TiO2 bone scaffolds with antibacterial properties

Biomaterials which promote tissue integration and resist microbial colonization are required in bone tissue engineering to prevent biomaterial associated infections. To prevent microbial colonisation, biomaterials with multi-functional coatings that combine antimicrobial activity and tissue integration, such as TiO2, have emerged as promising candidates. Interestingly, the antibacterial activity of TiO2 in the form of particles can be enhanced by combining it with H2O2. However, it remains unknown whether TiO2 surfaces elicit a similar effect. In this study, the antibacterial effect of porous TiO2 scaffolds due to the catalytic decomposition of H2O2 in the absence of light (dark catalysis) was investigated. Porous ceramic foams were fabricated and sol-gel coated for high catalytic activity. The degradation kinetics indicate that intermediate free radicals formed at the liquid - TiO2 interface are responsible for the oxidative behaviour of the surface. TiO2 surfaces were further pre-treated with 30% H2O2 for prolonged oxidative behaviour. The biological response towards such surfaces was assessed in vitro. S. epidermidis biofilms formed on modified surfaces showed reduced viability compared to non-modified surfaces. Further, the same surface modification showed no cytotoxic effects on pre-osteoblasts. To conclude, this study provides evidence that a simple surface modification based on the dark catalytic effect of TiO2 can be used to create antibacterial surface properties for ceramic bone scaffolds. Molecules that may cause cancer may have a new, health-promoting role. Now we are on the track of how the "radicals" can be used to prevent problems around implants and help keep them intact for a long period. Even though dentists recommend that we keep our own teeth for as long as possible, it is still a growing number of us who eventually need to replace a tooth or more with titanium implants. This is especially true for the older generations. However, dental implants often prove to be only a partial successful replacement. Bacteria can conquer the area around the implant. These bacteria ?eats? up the bone around the implant. In order for a dental implant to function like a tooth, it is essential that the implant gets a firm fit into the jaw bone. This means that the bone cells win over the bacteria in a "race" to conquer the surface of the implant, better known as ?the race for the surface?. If the bone cells win, they have good conditions to grow and integrate the implant firmly and well in the jaw bone. However, it is relatively common that the bacteria win the competition. Then they organize themselves in a biofilm; a thin layer of bacteria on the implant. - Biofilm is a smart way for bacteria to colonize surfaces, which makes the bacteria stronger together. Bacterial infected implants are usually treated with antibiotics. "When the bacteria are organizing themselves in biofilm, they are nevertheless so difficult to break down that antibiotics often do not do the job. With the large increase of antibiotic resistant bacteria that we see as well, there is therefore a great need to find alternative treatments. Thus we looked at the radicals. In its reactive nature, these molecules can stress the bacteria, which in turn can provoke an antibacterial effect. We are now able to control the bacterial infections that occur around dental implants and, to a greater extent, prevent them from occurring. The studies showed that the use of dark catalysis in the treatment of infections has a promising effect. The method creates radicals that help fight the bacteria. So we have actually developed one and conscious that free radicals can potentially overtake the role of antibiotics. The next step is to try this new product out in the clinical and examine the clinical effect of this new product.

This project continues the development of highly porous load-bearing titanium dioxide (TiO2) bone scaffolds for the regeneration of large bone lesion in oral and maxillofacial applications as collaboration between Corticalis AS and the Department of Biomaterials at the University of Oslo. The aim of this project is to modify the existing TiO2 bone scaffold surface to create multifunctional bone graft materials which provide both bactericidal and osteogenic properties to promote bone regeneration in patients suffering from chronic inflammatory periodontal diseases caused by bacterial infections. The main objective of the proposed PhD project is to develop a method for implementing antibacterial surface properties on porous TiO2 bone scaffolds and evaluate both the antibacterial properties and the capacity of the modified TiO2 surfaces to induce bone cell adhesion and differentiation in vitro and in vivo. A surface that resists bacterial adhesion and biofilm development while simultaneously supporting bone tissue regeneration would be particularly beneficial in restoration of bone defects that are in the risk of recurring bacterial infections, such as bone defects caused by advanced periodontitis. This project continues the development of highly porous load-bearing TiO2 bone scaffolds for the regeneration of large bone lesion in the oral and as collaboration between Corticalis AS and the Department of Biomaterials at the University of Oslo.