effort with Italian Institute of Technology physicist Francesco Bonaccorso, who is a Royal Society Newton Fellow of the University of Cambridge, and a Fellow of Hughes Hall.

“We are very proud of the joint effort of the many authors who have produced this roadmap,” says Jari Kinaret, director of the Graphene Flagship. “The roadmap forms a solid foundation for the graphene community in Europe to plan its activities for the coming years. It is not a static document, but will evolve to reflect progress in the field, and new applications identified and pursued by industry.”

I have skimmed through the report briefly (wish I had more time) and have a couple of comments. First, there’s an excellent glossary of terms for anyone who might stumble over chemical abbreviations and/or more technical terminology. Second, they present a very interesting analysis of the intellectual property (patents) landscape (Note: Links have been removed. Incidental numbers are footnote references),

In the graphene area, there has been a particularly rapid increase in patent activity from around 2007.45 Much of this is driven by patent applications made by major corporations and universities in South Korea and USA.53 Additionally, a high level of graphene patent activity in China is also observed.54 These features have led some commentators to conclude that graphene innovations arising in Europe are being mainly exploited elsewhere.55 Nonetheless, an analysis of the Intellectual Property (IP) provides evidence that Europe already has a significant foothold in the graphene patent landscape and significant opportunities to secure future value. As the underlying graphene technology space develops, and the GRM [graphene and related materials] patent landscape matures, re-distribution of the patent landscape seems inevitable and Europe is well positioned to benefit from patent-based commercialisation of GRM research.

Overall, the graphene patent landscape is growing rapidly and already resembles that of sub-segments of the semiconductor and biotechnology industries,56 which experience high levels of patent activity. The patent strategies of the businesses active in such sub-sectors frequently include ‘portfolio maximization’56 and ‘portfolio optimization’56 strategies, and the sub-sectors experience the development of what commentators term ‘patent thickets’56, or multiple overlapping granted patent rights.56 A range of policies, regulatory and business strategies have been developed to limit such patent practices.57 In such circumstances, accurate patent landscaping may provide critical information to policy-makers, investors and individual industry participants, underpinning the development of sound policies, business strategies and research commercialisation plans.

It sounds like a patent thicket is developing (Note: Links have been removed. Incidental numbers are footnote references),,

Fig. 13 provides evidence of a relative increase in graphene patent filings in South Korea from 2007 to 2009 compared to 2004–2006. This could indicate increased commercial interest in graphene technology from around 2007. The period 2010 to 2012 shows a marked relative increase in graphene patent filings in China. It should be noted that a general increase in Chinese patent filings across many ST domains in this period is observed.76 Notwithstanding this general increase in Chinese patent activity, there does appear to be increased commercial interest in graphene in China. It is notable that the European Patent Office contribution as a percentage of all graphene patent filings globally falls from a 8% in the period 2007 to 2009 to 4% in the period 2010 to 2012.

The importance of the US, China and South Korea is emphasised by the top assignees, shown in Fig. 14. The corporation with most graphene patent applications is the Korean multinational Samsung, with over three times as many filings as its nearest rival. It has also patented an unrivalled range of graphene-technology applications, including synthesis procedures,77 transparent display devices,78 composite materials,79 transistors,80 batteries and solar cells.81 Samsung’s patent applications indicate a sustained and heavy investment in graphene R&D, as well as collaboration (co-assignment of patents) with a wide range of academic institutions.82,83

 

image file: c4nr01600a-f14.tif
Fig. 14 Top 10 graphene patent assignees by number and cumulative over all time as of end-July 2014. Number of patents are indicated in the red histograms referred to the left Y axis, while the cumulative percentage is the blue line, referred to the right Y axis.

It is also interesting to note that patent filings by universities and research institutions make up a significant proportion ([similar]50%) of total patent filings: the other half comprises contributions from small and medium-sized enterprises (SMEs) and multinationals.

Europe’s position is shown in Fig. 10, 12 and 14. While Europe makes a good showing in the geographical distribution of publications, it lags behind in patent applications, with only 7% of patent filings as compared to 30% in the US, 25% in China, and 13% in South Korea (Fig. 13) and only 9% of filings by academic institutions assigned in Europe (Fig. 15).

