Bimetallic nanoparticles as sacrificial anode system: Synthesis, microstructure and application
Christina Sengstock, Bergmannsheil University Hospital/Surgical Research, Ruhr-University Bochum, Bochum, GermanyKateryna Loza, Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Essen, GermanyMarc Heggen, Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Jülich Research Centre, Juelich, GermanyMatthias Epple, Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Essen, GermanyManfred Koeller, Bergmannsheil University Hospital/Surgical Research, Ruhr-University Bochum, Bochum, Germany
Implant-associated infections remain a serious clinical problem. The inhibition of initial bacterial colonization will avoid most implant-related infections and reduces the chance of biofilm formation. Due to increasing antibiotic resistance, alternative or supportive antimicrobial agents such as nanosilver might be effective as silver has a remarkable antimicrobial effect against a broad spectrum of bacteria. The antibacterial efficiency of silver is related to the amount of released silver ions (Ag+). As we have shown previously, the release of Ag+ seems to involve a cooperative oxidation process that requires dissolved dioxygen and protons. Additionally, the Ag+ release rates increase with temperature and decrease with increasing pH . Therefore, a material with an increased ion release could be more efficient even using lower amounts of total silver.
In this study, nanosilver (enhancement of surface area) will be combined with an even more noble metal such as platinum. Due to the difference in the electrical potential, a less noble metal (silver) protects a more noble part (platinum) in an electrolytic environment by corroding. The effectiveness of such a sacrifical anode system was recently shown in collaboration with Prof. Ludwig (RUB) . Silver dot-arrays on a gold surface generate a highly active antibacterial microenvironment concomitant to low amounts of total silver. Now we want to establish such sacrificial anode systems as bimetallic nanoparticles.
The combination of silver with elements of the platinum group as nanoparticles is a very innovative approach. Therefore, the aim of this study is to find out firstly which element combination of the platinum group with silver is feasible and secondly which structural design produces the optimal antibacterial efficiency but also the lowest tissue effect. To answer these questions, the effectiveness of these systems will be determined for gram-negative/ gram-positive bacteria and for tissue cells such as human mesenchymal stem cells (hMSC) or for co-cultures of bacteria with hMSC. In addition, the microstructure of the bimetallic nanoparticles will be analyzed with high resolution electron microscopy.
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