ABSTRACT: Engineering organized microvascular networks remains a critical challenge in tissue engineering and regenerative medicine. While biochemical approaches for patterning angiogenesis via growth factor delivery have shown promise, their inability to pattern sustained growth factor gradients with precise spatiotemporal control limit their effectiveness. Here, we demonstrate that dynamically patterned mechanical forces can provide precise spatiotemporal control over angiogenic sprouting in 3D microvascular networks. We developed a magnetically actuated 3D human vessel-on-a-chip platform that integrates a perfusable endothelialized microchannel within a collagen matrix and allows non-invasive, tunable, multi-axial mechanical stimulation across all three spatial dimensions and time (4D). Using an automated 3-axis actuator, we systematically investigated how strain magnitude, frequency, and direction modulate endothelial cell behavior and vessel morphogenesis. Dynamic mechanical stimulation at physiological strain magnitudes (5–15%) enhanced endothelial alignment and barrier function while promoting angiogenesis in a strain-magnitude–dependent manner: lower dynamic strain (5%) maximized sprout initiation, whereas higher dynamic strain (15%) promoted elongation of individual sprouts. Sequential reorientation of strain direction further reprogrammed sprouting trajectories along X, Y, and Z directions, generating complex 3D microvascular geometries such as L-shaped branches. RNA sequencing revealed mechanically induced transcriptional profiles distinct from unstimulated controls, characterized by coordinated upregulation of angiogenic (VEGFA, FGFR1, PDGFA), mechanotransduction (ANKRD1, ZYX, FOSB), extracellular matrix remodeling (ABI3BP, SPOCK1, COL8A1), and barrier-associated (SERPINE2, P2RY1) genes and pathways. Functional perturbation of the mechanosensitive ion channel Piezo1 attenuated strain-induced sprouting without altering barrier stabilization, indicating that dynamic mechanical stimulation engages multiple mechanotransduction pathways to regulate angiogenic growth. Collectively, these findings establish a strategy for spatiotemporally controlled angiogenesis through engineered mechanical cues and demonstrate that 4D force patterning can program vascular morphogenesis while preserving function. This approach provides a foundation for engineering hierarchically organized vascular networks for tissue regeneration and disease modeling.
