Preparation of hexagonal-boron nitride and tungsten disulfide containing bioactive glass composite scaffold for bone tissue engineering applications

Bone tissue engineering is a multidisciplinary field of study that aims to repair and regenerate bone tissue that has been damaged for various reasons and cannot function. Bioactive glasses have wide range of uses in bone tissue engineering due to their high bonding ability with bone tissue. In this study, hexagonal-boron nitride (hBN) and tungsten disulfide (WS2) nanoparticle- containing borate-based 13-93B3 bioactive glass composite scaffolds were produced by polymer foam replication method. The addition of nanoparticles to the structure was carried out by two different approach. In the first approach, hBN and WS2 nanoparticles (0.1, 0.2, 0.5, 1 and 2 wt%), were directly added to the bioactive glass suspension and scaffolds were produced using the polymer foam replication method. In the second approach, bare bioactive glass scaffolds were coated by the hBN or WS2 nanoparticle - containing (0.1, 0.2, 0.5, 1 and 2 wt%) polycaprolactone or polycaprolactone/poly(lactic-co-glycolic) acid solution. The results showed that the addition of hBN and WS2 nanoparticles caused some changes in structral and morphological properties of the bioactive glass scaffols. Additionally, application of a polymer coating and inclusion of nanoparticles up to a specified concentration enhanced the compressive strength of the bioactive glass scaffolds. Fourier transform infrared spectroscopy (FTIR) analyzes and scanning electron microscope (SEM) micrographs showed that a hydroxyapatite (HA) layer is formed on the surface of the tissue scaffolds that were kept in simulated body fluid (SBF). Furthermore, the polymer coating layer did not inhibit the HA formation and incorcorporation of hBN and WS2 nanoparticles accelerated the HA formation rate. In vitro cytotoxicity experiments revealed that the presence of hBN and WS2 nanoparticles in the bioactive glass matrix up to a specified concentration and their presence in polymer matrix at all concentrations as coating on the bioactive glass scaffolds did not cause a cytotoxic effect in pre-osteoblast MC3T3-E1 cells. Addition of hBN and WS2 nanoparticles and application of a polymer coating layer, influenced the drug release behaviour of gentamicin sulphate-loaded bioactive glass scaffolds. It was concluded that due to their improved mechanical properties, in vitro bioactivity, biocompatibility and drug release properties, hBN and WS2-containing 13-93B3 bioactive glass scaffolds can be utilized in bone tissue engineering applications.