Development Of Porosity Gradient Bioglass Ceramic Scaffold

Abstract

In order to cure critical size bone defects, three dimensional scaffolds are required. The bone has a functionally graded structure, with the outer cortical bone having with 10-15% of porosity and inner cancellous bone possess 50-90% of porosity. Thus functionally graded scaffolds, fabricated with Class A biomaterial can be the better therapeutic design for curing critical size bone defects. In this work, an attempt had been made to develop porosity gradient bioglass scaffold. 45S5 bioglass and other two glasses, viz. 2P (with 2 wt.% P2O5) & 4P (with 4 wt.% P2O5) had been chosen to fabricate the scaffold. The bioactive glasses had been synthesized by melt quench method. Differential Scanning Calorimetry and Dilatometric study had been carried out to observe the thermal and sintering behavior of these bioactive glasses. Cytotoxicity, Haemocompatibility and Protein Absorption studies had been carried out on bioactive glasses as well as on sintered glass product. Porous scaffold preparation has been achieved using naphthalene as a pore former (0 wt.%, 30 wt.% & 50 wt.%), shaping by uniaxial pressing followed by sintering. Initially, single layer porous scaffolds had been fabricated and sintered at 800°C, 850°C & 900°C. Apparent porosity and bulk density had been measured for those single layer scaffolds and XRD phase analysis had been carried out. Diametral Tensile strength and flexural strength of those single layer scaffolds had been evaluated. Functionally graded scaffolds had been fabricated by incorporating 0wt.% naphthalene on outer layer and 30 wt.% & 50wt.% naphthalene on the inner layer, which had been sintered at 800°C, 850°C & 900°C. Apparent porosity and bulk density had been measured for the entire FGM system and graded layers separately. Splitting tensile strength had been calculated for the functionally graded scaffolds. Cell viability had been evaluated on those functionally graded scaffolds. The functionally graded scaffolds had been soaked in SBF for 1, 4, 7 & 14 days to observe the carbonated hydroxyapatite layer formation.