Abstract
Prosthetic joint infections (PJI) occur infrequently, but they represent the most devastating complication with high morbidity and substantial cost. Staphylococcus aureus and coagulase-negative S. epidermidis are the most common infecting agents associated with PJI.
During the past decades, novel materials have been developed to improve osseointegration of implants. Recently has been demonstrated that by using nanosized hydroxyapatite (HA) coatings, since it combines nanoroughness and bone-like chemistry in a synergistic effect, it promotes better osseointegration when compared to uncoated metal implants. In a further step, due to the known bactericidal properties of fluor, the aim of this study is to evaluate the biofilm development on fluorohydroxyapatite (FHA) compared to HA.
Coatings were grown on stainless steel substrates by Pulsed Laser Deposition (PLD) technique using fluorohydroxyapatite targets of marine origin. A comprehensive physicochemical characterization of the coatings was performed using SEM, EDS, XPS and XRD. Biological in vitro tests using the pre-osteoblastic cell line (MC3T3-E1) demonstrated the non-cytotoxicity of FHA coatings, the healthy cell proliferation and their osteogenic activity.
The S. aureus 15981 (Valle et al.) and S. epidermidis ATCC 35984 strains adherence study was performed introducing each probe in a well of 96-well plate with 200 µl containing 106 colony forming units (CFU/mL) intryptic soy broth supplemented with 1% glucose and was incubated at 37°C 5% CO2 for 24 hours. After incubation, the medium was removed and three washes with 0.9% NaCl sterile saline were performed. The biofilm was disrupted by sonication at 50–60 Hz for 5 min. The CFU/cm2 was estimated by drop plate method. All of the experiments were performed in triplicate.
Statistical analysis was performed by non-parametric unilateral Wilcoxon”s test with a level of statistical significance of 0.05.
The results showed a significant (p=0.02475) 2.4-fold reduction in S. epidermidis biofilm formation on FHA (logUFC/cm2 = 6.87) compared to HA (logUFC/cm2 = 7.25); and also a significant (p=0.042) 3.7-fold reduction in S. aureus 15981 biofilm formation.
In conclusion, according our results FHA is a promising biomaterial that promotes osseointegration and decreases the staphylococcal biofilm that could avoid PJI. Further studies will be necessary.
