Melt Electrowriting High Resolution Poly(ethylene-co-vinyl acetate) Scaffolds for Soft Tissue Engineering
Finn Snow1,2, Darcy De Rauch1,2, Lilith Mabel Caballero Aguilar2,3,4
1Department of Biomedical Engineering, School of Engineering, RMIT University, Melbourne, Victoria, Australia.
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Melt electrowriting (MEW) holds tremendous potential to advance regenerative engineering, yet its clinical translation is hindered by the inability to replicate the biomechanics of soft tissues. We present, for the first time, MEW of polyethylene vinyl acetate (PEVA), demonstrating its potential as a highly compliant and biocompatible polymer for high-resolution scaffold fabrication. Optimized printing parameters displayed a highly stable jet, enabling microscale fibers to be fabricated with pore sizes down to 100 µm, achieving the highest diameter-to-spacing ratio reported to date for elastic MEW polymers. MEW PEVA fibers exhibited markedly enhanced mechanical compliance under tensile loading, with 4-fold and 35-fold greater compliance than thermoplastic polyurethane (TPU) and polycaprolactone (PCL), respectively, while maintaining yield strains comparable to TPU. Under compression, macroporous PEVA scaffolds showed an extended toe region of up to 75%, approximately 250-fold greater compliance than PCL, and yield strains exceeding 85%. PEVA scaffolds supported strong cell attachment and survival, with initial growth dynamics analogous to PCL and a significant increase in metabolic activity by day 7. This breakthrough establishes PEVA as a transformative material that overcomes the mechanical mismatch between MEW scaffolds and native soft tissues, expanding its translational potential for soft tissue engineering.
