Chair for Multicomponent Materials

Biocompatible antibacterial coatings and controlled release

Antibacterial coatings have many applications ranging from prevention of hospital-acquired infection or implants to bathroom equipment. We have been exploring vapor phase co-deposition of Ag and other noble metals and alloys together with an organic or ceramic matrix component as a method to produce antibacterial coatings, where the precious metals are only incorporated into a thin surface layer. Moreover, the active metals are finely dispersed as nanoparticles, thus saving additional material and providing a very large effective surface for metal ion release.  In addition, the embedding of the noble metal nanoparticles ensures that only metal ions but no nanoparticles are released. This is important because the release of nanosilver and other metal nanoparticles is considered to be of environmental concern. Silver and copper ions are particularly effective due to their broadband antibacterial and antifungal activity and the reported absence of bacterial resistance.  

The antimicrobial effect of the nanocomposite coatings was evaluated by means of different assays in cooperation with Prof. Rainer Podschun from the University Hospital Schleswig-Holstein, Campus Kiel. Recent work was focused on biocompatible coatings with a large therapeutic window where bacteria are effectively killed while human cells can grow. The therapeutic window can be tailored by controlled release. In our approaches, controlled release was obtained by control of the nanoparticle filling factor profile, the properties of the matrix, the employment of barriers, and the use of noble metal alloy particles of well controlled composition.



Antimicrobial efficiency of Ag-TiO2 nanocomposites with different Ag filling factors for GFP-producing E. coli SAR18.


An important recent finding made together with Dr. Claudia Röhl, at that time member of the group of Prof.Edmund Maser from the Department of Toxicology and Pharmacology in Kiel, was that the therapeutic window is strongly increased on the coating surface compared to solution. This was attributed the lowering of the ph value upon bacterial colonization which enhances silver ion release (see figure below).


Sketch illustrating our finding of a huge increase in the therapeutic window of silver nanoparticle containing nanocomposites due to a local reduction of the ph value upon bacteria colonization which enhances local release of silver ions. 


Selected publications

Alissawi, N.; Peter, T.; Strunskus, T.; Ebbert, C.; Grundmeier, G.; Faupel, F.: Plasma-polymerized HMDSO coatings to adjust the silver ion release properties of Ag/polymer nanocomposites, Journal of Nanoparticle Research 15 (2013) 2080.

Hrkac, T.; Röhl, C.; Podschun, R.; Zaporojtchenko, V.; Strunskus, T.; Papavlassopoulos, H.; Garbe-Schönberg, D.; Faupel, F.: Huge increase of therapeutic window at bioactive silver/titania nanocomposite coating surface compared to solution,Materials Science and Engineering C 33 (2013) 2367-2375.

Alissawi, N.; Kienle, L.; Chakravadhanula, V.S.K.; Kocabas, I.; Garbe-Schönberg, D.; Strunskus, T.; Zaporojtchenko, V.; Faupel, F.: Effect of gold alloying on stability of silver nanoparticles and control of silver ion release from vapor-deposited Ag-Au/polytetrafluorethylene nanocomposites, Gold Bulletin 46:3-11 (2012) DOI 10.1007/s13404-012-0073-6.

Alissawi, N.; Zaporojtchenko, V.; Strunskus, T.; Hrkac, T.; Kocabas. I.; Erkartal, B.; Chakravadhanula, V.S.K.; Kienle, L.; Grundmeier, G.; Garbe-Schönberg, D.; Faupel, F.: Tuning of the ion release properties of silver nanoparticles buried under a hydrophobic polymer barrier, Journal of Nanoparticle Research Vol. 14 Issue 7 (2012) 10.107/s11051-012-0928-z.

Yliniemi, K.; Özkaya, B.; Alissawi, N.; Zaporojtchenko, V.; Strunskus, T.; Wilson, B.P.; Faupel, F.; Grundmeier, G.:Combined in situ electrochemical impedance spectroscopy - UV/Vis and AFM studies of AG nanoparticle stability in perflourinated films, Materials in Chemistry and Physics Online (2012) .

V.S.K. Chakravadhanula, T. Hrkac, V. Zaporojtchenko, R. Podschun, V.G. Kotnur, A. Kulkarni, T. Strunskus, L. Kienle and F. Faupel, Journal of Nanoscience and Nanotechnology, Vol. 11, 4893–4899, (2011).

V. Zaporojtchenko, R. Podschun, U. Schürmann, A. Kulkarni, and F. Faupel, Nanotechnology 17, 4904 (2006).