Electrical stimulation for treatment and prevention of implant-associated infections in a newly in vitro model

The application of electric and electromagnetic fields provides improved bone healing effects in therapy of bone fractures and diseases. Nevertheless, high infection rates of orthopaedic implants, mainly caused by Staphylococcus aureus and Staphylococcus epidermidis, impede a successful therapeutic treatment. Staphylococcal infections are accompanied by the formation of a biofilm on the implant surface and an increased bone resorption resulting in destruction of bone tissue, sepsis and high revision rates of implants. Although intensive research was done, optimal parameter combinations for enhanced bone growth and regeneration are still unknown. Therefore, parameter settings enhancing bone growth while simultaneously negatively influencing bacteria would be highly relevant for clinical use and optimal treatment.

A newly custom-made stimulation chamber was developed to simulate implant-associated infections in vitro. In this stimulation system, effects of electrical stimulation can be investigated directly on the implant surface, in this a case a titanium electrode, as well as in surrounding bone cells. In our experiments, sinusoidal alternating electrical fields are applied and the effects on both osteoblasts and bacteria are investigated. The results should provide a better understanding of the impact of electric stimulation on both bacteria and human bone cells co-cultured with bacteria, simulating implant-associated infections.

• Analysis of potential inhibitory effects of electrical stimulation with different parameters on Staph. aureus and Staph. epidermidis
• Electrical stimulation of bacterial suspension
• Electrical stimulation of pre-formed biofilms on the electrode
• Electrical stimulation of osteoblasts co-cultured with bacteria
• Determination of bacterial count, biofilm mass quantification, scanning electron microscopy, FACS
• Gene expression evaluation by RT-qPCR

So far, the following results were achieved:

• Establishment of a novel early-infection in vitro system for electrical stimulation of bacteria and cells using alternating current
• Successful generation of a corresponding simulation model
• The system allows electrical stimulation of bacteria and cells under similar cultivation conditions
• Establishment of a basic methodical setup concerning living bacteria and biofilm formation as well as antibiotic susceptibility
• Electrical stimulation shows negative effects on bacterial growth and biofilm formation

Peer-reviewed journal papers:

• DAUBEN, T., J., ZIEBART, J., BENDER, T., ZAATREH, S., KREIKEMEYER, B. and BADER, R., 2016. A novel in vitro system for comparative analyses of bone cells and bacteria under electrical stimulation. BioMed Research International, 2016, Article ID 5178640. DOI: 10.1155/2016/5178640.

Peer-reviewed paper important congresses:

• ZIEBART, J., DAUBEN, T., JONITZ-HEINCKE, J., MITTELMEIER, W., PODBIELSKI, A., KREIKEMEYER, B. and BADER, R., 2015. A novel in vitro system for the analysis of electrical stimulation on human osteoblasts and bacteria (abstract), IBI, Warnemünde, Germany, May 14.-15.
• DAUBEN, T., ZIEBART, J., BADER, R. and KREIKEMEYER, B., 2015. Introduction of a novel in vitro system for electrical stimulation of bacteria (abstract), 49th Deutsche Gesellschaft für Biomedizinische Technik, Jahrestagung, Hannover, Germany, September 16.-18.
• ZIEBART, J., DAUBEN, T., SU, Y., JONITZ-HEINECKE, A., WEIßMANN, V., KREIKEMEYER, B., NEBE, B. and BADER, R., 2015. Establishment of a novel in vitro system  for electric stimulation of human osteoblasts (abstract), 49th Deutsche Gesellschaft für Biomedizinische Technik, Jahrestagung, Hannover, Germany, September 16.-18.

• Prof Dr. Bader
• Prof. Dr. Kreikemeyer