In Vivo Study of Osseointegrable Bone Calcium Phosphate (CaP) Implants Coated with a Vanillin Derivative

<b>Background/Objectives</b>: Orthopaedic infections associated with implant surgery remain a major public health concern, often caused by bacterial colonization of implant surfaces. <i>Staphylococcus epidermidis</i> is among the most common pathogens involved. Developing antimicrobial bone implants that prevent infection without compromising bone regeneration is therefore essential. This study investigates the antimicrobial and osteointegrative performance of calcium phosphate (CaP) materials functionalized with vanillin, an essential oil component with known antimicrobial properties. <b>Methods</b>: Commercial CaP regenerative materials were covalently coated with vanillin. Antibacterial activity was evaluated against <i>Staphylococcus epidermidis</i> RP62A using viability assays. In vivo osseointegration was assessed in New Zealand female rabbits implanted with vanillin-coated and uncoated CaP scaffolds. <b>Results</b>: Vanillin-functionalized CaP scaffolds exhibited strong bactericidal activity at 24 h and bacteriostatic effects at 48 h at a concentration of 10 mg/mL. In vivo analyses showed no significant differences in osseointegration between vanillin-coated implants and control CaP materials. <b>Conclusions</b>: Vanillin-functionalized CaP materials maintain a high safety profile without impairing bone integration, supporting their potential use in clinical applications.