ABSTRACT
The predominant purpose of biomedical materials is to produce a part or facilitate a function of the human body in a safe, reliable, economical, and physiologically acceptable manner. A prerequisite for any synthetic material implanted in the body is that it should be biocompatible in the sense of not producing an in¢ammatory tissue reaction. In addition, the implanted material is expected to withstand applied physiological forces without substantial dimensional changes, catastrophic brittle fracture, or fracture in the long term from creep, fatigue, or stress corrosion. Accordingly, thermal sprayed bioceramic coatings, which have been extensively proposed as implants for bone and joint replacements, must possess acceptable biocompatibility and suf‹cient mechanical performances. This chapter addresses the fundamentals of coating deposition of the bioceramics, typically hydroxyapatite (HA) and HA-based composites, apart from other related issues, such as fabrication of nanostructured feedstock, characterization of the nanostructures inside the coatings and their in¢uence on coating properties, effect of the nanostructures and phase compositions on behaviors of the osteoblast cells cultured on the biomedical coatings, co-/postspray treatment of the coatings, and so forth. The biomaterials-cells interactions control
CONTENTS
Background and Current Problems .......................................................................................... 138 Principle of Thermal Spray ........................................................................................................ 142 Synthesis of HA Powder for Coating Deposition ................................................................... 145
Properties of HA ..................................................................................................................... 145 Synthesis and Fabrication of HA Powder ........................................................................... 145 HA-Based Composite Powder ............................................................................................. 148
Nanostructured HA-Based Bioceramic Coatings Deposited by Thermal Spray ............... 148 Mechanical Properties and Relationship between Nanostructure and Properties ............ 167 Nanostructured HA-Based Composite Coatings ................................................................... 171 Co-/Postspray Treatment of HA Coatings .............................................................................. 178
In¢uence of HA Feedstock .................................................................................................... 178 Biocompatibility Evaluation of the Nanostructured Bioceramic Coatings by In Vitro Cell Culture .................................................................................................................................. 185 References ..................................................................................................................................... 190
dynamic behaviors of the cells, such as adhesion, proliferation, and differentiation, on biomaterial surface. This chapter also discusses the problems encountered during the coating deposition and elucidates the overall fabrication procedure and applications of the thermal sprayed biomedical coatings.
