Biomedical Engineering Reference
In-Depth Information
Figure 6.1
SEM image of HCA formed on bioactive borate glass reacted
in vivo
.
in vivo
testing for reactive materials such as bioactive glass. Advances
in bioactive borate glass technology will describe new methods of
stimulating biological responses, such as bone and blood vessel for-
mation (angiogenesis), without the use of expensive growth factors. A
section will cover several applications of bioactive borate glasses in the
medical field, and the last section will cover biomaterial design and
provide insight into the design and development of new biomaterials
and commercial products.
6.2 WHAT DIFFERENTIATES A BIOACTIVE BORATE
GLASS FROM OTHER BIOACTIVE GLASSES?
Bioactive glasses that form HCA in general require calcium as a com-
ponent (typically
10 wt%) and, beyond that, the composition is fairly
open to customization. In the case of the bioactive borate glasses, the
major glass former is B
2
O
3
as opposed to SiO
2
or P
2
O
5
, and the
compositions can contain an array of alkali metal (Li, Na, K, etc.),
alkaline-earth (Mg, Ca, Sr, Ba, etc.) and transition-metal (Fe, Cu, Zn,
Ag, Au) elements. A list of the silicate and borate glass compositions
described in this and other chapters is shown in Table 6.1.
Bioactive glasses have been well documented to form a calcium
phosphate layer when immersed in a phosphate-containing solution like
simulated body fluid (SBF). The reaction that occurs in silicate glasses
is described in detail in Chapter 2. Once the glass surface has been
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