Effects of Boron Oxide Concentration and Carbon Nanotubes Reinforcement on Bioactive Glass Scaffolds for Bone Tissue Engineering.

Abstract

In this work, the effect of varying content of B₂O₃ with respect to SiO₂ on mechanical and bioactivity properties have been evaluated for borosilicate bioactive glasses containing SiO₂, B₂O₃, CaO and P₂O5. The bioactive glasses have been synthesized using the sol-gel technique. The synthesized glasses were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Field Emission Scanning electron microscopy (FESEM). These bioactive glasses were fabricated as scaffolds by using polymer foam replication method. Subsequently, in vitro bioactivity evaluation of borosilicate bioactive glass was done. Based on the XRD and energy-dispersive X-ray spectroscopy (EDS) results showing good apatite-formation ability when soaked in simulated body fluid (SBF), one of the bioactive glass (BG-B30 containing 30 mol% B₂O₃) was selected for further study. The compressive strength of the bioactive glass scaffolds was within the range of trabecular bone. However, it was found near the lower limit of the trabecular bone (0.2-12 MPa). Therefore, BG-B30 scaffold was reinforced with carbon nanotubes (CNTs) to allow for mechanical manipulation during tissue engineering applications. The compressive strength increased from 1.05 MPa to 7.42 MPa (a 606% increase) after reinforcement, while the fracture toughness rose from 0.12 MPa √ m to 0.45 MPa √ m (a 275% increase). Additionally, connectivity of the pores in the CNT reinforced BG-B30 scaffolds were evaluated and the pores were found to be well connected. The evaluated properties of the fabricated scaffolds demonstrate their potential as a synthetic graft for possible application in bone tissue engineering.