Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Empa researchers «design» therapeutic coatings of silver

05.07.2010
Empa researchers have demonstrated how they can adjust process conditions to influence the properties of novel plasma polymer coatings containing silver nanoparticles. Tailor-made films can be generated through a one-step plasma process.
The scientists developed these new coatings, which kill bacteria while having no negative effect on human tissue, in the frame of an EU project.

Silver ions are very efficient at killing bacteria, and in contrast to antibiotic drugs they are effective against hundreds of different bacterial strains thanks to different attacking mechanisms.

This makes silver ideal as an antibacterial additive for, e.g., implants and wound dressings. The idea that “a little is good, more is better” cannot be adopted to silver in every case, since higher ion concentrations might also damage human cells and tissues. Therefore, surface coatings need to be made with a therapeutically useful range of silver.

One possible solution is offered by the novel nanostructured polymers with integrated silver nanoparticles which a team of Empa scientists led by Enrico Körner and Dirk Hegemann are developing within the frame of an EU Project called EMBEK1 (“polymer-based, multifunctional, bactericidal materials”). In the context of this research work they investigate how varying plasma conditions during deposition influence the film structure and the associated silver ion release that determines the antibacterial effectiveness. The researchers have determined the basics for “designing” tailor-made coatings with desirable properties. The results of this work have recently been published in the scientific journal “Plasma Processes and Polymers”.

Silver nanoparticles are firmly incorporated in the plasma layer

The Empa team used a so-called RF Plasma Reactor, in which hydrocarbon coatings can be deposited on different substrates. As raw materials a hydrocarbon gas such as ethylene (C2H4) is mixed with a reactive gas such as carbon dioxide (CO2) in order to obtain a cross-linked plasma polymer matrix containing functional groups required for cell growth. The electrical energy necessary to drive this process is supplied by electrodes. In order to incorporate silver particles firmly in the plasma layer, one of the electrodes is made of pure silver where a high voltage has to be applied for sputtering conditions. Nevertheless, the film deposition occurs near room temperature allowing the treatment of temperature-sensitive materials.

The Empa scientists varied different process parameters such as the ratio of the two gases and the power input. They discovered that raising the ratio of CO2 to C2H4 leads to an increase of the incorporated amount of silver in the coating as well as to smaller, more homogenously distributed particles. Nanometer-sized, well-distributed silver particles have a significantly higher surface area than, for example, a pure silver layer. Increasing the input power also results in a higher incorporation of silver and at the same time increases the size of the incorporated silver particles. Finally, the researchers investigated the quantities of released silver ions of various coatings over different time periods. The obtained data were evaluated in context of the antibacterial and cell test results. A range could thus be determined for the silver nanocomposite coatings within they showed antibacterial properties and were yet found to be cytocompatible (i.e. friendly to cells).

These results can be used to transfer the deposition process from the laboratory scale to Empa’s in-house pilot plant, the first step towards industrial production of the tailor-made antibacterial coatings. In addition, the research team is attempting to create coatings with gradients in the silver concentration enabling the controlled release of silver ions over a certain time period. A polymer covering layer would thereby help human cells to grow optimally on the antibacterial coating.

Literature
“Formation and distribution of silver nanoparticles in a functional plasma polymer matrix and related Ag+ release properties”, E. Koerner, M. Aguirre, A. Ritter, G. Fortunato, J. Ruehe, D. Hegemann, Plasma Processes and Polymers, published online: 22 June 2010 (DOI: 10.1002/ppap.200900163)
Project data
This work was performed within the frame of the EU project Embek1 “Development and analysis of polymer based multifunctional bactericidal materials”; grant #211436 of the 7th framework program, coordinated by Max Planck Institute for Polymer Research Mainz.

Beatrice Huber | idw
Further information:
http://www.empa.ch
http://www3.interscience.wiley.com/journal/123548666/abstract

More articles from Materials Sciences:

nachricht Watching atoms move in hybrid perovskite crystals reveals clues to improving solar cells
22.11.2017 | University of California - San Diego

nachricht Fine felted nanotubes: CAU research team develops new composite material made of carbon nanotubes
22.11.2017 | Christian-Albrechts-Universität zu Kiel

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>