Therapeutic ions such as boron (B) and cobalt (Co), incorporated into bioactive glass, are capable of regulating genes responsible for new blood vessel formation (e.g., VEGF) through different signalling pathways [1]. In addition, B could act as the reinforcement element, improving the mechanical properties of bioactive glass. Additive manufacturing (AM) combined with co-doped bioactive glass systems is of great interest for the scaffold fabrication applicable to bone tissue engineering. AM techniques, and digital light processing (DLP) in particular, make it possible to transform digital objects into tangible biomedical substitutes. In the present study, the development of 3D scaffolds through a UV light-curable slurries from undoped (un-BG), and B and Co co-doped silicate-based bioactive glass (co-BG) was studied. The suspension optimization and 3D printing of Kagome [2] bioactive scaffolds were carried out by keeping the solid loading constant at 40% vol. The slurry was fine-tuned with an un-BG, based on the 45S5 Bioglass^®, where the effect of particle size distribution and dispersant ratio on cure depth and rheological behaviour were examined in detail. During the thermal treatment of scaffolds, the influence of the therapeutic ions described above was investigated for its effect on the crystallization tendency of the scaffolds in connection with bioactivity and mechanical properties. As the dispersant ratio increases, the polymerization of relatively low-viscosity slurry (0.4 Pa⋅s at 30⋅s^-1) begins at longer exposure times. The reduction in the particle size distribution (Dv(90)=10 ±2 μm) ensured the acquiring of a specific curing thickness at shorter curing times, thereby minimizing the total energy utilized per layer during printing. The 3D scaffolds with Kagome structure were printed at a wavelength of 385 nm with a layer thickness of 10 μm, an exposure intensity of 14.65 mW/cm², and an exposure time of 2.2 s. This shows that the co-BG, even if its colour change in the presence of Co, is suitable for DLP-printing at a wavelength of 385 nm, without the necessity of long curing times. The 3D scaffolds with high dimensional accuracy were obtained, and further investigated as a potential implant material for bone substitution.
Acknowledgment:
This item is a part of dissemination activities of project FunGlass. This project has received funding from the European Union´s Horizon 2020 research and innovation programme under grant agreement No 739566, and the Journal of the European Ceramic Society (JECS) Mobility Project JECS Trust, Contract number: 2022298. The financial support of this work by the grant APVV-20-0322 is gratefully acknowledged.
References:
[1] S. Chen et al., “Multi-targeted B and Co co-doped 45S5 bioactive glasses with angiogenic potential for bone regeneration,” Materials Science and Engineering C, vol. 112, Jul. 2020, doi: 10.1016/j.msec.2020.110909.
[2] M. S. Ghim, H. W. Kim, and Y. S. Cho, “Enhancement fidelity of Kagome scaffold for bone regeneration by design for additive manufacturing,” Mater Des, vol. 225, p. 111608, Jan. 2023, doi: 10.1016/J.MATDES.2023.111608.