Design and Synthesis of Photoreactive Polymers for Biomedical Applications - Biomimetics: Advancing Nanobiomaterials and Tissue Engineering - page 259

cells. The photoreactive LMW-O-CMCS was employed for in vivo animal
studies as a synthetic anti-adhesive material. Guardix® (hyaluronic acid-
carboxymethylcellulose membrane) treated with photoreactive LMW-O-
CMCS showed a nondistorted dural contour, but adhesion was more than
two-thirds [38]. However, photoreactive LMW-O-CMCS showed no dural
adhesion and adequate space in the laminotomy space was sustained [38].

11.2.2.4 Pullulan

Pullulan is a linear homopolysaccharide of glucose that is often described
as a -(1-6)-linked maltotriose, secreted primarily by strains of the fungus
Aureobasidium pullulans . The unique linkage pattern of pullulan endows it
with distinctive physical traits, including adhesive properties and the capac-
ity to form fi bers, compression moldings, and strong, oxygen-impermeable
fi lms. Pullulan and its derivatives have numerous uses in foods, phar-
maceuticals, manufacturing, and electronics. UV-reactive pullulan was
synthesized by incorporating azidophenyl groups using a conventional
coupling between 4-azidobenzoic acid and pullulan in the presence of
ethyl(dimethylaminopropyl)carbodiimide/ N -hydroxysuccimide [39]. The
synthesized polymer was photoimmobilized/crosslinked onto polymeric
surfaces such as polystyrene, polyethylene, and silane coupled onto glass
surfaces using photomasking. The resultant surface has antifouling prop-
erties. The micropatterned polymer was employed for culture of RAW264
cells obtained from mouse leukemic monocytes. The immobilized pullulan
micropatterns did not allow the cells to adhere, and reduced protein interac-
tions with the surface. Thus, the nonionic and hydrophilic layer produced
by photoreactive pullulan upon exposure to an aqueous environment leads
to reductions in cell and protein attachment.

11.3 UV-Reactive Synthetic Polymers

11.3.1 Bio-nonfouling Polymers

Bio-nonfouling is important for reducing the nonspecifi c adsorption of
proteins on biomaterial surfaces. To prepare such surfaces, zwitterionic
groups such as phosphobetaine, sulfobetaine, and carbobetaine and
amphiphilic polymers such as poly(ethylene glycol) (PEG) or poly(vinyl
alcohol) have usually been used. We have developed some new photore-
active bio-nonfouling polymers for surface treatment and microarray chip
preparation, as described below.

11.3.1.1 Phosphobetaine

2-Methacryloyloxyethyl phosphorylcholine (MPC) polymer is a biomi-
metic polymer that acts to block thrombogenesis by reducing platelet