Figure 1.

Schematic of in situ crosslinking approach for 3D bioprinting. Bioinks are loaded into a syringe and irradiated with light through a photopermeable capillary during extrusion, resulting in the plug flow of filaments through the end of the capillary. There are numerous variables within the printing approach, including the bioink formulation, the printing parameters, and the capillary setup, all of which can influence printing success. These should be balanced to regulate the residence time of the bioink within the light path (Q, L, W), as well as the reaction kinetics of crosslinking ([I], I₀). The intensity of light across the capillary lumen varies as a function of light attenuation due to the capillary walls and absorbing species within the designed bioink.