Vibration-controlled extrusion-based 3D-printing of graphene-hydroxyapatite scaffolds: structural, mechanical, and electrical insights.

This study presents a comprehensive investigation into the effects of nonlinear vibrational regimes on the structural and functional integrity of reduced graphene oxide- hydroxyapatite (rGO-HA) scaffolds fabricated via extrusion-based 3D-printing. A coupled Van der Pol-Duffing oscillator model was developed to simulate vibrational dynamics during deposition, and its influence was experimentally validated using MEMS accelerometry and scaffold characterization. rGO-HA composite powders were synthesized via hydrothermal methods and formulated into inks with varying HA content. Scaffolds printed under vibrational excitation exhibited pronounced morphological defects, including anisotropic pore geometry, surface cracking, and disrupted layer alignment. Elemental mapping revealed compositional heterogeneity, while pore size analysis indicated increased defect density. Mechanical testing showed a ∼17% reduction in compressive strength, and electrical conductivity declined by ∼78% under vibrational conditions, attributed to disrupted graphene networks and poor interfacial bonding. Comparative analyses confirmed the detrimental impact of dynamic perturbations on scaffold fidelity. These findings underscore the critical importance of vibration control in biofabrication and offer a predictive framework for optimizing scaffold performance in tissue engineering and smart biomaterial applications.