Novel High-Efficient Method to Generate Fragmented Nano- and Microfibers Enabling an Additive for Bio-Inks.

As an emerging technology, biofabrication combines biopolymers and living cells to create functional tissues, allowing the development of structures that closely mimic native tissues. The use of fiber-reinforced materials is of particular interest, as it enhances both mechanical properties and cellular behavior. Incorporating fiber fragments into bio-inks not only strengthens printed structures but also supports cell survival by lowering polymer concentrations and thus the stress exerted on the cells during printing. A key factor in optimizing fiber-reinforced bio-inks is the controlled fiber shortening, comprising cutting or breaking, which improves printability and mechanical integrity of printed constructs. However, current methods for fiber fragmentation face significant limitations, including material-specific dependencies, scalability challenges, and requirements of specialized equipment, which may not be accessible in all laboratories. To overcome these challenges, we introduce a novel approach utilizing ultraviolet irradiation to achieve controlled fiber fragmentation. The average fiber length resulting from specific irradiation times can be estimated using a multi-modal Weibull analysis. This technique is validated on fibers made of polycaprolactone (PCL) and gelatin blends, demonstrating its cost-effectiveness, biocompatibility, and simplicity. This study provides a practical solution for fiber fragment production and average length estimation, offering an accessible and scalable alternative for fiber-based biofabrication applications.