 

image file: c4nr01600a-f15.tif
Fig. 15 Geographical breakdown of academic patent holders as of July 2014.

While Europe is trailing other regions in terms of number of patent filings, it nevertheless has a significant foothold in the patent landscape. Currently, the top European patent holder is Finland’s Nokia, primarily around incorporation of graphene into electrical devices, including resonators and electrodes.72,84,85

This may sound like Europe is trailing behind but that’s not the case according to the roadmap (Note: Links have been removed. Incidental numbers are footnote references),

European Universities also show promise in the graphene patent landscape. We also find evidence of corporate-academic collaborations in Europe, including e.g. co-assignments filed with European research institutions and Germany’s AMO GmbH,86 and chemical giant BASF.87,88 Finally, Europe sees significant patent filings from a number of international corporate and university players including Samsung,77 Vorbeck Materials,89 Princeton University,90–92 and Rice University,93–95 perhaps reflecting the quality of the European ST base around graphene, and its importance as a market for graphene technologies.

There are a number of features in the graphene patent landscape which may lead to a risk of patent thickets96 or ‘multiple overlapping granted patents’ existing around aspects of graphene technology systems. [emphasis mine] There is a relatively high volume of patent activity around graphene, which is an early stage technology space, with applications in patent intensive industry sectors. Often patents claim carbon nano structures other than graphene in graphene patent landscapes, illustrating difficulties around defining ‘graphene’ and mapping the graphene patent landscape. Additionally, the graphene patent nomenclature is not entirely settled. Different patent examiners might grant patents over the same components which the different experts and industry players call by different names.

For anyone new to this blog, I am not a big fan of current patent regimes as they seem to be stifling rather encouraging innovation. Sadly, patents and copyright were originally developed to encourage creativity and innovation by allowing the creators to profit from their ideas. Over time a system designed to encourage innovation has devolved into one that does the opposite. (My Oct. 31, 2011 post titled Patents as weapons and obstacles, details my take on this matter.) I’m not arguing against patents and copyright but suggesting that the system be fixed or replaced with something that delivers on the original intention.

Getting back to the matter at hand, here’s a link to and a citation for the 200 pp. 2015 European Graphene roadmap,

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems by Andrea C. Ferrari, Francesco Bonaccorso, Vladimir Fal’ko, Konstantin S. Novoselov, Stephan Roche, Peter Bøggild, Stefano Borini, Frank H. L. Koppens, Vincenzo Palermo, Nicola Pugno, José A. Garrido, Roman Sordan, Alberto Bianco, Laura Ballerini, Maurizio Prato, Elefterios Lidorikis, Jani Kivioja, Claudio Marinelli, Tapani Ryhänen, Alberto Morpurgo, Jonathan N. Coleman, Valeria Nicolosi, Luigi Colombo, Albert Fert, Mar Garcia-Hernandez, Adrian Bachtold, Grégory F. Schneider, Francisco Guinea, Cees Dekker, Matteo Barbone, Zhipei Sun, Costas Galiotis,  Alexander N. Grigorenko, Gerasimos Konstantatos, Andras Kis, Mikhail Katsnelson, Lieven Vandersypen, Annick Loiseau, Vittorio Morandi, Daniel Neumaier, Emanuele Treossi, Vittorio Pellegrini, Marco Polini, Alessandro Tredicucci, Gareth M. Williams, Byung Hee Hong, Jong-Hyun Ahn, Jong Min Kim, Herbert Zirath, Bart J. van Wees, Herre van der Zant, Luigi Occhipinti, Andrea Di Matteo, Ian A. Kinloch, Thomas Seyller, Etienne Quesnel, Xinliang Feng,  Ken Teo, Nalin Rupesinghe, Pertti Hakonen, Simon R. T. Neil, Quentin Tannock, Tomas Löfwander and Jari Kinaret. Nanoscale, 2015, Advance Article DOI: 10.1039/C4NR01600A First published online 22 Sep 2014

