MorphoPipe: A pipeline for seamless toolpath design of heterogeneous tubular melt electrowritten scaffolds

Melt electrowriting (MEW) enables the fabrication of tubular scaffolds with micrometer-scale precision but critically depends on continuous and smooth toolpaths. Together with the intrinsically unintuitive nature of tubular design, this requirement has constrained the realization of spatially heterogeneous microarchitectures characteristic of many native tubular organs. Here, we present MorphoPipe , a workflow that enables intuitive and rational engineering of architecturally heterogeneous tubular scaffolds while preserving uninterrupted MEW jet deposition. In MorphoPipe , a conventional tubular toolpath is conceptually cut along a longitudinal seam and unwrapped into a planar curve, which is then strategically deformed to introduce controlled microarchitectural heterogeneity before being rewrapped onto the tubular surface. Toolpath continuity and smoothness after rewrapping are ensured by three theoretical principles: ( i ) a smoothness condition for planar curves, ( ii ) a periodicity criterion for intrinsically periodic deformations, and ( iii ) a finite-replication strategy that periodizes local deformations without compromising print continuity. The complete workflow is implemented within an integrated design platform and experimentally validated through the fabrication of four biomimetic tubular scaffolds, including arteriovenous grafts, heart-valve grafts, flow diverters, and tracheal grafts. Collectively, this work establishes a robust and generalizable foundation for MEW-based engineering of spatially sophisticated tubular tissues.