Scalable Borophene Nanosheet Coatings Strengthen Monetite Scaffolds and Drive Osteogenic Differentiation

Calcium phosphate cements (CPCs) are widely used in bone repair; however, their limited mechanical strength restricts application in load‑bearing environments. While graphene‑based nanomaterials have been investigated as reinforcing agents, concerns related to their biodegradability and long‑term cytotoxicity remain unresolved. Here, we report for the first time a borophene‑functionalized monetite scaffold incorporating biodegradable two‑dimensional boron nanosheets to simultaneously enhance mechanical integrity and osteoinductive performance. Borophene nanosheets were synthesized via a scale-up exfoliation approach and integrated into monetite scaffolds, resulting in a 40% increase in diametral compressive strength compared to pristine monetite. In vitro evaluation using MC3T3‑E1 preosteoblasts demonstrated excellent cytocompatibility, with significantly enhanced cell proliferation and osteogenic differentiation. Osteoinductive activity was confirmed by elevated alkaline phosphatase activity and pronounced upregulation of osteogenic markers, including Sparc (2.31‑fold, day 7), Runx2 (1.80‑fold, day 14), and Bglap (4.42‑fold, day 21). The results of this study identify borophene as a biocompatible and degradable alternative to graphene and MXene-based nanofillers and highlight its potential as a multifunctional reinforcement strategy for CPC scaffolds aimed at mechanically robust and biologically active bone regeneration.