Print 10 comment(s) - last by fildaben.. on May 20 at 8:29 PM

MIT researchers bring in some new armor to help defense in the war on harmful bacteria.

Medical equipment related bacterial infections are a problem in hospitals worldwide. An estimated 100,000 people die each year to hospital-acquired infections. Various methods of preventing bacterial growth on medical tools have definitely helped to combat the problem, but it remains an issue worthy of research. Researchers at MIT may bring to bear another weapon for the war on harmful bacteria in the form of polymer films that measure only a few tens of nanometers thick.

Previously, research into preventing bacterial growth on surfaces focused on variables like surface roughness, surface charge and attraction or repulsion to water. The stiffness of the surface was generally overlooked. The MIT team has found this to be in error, and their research shows that growth can be inhibited, or fostered, by altering the mechanical stiffness of the surface in question.

While the group suffers no delusions that their film can prevent growth from happening, the ultimate goal is to help prevent as much as possible. The polyelectrolyte films, when combined with other already practiced methods of growth inhibition -- like impregnating the surface of an instrument with nanoscale metal particles to disrupt bacterial cell walls, or even simple antibacterial chemicals -- could serve to dramatically reduce the amount of biofilm growth.

The researchers found that they could control the stiffness of their nanofilm by adding alternating layers at different levels of pH. A more neutral pH creates a stiffer layer when hydrated by a near-neutral substance, like water, because the polymer chains more easily crosslink and suffer less swelling. Adding layers at a lower, or more acidic, pH creates a more compliant surface.

The group has already tested their films with three different strains of bacteria; two types of Escherichia coli, as well as the common Staphylococcus epidermidis. The experiments showed the same trend of growth inhibition based on surface stiffness. The trend may be explained by the relationship between pili, tiny projections from bacterial cell walls, and the stiffness of the surface they come into contact with. The pili may be encouraged to form more stable bonds to a stiffer surface.

The films could be used on just about any sort of medical device that comes in contact with the body, including implants like stents and pacemakers. Limiting the amount of bacteria that may find a home on such devices before they are inserted will help the immune system deal with infection by limiting the number of insurgents it needs to gun down.

On the flip side, the film could also be engineered to foster bacterial growth, aiding in applications that require such things, like medical testing and the production of the now famous or infamous alternative fuel ethanol.

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Utterly ridiculous
By chrisld on 5/20/2008 10:04:15 AM , Rating: 2
As an experienced scientist this seems like rubbish to me. You vary the pH to change the stiffness and see that bacteria growth is affected. Then you attribute that to the stiffness change when it is far, far more likely due to the change in pH. Everyone knows that pH affects growth.

I think I will publish work where I add more and more lead and copper flakes to a polymer film to increase its stiffness and then claim that the lack of bacterial growth is due to the stiffness.

Laughable except for that fact that MIT is associated with it so people may believe this stuff. I have not read the original work though so perhaps some crucial detail was lost in translation.

RE: Utterly ridiculous
By ralith on 5/20/2008 10:19:15 AM , Rating: 3
You definately should've reread the article and read the original article before posting. The varying of the PH only applies to the process used in the creation of the film they didn't try to grow the bacteria in those solutions.

RE: Utterly ridiculous
By oTAL on 5/20/2008 10:47:42 AM , Rating: 4
As an experienced scientist this seems like rubbish to me.
I have not read the original work though so perhaps some crucial detail was lost in translation.

How about you start behaving like an experienced scientist and get your facts before drawing conclusions? You have the right to your opinion, but you shouldn't write aggressive posts ("rubish") minimizing someone else's work just because the article simplifies the experience a bit (as it should - we don't want to be bored with every single detail).

RE: Utterly ridiculous
By chrisld on 5/20/2008 10:52:52 AM , Rating: 2
If you deposit a film at a certain pH where do you think those protons go? They are still in the film to affect the bacteria. As soon as a water containing bacterium is there then the acidity can be releases.

On top of that I find it hard to swallow that the hardness has an affect. Afterall we know that bacteria grow just fine on surfaces of just about any hardness from ceramic all the way down to wood and so on.

RE: Utterly ridiculous
By masher2 on 5/20/2008 11:18:03 AM , Rating: 2
> "Afterall we know that bacteria grow just fine on surfaces of just about any hardness from ceramic all the way down to wood and so on. "

Stiffness is not the same as hardness. And the research isn't measuring inhibition of growth per se, but how well bacteria can cling to that particular surface.

RE: Utterly ridiculous
By chrisld on 5/20/2008 4:04:29 PM , Rating: 2
You may be right but I am tired of reading thousands of nanotubes will save the world articles and other silly claims. I want to see some credible work with actual potential not a load of posturing and hype.

RE: Utterly ridiculous
By etriky on 5/20/2008 1:10:57 PM , Rating: 2
With an attitude like that, why bother thinking? You obviously know it all already. Gee.

RE: Utterly ridiculous
By chrisld on 5/20/2008 1:21:41 PM , Rating: 2
I am very accepting of new ideas but I'm not gullible enough to believe every bit of nonsense that gets published. We'll wait and see whether this gets commercialized. There are way better and cheaper ways of doing the same thing even if this did prove true.

I think that scientists have a duty not to hype up things that make no sense and mislead the public. This does only harm in the long-term as credibility is lost.

RE: Utterly ridiculous
By fildaben on 5/20/2008 8:29:23 PM , Rating: 2
really, what credibility do you have? stating your an experienced scientist, then go off and misquoting the article does not lend much credibility it seems..

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