Evaluation of three-dimensional silver-doped borate bioactive glass scaffolds for bone repair: Biodegradability, biocompatibility, and antibacterial activity

The development of synthetic scaffolds with a desirable combination of properties, such as bioactivity, the ability to locally deliver antibacterial agents and high osteogenic capacity, is a challenging but promising approach in bone tissue engineering. In this study, scaffolds of a borosilicate bioactive glass (composition: 6Na 2 O, 8K 2 O, 8MgO, 22CaO, 36B 2 O 3 , 18SiO 2 , 2P 2 O 5 ; mol%) with controllable antibacterial activity were developed by doping the parent glass with varying amounts of Ag 2 O (0.05, 0.5, and 1.0 wt%). The addition of the Ag 2 O lowered the compressive strength and degradation of the bioactive glass scaffolds but it did not affect the formation of hydroxyapatite on the surface of the glass as determined by energy dispersive x-ray analysis, x-ray diffraction, and Fourier transform infrared analysis. The Ag 2 O-doped scaffolds showed a sustained release of Ag ions over more than 8 weeks in simulated body fluid and resistance against colonization by the bacterial strains Escherichia coli and Staphylococcus aureus . In vitro cell culture showed better adhesion, proliferation, and alkaline phosphatase activity of murine osteoblastic MC3T3-E1 cells on the Ag 2 O-doped bioactive glass scaffolds than on the undoped scaffolds. The results indicate that these Ag-doped borosilicate bioactive glass scaffolds may have potential in repairing bone coupled with providing a lower risk of bacterial infection.