Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Selenium controls staph on implant material

Selenium solution	Qi Wang swirls a solution of selenium nanoparticles in the lab. Coatings of the nanoparticles appear effective in fighting staph bacteria in medical device materials, according to a new study.	Credit: Webster Lab/Brown University
Selenium solution Qi Wang swirls a solution of selenium nanoparticles in the lab. Coatings of the nanoparticles appear effective in fighting staph bacteria in medical device materials, according to a new study.

Credit: Webster Lab/Brown University

Abstract:
A coating of selenium nanoparticles significantly reduces the growth of Staphylococcus aureus on polycarbonate, a material common in implanted devices such as catheters and endotracheal tubes, engineers at Brown University report in a new study.

Selenium controls staph on implant material

Providence, RI | Posted on June 21st, 2012

Selenium is an inexpensive element that naturally belongs in the body. It is also known to combat bacteria. Still, it had not been tried as an antibiotic coating on a medical device material. In a new study, Brown University engineers report that when they used selenium nanoparticles to coat polycarbonate, the material of catheters and endotracheal tubes, the results were significant reductions in cultured populations of Staphylococcus aureus bacteria, sometimes by as much as 90 percent.

"We want to keep the bacteria from generating a biofilm," said Thomas Webster, professor of engineering and orthopaedics, who studies how nanotechnology can improve medical implants. He is the senior author of the paper, published online this week in the Journal of Biomedical Materials Research A.

Biofilms are notoriously tough colonies of bacteria to treat because they are often able to resist antibiotic drugs.

"The longer we can delay or inhibit completely the formation of these colonies, the more likely your immune system will clear them," Webster said. "Putting selenium on there could buy more time to keep an endotracheal tube in a patient."

Meanwhile, Webster said, because selenium is actually a recommended nutrient, it should be harmless in the body at the concentrations found in the coatings. Also, it is much less expensive than silver, a less biocompatible material that is the current state of the art for antibacterial medical device coatings.

Webster has been investigating selenium nanoparticles for years, mostly for their possible anticancer effects. As he began to look at their antibiotic properties, he consulted with Hasbro Children's Hospital pediatrician Keiko Tarquinio, assistant professor of pediatrics, who has been eager to find ways to reduce biofilms on implants.

Studying selenium

For this study, Webster and first author Qi Wang grew selenium nanoparticles of two different size ranges and then used solutions of them to coat pieces of polycarbonate using a quick, simple process. On some of the polycarbonate, they then applied and ripped off tape not only to test the durability of the coatings but also to see how a degraded concentration of selenium would perform against bacteria.

On coated polycarbonate both the originally coated and the tape-tested pieces Wang and Webster used electron and atomic force microscopes to measure the concentration of nanoparticles and how much surface area of selenium was exposed to interact with bacteria.

One of their findings was that after the tape test, smaller nanoparticles adhered better to the polycarbonate than larger ones.

Then they were ready for the key step: experiments that exposed cultured staph bacteria to polycarbonate pieces, some of which were left uncoated as controls. Among the coated pieces, some had the larger nanoparticles and some had the smaller ones. Some from each of those groups had been degraded by the tape, and others had not.

All four types of selenium coatings proved effective in reducing staph populations after 24, 48, and 72 hours compared to the uncoated controls. The most potent effects reductions larger than 90 percent after 24 hours and as much as 85 percent after 72 hours came from coatings of either particle size range that had not been degraded by the tape. Among those coatings that had been subjected to the tape test, the smaller nanoparticle coatings proved more effective.

Staph populations exposed to any of the coated polycarbonate pieces peaked at the 48-hour timeframe, perhaps because that is when the bacteria could take fullest advantage of the in vitro culture medium. But levels always fell back dramatically by 72 hours.

The next step, Webster said, is to begin testing in animals. Such in vivo experiments, he said, will test the selenium coatings in a context where the bacteria have more available food but will also face an immune system response.

The results may ultimately have commercial relevance. Former graduate students developed a business plan for the selenium nanoparticle coatings while in school and have since licensed the technology from Brown for their company, Axena Technologies.

The Hermann Foundation funded the research.

####

For more information, please click here

Contacts:
David Orenstein
401-863-1862

Copyright © Brown University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Quantum memory with record-breaking capacity based on laser-cooled atoms December 15th, 2017

Record high photoconductivity for new metal-organic framework material December 15th, 2017

Error-free into the quantum computer age December 15th, 2017

Leti Will Demonstrate First 3D Anti-Crash Solution for Embedding in Drones: Fitted on a Mass-Market Microcontroller, 360Fusion Software Technology Detects any Dynamic Obstacle and Helps Guide Drones Away from Collisions December 15th, 2017

Nanomedicine

Synthetic protein packages its own genetic material and evolves computationally designed protein assemblies are advancing research in synthetic life and in targeted drug delivery December 15th, 2017

Perking up and crimping the 'bristles' of polyelectrolyte brushes December 13th, 2017

Leti to Demo Wristband with Embedded Sensors to Diagnose Sleep Apnea: APNEAband, Which Will Be Demonstrated at CES 2018, Also Monitors Mountain Sickness, Dehydration, Dialysis Treatment Response and Epileptic Seizures December 12th, 2017

Untangling DNA: Researchers filter the entropy out of nanopore measurements December 8th, 2017

Discoveries

Quantum memory with record-breaking capacity based on laser-cooled atoms December 15th, 2017

Record high photoconductivity for new metal-organic framework material December 15th, 2017

Error-free into the quantum computer age December 15th, 2017

Synthetic protein packages its own genetic material and evolves computationally designed protein assemblies are advancing research in synthetic life and in targeted drug delivery December 15th, 2017

Announcements

Quantum memory with record-breaking capacity based on laser-cooled atoms December 15th, 2017

Record high photoconductivity for new metal-organic framework material December 15th, 2017

Error-free into the quantum computer age December 15th, 2017

Leti Will Demonstrate First 3D Anti-Crash Solution for Embedding in Drones: Fitted on a Mass-Market Microcontroller, 360Fusion Software Technology Detects any Dynamic Obstacle and Helps Guide Drones Away from Collisions December 15th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project