Patterning the Void: Combining L-Systems with Archimedean Tessellations as a Perspective for Tissue Engineering Scaffolds

Scaffold architecture plays a crucial role in tissue regeneration. Common scaffold design typically involves defining an outer shape and subsequently filling it with a conventional infill pattern. Here, a novel multi-scale design approach is proposed, which uses L-fractals with regular outer borders as the constituent tiles of an Archimedean tessellation. To assess tile-to-tile attachment, different force application sites are studied experimentally and computationally. While the porosity of all tiles is similar, their responses to tensile loading are vastly different, exhibiting moduli ranging from 1 to 100 MPa and distinct deformation morphologies. Fractal tiles are also evaluated for their In vitro performance, using human mesenchymal stromal cells (hMSCs). After 21 days in culture, geometry-dependent metabolic activity, tissue growth and cytoskeleton alignment are observed, underscoring their potential value for tissue engineering applications. By treating each tile and gripping configuration as an individual unit, more than 4000 possible Archimedean combinations are identified, with this number exceeding 55 000 when order specificity is considered. Characterization of Archimedean-fractal combinations reveals that individual tiles exhibit deformations similar to those observed during single-tile tests. This study demonstrates a novel multi-scale design approach with potential applications in tissue regeneration.