Biomedical Engineering Reference
In-Depth Information
(a)
(b)
50 µm
100 µm
(c)
(d)
50 µm
100 µm
FIGURE 4.13
SEM images of hMSC attached on the surface of (a, b) biphasic CPC-alginate scaffolds and (c,
d) mixed CaP-alginate scaffolds on (a, c) day 1 and (b, d) day 7 of culture in the presence of
osteogenic supplements (white arrows indicate the formed apatite deposition and black arrow
attached cells).
engineering and regeneration. The incorporation of GF and drugs into a bio-
material prior to scaffold building is a good strategy to heighten loading
efficiency and to prolong the release period in comparison to surface-loading
approaches. However, most methods of scaffold fabrication involve usage of
organic solvents or heat treatment making the incorporation of biological
components into the material impossible, in contrast to the 3D plotting tech-
nique applied in our work for building of biphasic and mixed alginate-CPC
scaffolds that took place under nearly physiological conditions. The integra-
tion of proteins into scaffolds during the plotting process was evaluated by
mixing of bovine serum albumin (BSA), as a model protein, into the pastes,
which were used to produce pure alginate, pure CPC, and mixed alginate-
CPC scaffolds. BSA was homogeneously distributed in the plotted structures
without denaturation. The initial burst of release within the first 12 h was
determined to be lower than 20% for CPC and 40% for alginate scaffolds.
For the mixed alginate-CPC scaffolds intermediate amounts were released
within the first 12 h. Later on, a sustained release behavior has been observed
for all three scaffold types but with considerable differences with respect to
the amount of released BSA. The pure CPC scaffolds released clearly smaller
amounts of BSA signifying that the main part of BSA remained bound to the
calcium phosphate matrix. In contrast, much higher amounts of BSA were
 
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