Biomedical Engineering Reference
In-Depth Information
ticle surface with a variety of water-soluble polymers and polyelectrolyte brushes
(both cationic and anionic). The process is illustrated schematically in Figure 10.5.
With ricinoleic acid as the ligand, particles that were soluble in nonpolar and
weakly polar solvents were obtained. These particles could either undergo surface-
initiated ring - opening polymerization ( ROP ), through which polylactic acid
brushes were grown on the particles, or be further functionalized with 2-bromo-
2-methyl propionyl bromide (BMPB) to provide the ATRP macroinitiators. The
ATRP of trimethylsilylacrylate ( TMSA ) or trimethylsilyl methacrylate ( TMSMA )
resulted in poly(acrylic acid) or poly(methacrylic acid) brushes, respectively, on the
particle surfaces. In addition, the ATRP initiators were also used to polymerize
hydroxyethylmethacrylate ( HEMA ) in 1,2 - dichlorobenzene, and the poly(HEMA)
brushes could be further reacted with succinic anhydride to produce a poly
acid on the particle surface. These particles were all water-soluble. With galactaric
acid as the ligand, and with it being further acylated with BMPB, particles coated
with poly(dimethylaminoethyl methacrylate) could be produced by ATRP in
Figure 10.5
Scheme for the magnetic
nanoparticles functionalization procedure
described in the text. Steps 1A and 1B:
ligand-exchange reactions. Step 2: acylation of
hydroxyl groups to prepare ATRP surface
initiators. Step 3A: surface-initiated ring-
opening polymerization of L - lactide. Step 3B:
surface-initiated ATRP. Step 4: deprotection or
additional reaction after polymerization. Step
5: grafting of end-functionalized PEG chains
onto the nanoparticle surface using amidation
chemistry. Reprinted with permission from
Ref. [65]; © 2007, American Chemical Society.
