• Inspired by the framework of loofah, a bone-like scaffold was designed. • Bionic scaffold with hierarchical porosities is fabricated by hybrid additive manufacturing. • Loofah-inspired NiTi/hydrogel composite scaffold with favorable biological and biomechanical compatibilities. Bone scaffolds must simultaneously provide high porosity for tissue ingrowth and sufficient mechanical properties to sustain physiological loading, yet achieving this balance remains difficult. We report loofah-inspired hierarchical porous NiTi/hydrogel composite scaffolds with dual-scale porosity (including millimeter-scale and micrometer-scale pores), fabricated by laser powder bed fusion (LPBF) followed by hydrogel infiltration and freeze-drying. Inspired by the fibrous network of loofah and guided by topology optimization further, the scaffolds exhibit tunable porosity (55%-80%) and show an optimized balance between porosity, stiffness, and strength that closely mimics natural bone. Under compression, the loofah-like structure enables radial stress redistribution and gradual crack propagation, avoiding the abrupt failure observed in periodic lattices. The corresponding finite-element analysis (FEA) accurately captures the deformation behavior and validates the stress-transfer mechanism. Scaffolds with intermediate porosity (60%-70%) achieve stiffness comparable to cancellous bone (0.55-1.14 GPa) and strength approaching cortical bone (64-124 MPa), while maintaining excellent cyclic stability (irreversible strain=1.51%). In vitro cytocompatibility tests using human osteoblasts confirm good cell viability and adhesion, which are attributed to the micrometer-scale pores (average size ∼127 μm) and the excellent biocompatibility of both the hydrogel and NiTi alloy. This work demonstrates that a bioinspired, hierarchically porous composite design can reproduce bone-like mechanical performance through an integrated material–structure–function design, offering a rational strategy for architecting load-bearing and biocompatible scaffolds.
Zhang et al. (Sun,) studied this question.