Microbiological and Cellular Evaluation of a Fluorine-Phosphorus-Doped Titanium Alloy, a Novel Antibacterial and Osteostimulatory Biomaterial with Potential Applications in Orthopedic Surgery

Abstract

Joint prosthesis failure is mainly related to aseptic loosening and prosthetic joint infections, both of which are associated with high morbidity and substantial costs for patients and health systems. The development of a biomaterial that is capable of stimulating bone growth while minimizing bacterial adhesion would reduce the incidence of prosthetic failure. We report antibacterial and osteostimulatory effects in a novel fluorine-phosphorus (F-P)-doped TiO2 oxide film grown on Ti-6Al-4V alloy with a nanostructure of bottle-shaped nanotubes (bNT) using five bacterial species (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia) and MCT3T3-E1 osteoblastic cells. The interaction between the bacteria and bNT Ti-6Al-4V was complex, as the adhesion of four bacterial species decreased (two staphylococcus species, E. coli, and S. maltophilia), and the viability of staphylococci and S. maltophilia also decreased because of the aluminum (Al) released by bNT Ti-6Al-4V. This released Al can be recruited by the bacteria through siderophores and was retained only by the Gram-negative bacteria tested. P. aeruginosa showed higher adhesion on bNT Ti-6Al-4V than on chemically polished (CP) samples of Ti-6Al-4V alloy and an ability to mobilize Al from bNT Ti-6Al-4V. The cell adhesion and proliferation of MCT3T3-E1 osteoblastic cells significantly increased at 48 and 168 h, as did the matrix mineralization of these cells and the gene expression levels of three of the most important markers related to bone differentiation. According to our results, the bNT Ti-6Al-4V alloy could have clinical application, preventing infection and stimulating bone growth and thus preventing the two main causes of joint prosthesis failure. IMPORTANCE This work evaluates F-P-doped bNT Ti-6Al-4V from microbiological and cellular approaches. The bacterial results highlight that the antibacterial ability of bNT Ti-6Al-4V is the result of a combination of antiadhesive and bactericidal effects exerted by Al released from the alloy. The cell results highlight that F-P bNT Ti-6Al-4V alloy increases osseointegration due to modification of the chemical composition of the alloy resulting from P incorporation and not due to the nanostructure, as reported previously. A key finding was the detection of Al release from inside the bNT Ti-6Al-4V nanostructures, a result of the nanostructure growth during the anodizing process that is in part responsible for its bactericidal effect.

Staphylococcus aureus Prosthetic Joint Infection Is Prevented by a Fluorine‐ and Phosphorus‐Doped Nanostructured Ti–6Al–4V Alloy Loaded With Gentamicin and Vancomycin

“…The Ti–6Al–4V alloy is commonly used in orthopedic implants due to its favorable mechanical properties, corrosion resistance, and biocompatibility . We described the possibility of fabricating bottle‐shaped nanotubular oxide layers doped with fluorine (F) and phosphrous (P) by anodizing from Ti–6Al–4V to provide osseostimuling effect both in vitro and in vivo by avoiding aseptic loosening. Furthermore, these bottle‐shaped nanotubes can be loaded with drugs such as ibuprofen .…”

Urine Aluminum Concentration as a Possible Implant Biomarker of Pseudomonas aeruginosa Infection Using a Fluorine- and Phosphorus-Doped Ti-6Al-4V Alloy with Osseointegration Capacity

“…This Al 3+ is not only the product of corrosion but also the result of the release of the cation retained inside the bottle-shaped nanotubes after the anodizing process. 19 The urine of P. aeruginosa -infected animals had lower Al levels than their noninfected counterparts. It had previously been shown that P. aeruginosa is capable of capturing a limited amount of Al released from bNT Ti-6Al-4V in vitro through an irreversible uptake mediated by pyochelin.…”

“…F- and P-doped bottle-shaped nanotubular (bNT) oxide layers of Ti-6Al-4V alloy 18 were obtained by the anodizing process and evaluated at microbiological and cellular levels. 19 Despite bNT layers releasing aluminum (Al) from the inside of the nanostructure and the resulting ions being captured by P. aeruginosa , this biomaterial is noncytotoxic and displays improved osteoblastic proliferation, mineralization, and differentiation in vitro. 19 Thus, the aim of this study was to evaluate the osseointegration of the F- and P-doped bottle-shaped nanostructured Ti-6Al-4V alloy and to monitor of urine aluminum concentration as a biomaterial marker of P. aeruginosa infection in Ti-6Al-4V implants in an in vivo rabbit model.…”

“…Thus, by using together both ions, an anti-adherent and osteoinductive material could be obtained. F- and P-doped bottle-shaped nanotubular (bNT) oxide layers of Ti-6Al-4V alloy were obtained by the anodizing process and evaluated at microbiological and cellular levels . Despite bNT layers releasing aluminum (Al) from the inside of the nanostructure and the resulting ions being captured by P.…”

“…Despite bNT layers releasing aluminum (Al) from the inside of the nanostructure and the resulting ions being captured by P. aeruginosa, this biomaterial is noncytotoxic and displays improved osteoblastic proliferation, mineralization, and differentiation in vitro . Thus, the aim of this study was to evaluate the osseointegration of the F- and P-doped bottle-shaped nanostructured Ti-6Al-4V alloy and to monitor of urine aluminum concentration as a biomaterial marker of P.…”