Structured light projection using image guide fibers for in situ photo-biofabrication

Light-based biofabrication techniques have revolutionized the field of tissue engineering and regenerative medicine. Specifically, the projection of structured light, where the spatial distribution of light is controlled at both macro- and micro-scale, has enabled precise fabrication of complex three-dimensional structures with high resolution and speed. However, despite almost two decades of progress, biofabrication processes have been mostly limited to benchtop devices which limit the flexibility in terms of where the fabrication can occur. Here, we demonstrate a Fiber-assisted Structured Light (FaSt-Light) projection apparatus for rapid in situ crosslinking of photoresins. This approach uses image-guide fiber bundles which can project bespoke images at multiple wavelengths, enabling flexibility and spatial control of different photoinitiation systems and crosslinking chemistries and also the location of fabrication. We demonstrate coupling of different sizes of fibers and different lenses attached to the fibers to be able to project small (several mm) or large (several cm) images for material crosslinking. FaSt-Light allows control over the cross-section of the crosslinked resins and enables the introduction of microfilaments which can further guide cellular infiltration, differentiation and anisotropic matrix production. The proposed approach could lead to a new range of in situ biofabrication techniques which improve the translational potential of photo-fabricated tissues and grafts.