Fabrication and Preliminary Physical Characterization of 3D-Printed PLA/TPU Vascular Patch Prototypes Using Fused Deposition Modeling

Background/Objectives: Vascular patches used in cardiovascular reconstruction remain limited by thrombosis, calcification, restricted remodeling, and inability to accommodate somatic growth. This proof-of-concept study aimed to fabricate and characterize porous vascular patches by fused deposition modeling (FDM) using polylactic acid (PLA) and thermoplastic polyurethane (TPU) in single-material and multilayer configurations. Methods: PLA/TPU patches with different polymer compositions, layer sequences, interfilament spacing, and staggered layer arrangements were fabricated by FDM. Mass and dimensional changes during in vitro immersion were assessed for the constituent polymers (n = 3 per polymer) and selected patch configurations (n = 1 per configuration). Patch microstructure and the in-plane dimensions of surface-visible pore openings were evaluated by top-view optical microscopy and ImageJ analysis, while time to first visually detectable fluid passage was assessed using a 22% (w/w) aqueous glycerol test solution under low hydrostatic pressure. Results: PLA and TPU exhibited distinct mass and dimensional profiles during 140 days of immersion, with mean mass increases of 1.37% and 3.68%, respectively. Selected patch specimens showed different temporal mass-change profiles during 42 days of immersion in phosphate-buffered saline (PBS). Descriptive pore measurements varied among the investigated configurations; V7b showed mean dimensions of 96.5 × 93.2 µm. In the exploratory test, fluid passage was first visually detected at 18 min (V5-TPU), 59 min (V6b) and 135 min (V7b). Conclusions: FDM enabled the fabrication of porous PLA/TPU vascular patch prototypes with different material composition and multilayer architectures. These findings establish a preliminary basis for further physicochemical, mechanical, biological, and hemodynamic evaluations of FDM-fabricated PLA/TPU vascular patches.