Path Planning and Optimization for Embedded Bioprinting of Vascular Networks

The vascular system plays a crucial role in the biomanufacturing of artificial organs and tissues, which enables the transport, exchange, and regulation of essential substances throughout printed constructs. However, the intricate geometrical architecture and potential spatial interconnections of vascular networks present a grand challenge to accurately replicate such systems through three-dimensional (3D) bioprinting. In this work, a path-planning platform is developed to fulfill two essential requirements: 1) eliminating undesired spatial conflicts during the printing of vascular networks and 2) maximizing printing efficiency. Using this platform, the printing paths of complicated vascular architectures are generated and optimized. Due to its exceptional capability of printing complex 3D structures, embedded bioprinting is leveraged as the biomanufacturing approach to construct the vascular architectures, in which a yield-stress liquid bath with suitable rheological properties is developed. A photocurable hydrogel ink is selected and designed to enable branch-by-branch printing of vascular architectures along the optimized printing paths. By monitoring the printing process and comparing the printing time, toolpath length, and extrusion start/stop events, the efficacy of the path-planning platform is validated. This work not only provides an engineering solution for the path planning and optimization for embedded 3D bioprinting but also paves the way for efficient fabrication of vascular systems with complicated architectures and living cells in the future.