Filament Extrusion‐Based Conductive TPU Composite Scaffolds Enable Superior Neuronal Growth and Synaptic Maturation In Vitro

Fused filament fabrication (FFF) three‐dimensional (3D) printing technologies offer new opportunities for fabricating customizable, low‐cost platforms for tissue engineering applications. Here, we developed and characterized 3D‐printed scaffolds using conductive thermoplastic polyurethane (cTPU) filaments and evaluated their mechanical, electrical, and biological performance in vitro. Dynamic mechanical analysis (DMA) across a range of temperatures and frequencies revealed that both TPU and cTPU exhibit temperature‐ and rate‐dependent elastic moduli, with cTPU showing enhanced mechanical stiffness due to the incorporation of conductive fillers. Electrical testing confirmed that cTPU exhibited a stable conductivity (∼1–2 mS/cm) resembling physiological conditions. Surface characterization showed that cTPU was significantly more hydrophilic and exhibited higher nanoscale roughness, both of which are favorable for cell‐material interactions. Mouse embryonic fibroblasts (MEFs) cultured on both scaffolds showed high viability (>85%) and significant proliferation. Notably, immunofluorescence analysis of cultured hippocampal neurons revealed significantly higher density of neuronal networks represented by higher microtubule‐associated protein 2 (MAP‐2)‐positive cell density, greater MAP‐2 area coverage, larger average MAP‐2 cell area, and enhanced postsynaptic density protein 95 (PSD‐95) expression on cTPU scaffolds. Together, these results demonstrate that FFF 3D‐printed cTPU platforms can support long‐term neuronal growth and synaptic maturation, offering promising applications in neural tissue modeling and bioelectronic interfaces.