Hollow-walled metamaterials: Unifying mechanical resilience and biointegration through continuous curvature

Conventional lattice materials for load-bearing implants often struggle to combine high strength, stable failure modes, and effective biointegration, a challenge rooted in their discontinuous geometries and stress-concentrating nodal junctions. Here, we introduce hollow-walled triply periodic minimal surface (TPMS) metamaterials, a biomimetic architecture that merges the continuous curvature of minimal surfaces with engineered voids to overcome these limitations. Unlike prior hollow-strut designs prone to powder occlusion and stress localization, our Ti–6Al–4V lattices, fabricated through a single-step Boolean subtraction strategy, eliminate nodal stress risers while retaining open, interconnected channels. As a result, these structures achieve compressive strengths exceeding 270 MPa, surpassing cortical bone benchmarks, and specific energy absorption of 32 J g −1 —twice that of state-of-the-art lattices—enabled by progressive layer-by-layer buckling that prevents catastrophic collapse. In parallel, the hollow-walled design amplifies surface area by 80 %, driving 66 % greater human fibroblast proliferation and 40 % higher metabolic activity compared to solid TPMS scaffolds. By unifying mechanical resilience with biofunctional efficacy through geometry-driven innovation, this work presents a versatile design paradigm for next-generation implants, aerospace systems, and multifunctional metamaterials.