A New Perspective in Nanocellulose-Based Materials for Biomineralization and Strategies for Bone Repair.

Repairing large bone defects is a significant clinical challenge. In this context, cellulose nanomaterials, such as bacterial nanocellulose (BNC), cellulose nanofibrils (CNF), and cellulose nanocrystals (CNC), have emerged as promising alternatives due to their natural origin and mechanical properties. Particularly noteworthy is their chemical malleability, which thereby confers specific functionalities. This comprehensive literature review evaluates the efficacy of nanocellulose scaffolds for the repair of critical bone defects, with a focus on the impact of surface modifications. The effects of inserting bioactive functional groups and adding metal ions are analyzed in vitro and in vivo models. The parameters evaluated include material mineralization (production and precipitation of biogenic apatite, Ca/P ratio), cell adhesion and proliferation, bioadsorption, degradation, and toxicity. The results discussed provide valuable insights into the chemical and biological processes of bone formation, supporting a new paradigm: cellulose is no longer just an "eco-friendly filler" but has become a programmable structural scaffold. The trends highlighted in this review open new avenues for the treatment of bone diseases and tissue regeneration.