Bioactive glass (BG) granules are used in clinical bone regeneration [1]. They enable bone cell adhesion and proliferation, stimulate cell maturation, and bone formation [2, 3]. BG is used clinically for the treatment of chronic bone infections (osteomyelitis) [4]; however, so far, the exact mechanism of its antimicrobial action remains unknown. Various mechanisms for BG antimicrobial action have been suggested, but a method to custom-design BG possessing osteoconductive and antimicrobial properties needs to be identified. This presentation provides an overview of melt-derived antimicrobial bioactive glasses: their composition, properties as well as in vitro and in vivo. While many studies incorporate ions of known antimicrobial action (e.g. silver) into bioactive glasses, other studies show that glasses in the sodium calcium phospho-silicate system show antimicrobial action [5-7].

Furthermore, experimental studies will be designed to investigate routes towards the custom design of BG combining osteoconductive and antimicrobial properties, as part of a Research Training Group (RTG 2723) funded by the German Research Foundation (DFG). Melt-derived BG in the sodium calcium phospho-silicate system without any addition of further antimicrobial ions will be characterised with regard to their chemical (degradation, ion release, pH changes) and mechanical (particle size, surface roughness, sphericity) properties. The antimicrobial properties of those BG samples will be tested in a 3D cell culture model. This is approached initially by screening tests of metabolic activity, gene expression, and proliferation, and later followed by detailed analyses of osteoblast differentiation including bone formation. In addition, antimicrobial studies focusing on microbial adhesion, viability, virulence (transcriptomics), and phenotype switching will be performed.

Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 444711651, RTG 2723 Materials-Microbes-Microenvironments (M-M-M)