Resolving differential vascular graft remodeling using longitudinal multiphoton tracking in a 3D culture platform

The long-term performance of tissue-engineered scaffolds, particularly small-diameter vascular grafts, is shaped by remodeling events at the tissue-graft interface, yet these processes remain difficult to resolve longitudinally and at microstructural resolution in conventional implantation models. Here we develop an organotypic artery-graft model that preserves cylindrical vessel geometry and enables non-destructive label-free multiphoton monitoring of interface remodeling. Using second harmonic generation and two-photon excited fluorescence, we capture evolving fibrillar collagen architecture and cellularization over time, demonstrate compatibility with multiple biomaterial classes, and show integration with rat and mouse explants, live-cell dyes, and fluorescent reporter tissues. The platform resolved distinct remodeling responses to transforming growth factor-β isoforms (TGF-β1, -β2, and -β3), with differential shifts in collagen-fiber distributions, accompanied by changes in matrix-remodeling and contractile gene expression. Across two graft designs, culture-derived remodeling phenotypes, collagen fiber distributions, and initial trajectories agreed with those observed in long-term 6-month interpositional explants. Together, these results establish an accessible intermediate platform for interrogating artery-graft remodeling, tracking these trajectories, and prioritizing graft designs through interface-resolved outcomes before and alongside animal implantation studies.