Characterisation, biocompatibility, and immunogenicity of tunicate-derived nanocellulose for tissue engineering

Nanocellulose has gained significant traction as a viable material for tissue engineering. We investigated 3 chemically distinct varieties of tunicate-derived nanocellulose: carboxymethylated (CTC), enzymatically pretreated (ETC), and TEMPO-oxidised (TTC), with the objective of determining a candidate scaffold material for tissue engineering. The physicochemical properties of each variant were characterised by SEM, AFM, Raman spectroscopy, and mechanical compression. Notably, ETC had the lowest aspect ratio, smallest pore diameter, greatest optical clarity, and highest ultimate compressive strength, indicating superiority as a candidate tissue engineering scaffold. Rheological analysis revealed a significantly higher loss tangent for ETC and reduced viscosity at higher temperature, compared with CTC and TTC. ETC also demonstrated superior line width resolution both before and after calcium chloride crosslinking, indicating superior print fidelity and post-printing shape retention. All materials exhibited excellent biological compatibility by live/dead staining of embedded primary chondrocytes. NC was nonimmunogenic and did not stimulate the secretion of proinflammatory mediators when combined with whole blood. The implantation of NC-based bioink into immunocompetent mice did not evoke an adverse immunological reaction, and explanted constructs retained a stable form for 14 days. Tunicate-derived NC, particularly ETC, demonstrates excellent structural, biological, and mechanical properties with great potential for tissue engineering applications.