Antibacterial properties of antibiotic-loaded PHB grafted on titanium surface for biomedical applications
Tutor / director / evaluatorManero Planella, José María
Document typeMaster thesis
Rights accessOpen Access
With the evolution of human civilization, the field of biomaterials evolved relating different materials with a simple focus: to extend human life and improve the quality of life. Materials used for biomedical applications must exhibit specific properties. Titanium is well-known to be a material used for implants because of its high strength, biocompatibility and high resistance corrosion. It can be used as hard tissue implant, such as artificial bone, hip joint, dental and bone plate. Nevertheless, a relevant aspect of the use of biomaterials is linked with medical device-related and post-operative infections. A promising approach for reducing the occurrences of infections is to provide the surfaces of biomedical devices and implants with features that are unfavourable for bacterial attachment and proliferation. Therefore, the aim of the present work is focused to develop a new method to combine the antibacterial properties of antibiotic-loaded Poly(3-hydroxybutyrate) (PHB) nano- and microspheres, and poly(ethylene glycol) (PEG) as an antifouling agent, with titanium, as the base material for implants, in order to obtain biomimetic surfaces with antibacterial activity. The titanium surfaces were linked to both PHB particles and PEG by covalent bond. This attachment was carried out by firstly activating the titanium surfaces with either plasma or sodium hydroxide. Further functionalization of the activated surfaces were carried out with two different alkoxysilanes which provided the titanium surfaces different organofunctional groups that allowed the reaction with PHB particles or with PEG. A difunctionalized PEG was used in one last step, which allowed the covalent attachment with the PHB particles. Therefore, the antifouling properties of PEG were related with the antibacterial ones of the PHB spheres. Finally, the different steps of the process were evaluated. The success of the surfaces functionalization as well as the different superficial linkages was confirmed by means of the following characterization methods: contact angle, field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The antibacterial properties of the titanium treated surfaces were tested by means of an in vitro antibacterial assay using a Gram + and Gram – bacteria. Finally, it was confirmed that the titanium surfaces achieved the antibacterial properties by combining antibiotic-loaded PHB nano- and micro-spheres, and PEG as an antifouling agent.