Biomimetic Fibrous Bone Substitute Manufacture Through Non-Solvent-Assisted 3D Printing

Abstract

The manufacturing of biomimetic bone characterized by an organic–inorganic combination and fibrous structure has garnered significant attention. Inspired by the formation of multi-layered fibrous structures in bone tissue, this study is based on the fibril assembled from poly(γ-benzyl-L-glutamate) (PBLG) in helicogenic solvent, proposing a non-solvent-assisted 3D printing method for realizing the PBLG 3D printing while generating biomimetic fiber structures in One-Step to mimic the formation of collagen fiber bundles. The unprintable mixture of PBLG and hydroxyapatite nanoparticles (nHA) in 1,4-dioxane exhibits extrudability, self-supporting properties, and plasticity in ethanol. Meanwhile, ethanol-assisted printing leads to the spontaneous growth of PBLG-fibrils into submicron-fibers. Moreover, the integration of nHA with PBLG-fibers through hydrogen bonding contributes to the improvement of printability and mechanical properties. This method of ethanol-assisted fiber generation is successful with concentrated PBLG solutions, overcoming the limitation of previous research that focused only on dilute solutions. To expand the printable window, an ethanol-gel is developed as a support to achieve omnidirectional printing, resolving the issue of interlayer collapse caused by gravity and the conflict between printability and biomimetic fibers generation, optimizing the biomimetic bone manufacturing, leading to the precise biomimetic design of bone structures.