Biomedical Engineering Reference
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formed. Scanning electron microscope (SEM) studies confi rmed that
free HAp nanoparticles that were not adsorbed on the PS microspheres
were observed in the molecular weight of 64,500 system, and it was clear
that the PS microspheres surface was not completely coated with HAp
nanoparticles (Figure 9.4). In the PS molecular weight of 26,100 system,
free HAp nanoparticles were present among the PS microspheres, and
most microsphere surfaces were completely covered by HAp nanopar-
ticles. On the other hand, few free HAp nanoparticles were observed in
PS-COOH
(Mw, 64,500)
PS-COOH
(Mw, 26,100)
PS-COOH
(Mw, 6,700)
( a )
( b )
( c )
5 μm
100 μm
5 μm
100 μm
5 μm
100 μm
(d-1)
(e-1)
(f-1)
20 μm
20 μm
20 μm
(d-2)
(e-2)
(f-2)
2 μm
2 μm
2 μm
(d-3)
(e-3)
(f-3)
200 nm
200 nm
200 nm
Figure 9.4 (a-c) Optical micrographs and (d-f) SEM photographs of HAp
nanoparticle-coated PS microspheres prepared from the emulsions containing
(a,d) PS-COOH (Mw, 64,500), (b,e) PS-COOH (Mw, 26,100), and (c,f) PS-COOH
(Mw, 6,700), observed at different magnifi cations. PS-COOH, 1.0 wt% in
dichloromethane; HAp nanoparticles, 0.04 wt% in water; oil/water, 1/10 (w/w).
Reprinted with permission from [51]. Copyright © 2012 American Chemical
Society.
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