Organic-Inorganic Dual-Nanofiber Interpenetrating Network Scaffolds for Complementary Enhancement of Mechanical Stability and Osteogenic Bioactivity.

Abstract

Incorporating nanofibers into 3D-printed scaffolds is an effective strategy to enhance the physicochemical properties and osteogenic bioactivity of bone tissue engineering constructs. In this study, we developed a composite scaffold featuring a dual-nanofiber interpenetrating network composed of silica (SiO2) and poly(L-lactic acid)/gelatin (PLLA/GEL) nanofibers. SiO2 nanofibers were employed to reinforce mechanical properties and release bioactive Si elements, establishing a favorable osteogenic microenvironment. Concurrently, PLLA/GEL nanofibers were chemically crosslinked with the sodium alginate (SA) matrix to stabilize the scaffold structure. This design effectively addresses the structural instability often observed in single-component inorganic fiber systems. Notably, systematic comparative experiments clarified the distinct contributions of each component. Results indicated that PLLA/GEL nanofibers primarily contributed to mechanical stability; however, their osteogenic contribution was not significantly superior to PLLA particles. In contrast, SiO2 nanofibers exhibited superior bioactivity compared to nanoparticles in inducing osteogenic differentiation and promoting pro-reparative macrophage polarization, leading to enhanced in vivo bone repair. This dual-nanofiber network complementarily improves mechanical stability, modulates inflammation, and promotes osteogenic efficacy, offering a novel strategy for designing high-performance functional bone tissue engineering scaffolds.