A novel bio-inspired hydrogel-based lattice structure to mechanically mimic human annulus fibrosus: A finite element study

Abstract

Intervertebral disc hernia and dysfunctions are the most common health problems that affect humans. For this reason, the need of disc prosthetics, and especially annulus fibrosus replacements, is becoming increasingly mandatory and urgent. In the present paper, we present a novel bio-inspired hydrogel-based replacement system with rational mechanically mimetic designs of human annulus fibrosus. The new system consists of hydrogel-based lattice structure with octagonal cells separated by polylactide fibers reinforced hydrogel-based sheets. The mechanics of the new designs may be rationally controlled by tailoring microstructure, in terms of polylactide fibers orientation and hydrogel intrinsic viscosity, and mesostructure in terms of cell walls/sheets thickness. The new designs are successfully compared to the natural annulus fibrosus mechanics in terms of nonlinear stiffness and transversal behavior while considering regional dependency. The impressive biomimetic capabilities of the proposed hydrogel-based lattice structure allow foreseeing the possibility of designing personalized disc prosthetics by advanced 3D printing technologies.