Anti-Bacterial Surface Based on Nanostructurs and Biocompatible Materials for Surgical Titanium Plate In Vivo

In the modern era, the anti-bacterial efficacy of surgical implants in the body is attracting great attention. The method is to modify the surface of the implant to reduce the adhesion of bacteria to limit the formation of a biofilm or, on the other hand, to coat the implant with a functional material that kills the surrounding bacteria. However, most of these research results are difficult to mass-produce, or there are hurdles in practical application as materials that have not yet received FDA approval in the human body. In the case of the SLIPS surface, which has recently attracted attention, its excellent effect has been demonstrated by applying a physical barrier that bacteria cannot settle. However, in the case of an actual infection model, not only the problem of biofilm formation on the surface, but also the occurrence of infection around the implant, so simply a physical barrier on the surface cannot prevent the deterioration of the affected area. Additionally, fluoroalkyl silane used in the SLIPS method applied to implants is a material that has not yet been approved. Therefore, for practical application, the use of materials available to the human body, prevention of biofilm formation on the surface, and prevention of bacterial infection in the vicinity should be provided.<br/>In this study, we used TiAl6V4 implant, which is currently the most used material in the medical industry, and manufactured an innovative coating that overcomes both infection models using only materials approved for the human body. In addition, SLIPS surfaces with proven superior function was fabricated, and comparison and efficacy were demonstrated through in vivo experiments.<br/>TiAl6V4 plates were immersed in NaOH solution with 0.5 mol concentration at 180°C in the oven for formation of nanostructure. The formation of 20 nm scale structures of titanium dioxide (TiO₂) is a process of dissolution and precipitation reactions. Next, a mixture of Poloxamer 407, Octanoic acid, and EGCG was coated on the nano Ti surface. Poloxamer 407 and EGCG are mixed and placed in an oven at 100°C for about 30 minutes to liquefy. Since the mixed solution of Poloxamer407 and EGCG has a very high viscosity and is difficult to use for coating, Octinoic acid is used to dilute it.<br/>The usefulness of titanium implant with nano-structure having a sustained-release coating of Poloxamer/Octanoic Acid both was verified in vitro and in vivo. In particular, we made a rabbit surgery model similar to fracture surgery performed in humans. We confirmed the usefulness of our coating by inducing Pseudomonas aeruginosa infection and biofilm formation. Our results confirmed that the poloxamer/octanoic acid coating material lowered the infection rate and had a low toxicity. We propose that a titanium implant with a nano surface structure having a poloxamer/octanoic acid coating could be a novel alternative for surgical metal processing.