Assessment of permeability and microstructural parameters via fractal modelling in bioactive glass-derived scaffolds produced by vat photopolymerization

Porosity-related characteristics of biomedical three-dimensional (3D) scaffolds govern mass transport properties which, in turn, dictate the success of implants in vivo. The accurate determination of permeability and microstructural properties in highly-porous materials - like implantable bone scaffolds - still represents a challenge due to the complex architecture of struts and voids in 3D. In the present study, the complete set of mass transport properties of bioactive glass scaffolds produced by vat photopolymerization was reliably determined by combining experimental assessment, advanced imaging and mathematical modelling based on the Ergun-Wu approach. Specifically, the intrinsic permeability of the scaffolds was experimentally estimated by acoustic measurements, and the pore diameter was calculated through implementing an innovative fractal model. An accurate statistical analysis of the results provided evidence of the robustness of the overall strategy, which can be potentially extended and adapted to the analysis of other types of sintered porous (bio)materials.