Dr. Svea Sachse (Jena, DE), Manuela Dubs (Jena, DE), Dr. Hanen Ferjani (Jena, DE), Dr. Carolin Witt (Mörsdorf, DE), Dr. Martin Liebelt (Mörsdorf, DE), Thomas Oberbach (Mörsdorf, DE), Dr. Matthias Schnabelrauch (Jena, DE)
Abstract text (incl. figure legends and references)
Introduction
Currently, no implant system exists that offers an osseointegrative coating with simultaneous protection against infection. The object of this work was to develop a cementless ceramic knee prosthesis with antibiotic activity. ATZ (alumina toughened zirconia) with a porous titanium layer provides the ingrowth into bone and is developed by Mathys Orthopaedie GmbH. Gentamicin compounds applied as antibiotic coatings to prevent implant-associated infections.
Materials & Methods
Methanolic solution or suspension of gentamicin phosphate or gentamicin phosphonate were coated onto implant substrate ATZ samples with porous TPS (Titan Vacuum Plasma Spraying) according to literature [1]. The biological testing included in vitro cytocompatibility tests with differential staining of cells MC3T3-E1 to determine the cell viability after 1 and 4 days, the antibiotic releasing from coated samples by agar diffusion (activity) and fluram test (determination of amino groups). Additionally, the log reduction were analysed by CFU test with bacterium Staphylococcus capitis. Finally, the quality of coated surface were detected by SEM.
Results
The release and cytotoxicity behaviour as well as the log reduction capability against S. capitis of various gentamicin compounds coated samples show a continuous and controlled antibiotic release over several days. The SEM images demonstrate that the porous structure (TPS) is retained after the gentamicin coating with only differences in the fine structure. The results of fluram tests correspond to the gentamicin activity obtained by growth inhibition test. Gamma sterilization seems to have no effect on the release and cytotoxicity of the gentamicin compounds.
Conclusion
The newly developed gentamicin coating system represents a new highly potent antibiotic coating system for bone implants under in vitro conditions. Currently, the bio-function is evaluated in an animal in vivo test study.
References
[1] DE 102015214603 A1