Rational design and modeling of auxetic fiber scaffolds for soft tissue engineering via melt electrowriting

This study presents a rational, computationally guided framework for designing auxetic micro-fibrous scaffolds for soft tissue engineering applications using melt electrowriting (MEW). Four re-entrant auxetic geometries (HCELL, SREG, SINV, STRI) were parametrically designed, fabricated from polycaprolactone, and mechanically characterized. Finite element method (FEM) models were developed to predict scaffold behavior under biaxial loading and were iteratively refined to account for fabrication-induced geometric deviations. Experimental biaxial tensile testing revealed a characteristic biphasic, non-linear mechanical response, with an initial low-stress auxetic regime followed by strain-induced stiffening. The FEM predictions closely matched experimental results across designs, validating the modeling framework as a predictive design tool. Short-term fibroblast culture confirmed scaffold cytocompatibility, supporting the potential of MEW-fabricated auxetic scaffolds as mechanically tunable platforms for soft tissue engineering.