An investigation on injectable composites fabricated by 45S5 bioactive glass and gum tragacanth: Rheological properties and in vitro behavior

The injectable composites were formulated from melt-derived 45S5 bioactive glass powder and gum tragacanth. The effect of tragacanth concentration (2 and 4 w/v%) and powder to liquid ratio (P/L= 1.5 to 2.5) on rheological properties, injectability, degradation, swelling, and bioactivity the composites was studied. With the increase of P/L ratio and tragacanth concentration, the force required for injection of the composites increased, however, the formulated composites showed maximum injection force of 15 N, which seems to be proper for surgical purposes. The formulated composites showed positive thixotropic behavior and the composites prepared with 2% tragacanth showed greater thixotropy than ones made of 4% tragacanth. The composites formulated by 2% tragacanth showed much more resistance against degradation and swelling. The bioactivity assay confirmed the formation of flake-like apatite nanostructures on the surface of nanocomposites on initial days of immersion in the SBF.