Mechanical properties and optical evaluation of scaffolds produced from 45S5 bioactive glass suspensions via stereolithography

The optical and physical properties of 45S5 bioactive glass suspensions for bone tissue engineering applications were studied by (1) varying the volume fraction of 45S5 in the suspension, and (2) assessing the effects of sintering on the mechanical and morphological features of the glass. The 45S5 specimens were manufactured using stereolithography. Five types of binders with different ratios of photocurable and acrylate resins were fabricated. 45S5 bioactive glass suspensions were prepared by adding 45S5 glass powder to the binder with the highest reactivity and cure depth. The prepared suspensions were divided into five groups with 45S5 volume fractions varying in the range of 32-40 vol% (denoted as BG32-BG40, respectively). The cure depth, measured after passing a laser with a wavelength range of 390-420 nm through the suspension once, was found to decrease with increasing volume fraction of 45S5. Moreover, as the 45S5 volume fraction increased, the strength of the sample reached a maximum of 37.9 +/- 5 MPa at 40 vol% (BG40). More importantly, the viscosity of the suspensions prepared with various glass fractions was found to gradually increase with increasing volume fraction. The Fourier-transform infrared spectra of the non-sintered and sintered green bodies showed three main peaks (at 1040, 920, and 445 cm(-1)) corresponding to the Si-O-Si bond vibrations of 45S5. Clear signals corresponding to C-H stretching and C = C bonds were observed before sintering; however, these peaks disappeared after sintering. Optical analysis showed no residual effects of the binder after sintering. These results demonstrate that the suspension with 40 vol% 45S5 (BG40) can be successfully employed in the fabrication of scaffolds for bone regeneration and tissue engineering applications in the near future.