Abstract text (incl. figure legends and references)
Question: In the context of tissue engineering and regenerative medicine, biofabrication can be defined as "'the automated generation of biologically functional products with structural organization from living cells, bioactive molecules, biomaterials, cell aggregates such as micro-tissues, or hybrid cell-material constructs, through bio-printing or bio-assembly and subsequent tissue maturation processes".
Bio-inks are fundamental to high-resolution bio-printing of dimensionally stable scaffolds with sufficient mechanical properties. The development of bio-inks capable of being 3D-printed into cell-containing bio-fabricates is highly demanding. Structural integrity and favorable mechanical properties can be achieved by applying high polymer concentrations in hydrogels. This often comes at the expense of cell performance since cells may become entrapped in the dense matrix. This drawback can be addressed by incorporating fibers as reinforcing fillers that strengthen the overall bio-ink structure and provide a second hierarchical micro-structure.
Methods: In this work, we systematically studied the potential impact of collagen-coated short PCL-nano-fibers on cells after being printed in eADF4(C16) bio-inks. We used U-87 MG cells, to investigate the impact of PCL-fiber-reinforcement on cell performance with respect to cell performance studying survival, proliferation and cell morphology up to 7 days in culture. Healthy cells in a cell-friendly environment undergo a change in morphology from a roundish shape, after printing, to an extended, differentiated state. Therefore, individual cells were analysed according to circularity, roundness, solidity and sphericity.
Results and Conclusions: In general, we observed that PCL nano-fibers improve cell viability and induced significant morphological changes. Therefore nano-fibers have a positive impact for the overall cell performance in 3D constructs and should be considered as easy-modifiable fillers to upgrade bio-inks.