Development of a Modified FDM-Based Bioprinter with Optimized Extrusion Parameters for High-Fidelity Alginate Bioinks and Aortic Valve Scaffold Manufacturing

Aortic valve disease is a major cause of cardiovascular deaths worldwide. Aortic stenosis increases the workload on the heart and severely alters hemodynamic function by impairing effective blood flow. In recent years, extrusion-based bioprinting technologies have made significant progress in producing patient-specific, biocompatible cardiovascular structures, opening up new opportunities for advanced therapeutic applications. In this study, a commercially available FDM-type 3D printer (ENDER-3 Pro) was mechanically and electronically modified into a fully functional, low-cost bioprinter capable of depositing alginate-gelatin hydrogels with high structural fidelity, despite their low viscosity. The redesigned system integrates a NEMA-17 driven syringe extrusion module equipped with a TR8X8 lead screw, enabling high-resolution pressure-controlled deposition of viscoelastic bioinks. A three-leaflet aortic valve geometry was digitally reconstructed and simplified using Fusion 360 to ensure printability while preserving essential anatomical features. The printing parameters were systematically investigated according to the alginate-based bioinks and set to a nozzle diameter (0.6 mm), layer height (0.6 mm), extrusion multiplier (0.02), and printing speed (5 mm/s). Quantitative shape fidelity assessment, including top-down geometric deviation analysis, confirmed that the bioprinted aortic valve constructs successfully maintained the nominal CAD boundaries. By dynamically optimizing slicing parameters, specifically the extrusion multiplier, rheologically driven deformations such as excessive lateral spreading were effectively mitigated. Although comprehensive evaluation of hemodynamic performance requires future in vitro experiments and coupled fluid–structure interaction (FSI) simulations, the present study establishes a robust and accessible biofabrication framework capable of producing highly complex cardiovascular geometries. Cost-effective and adaptable bioprinting platforms, derived from consumer-grade fused deposition modeling (FDM) systems, can achieve the geometric fidelity and structural stability necessary for advanced cardiovascular tissue engineering. This approach significantly enhances the accessibility of high-precision bioprinting technologies, thereby facilitating broader adoption in both research and translational applications.