3D vector field-guided toolpathing for 3D bioprinting.

Complex fibrous microarchitectures are common in biology, with fiber orientation playing a key role in the structure-function relationships that govern tissue behavior. Directional imaging modalities, such as diffusion tensor magnetic resonance imaging (DTMRI), can be used to derive a 3D vector map of fiber orientation. Incorporating this alignment information into engineered tissues remains a challenging and evolving area of research, with direct incorporation of directional imaging data into engineered tissue structures yet to be achieved. Here we describe an algorithmic framework, entitled Nonplanar, Architecture-Aligned Toolpathing for In Vitro 3D bioprinting (NAATIV3), which processes DTMRI data to map tissue fibers, reduce them to a representative subset, remove conflicting fibers, select a printable sequence, and output a G-code file. DTMRI data from a human left ventricle was used to 3D print fibered models with high accuracy. It is anticipated that NAATIV3 is generalizable beyond the cardiac application demonstrated here. Directional imaging data from a variety of organs, disease states, and developmental timepoints may be processible by NAATIV3, enabling the creation of models for understanding development, physiology, and pathophysiology. Furthermore, the NAATIV3 framework could be extended to bioengineered food manufacturing, plant engineering, and beyond.