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 nan toxicity should help engineers design safer materials at the nan scale.
PROVIDENCE, R.I. [Brown University] — Researchers from Brown University have shown how tiny graphene micro sheets — 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 nanomaterial’s. 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 micro sheet 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.