Posted on 07/10/2013 11:21:04 PM PDT by neverdem
Scientists in the US and China have revealed that graphene kills bacteria by slicing through their membranes and yanking out their phospholipids. They say graphene could become a new type of ‘green’ antimicrobial material for everyday use, applied directly to wounds.
Modelling and transmission electron microscopy showed that . It cut through the membranes and extracted large amounts of phospholipids from cell membranes because of strong dispersion interactions between graphene and lipid molecules.
Graphene kills bacteria by slicing through their membranes and yanking out their phospholipids
‘Once extracted, the strong hydrophobic interactions between graphene and phospholipids – as they are pushed together by water – also play a significant role,’ Ruhong Zhou from IBM research explains. The findings might have implications in the design of novel antibiotics and other chemical applications, according to the researchers.
‘The easiest and most straightforward way is to use graphene or graphene oxide in a band-aid. So you combine graphene and graphene oxide nanosheets with cotton fabric and apply to wounds along with bandages,’ Zhou says. Graphene oxide nanosheets were used because they have better solubility in water than pristine graphene.
The authors argue that graphene offers the advantage of little bacterial resistance developing due to its physical damage-based bacterial mechanism. The group now plans to study graphene’s killing potential in other bacteria and to study potential side effects to human cell membranes.
It is indisputable that graphene is toxic to E. coli, but there have not been plausible explanations for its mechanism, says materials engineer Miriam Rafailovich of Stony Brook University, New York. She had heard that graphene has unusual conductivity properties or a high degree of crystalline order in two dimensions but none of these reasons satisfied her as to its observed toxicity. ‘This paper gives a very good insight into what may be the problem. The simulations are spectacular and should definitely be verified experimentally,’ she says.
Bart Hoogenboom of the London Centre for Nanotechnology adds that he thinks the work is interesting from a mechanistic point of view, but ‘with the weakness that it heavily relies on computational work on idealised model membranes, at a much shorter time scale – nanoseconds – than the experiments on the bacteria – 2.5 hours of incubation – the membranes of which also contain large amounts of proteins that may affect the way extraneous particles interfere with the membrane.’
‘As far as potential antibiotic design is concerned, it is slightly worrying that the mechanism appears to be rather independent of membrane composition, and can therefore also be toxic for healthy, non-bacterial cells in a host organism such as a human being,’ says Hoogenboom. ‘Such toxicity will be dependent on dose and on particle size,’ so it’s important not to infer that exposure to graphene is toxic per se, he adds.
Graphene is less of a threat to humans or other mammals because nanosheets become surrounded by serum proteins, says Liu Zengrong of the Institute of Systems Biology in Shanghai, though he acknowledges that nanomaterial toxicity is of ‘great concern’ and will require further study.
Rafailovich says that the findings could now be verified independently of the E. coli organism. What would make their case very persuasive is if direct experiments on phospholipid membranes and vesicles were performed in contact with graphene, she explains: ‘Then their simulations and the time dependence could be imaged and verified.’
J Tu Yusong et al., Nature Nanotechnology, 2013, DOI: 10.1038/nnano.2013.125
Is this how Cyborgs, and then ‘Borgs, began?
Pandora’s box being opened once again...Monsanto was first with gmo.
And what, pray tell, is graphene?
Ping....
ADHD Drugs Don't Boost Kids' Grades
Italian stem-cell trial based on flawed data
FReepmail me if you want on or off my health and science ping list.
As I read this I thought about human cell toxicity. If that can be managed or is very slight then this would be a great breakthrough. Cost is an issue.
Graphene is graphite - which is actually composed of single-atom-thick planes of carbon atoms in a planar lattice arrangement. An individual plane of graphite, called graphene, can be separated from a piece of graphite by simply putting Scotch tape on graphite and then pulling the tape off. The gray that can be seen sticking to the transparent tape will be one, or a few, layers of graphene. Graphene has interesting properties and is thought to be a candidate for microelectronic application. You should definitely do a search on the term and learn more.
As I read this I thought about human cell toxicity. If that can be managed or is very slight then this would be a great breakthrough.
The toxic mechanism is purely mechanical, it slices through the cell wall (membrane) and extracts phospholipids killing the cell. The effect is the same with human cells, but we have so many that the graphene ends up surrounded with serum and unable to touch more cells.
It's not something you would want to ingest or inject. Surface use on wounds and non-living surface sterilization appear to be the best use.
I had a girl friend once who yanked out my phospholipids; it can be exceedingly painful.
Agreed and I saw that, too. I was thinking of more serious trauma or battlefield injuries and the risk of introducing it into the bloodstream v. preventing bacterial infection.
So from now on I can just rub a pencil on it?
bttt
I've heard that Eaker threatens to do that to folks who cross him.
You win one internet for the best answer to a question.
You provided sufficient information to answer the question.
You provided accurate information.
You provided readily understandable information.
You encouraged further study.
Are you perchance a teacher?
Typically only on Thursdays.
You encouraged further study . . . You win one internet for the best answer to a question.
Thanks. In my mind neverdem’s simple link to Wikipedia (see #8) was very possibly more excellent.Are you perchance a teacher?
Although both my parents taught, one as a lifetime career and the other not, and three of my grandparents were teachers, my brother and I were both engineers. Tho my brother has done volunteer tutoring for a coworker taking college courses and for a child who wasn’t getting what the “math” book - he said there the book was so pathetic that there wasn’t actually any actual math in it - should have been teaching. I confess that this isn’t actually the first time someone has asked me the question, tho. and if you saw the FReepmail note I dropped to AnalogReigns about his screen name, I suppose that you would really think I was a pedant - if not pedantic.
Engineer was my second guess...
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.