It has long been known that asbestos spells a problem for human cells. Scientists have been stabbed with spiked cells, the long fibers of asbestos, and the image is Gore: A portion of the fiber protruding from the cell, shaking like a white arrow.
But the researchers were able to understand why cells would be interested in asbestos fibers and other materials at the nanoscale that are too long to be completely consumed. Now a group of researchers at Brown University, explains what is happening. Through molecular simulations and experiments, the team reports in Nature Nanotechnology that some nanomaterials such as carbon nanotubes enter cells advanced first, and almost always on a 90 degree angle. The briefing ends deceive the cell, taking the rounded end first, the error of the cell to the particle a sphere instead of a long cylinder. At that time, the cell sees the material is too long to be completely consumed, it is too late.
"It's like we're eating a candy longer than us," said Huajian Gao, a professor of engineering at Brown University and lead author of the article. "It would be caught."
The study is important because of nanomaterials such as carbon nanotubes have promise in medicine, such as operating vehicles to transport drugs to specific cells or specific points of the human body. If researchers are able to fully understand how nanomaterials interact with cells, so that they can be to design products that help the cells, rather than hurt them.
"If we can understand (the cells of nanomaterials dynamic), we can make other tubes that can control how cells interact with non-toxic nanomaterials," said Gao. "We want to eventually halt the attraction nanotip and between cells."
As asbestos fibers, carbon nanotubes are commercially available and gold nanowires have rounded tips, which often range from 10 to 100 nanometers in diameter. Size is important in this case, the diameter is within the parameters of the cell so it can handle. Brushing against the nanotubes, special proteins called receptors on the cells spring into action, consolidation, and the curvature of the wall of the cell membrane to wrap around the tip of the nanotubes in a sequence that the authors call "The recognition technology." Anyway, the nanotube is tilted at an angle of 90 degrees, which reduces the amount of energy needed for the cell to engulf the particle.
When the swallows - endocytosis - beginner, there is no return. A few minutes later, the direction of cell can not fully engulf nanostructure and demand mainly 911th "At this stage it is too late," said Gao. "He is in trouble and asks for help, which triggers an immune response that can cause inflammation repeated."
The team hypothesized interaction with a coarse-grained molecular simulation and capped multiwalled carbon nanotubes. Experiments using nanotubes and nanowires of gold, and liver cells in mice and human mesothelial cells, nanomaterials, the cells became the top-first, and 90 degrees, about 90 percent of the time, the researchers report.
"We think that the tube was going to bed in the cell membrane in order to obtain more binding sites. However, the simulations showed the constant pivoting at a high level of entry, with the tip is completely surrounded," said Shi Xinghua, the first author on the paper he received his Ph.D. from Brown and the China Academy of Sciences in Beijing. "It's counterintuitive and is mainly due to the release of energy from the bending of the membrane surrounding the tube."
The staff wants to study whether nanotubes without rounded - and less stiff materials such as nano-nanoribbons - cells represent a similar dilemma.
"It is interesting to note that if the rounded tip of a carbon nanotube is broken (ie the tube is open and quarries), the tube is located in the cell membrane, the cell would give a high degree," said Shi.
Agnes Kane, professor of pathology and laboratory medicine, Brown, is the corresponding author on the paper. Other authors are Annette von dem Bussche Department of Pathology and Laboratory Medicine Brown and Robert Hurt, Institute of Molecular Medicine and Nanoscale Innovation Brown.
The National Science Foundation, the US Department of Commerce National Institute of Standards and Technology, National Institute of Environmental Health Sciences Superfund Research Program and the American Recovery and Reinvestment Act funded the research.
Why Carbon Nanotubes Spell Trouble For Cells
