Evaluation of the effects of nano-TiO2 on bioactivity and mechanical properties of nano bioglass-P3HB composite scaffold for bone tissue engineering

Abstract

To emulate bone structure, porous composite scaffold with suitable mechanical properties should be designed. In this research the effects of nano-titania (nTiO(2)) on the bioactivity and mechanical properties of nano-bioglass-poly-3-hydroxybutyrate (nBG/P3HB)-composite scaffold were evaluated. First, nBG powder was prepared by melting method of pure raw materials at a temperature of 1400 degrees C and then the porous ceramic scaffold of nBG/nTiO(2) with 30 wt of nBG containing different weight ratios of nTiO2 (3, 6, and 9 wt of nTiO(2) with grain size of 35-37 nm) was prepared by using polyurethane sponge replication method. Then the scaffolds were coated with P3HB in order to increase the scaffold's mechanical properties. Mechanical strength and modulus of scaffolds were improved by adding nTiO(2) to nBG scaffold and adding P3HB to nBG/nTiO(2) composite scaffold. The results of the compressive strength and porosity tests showed that the best scaffold is 30 wt of nBG with 6 wt of nTiO(2) composite scaffold immersed for 30 s in P3HB with 79.5-80 of porosity in 200-600 mu m, with a compressive strength of 0.15 MPa and a compressive modulus of 30 MPa, which is a good candidate for bone tissue engineering. To evaluate the bioactivity of the scaffold, the simulated body fluid (SBF) solution was used. The best scaffold with 30 wt of nBG, 6 wt of P3HB and 6 wt of nTiO(2) was immersed in SBF for 4 weeks at an incubation temperature of 37 degrees C. The bioactivity of the scaffolds was characterized by AAS, SEM, EDXA and XRD. The results of bioactivity showed that bone-like apatite layer formed well at scaffold surface and adding nTiO(2) to nBG/P3HB composite scaffold helped increase the bioactivity rate.