Biomedical Engineering Reference
In-Depth Information
6
Bioactive Borate Glasses
Steven B. Jung
MO-SCI Corporation, MO, USA
6.1 INTRODUCTION
Bioactive borate glasses are a subset of the bioactive glass family that
includes silicate, borate and phosphate glasses. Traditionally, bioactive
glasses are glassy materials that will react in an aqueous environment
such as body fluids to form inorganic crystalline calcium compounds.
Hydroxycarbonate apatite (HCA) is the compound that forms on most
bioactive glasses and also happens to be very similar to the inorganic
component of bone. Bioactive glasses will readily bond to connective
tissue, such as bone and soft tissues, and they can also elicit biological
responses, such as promoting cell migration and cell differentiation,
and deliver ions necessary for the healing process (Chapter 2). An
image of reacted bioactive borate glass converted to HCA is shown in
Figure 6.1. Notice the porous nanocrystalline needle-like microstructure
of the HCA.
This chapter will begin by discussing the typical bioactive borate glass
reaction to form HCA and the reaction kinetics of borate glasses and
how they differ from silicate glasses. Testing methods will be described
in a general manner to discuss the pros and cons of
in vitro
and
