Scalable Biofabrication of Functional 3D Scaffolds via Synergy of Autopilot Single-Jet Electrospun 3D PCL Fiber Scaffolds and Cell-Laden Hydrogels.

3D bioprinting enables cell-laden hydrogel construct fabrication in a layer-by-layer fashion but faces scalability challenges due to the mechanical weakness of hydrogels. Matrix reinforcement compromises cellular activity, creating a scalability-functionality trade-off that remains unresolved as sophisticated strategies including sequential and embedded printing fail to effectively overcome these limitations. This study presents an alternative approach by integrating autopilot single-jet electrospun (AJ-3D ES) 3D PCL fiber scaffolds with hydrogels, achieving anatomical precision, mechanical robustness, and enhanced cell function. Hydrogel dip-coating of anatomically structured PCL scaffolds enabled organ-scale cellular constructs. By providing an ECM-mimicking porous fiber network, embedded cells mitigated the limitations of hydrogel stiffness (even ∼50 kPa) and facilitated cell-cell interactions, supporting epithelialization, fibroblast clustering, and 3D phase-separated HepG2-HUVEC co-cultures. Contour 3D bioprinting along PCL fiber scaffold topographies facilitated endothelial patterning for vascularization and native-tissue mimicking complexity. Volumetric scalability was demonstrated through hydrogel casting, embedded bioprinting, and modular stacking within 3D PCL fiber scaffolds, ensuring hydrogel integrity while maintaining medium diffusion for sustained cell survival and function. In vivo studies confirmed the proangiogenic nature of PCL fiber scaffolds with tissue bridging via cell infiltration and ECM collagen deposition, underscoring clinical translational potential. By integrating topographic and volumetric flexibility, this approach advances biofabrication strategies for functional tissue and organ constructs.