Nosocomial Bacterial Infection of Orthopedic Implants and Antibiotic Hydroxyapatite/Silver-Coated Halloysite Nanotube With Improved Structural Integrity as Potential Prophylaxis

Over the years, hydroxyapatite and its nanocomposites have continued to proliferate the orthopedic market as suitable materials for bone replacement, bone repair, and bone regeneration. This incidence is preeminently attributed to their excellent biocompatibility, bioactivity, hydrophilicity, osteoconductive characteristics, biomechanical properties, and biogenic synthesis routes. However, previous research findings have shown that the load-bearing capacity of natural hydroxyapatite that is essential for orthopedic applications is insufficient. In addition, they are highly susceptible to various bacterial infections, otherwise functionalized with antibiotic agents such as silver nanoparticles or nanofilms. In this chapter, the degree of mechanical improvement possible by reinforcing hydroxyapatite with halloysite and boron nitride nanotubes coated and uncoated with silver nanoparticles based on continuum mechanics was investigated. The effect of coating thickness on the elastic behavior of the composites was also studied. By employing representative volume models, the load-bearing capacity of the nanocomposites developed was predicted by finite element analysis, and the results were compared with that of the modified Halpin-Tsai model's prediction and experimental results available in the literature. The comparisons showed significant correlations with enhanced properties for both reinforcements. More importantly, the first section of this chapter covers the role of bioceramics in orthopedics, nosocomial infection of orthopedic implants, bacterial biofilm formation, their mechanism of antibiotic resistance, and associated implant failures. Furthermore, added to this section as a supplementary literature is a mini-review of antibiotic therapy for orthopedic implant infections and the emergence of silver, silver nanoparticle, and silver nanoparticle-based materials as prophylaxis for orthopedic implant infections. Necessary antibiotic materials discussed in this section include biogenic silver nanoparticle, silver nanoparticle-decorated nanotubes, and silver nanoparticle-hydroxyapatite nanocomposites. The second section presents the materials and methods for composites development, and the third section presents the results and corresponding discussions. The chapter concludes with hydroxyapatite nanocomposite reinforced with silver nanoparticle-coated halloysite nanotube as a potential material for the prophylaxis of orthopedic implant infections.