Printability assessment workflow of thermosensitive photocurable biomaterial ink for microextrusion bioprinting.

Microextrusion bioprinting enables heterogeneous constructs with high shape fidelity to be fabricated through the deposition of a bioink with the desired physico-chemical and biological characteristics. In this work, a novel semi-synthetic hydrogel, consisting of gelatin methacrylate and Pluronic F127, has been specifically formulated to match the requirements of microextrusion bioprinting process. By merging the thermosensitive characteristics of Pluronic with the cross-linking features of gelatin methacrylate, the formulation showed a printability window characterized by good shape retention and chemical stability following photo- crosslinking, as demonstrated by a thorough printability assessment, performed employing empirical predictive models. The mechanical properties of the constructs were comparable to those of soft tissues, widening the range of applicability in soft tissue engineering. The bioink was successfully applied to the fabrication of multilayered porous constructs preserving high levels of cell viability. Interestingly, the spatial arrangement of the cells showed a high degree of alignment along the deposition direction. Overall, the manufacturing process developed herein could represent a promising strategy to design three-dimensional models with predetermined cellular alignment.