Nanocomposite hydrogel-based bioinks composed of a fucose-rich polysaccharide and nanocellulose fibers for 3D-bioprinting applications

Hydrogels are the most common type of bioinks, yet, finding adequate biomaterials to develop suitable bioinks for 3D bioprinting remains challenging. Herein, innovative hydrogel bioinks were developed by combining nanofibrillated cellulose (NFC) with a fucose-rich polysaccharide, FucoPol (FP), still unexplored for 3D bioprinting. NFC/FP bioinks with different mass proportions, namely 1:1, 2:1, 3:1 and 4:1, were prepared and denominated as NFC1FP, NFC2FP, NFC3FP and NFC4FP. A formulation without NFC was also prepared for comparison purposes (NFC0FP). The rheological properties of the bioinks were enhanced by the addition of NFC, as evidenced by the increase in shear viscosity from 1.39 ± 0.03 Pa s (NFC0FP) to 2933.7 ± 137.9 Pa s (ink NFC4FP) and by the 3D printing of complex structures with high shape fidelity (Pr ≈ 0.9). The stability and mechanical properties of the crosslinked hydrogels were also improved, with Young’s modulus increasing from 0.12 ± 0.04 MPa (NFC0FP) to 2.45 ± 0.06 MPa (NFC4FP). The successful 3D bioprinting of both A375 (melanoma) and HaCaT (keratinocyte) cell-laden bioinks translated into elevated cell viabilities (above 88 %) up to 21 days post-bioprinting. These results highlight the potential and versatility of NFC/FP bioinks for the bioprinting of 3D skin tissue analogues for biomedical applications.