Bioactive Inorganic and Organic Composite Materials for Bone Regeneration and Gene Delivery - Advanced Bioactive Inorganic Materials for Bone Regeneration and Drug Delivery - page 193

(a)

(b)

(c)

FIGURE 7.5
The cross section of pore walls for (a) 2.5 silk/MBG, (b) 5.0 silk/MBG, and (c) silk form a thin
layer on the surface of pore walls.

MBG/silk scaffolds induced a slightly higher rate of new bone formation in
the defects than did BG/silk scaffolds and immunohistochemical analysis
showed greater synthesis of type I collagen in MBG/silk scaffolds compared
to BG/silk scaffolds (Figure 7.6) (Wu, Zhang, Zhou, et al. 2011).
Georgiou et al. (2007) applied phosphate glass (PG) of the composition
0.46(CaO)-u0.04(Na(2)O)-0.5(P(2)O(5)) as filler in poly-L-lactic acid (PLA)
foams to form degradable scaffolds for bone tissue engineering. BG share
some properties with other bioactive inorganic material such as HAp and
β-TCP, in which it can bond with host bone tissue, but BG, on the whole,
have better bioactivity and degradation properties (Wu, Zhang, et al. 2010).
Two different composite types were manufactured that contained either
S2-high content silica S-BG, or A2-high content lime S-BG. The composites
were evaluated in the form of sheets and 3D scaffolds. Sheets containing
12, 21, and 33 vol% of each bioactive glass were characterized for mechani-
cal properties, wettability, hydrolytic degradation, and surface bioactivity.
Sheets containing A2 S-BG rapidly formed a HAp layer after incubation in
simulated body fluid.