Bioactive glass containing silicone composites for left ventricular assist device drivelines: role of Bioglass 45S5® particle size on mechanical properties and cytocompatibility

Aside its historical use in contact with bone and teeth, an increasing number of studies use bioactive glasses (BG) in contact with soft tissue. BG could provide solutions for various medical problems. This study presents a first evaluation, whether BG containing silicone elastomers are a suitable material for left ventricular assist device drivelines and could enhance skin biointegration thereof. Three different nano- or microparticles of BG45S5 (R) were incorporated into medical grade silicone elastomer, and thin films of the composites were manufactured. Physicochemical, mechanical and in vitro experiments using primary human dermal fibroblasts were used to evaluate the nano- and microcomposites. The incorporation of BG particles reduced the tensile strength at break and percent elongation at break of the composites and increased the stiffness of the material. Especially, the incorporation of nanosized BG decreased the percent elongation at break after immersion in SBF due to agglomerate formation and increased hydroxyapatite formation compared to commercially available microparticles. The cytocompatibility of BG containing composites increased significantly with increasing particle concentration. A clear trend regarding particle size was not observed. In general, the simple incorporation of particles into medical grade silicone elastomer allowed an easy modification of the mechanical properties and improvement in bioactivity (assessed by hydroxyapatite formation) of the material. The choice of either nano- or microparticles depends on the specific application and requirements for the material, as different particle types show different advantages and disadvantages.