Development of advanced biomedical coatings via plasma electrolytic oxidation

Abstract

For many decades, the implantation of Ti based biomedical implants has been extensively utilized to improve and restore the patients’ quality of life. However, despite advances in technology, failures of the implant do occur. In many cases, the failed Ti implants require immediate removal or correction through surgical operation, which, apart from the substantial economic impact on patients and governments, would cause prolonged suffering for patients. Moreover, the rapid increase in the population’s life expectancy necessitates the fabrication and engineering of more reliable orthopaedic implants based on Ti and its allosys for the aged population to address the current issues associated with implant failure. Several factors are involved in bone implant failures, such as bacterial infection and inflammation and poor integration of the bone with the implant surface. Among them, the infection problem requires special attention, as almost two-thirds of the infected implants are not treatable and eventually fail. The emergence of multi-drug resistant (MDR) bacteria is another horrifying issue, which poses a real threat to humankind and is responsible for high mortality rates among vulnerable patients. Fortunately, the emerging advances in nanotechnology and surface engineering can be a promising solution to this crisis. The ideal bone implant should possess antibacterial properties as well as the high bioactivity required for osseointegration improvement. In this regard, novel surface modification treatments such as the plasma electrolytic oxidation technique (PEO) has proven to be effective in the bioactivity improvement of titanium-based implants. However, the development of the PEO treated surface with antibacterial properties is still challenging. This study aims to implement innovative approaches to address the critical factors associated with titanium implant failure by applying post-PEO treatments such as hydrothermal process and functionalizing the surface with novel 2D materials. This thesis is presented in eight chapters, including a comprehensive literature review and several published, under review or confidential unpublished papers. In brief, the significant contributions of this work fall into four categories as follows: •Engineering of nanostructured titania surfaces with tunable and mixed topography (paper 1). • Optimal fabrication of antibacterial titania nanostructures, a combined approach of plasma electrolytic oxidation and hydrothermal treatment (paper 2). • Antibacterial development of titania surface with the application of graphene oxide and PEO-EPD technique (paper 3). • Comparative antibacterial activity of 2D materials coated on the porous-titania against gram-positive (S. aureus) and gram-negative (E.coli) bacteria (paper 4).