Polydopamine-Modified Composite Bone Cement for Cancellous Bone Repair: Synergism of Bioactivity, Antibacterial Properties, and Biodegradability

Infection-prone bone defects require multifunctional materials. We developed a novel degradable composite bone cement: polydopamine-modified calcium polyphosphate (CPP@PDA) combined with tricalcium silicate (C3S). CPP@PDA provides bioactivity and antibacterial effects, while C3S ensures sustained bioactive ion release. The cement exhibited >74% antibacterial efficacy (Staphylococcus aureus, Escherichia coli), with bacterial survival at 15.9 ± 1.2% and 26.1 ± 0.8%. Controlled degradation released Ca2+ and silicon species, stimulating osteogenesis, shown by increased alkaline phosphatase (ALP) activity and upregulated RUNX2, COL1, and OPN markers. The material also demonstrated antioxidant and antiinflammatory properties, reducing oxidative stress and modulating immune responses to support bone regeneration. This CPP@PDA composite cement, with synergistic antibacterial, biodegradable, and osteogenic functionalities, shows significant potential for treating infection-prone cancellous bone defects.