Bioactive evaluation of 45S5 bioactive glass fibres and preliminary study of human osteoblast attachment.

Bioactive glass fibres can be used as tissue engineering scaffolds. In this investigation, the bioactive response of 45S5 glass fibres was assessed in simulated body fluid (SBF). Preliminary attachment of osteoblasts to the fibre surface was assessed, as were the fibre tensile strength and fracture toughness. Fourier transform infrared spectroscopy (FTIR) analysis revealed that hydroxyapatite (HA) was formed on the fibres' surface after 2-4 days in SBF. Raman micro-spectroscopic analysis was used to monitor development of the HA layer during immersion. A correlation was found between increase in intensity of the PO4(3-) peak near 964cm(-1) and appearance of crystalline HA (P-O bending peaks) using FTIR. Such results are encouraging for in situ bioactivity monitoring, as Raman spectra are insensitive to the presence of water, unlike FTIR. Average tensile strength of 45S5 fibres (79 microm diameter) was 340+/-140 MPa. Fracture toughness, determined using fracture surface analysis, was 0.7+/-0.1 MPa m1/2. Confocal microscopy revealed osteoblasts attached and spread along the fibres after 15-90 min culture. Scanning electron microscopy analysis showed that cells with filopodia and dorsal ruffles remained attached after 14 days in culture. These results are encouraging, as cell adhesion is an important first step prior to proliferation and differentiation.