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A story from scienceblog.com looks at a novel treatment and prevention of tooth decay:
The bacteria that live in dental plaque and contribute to tooth decay often resist traditional antimicrobial treatment, as they can "hide" within a sticky biofilm matrix, a glue-like polymer scaffold.
A new strategy conceived by University of Pennsylvania researchers took a more sophisticated approach. Instead of simply applying an antibiotic to the teeth, they took advantage of the pH-sensitive and enzyme-like properties of iron-containing nanoparticles to catalyze the activity of hydrogen peroxide, a commonly used natural antiseptic. The activated hydrogen peroxide produced free radicals that were able to simultaneously degrade the biofilm matrix and kill the bacteria within, significantly reducing plaque and preventing the tooth decay, or cavities, in an animal model.
"Even using a very low concentration of hydrogen peroxide, the process was incredibly effective at disrupting the biofilm," said Hyun (Michel) Koo, a professor in the Penn School of Dental Medicine's Department of Orthodontics and divisions of Pediatric Dentistry and Community Oral Health and the senior author of the study, which was published in the journal Biomaterials [DOI: 10.1016/j.biomaterials.2016.05.051]. "Adding nanoparticles increased the efficiency of bacterial killing more than 5,000-fold."
The paper's lead author was Lizeng Gao, a postdoctoral researcher in Koo's lab. Coauthors were Yuan Liu, Dongyeop Kim, Yong Li and Geelsu Hwang, all of Koo's lab, as well as David Cormode, an assistant professor of radiology and bioengineering with appointments in Penn's Perelman School of Medicine and School of Engineering and Applied Science, and Pratap C. Naha, a postdoctoral fellow in Cormode's lab.
The work built off a seminal finding by Gao and colleagues, published in 2007 in Nature Nanotechnology [DOI: 10.1038/nnano.2007.260], showing that nanoparticles, long believed to be biologically and chemically inert, could in fact possess enzyme-like properties. In that study, Gao showed that an iron oxide nanoparticle behaved similarly to a peroxidase, an enzyme found naturally that catalyzes oxidative reactions, often using hydrogen peroxide.
(Score: 3, Insightful) by jdavidb on Thursday July 28 2016, @01:08PM
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(Score: 5, Informative) by Hyperturtle on Thursday July 28 2016, @01:23PM
This isn't quite the same.
With microbeads, they replaced the silica (sand, essentially, to act as grit for the face) with plastic. Plastic that doesn't break down and clogs municpal water filters and lasts forever.
This is discussing incorporating something of significantly less permanence--iron oxide is rust and using it as an additive will probably react to water similarly to how it already does.
The real issue to me is that a lot of these nano particles are not really well behaved inside the body -- generally, anti-oxidants are used to help prevent age related declines and various body tissue repair needs.
Hydrogen peroxide was already used for tooth bleaching; they must have noticed it killed lots of stuff at the same time. Bleaching of teeth (to whiten them) can cause premature aging of the gums and other areas of the mouth, but few are concerned about this; the mouth heals quickly. I am not aware of any long term studies of the results.
There are, however, studies about what nano particles in the body can do. Not all such nano particles are inherently bad... but usually rust in the body is a problem, and they are suggesting applying it directly inside the mouth.
I would be more concerned about the long term effects of this than I would of your microbead concern. This will break down in the environment--and possibly break down in the body and damage parts of it at the same time. It's killing bacteria and likely doing collateral damage in the neighboring cells.
Previous teeth bleaching/whitening efforts did not use nano particles, and the hydrogen peroxide and other chemicals are at least blocked by the brain/blood barrier, for the most part. Nanoparticles are much smaller and probably are going to get through -- and cause oxidative stresses inside the brain, which would likely be unaccustomed to such visitors.
(Score: 2) by takyon on Thursday July 28 2016, @01:32PM
If they're 1/1000th the size, they'll do 1/1000th the damage!!!
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(Score: 2) by Bobs on Thursday July 28 2016, @01:42PM
So now we're going to fill our toothpaste with even smaller microbeads (nanoparticles). What could possibly go wrong?
If they're 1/1000th the size, they'll do 1/1000th the damage!!!
And since they are so much smaller they will get into / affect 1,000^1,000 more things.
I'm really curious about the short and longer term impacts of putting this stuff into a living organism (like me!).