Research Projects

Traditional metallic implant materials such as stainless steels, cobalt- chromium-molybdenum alloys, and titanium alloys have been used as internal fracture fixation devices for rods, plates, screws, and wires to stabilize the fractured bone and to promote their self-healing process. However, the medical complications with these permanent metallic implants, such as the stress shielding effect (caused by their higher elastic modulus than natural bone), allergenicity, toxicity of their released ions, non- biodegradability are the primary concern. Moreover, the non-biodegradability of these materials needs a second surgery to remove the fixed implants, which adds additional pain and cost to the patient. These limitations motivated to look for temporary biodegradable implants that can completely degrade with time without losing their mechanical integrity during the healing process. In this matter, Magnesium-based materials got increased attention in the field of biodegradable orthopedic implant materials due to their excellent biocompatibility, biodegradability, non-toxicity, and near-bone elastic modulus. The successful use of magnesium-based materials in bone fracture fixation will eliminate the stress-shielding effect and the need for revision surgery. However, magnesium's low mechanical strength and excessive degradation rate in the corrosive physiological environment (pH=7.4) loses its mechanical integrity before the complete healing of a fracture site. Hence, improving magnesium-based materials' strength and corrosion resistance is crucial for their successful use in orthopedic implant applications. In a recent investigation by the PI and Co-PI team, Silicon Nitride (Si₃N₄) reinforced Magnesium matrix nanocomposites showed significant improvement in mechanical properties, corrosion resistance, and in-vitro biological properties. The findings indicated the potential use of these nanocomposites in temporary bone fracture fixation implants (i.e. Osteosynthesis Implants). Nevertheless, to ensure the long-term success of the prepared Mg/Si3N4 implant materials, further research is necessary to test these implants under in vitro conditions that accurately replicate in vivo conditions, especially the tribological properties. Implants wear is a critical parameter that can lead to premature implant failure. In vivo conditions can cause implants to experience several types of wear (such as Abrasive wear, adhesive wear, fretting wear, and corrosion wear i.e. Tribocorrosion), which can lead to a loss of functionality and potential tissue damage. Accordingly, the project's main aim is to develop a magnesium metal matrix nanocomposite by reinforcing Si₃N₄ nanoparticles and asses their tribological behavior in simulated physiological environments, such as saline or artificial body fluids, and subjecting them to cyclic loading and motion. The outcome of this study will make breakthroughs in orthopedic implants for temporary fracture fixation applications.