Out-of-plane auxetic nonwoven as a designer meta-biomaterial

Biomaterials are porous and three-dimensional (3D) templates, which are used as biological substitutes in tissue engineering. Targeting the optimal design of biomaterials requires a synergy between mechanical, porous, mass transport, and biological properties. To address this challenge, we propose a non-periodic meta-biomaterial in the form of an out-of-plane auxetic nonwoven scaffold that possesses a 3D interconnected highly porous structure with remarkable mechanical properties corresponding to conventional nonwoven material. A design strategy of utilizing larger fiber diameters to enhance the porosity and permeability characteristics successfully devised the nonwoven scaffold with an extraordinary out-of-plane auxetic effect. In situ tensile-X-ray microcomputed tomography (microCT) analysis has been carried out to monitor the variation in the morphological characteristics.