A comparative analysis of pulp-derived nanocelluloses for 3D bioprinting facial cartilages

Nanocelluloses have attracted significant interest in the field of bioprinting, with previous research outlining the value of nanocellulose fibrils and bacterial nanocelluloses for 3D bioprinting tissues such as cartilage. We have recently characterised three distinct structural formulations of pulp-derived nanocelluloses: fibrillar (NFC), crystalline (NCC) and blend (NCB), exhibiting variation in pore geometry and mechanical properties. In light of the characterisation of these three distinct entities, this study investigated whether these structural differences translated to differences in printability, chondrogenicity or biocompatibility for 3D bioprinting anatomical structures with human nasoseptal chondrocytes. Composite nanocellulose-alginate bioinks (75:25 v/v) of NFC, NCC and NCB were produced and tested for print resolution and fidelity. NFC offered superior print resolution whereas NCB demonstrated the best post-printing shape fidelity. Biologically, chondrogenicity was assessed using real time quantitative PCR, dimethylmethylene blue assays and histology. All biomaterials showed an increase in chondrogenic gene expression and extracellular matrix production over 21 days, but this was superior in the NCC bioink. Biocompatibility assessments revealed an increase in cell number and metabolism over 21 days in the NCC and NCB formulations. Nanocellulose augments printability and chondrogenicity of bioinks, of which the NCC and NCB formulations offer the best biological promise for bioprinting cartilage.