Effect of nano-hydroxyapatite and post heat treatment on biomedical implants by sol-gel and HVOF spraying

Abstract

Nanostructured materials, when compared to typical micro-phase materials, have the potential to provide considerable improvements in mechanical and biological performance by reducing the grain to the nanoscale. Comparing them to their larger counterparts, nanomaterials (NMs) show distinct physicochemical and biological characteristics. The majority of human tissues and organs in the body also contain nanoscale components, which are made up of tiny units of protein, lipid, and amino acids. The biomimetic structure of nanoscale materials is exceptional. NMs can interact with biomolecules and cells significantly depending on their size, shape, chemical content, surface structure, charge, aggregation, solubility, etc. Implants still fail due to fracture, infection, corrosion, and excessive load despite the fact that extensive research has been done over the past decade to develop medical implants for bone regeneration and repairing body tissues. This chapter addresses the thermal-sprayed coating (i.e., high-velocity oxy-fuel coating, HVOF) and sol-gel sprayed nanocoatings’ deposition typically on metallic substrates for biomedical applications and also discusses the effect of post heat treatment on hydroxyapatite (HA) coatings. This article explores in detail the various problems encountered in the selection of suitable biomaterials for particular applications. The explanations pertaining to the superiority of nano-HA to micro-HA along with the influence of TiO2 in nano-HA coatings have also been brought forth. Several properties of the developed coatings, such as fracture strength, osteoblast adhesion, antimicrobial properties, corrosion, etc., have also been discussed. Finally, a comparison has been drawn from HVOF and sol-gel coating techniques based on microstructure and nanostructure HA coatings.