Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Jagged graphene can slice into cell membranes

11.07.2013
A collaboration of biologists, engineers, and material scientists at Brown University has found that jagged edges of graphene can easily pierce cell membranes, allowing graphene to enter the cell and disrupt normal function.

Understanding the mechanical forces of nanotoxicity should help engineers design safer materials at the nanoscale.


Rough edges at the nanoscale
The bottom corner of a piece of graphene penetrates a cell membrane. Mechanical properties — rough edges, sharp corners — can make graphene dangerous to human cells. Scale bar represents two microns. Credit: Kane lab/Brown University

Researchers from Brown University have shown how tiny graphene microsheets — ultra-thin materials with a number of commercial applications — could be big trouble for human cells.

The research shows that sharp corners and jagged protrusions along the edges of graphene sheets can easily pierce cell membranes. After the membrane is pierced, an entire graphene sheet can be pulled inside the cell where it may disrupt normal function. The new insight may be helpful in finding ways to minimize the potential toxicity of graphene, said Agnes Kane, chair of the Department of Pathology and Laboratory Medicine at Brown and one of the study’s authors.

“At a fundamental level, we want understand the features of these materials that are responsible for how they interact with cells,” Kane said. “If there’s some feature that is responsible for its toxicity, then maybe the engineers can engineer it out.”

The findings were published online July 9 in Proceedings of the National Academy of Sciences.

Discovered about a decade ago, graphene is a sheet of carbon just one atom thick. It is incredibly strong despite being so thin and has remarkable electronic, mechanical, and photonic properties. Commercial applications in small electronic devices, solar cells, batteries and even medical devices are just around the corner. But not much is known about what effect these materials might have if they get inside the body either during the manufacturing process or during a product’s lifecycle.

“These materials can be inhaled unintentionally, or they may be intentionally injected or implanted as components of new biomedical technologies,” said Robert Hurt, professor of engineering and one of the study’s authors. “So we want to understand how they interact with cells once inside the body.”

These latest findings come from an ongoing collaboration between biologists, engineers, and material scientists at Brown aimed at understanding the toxic potential of a wide variety of nanomaterials. Their work on graphene started with some seemingly contradictory findings.

Preliminary research by Kane’s biology group had shown that graphene sheets can indeed enter cells, but it wasn’t clear how they got there. Huajian Gao, professor of engineering, tried to explain those results using powerful computer simulations, but he ran into a problem. His models, which simulate interactions between graphene and cell membranes at the molecular level, suggested that it would be quite rare for a microsheet to pierce a cell. The energy barrier required for a sheet to cut the membrane was simply too high, even when the sheet hit edge first.

The problem turned out to be that those initial simulations assumed a perfectly square piece of graphene. In reality, graphene sheets are rarely so pristine. When graphene is exfoliated, or peeled away from thicker chunks of graphite, the sheets come off in oddly shaped flakes with jagged protrusions called asperities. When Gao reran his simulations with asperities included, the sheets were able to pierce the membrane much more easily.

Annette von dem Bussche, assistant professor of pathology and laboratory medicine, was able to verify the model experimentally. She placed human lung, skin and immune cells in Petri dishes along with graphene microsheets. Electron microscope images confirmed that graphene entered the cells starting at rough edges and corners. The experiments showed that even fairly large graphene sheets of up to 10 micrometers could be completely internalized by a cell.

“The engineers and the material scientists can analyze and describe these materials in great detail,” Kane said. “That allows us to better interpret the biological impacts of these materials. It’s really a wonderful collaboration.”

From here, the researchers will look in more detail into what happens once a graphene sheet gets inside the cell. But Kane says this initial study provides an important start in understanding the potential for graphene toxicity.

“This is about the safe design of nanomaterials,” she said. “They’re man-made materials, so we should be able to be clever and make them safer.”

Other contributors to the study were Brown graduate students Yinfeng Li (now a professor at Shanghai Jiao Tong University), Hongyan Yuan, and Megan Creighton. The research was supported by the National Science Foundation (grants CMMI-1028530 and CBET-1132446) and the Superfund Research Program of the National Institute of Environmental Health Sciences (grant P42 ES013660).

Editors: Brown University has a fiber link television studio available for domestic and international live and taped interviews, and maintains an ISDN line for radio interviews. For more information, call (401) 863-2476.

Kevin Stacey | EurekAlert!
Further information:
http://www.brown.edu

More articles from Physics and Astronomy:

nachricht Smooth propagation of spin waves using gold
26.06.2017 | Toyohashi University of Technology

nachricht A 100-year-old physics problem has been solved at EPFL
23.06.2017 | Ecole Polytechnique Fédérale de Lausanne

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>