Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Implant bacteria, beware: Researchers create nano-sized assassins

30.06.2009
Staphylococcus epidermidis is quite an opportunist. Commonly found on human skin, the bacteria pose little danger. But S. epidermidis is a leading cause of infections in hospitals. From catheters to prosthetics, the bacteria are known to hitch a ride on a range of medical devices implanted into patients.

Inside the body, the bacteria multiply on the implant's surface and then build a slimy, protective film to shield the colony from antibiotics. According to a study in the journal Clinical Infectious Diseases, up to 2.5 percent of hip and knee implants alone in the United States become infected, affecting thousands of patients, sometimes fatally.

More ominously, there is no effective antidote for infected implants. The only way to get rid of the bacteria is to remove the implant. "There is no [easy] solution," said Thomas Webster, a biomedical engineer at Brown University.

Now, Webster and Brown graduate student Erik Taylor have created a nano-sized headhunter that zeroes in on the implant, penetrates S. epidermidis's defensive wall and kills the bacteria. The finding, published in the International Journal of Nanomedicine, is the first time iron-oxide nanoparticles have been shown to eliminate a bacterial infection on an implanted prosthetic device.

In lab tests, Taylor, the lead author, and Webster, associate professor of engineering and orthopaedics, noted that up to 28 percent of the bacteria on an implant had been eliminated after 48 hours by injecting 10 micrograms of the nanoparticle agents. The same dosage repeated three times over six days destroyed essentially all the bacteria, the experiments showed.

The tests show "there will be a continual killing of the bacteria until the film is gone," said Webster, who is editor-in-chief of the peer-reviewed journal in which the paper appears.

A surprising added benefit, the scientists learned, is the nanoparticles' magnetic properties appear to promote natural bone cell growth on the implant's surface, although this observation needs to be tested further.

To carry out the study, the researchers created iron-oxide particles (they call them "superparamagnetic") with an average diameter of eight nanometers. They chose iron oxide because the metallic properties mean the particles can be guided by a magnetic field to the implant, while its journey can be tracked using a simple magnetic technique, such as magnetic resonance imaging (MRI). Moreover, previous experiments showed that iron seemed to cause S. epidermidis to die, although researchers are unsure why. (Webster said it may be due to iron overload in the bacteria's cell.)

Once the nanoparticles arrive at the implant, they begin to penetrate the bacterial shield. The researchers are studying why this happens, but they believe it's due to magnetic horsepower. In the tests, the researchers positioned a magnet below the implant, producing a strong enough field to force the nanoparticles above to filter through the film and proceed to the implant, Webster explained.

The particles then penetrate the bacterial cells because of their super-small size. A micron-sized particle, a thousand times larger than a nanoparticle, would be too large to penetrate the bacterial cell wall.

The researchers plan to test the iron-oxide nanoparticles on other bacteria and then move on to evaluating the results on implants in animals. The research was funded by the private Hermann Foundation Inc. In addition, Taylor's tuition and stipend are funded through the National Science Foundation GK-12 program.

Richard Lewis | EurekAlert!
Further information:
http://www.Brown.edu

More articles from Health and Medicine:

nachricht Nanoparticles as a Solution against Antibiotic Resistance?
15.12.2017 | Friedrich-Schiller-Universität Jena

nachricht Plasmonic biosensors enable development of new easy-to-use health tests
14.12.2017 | Aalto University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>