Nanographene oxide-calcium phosphate to inhibit Staphylococcus aureus infection and support stem cells for bone tissue engineering.

Staphylococcus aureus (S. aureus) is a major pathogen for osteomyelitis. Calcium phosphate bone cement (CPC) paste is promising for orthopedic uses. Nanostructured graphene oxide (GO) showed antibacterial effect on Gram-positive bacteria. However, there has been no report of incorporating GO into CPC. The objectives of this study were to (a) develop an injectable and mechanically strong CPC-chitosan paste containing GO and (b) investigate the inhibition of S. aureus infection and the promotion of human umbilical cord mesenchymal stem cells (hUCMSCs) for bone regeneration. Injectable CPC-chitosan-GO paste was fabricated. Flexural strength, elastic modulus, and work-of-fracture of the CPC-chitosan and CPC-chitosan-GO bars were evaluated. Antibacterial effects against S. aureus biofilms were determined. hUCMSC growth and viability on disks were investigated. CPC-chitosan-GO bars had a flexural strength of 7.2 ± 1.6 MPa, matching that of CPC-chitosan control without GO. CPC-chitosan-GO had strong antibacterial effects on S. aureus, with an inhibition zone of 55.2 ± 2.5 mm, greater than that of CPC-chitosan control (30.1 ± 2.0 mm) (p < 0.05). CPC-chitosan-GO had potent antibacterial activity on S. aureus biofilms in vitro (p > 0.05). The injectable and antibacterial CPC-GO paste had no toxic effect, yielding excellent hUCMSC growth and viability on disks. The CPC-chitosan-GO had injectability, good strength, strong antibacterial effects, and excellent stem cell attachment and growth. CPC-chitosan-GO is promising for dental, craniofacial, and orthopedic applications to control infections and good biocompatibility to support stem cell viability to enhance bone regeneration.