Azopolymer

Saffran, M., Kumar, G.S., Neckers, D.C., Pena, J., Jones, R.H., and Field, B., Biodegradable azopolymer coating for oral delivery of peptide drugs, Biochem. Soc. Trans., 18 752-754 (1990). 

Key words Photoirradiation, Immobilization, Azopolymer, Immunochip, Biomarker, Chemiluminescence... 

Fig. 1. The chemical structure of typical azopolymer. Azobenzene moiety isomerizes between fra/rs and c/s form.

Fig. 2. Schematic Illustration of the photolmmoblllzatlon of blomolecules (Immunoglobulin) on the surface of an azopolymer. The surface of the azopolymer Is deformed to the shape of the Immunoglobulin after photoirradlatlon.

Second, we tried the immobilization of DNA molecules as a potential target material for the immobilization of biological macromolecules. An aqueous solution of 1 mg/mL A.-DNA was spotted onto the surface of an azopolymer and covered with a cover glass, where the A.-DNA was stained with a fluorophore (YOYO-1 iodide, Molecular Probes Inc., Eugene, OR) in advance and the surface was then irradiated with the linearly shaped laser beam for 5 min, as shown in Fig. 3b. The surface was washed for 5 min in an aqueous solution and was then observed using... 

We first examined specific reactions of photoimmobilized antibodies on azopolymer surfaces for the immunochip application. Solutions of antigoat antibodies (left-hand side) and antirabbit antibodies (right-hand side) were spotted onto an azopolymer surface at different concentrations, the layout of which is shown in Fig. 5a. After photoimmobilization and washing, the sample was reacted separately with Cy-5 labeled antigens (goat... 

IgG and rabbit IgG). The antigoat IgG antibody recognized goat IgG when Cy-5 labeled goat IgG was introduced onto the sample, while on the other hand, antirabbit IgG recognized rabbit IgG when Cy-5 labeled rabbit IgG was introduced, as shown in Figs. 5b, c. The specific reactivity of the antibodies was reali zed by fixing photoimmobilized antibodies on the surface of the azopolymer. 

Narita M, Hoshino F, Mouri M, Tsuchimori M, Ikawa Y, Watanabe O. (2007) Photoin-duced immobilization of biomolecules on the surface of azopolymer films and its dependence on the concentration and type of the azobenzene moiety. Macromolecules AO, 623-... 

Watanabe O. (2004) Molecular recognition and immobilization ofbiomolecules induced byphoto-irradiation on the sufrace of an azopolymer. R D Review of Toyota CRDL 39, 46. 

Watanabe O, Ikawa T, Kato T, Tawata M, Shimoyama H. (2006) Area-selective photoimmobilization of a two-dimensional array of colloidal spheres on a photodeformed template formed in photoresponsive azopolymer film. Appl Phys Lett 88, 204107. 

Large intestine 1.5 4-16 5.5-7 Contains specific enzymes that may be exploited for drug release. Polymers that are specifically degraded by such enzymes include saccharide-containing polymers or azopolymers... 

In an effort to develop a peroral application system for insulin, Saffran was the first to use azopolymers as protective colon delivery coating, by use of the aforementioned strategy of azo-linked prodrugs [58, 59], Originally, he used azo-linked copolymers of styrene and hydroxyethylmethacrylate to coat and protect the insulin. However, this approach is not restricted to hydroxyethylmethacrylate and can indeed be accomplished in the same way by an almost unlimited number of similar polymer types. 

S. I. Kim, M. Yamamoto, H. Terashima, H. Tozaki, A. Yamamoto, S. Muranishi, and Y. Kimura, Improvement of oral bioavailability of insulin by colon targeting system using azopolymer, Proceed. Intern. Symp. Control. Rel. Bioact. Mater. 24 377-378 (1997). 

Oxidative coupling is also to be used to prepare azopolymers from... 

Polymerization of Primary Aromatic Diamines to Azopolymers by Oxidative Coupling... 

In the last few years, the catalyzed oxidative coupling of primary aromatic diamines has been investigated extensively in our laboratories (1, 2, 3) and also by Kotlyarevskii (19, 20, 30). Results of these investigations are reviewed in this chapter as well as the properties of the class of aromatic azopolymers. 

In studying this novel oxidative polymerization we investigated the following points in particular (a) scope of the reaction, (b) side reactions, (c) catalysis, (d) molecular weights obtainable, (e) properties of aromatic azopolymers in bulk and fabricated form. 

Side reactions in the oxidative coupling of primary aromatic diamines to azopolymers could severely limit the molecular weights of polymers obtainable and disrupt their ordered, linear structure. To investigate this point the following polymer... 

In the oxidative coupling of primary aromatic diamines to azopolymers cupric ion/nitrogen base complexes serve as homogeneous catalysts. Such complexes are best prepared in situ by oxygenating a cuprous species, preferably CuCl or Cu O/HCl, in the presence of the nitrogen base. Cupric salts investigated except for cupric acetate yielded inactive species. 

Pyridine, a tertiary amine, yields a very active catalyst complex, [Py2Cun(OH)Cl] (7), for the coupling reaction giving high rates of oxidation at low temperatures. However, molecular weights of the azopolymers preparable in this medium proved to be somewhat limited (see Table I) owing to the generally low solubility of the azopolymers formed. 

Aromatic Azopolymers. Through the described catalyzed oxidative coupling of primary aromatic diamines a great variety of aromatic azopolymers has become easily accessible. Therefore, an investigation of their properties in bulk as well as fabricated form seemed warranted. 

Color. All aromatic azopolymers are colored owing to the strongly chromophoric azogroup. Even the azoblock copolymer derived from a phenyl oxide-isophthalamide backbone (discussed earlier) which has only one azogroup per repeat unit of a molecular weight of 3500 is bright yellow. Naturally, the shade of color of individual polymers depends on the structure of the repeat unit as expected, fully conjugated polymers... 

Fully aromatic azopolymers described show no melting or softening up to the temperature of thermal degradation. Therefore, films and fibers must be prepared from solution films cast are strong, tough and flexible. 

Fiber Properties. One of the polymers, the poly(isophthalamide) of 4,4 -diaminoazobenzene (IV), was selected for investigation of fiber properties of aromatic azopolymers. Table III shows standard tensile data of the "as spun as well as the hot-drawn (1.5X, 350°C.) fiber. As shown, this polymer has tensile properties fairly typical of an aromatic polyamide. 

Table III. Standard Tensile Data of an Azopolymer Fiber...

In view of the good stability of aromatic azopolymers at elevated temperatures, it is not surprising to find a fair retention of tensile properties up to about 400°C. (Table IV). 

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