Decoupling mechanical and morphometric properties in meta-biomaterials

A significant challenge in developing meta-biomaterials is the effective decoupling of their intrinsically intertwined mechanical properties (e.g., elastic and shear moduli, Poisson's ratio, and anisotropy level), morphometric properties (e.g., relative mass density, pore size, and surface-to-volume ratio), and mass-transport properties (e.g., permeability). To address this challenge, we introduce a general framework for decoupling mechanical and morphometric properties in non-stochastic, three-dimensional meta-biomaterials. We first derived explicit geometrical relationships to determine the upper and lower bounds of the input geometrical parameters while ensuring relevance to in vitro biological conditions. Using a high-throughput numerical homogenization method (44,837 simulations) combined with systematic multi-objective optimization, we successfully decoupled Poisson's ratio and relative mass density from all other properties, with average deviations below ~14%. The optimized meta-biomaterials were additively manufactured at the macro- and microscales using PolyJet 3D printing and two-photon polymerization, respectively, and experimentally validated in terms of effective elastic modulus, Poisson's ratio, and permeability. The established decoupling framework provides a promising route for advancing tissue engineering and cell mechanobiology studies by enabling independent investigation of the effects of individual scaffold properties on cell behavior.