NANOINDENTATION OF BONE - Nanoindentation with Biological Applications - page 180

CHAPTER 7
NANOINDENTATION OF BONE
Virginia L. Ferguson and Sara E. Olesiak
Department of Mechanical Engineering, University of Colorado
E-mail: [e-mail]
While nanoindentation is an ideal tool for mechanically testing at the
“tissue-level” of bone, unique challenges exist in both testing methods
and analytical approaches. Bone is heterogeneous in composition and
structure. Bone's hierarchical organization, typical of many biological
tissues, implies that multiple structural levels may influence a single
nanoindentation site. Mineral forms a complicated 3-D structure within
and around a fibrillar collagen matrix. The degree of organization and
mineral infilling varies with factors including the age, type, and
location of bone material. Pores sized from nanometers to millimeters
contain interstitial fluid that interacts electrochemically and structurally
with bone's material constituents, adding further complexities to bone's
mechanical response. This chapter reviews practices for the collection
of high quality data at small scales where the organization of bone's
three phases complicate our ability to prepare samples, visualize 3-D
structure, and obtain exact measurements of material properties at
small length scales. Nanoindentation, in combination with additional
independent measures of the tissue, enable the detailed study of
bone's poorly understood 3-D construction, material properties, and
mechanical behavior at sub-micrometer scales. This chapter addresses
the use of nanoindentation to study bone through consideration of the
interactions within and between the collagen, mineral and water phases.
1. Introduction
Bone is a complex biocomposite that serves a wide range of structural
and biological functions such as mechanical support, protection of vital
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