Here’s a diagram illustrating the roadmap process,

Fig. 122 The STRs [science and technology roadmaps] follow a hierarchical structure where the strategic level in a) is connected to the more detailed roadmap shown in b). These general roadmaps are the condensed form of the topical roadmaps presented in the previous sections, and give technological targets for key applications to become commercially competitive and the forecasts for when the targets are predicted to be met.  Courtesy: Researchers and  the Royal Society's journal, Nanoscale

Fig. 122 The STRs [science and technology roadmaps] follow a hierarchical structure where the strategic level in a) is connected to the more detailed roadmap shown in b). These general roadmaps are the condensed form of the topical roadmaps presented in the previous sections, and give technological targets for key applications to become commercially competitive and the forecasts for when the targets are predicted to be met.
Courtesy: Researchers and the Royal Society’s journal, Nanoscale

The image here is not the best quality; the one embedded in the relevant Nanowerk news item is better.

As for the earlier roadmap, here’s my Oct. 11, 2012 post on the topic.

The yin and the yang of carbon nanotubes and toxicity

 

Illustration courtesy of the University College of London (UCL). Downloaded from http://www.ucl.ac.uk/news/news-articles/0113/130115-chemistry-resolves-toxic-concerns-about-carbon-nanotubes

Illustration courtesy of the University College of London (UCL). Downloaded from http://www.ucl.ac.uk/news/news-articles/0113/130115-chemistry-resolves-toxic-concerns-about-carbon-nanotubes

Researchers at the University College of London (UCL), France’s Centre national de la recherche scientifique (CNRS), and Italy’s University of Trieste have determined that carbon nanotube toxicity issues can be addressed be reducing their length and treating them chemically. From the Jan. 15,2013 news item on ScienceDaily,

In a new study, published January 15 [2013] in the journal Angewandte Chemie, evidence is provided that the asbestos-like reactivity and pathogenicity reported for long, pristine nanotubes can be completely alleviated if their surface is modified and their effective length is reduced as a result of chemical treatment.

First atomically described in the 1990s, carbon nanotubes are sheets of carbon atoms rolled up into hollow tubes just a few nanometres in diameter. Engineered carbon nanotubes can be chemically modified, with the addition of chemotherapeutic drugs, fluorescent tags or nucleic acids — opening up applications in cancer and gene therapy.

Furthermore, these chemically modified carbon nanotubes can pierce the cell membrane, acting as a kind of ‘nano-needle’, allowing the possibility of efficient transport of therapeutic and diagnostic agents directly into the cytoplasm of cells.

Among their downsides however, have been concerns about their safety profile. One of the most serious concerns, highlighted in 2008, involves the carcinogenic risk from the exposure and persistence of such fibres in the body. Some studies indicate that when long untreated carbon nanotubes are injected to the abdominal cavity of mice they can induce unwanted responses resembling those associated with exposure to certain asbestos fibres.

In this paper, the authors describe two different reactions which ask if any chemical modification can render the nanotubes non-toxic. They conclude that not all chemical treatments alleviate the toxicity risks associated with the material. Only those reactions that are able to render carbon nanotubes short and stably suspended in biological fluids without aggregation are able to result in safe, risk-free material.

Here’s a citation and link for this latest  research, from the ScienceDaily news item where you can also read the lead researcher’s comments about carbon nanotubes, safety, and unreasonable proposals to halt production,

Hanene Ali-Boucetta, Antonio Nunes, Raquel Sainz, M. Antonia Herrero, Bowen Tian, Maurizio Prato, Alberto Bianco, Kostas Kostarelos. Asbestos-like Pathogenicity of Long Carbon Nanotubes Alleviated by Chemical Functionalization. Angewandte Chemie International Edition, 2013; DOI: 10.1002/anie.201207664

The article is behind a paywall. I have mentioned long carbon nanotubes and their resemblance to asbestos fibres in several posts. The  Oct. 26, 2009 posting [scroll down about 1/3 of the way] highlights research which took place after the study where mice had carbon nanotubes injected into their bellies; in this second piece of research they inhaled the nanotubes.

ETA Jan. 21, 2013: Dexter Johnson gives context and commentary about this latest research into long multiwalled nanotubes (MWNTs) which he sums up as the answer to this question “What if you kept the MWNTs short?”  in a Jan. 18, 2013 posting on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website)