Super-antibacterial Ti surfaces via pulse laser 3D patterning of Ag followed by catalytic ceramic conversion

Control of microorganism spread is a key concern for biomedical applications. The presence of bacteria and other pathogens on surfaces can lead to detrimental biological effects, such as infection or implant failure, hence contamination control is vital. Common sterilisation techniques include disinfectants, and high intensity light, however these processes have limited duration and re-exposure to environments will reintroduce contaminants. Furthermore, repeated use of sterilisation techniques may have deleterious health effects, therefore inherent antibacterial properties are desirable

Surface patterning of materials has been evidenced to be effective in resisting bacterial adhesion and biofilm formation, furthermore implantation of ions, such as silver, has established precedent for antimicrobial action. Within this PhD project, novel super-antibacterial Ti surfaces for biomedical applications will be designed and created. To this end, 3D patterned Ag will be deposited on titanium surfaces using pulse laser printing followed by advanced catalytic ceramic conversion to generate innovative 3D patterned TiO2 doped with Ag, combining both surface patterning and antibacterial material doping.

Furthermore, patterned diamond-like carbon (DLC) deposition and properties on varied substrates will be examined. DLC presents excellent biocompatibility in conjunction with high hardness and low coefficients of friction, making it widely applicable for biomedical applications; surface DLC can act to both aid tissue formation on implants, and to prevent ion release from metallic substrates.

DLC coatings also present opportunity for templating of antibacterial patterns through use in injection moulding inserts. Moreover, DLC coatings reduce the friction which opposes mould infilling as well as the forces required for demoulding, therefore improving performance of part production, and increasing mould lives. Femtosecond laser processing facilitates precise formation of textured surfaces, hence, laser-induced periodic surface structures (LIPSS) will be produced on DLC for antibacterial efficacy; patterns which may then be transferred onto injection moulded plastics, such as those used in orthodontics.

If necessary, tri-beam (laser, ion, and electron) surface selective alloying with N and O will be investigated for further property enhancement. The 3D layer structures, microstructures and interfaces will be fully studied using the tri-beam facility, AFM, XPS, Raman spectroscopy, SEM, and TEM. The mechanical properties will be probed using an environmental nano-indentation platform, and the durability of the functionally patterned surfaces will be evaluated through electrochemical and tribological testing. The mechanisms involved will be investigated to advance scientific understanding.