Alginate-Lysozyme Nanofibers Hydrogels with Improved Rheological Behavior, Printability and Biological Properties for 3D Bioprinting Applications

In this study, alginate nanocomposite hydrogel bioinks reinforced with lysozyme nanofibers (LNFs) were developed. Alginate-LNF (A-LNF) suspensions with different LNF contents (1, 5 and 10 wt.%) were prepared and pre-crosslinked with 0.5% (w/v) CaCl2 to formulate A-LNF inks. These inks exhibit proper shear-thinning behavior and good recovery properties (similar to 90%), with the precrosslinking step playing a crucial role. A-LNF fully crosslinked hydrogels (with 2% (w/v) CaCl2) that mimic 3D printing scaffolds were prepared, and it was observed that the addition of LNFs improved several properties of the hydrogels, such as the morphology, swelling and degradation profiles, and mechanical properties. All formulations are also noncytotoxic towards HaCaT cells. The printing parameters and 3D scaffold model were then optimized, with A-LNF inks showing improved printability. Selected A-LNF inks (A-LNF0 and A-LNF5) were loaded with HaCaT cells (cell density 2 x 10(6) cells mL(-1)), and the cell viability within the bioprinted scaffolds was evaluated for 1, 3 and 7 days, with scaffolds printed with the A-LNF5 bioink showing the highest values for 7 days (87.99 +/- 1.28%). Hence, A-LNF bioinks exhibited improved rheological performance, printability and biological properties representing a good strategy to overcome the main limitations of alginate-based bioinks.

Automated summary

In this study, alginate nanocomposite hydrogel bioinks reinforced with lysozyme nanofibers were developed. The bioinks showed improved rheological performance, printability, and biological properties, making them a promising solution to overcome the limitations of alginate-based bioinks. The optimized A-LNF inks exhibited good shear-thinning behavior, recovery properties, and noncytotoxicity, providing a solid foundation for bioprinting applications.