Introduction: New biologically relevant materials are needed as scaffolds for human cells in drug development, tissue models and regenerative medicine. Currently there is wide transition from animal-derived materials to synthetic and other natural ones. Wood-derived nanofibrillated cellulose (NFC) hydrogel is highly biocompatible and inert material that has been shown to provide an effective support matrix for culturing various cell types in vitro in 3D. NFC has been shown to be biocompatible also in vivo. As an animal-free matrix, NFC enables possibilities in applications aiming for clinical use, such as stem cell proliferation, organoids, and wound care.

Materials and Results: (A) Pluripotent stem cells were embedded in NFC hydrogel and cultured up to 26 days. Pluripotency was analysed with OCT4 and SSEA-4 marker expression, in vitro EB-mediated differentiation, and teratoma assay. Cells proliferated in NFC without feeder cells, formed spheroids with 100-200 µm diameter, and the cells retained their pluripotency without changes in karyotypes. (B) Renal organoids can mimic the structure and function of in vivo kidneys. Organoids were cultured from primary mouse embryonic kidney metanephric mesenchymal cells followed by chemical induction to undergo nephrogenesis. Cells were embedded in NFC which reduced the distortion or stress-induced effects during the nephrogenesis process. This allowed the organoids to grow in conditions mimicking better the natural physiological environment. (C) Wound healing is a complex and continuous process which involves a variety of cells, soluble factors, and extracellular matrices. The potential of NFC for wound treatment was studied as hydrogel-based dressing and hydrogels. In addition, its potential as a cell scaffold for human adipose-derived mesenchymal stromal cells (hASCs) was studied. Clinically, NFC wound dressing has been shown to provide efficient wound healing at skin graft donor sites, and as hydrogel it did not affect wound closure rate in vivo or altered a normal healing process. Foreign-body reaction was also not observed. ASCs cultured on top of NFC dressing maintained their undifferentiated state, immunological properties and high cell viability. These findings offer a good platform to continue the development of the cell-based wound treatment.

Conclusion: Nanofibrillated cellulose is a highly biocompatible material that offers well-defined matrix for various cell types in vitro and enables opportunities also in regenerative medicine applications, such as cell transplantations, due to its excellent physical properties. Authors would like to thank Yan-Ru Lou, Ulla Saarela, and Jasmi Snirvi for performing the experiments.