3D cellulose nanofiber scaffold with homogeneous cell population and long-term proliferation

Tumor-originated and undefined extracellular matrices (ECMs) such as Matrigel™ have been widely used in three-dimensional (3D) cell and tissue culture, but their use is unacceptable in clinical cell therapies. In this study, we proposed a 3D cellulose nanofiber (CNF) hydrogel that has great potential as a defined tissue-engineering scaffold, especially for osteoblast culture. The CNF hydrogel showed attractive features as a cell scaffold material. It exhibited a ~ 1.4-fold higher diffusion coefficient (~ 2.98 × 10⁻⁷ cm²/s) of macromolecules such as bovine serum albumin than does Matrigel™ (< 2.2 × 10⁻⁷ cm²/s) due to the former’s higher porosity (> 95%) and pore size (~ 310.8 μm). Most pre-osteoblast cells that are encapsulated in the CNF hydrogel were immediately locked without sinking by instant hydrogen bond cross-linking between CNFs, whereas cells encapsulated in Matrigel™ sank to the bottom of the scaffold due to the slow sol–gel transition (> 20 min). The elastic modulus of the cell-encapsulated CNF hydrogel could be reinforced by further calcium-mediated cross-linking without cytotoxicity. As a result, the pre-osteoblast cells in the CNF hydrogels were homogeneously distributed in the 3D structure, proliferated for 3 weeks, and successfully differentiated. Overall, CNFs showed that it has potential to be used in tissue engineering as a defined ECM component.