NANOMATERIALS FOR IMPROVED ORTHOPEDIC AND BONE TISSUE ENGINEERING APPLICATIONS - Advanced Biomaterials: Fundamentals, Processing, and Applications - page 202

7.3.3.2 Nanostructured and Injectable Hydrogels as Bone Tissue
Engineering Scaffolds 225

7.3.4 Nanostructured Composites 226

7.3.5 Role of Chemistry 228

7.4 Future Challenges 231

References 233

7.1 OVERVIEW

With the strikingly increasing number of elderly patients and the relatively high
percentage of orthopedic revision procedures performed around the world,
conventional materials which have many shortcomings cannot satisfy the high
requirements necessary for current orthopedic implants. Novel nanomaterials
with basic structures below 100 nm exhibit superior mechanical, cytocompatibility
and electrical properties over conventional micron-materials, thus potentially
serving as improved orthopedic implants. To date, a wide range of nanostructured
ceramics, metals, polymers, organic materials and composites have been investi-
gated and have shown promise towards lowering the rate of implant failures by
promoting early, quick osseointegration. Thus, due to the potentially numerous
applications of nanomaterials as orthopedic implants and other tissue engineer-
ing applications, they have been proposed as the next generation of improved
tissue growing materials. This chapter will give an overview of contemporary
developments of various nanomaterials for improved orthopedic and bone tissue
engineering applications.

7.2 INTRODUCTION

As an emerging interdisciplinary fi eld, bone tissue engineering has evoked in-
creasing interest from scientists wishing to develop biological substitutes that re-
store, maintain, or improve bone cell functions. It is widely known that natural
bone is a well-organized matrix that consists of a protein-based soft hydrogel
template (i.e., collagen) and hard inorganic components—specifi cally, hydroxy-
apatite. The special structure of natural bone supplies unique physical properties
(such as Young's modulus, elasticity, and strength) in order to support various
mechanical loading [1]. Novel biomaterials that biomimic the nano-structure of
natural bone have, thus, been investigated and have shown promise as improved
orthopedic implants.
In the following sections, the problems with current orthopedic implants
will be introduced. Then, the main part of this chapter will focus on a variety of
nanomaterials (nanostructured ceramics, metals, polymers, composites, and
so on) that have been tested for better orthopedic implant effi cacy. Important
future research directions concerning nanomaterials will be presented in the last
section.