Figure 8.13. Synthesis of Tethered OEG
-Containing Polymer Brushes and |-OEG
blies on SiO
.Images adapted from Ref. 84.
Figure 8.14. Chemical structure of phosphorylcholine (a), sulfobetaine (b) and cabocybe-
for their resistance to protein adhesion.
Zwitterionic structures similar to
phosphorylcholine such as phosphobetaine, sulfobetaine, and carboxybetaine
(Fig. 8.14) were also ideal for developing non-fouling surfaces when the surface
density and chain length of zwitterionic groups were well controlled.
We will discuss two important modiﬁcation strategies (a) self assembled
monolayers containing zwitterionic groups
and (b) surface initiated polymer-
ization of a zwitterionic group containing monomers
in the follow-
ing section. The physical adsorption of zwitterionic group based polymers was
also used as a method to make non-fouling surfaces
but will not be discussed
8.3.1 Self-assembled Monolayers Containing Zwitterionic Groups
Holmlin and Whitesides fabricated SAMs terminated with charged groups on the
gold surface to evaluate their ability to resist the nonspeciﬁc adsorption of proteins
from aqueous buffer solutions.
Single-component SAMs with all positive groups
(trimethylammonium group) and all negative groups (sulfonate group) adsorbed
nearly full monolayers of ﬁbrinogen and lysozyme. SAMs formed from a 1:1
mixture of thiols terminated with a negatively charged group and a positively
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