The development of cost-effective, flexible, and scalable microfluidic devices is crucial for advancing organ-on-a-chip (OoC) technology for drug discovery and disease modeling applications. In this study, we present a novel 3D-printed flexible microfluidic device (3D-FlexTPU-MFD) fabricated through a one-step fused deposition modeling (FDM) process using thermoplastic polyurethane (TPU) as the printing filament and polyvinyl chloride (PVC) as the bonding substrate. The device's compatibility was evaluated with various cell types, including human primary myoblasts, human primary endothelial cells (HUVEC), and human iPSC-derived optic vesicle (OV) organoids. Myoblasts cultured within the device exhibited high viability, successful differentiation, and the formation of aligned myotube bundles, outperforming conventional well-plate cultures. Additionally, iPSC-derived OV organoids-maintained viability, displayed neurite outgrowth, and sustained expression of the eye marker PAX6. These results demonstrate that the 3D-FlexTPU-MFD effectively supports cell growth, differentiation, and alignment, making it a promising platform for tissue modeling and OoC applications in future.