Thermo-/Photo-Responsive Bioink for Improved Printability in Extrusion-Based Bioprinting

Extrusion-based bioprinting has shown great promise for manufacturing constructs, especially for 3D cell culture. However, the number of bioink candidates suitable for extrusion-based bioprinting techniques is greatly limited, as they meet the opposing requirements for printability with certain rheological features and for biochemical functionality with a desirable microenvironment. In this study, a blend of silk fibroin (SF) and iota-carrageenan (CG) was chosen as a cell-favorable printable material. The SF/CG ink exhibited appropriate viscosity and shear-thinning behaviors, along with the rapid sol-gel transition characteristic of CG. By employing photo-crosslinking of SF, the printability with a Pr value close to 1 and the structural integrity of the 3D constructs were significantly improved within a matter of seconds. The printed constructs had a Young's modulus of around 250 kPa, making them suitable for keratinocyte and myoblast cell culture. Additionally, the high cell adhesiveness and viability (exceeding 98%) of the encapsulated cells demonstrated the significant potential of this 3D cellular scaffold for applications in skin and muscle tissues, which can be easily managed with an extrusion-based bioprinter.