New Progress in Carboxymethyl Chitosan-rGO Scaffold Research for Oral Bone Regeneration: Optimal Efficacy at The 0.5%-1% Concentration Window

Recently, a research team from the School and Hospital of Stomatology, Fujian Medical University published a study in the Journal of Biomedical Materials Research Part A, systematically revealing the concentration-dependent effects of composite scaffolds made of carboxymethyl chitosan (CMC) and reduced graphene oxide (rGO) on oral bone regeneration, and identifying 0.5%-1% rGO as the optimal concentration window.

To address the limitations of traditional graft materials in alveolar bone defect repair, the research team prepared CMC-rGO composite scaffolds with rGO mass fractions of 0%, 0.5%, 1%, and 2%, and systematically evaluated them from morphology and mechanical properties to in vitro cytocompatibility and in vivo osteogenic performance. The results showed that the addition of rGO increased the scaffold tensile strength from 1.64 MPa to 8.13 MPa and the elastic modulus from 1.14 MPa to 25.05 MPa, with mechanical properties showing significant concentration-dependent enhancement. In in vitro experiments, 0.5%-1% rGO scaffolds significantly promoted the survival and alkaline phosphatase activity of MC3T3-E1 osteoblast precursor cells, and markedly enhanced osteogenic differentiation; 2% rGO scaffolds exhibited cytotoxicity. A rat calvarial defect model further confirmed that new bone formation, mineralization, and trabecular maturity in the 1% rGO group were superior to those in the other groups.

This study is the first to clarify the "double-edged sword" effect of rGO in CMC-based bone repair scaffolds: an appropriate amount of rGO can simultaneously improve scaffold mechanical integrity and osteogenic activity, whereas an excessive amount is counterproductive. The optimal concentration window of 0.5%-1% provides a key dose-design basis for the clinical translation of scaffolds for oral bone tissue engineering.