Hydroxyapatite-Biodegradable Polymer Nanocomposite Microspheres Toward Injectable Cell Scaffold - Biomimetics: Advancing Nanobiomaterials and Tissue Engineering - page 228

(a) HAp nanoparticles

(b) PLLA

(c) PLLA + HAp
mixture

-COO - Ca +

-COO -

2000 1900 1800 1700 1600 1500

Wavenumbers / cm -1

Figure 9.6 FT-IR spectra of (a) pure HAp nanoparticles, (b) PLLA homopolymer
and (c) the mixture of PLLA and the HAp nanoparticles. Reprinted with
permission from [52]. Copyright © 2009 American Chemical Society.

( a ) HAp nanoparticle-stabilized
emulsion (Pickering emulsion)

( b ) HAp nanoparticle-coated
PLLA microspheres

HAp nanoparticle HAp nanoparticle

PLLA

50 μ m 50 μ m

CH 2 Cl 2 solution of PLLA

Figure 9.7 Representative optical micrographs of CH 2 Cl 2 solution of PLLA-in-
water emulsion stabilized with HAp nanoparticles as a particulate emulsifi er,
before (a) and after (b) evaporation of CH 2 Cl 2 from the emulsion. The images
were taken at the same area. The HAp-PLLA nanocomposite microspheres were
colloidally stable at least for 6 months at 4

C. Reprinted with permission from
[52]. Copyright 2009 American Chemical Society.

°

CH 2 Cl 2 as a Class II solvent and described that the concentration limit
of 600 ppm in a product can be applicable under the assumption that
the product mass of 10 g is administered daily [63]. The residual CH 2 Cl 2
amount in the microspheres produced in this study is one order of mag-
nitude lower than that limited in ICH. The surface of the nanocomposite