Polyion-complexation

The optimum conditions for polyion complex formation between chitosan and hyaluronate were identified fhe compression exerfed fo manufacture the implant had no role to play in the release kinetics [28,92]. Various authors published data confirming fhaf fhe combinafion of chifosan and hyaluronic acid is always suscepfible fo swelling, even in fhe presence of cross-hnking. 

The stoichiometry of the recharged DNA/PLL/SPLL particles was studied using sucrose-gradient ultracentrifugation of fluorescently labeled polyion complexes in 25 mM HEPES buffer. Rhodamine-labeled DNA (Rh-DNA) and either fluorescein-labeled PLL (Fl-PLL) or SPLL (Fl-SPLL) were used to determine their relative amounts within DNA... 

Surini S, Akiyama H, Morishita M, Nagai T, Takayama K. Release phenomena of insulin from an implantable device composed of a polyion complex of chitosan and sodium hyaluronate. J Controlled Release 2003 90 291-301. 

Tamura A, Oishi M, Nagasaki Y (2009) Enhanced cytoplasmic delivery of siRNA using a stabilized polyion complex based on PEGylated nanogels with a cross-linked polyamine structure. Biomacromolecules 10 1818-1827... 

Polymer complexes associated with two or more complementary polymers are widely used in potential applications in the form of particles, hydrogels, films, and membranes. In particular, a polyion complex (PIC) can be easily formed when oppositely charged polyelectrolytes are mixed in aqueous solution and interact via... 

Fig. 9 Stabilization of polyion complex nanoparticles composed of poly(amino acid)s using hydrophobic interactions...

Y. Sato, T. Sawaguchi, Hirata, Y., F. Mizutani, and S. Yabuki, Glucose xidse/polyion complex-bilayer membrane for elimination of electroactive interferents in amperometric glucose sensor. Anal. Chim. Acta 364, 173-179 (1998). 

K.V. Gobi, Y. Sato, and F. Mizutani, Mediatorless superoxide dismutase sensors using cytochrome c-modified electrodes xanthine oxidase incorporated polyion complex membrane for enhanced activity and in-vivo analysis. Electroanalysis 13, 397-403 (2001). 

Preparation of polymeric bilayer cast films by polyion complex technique... 

Polyion complex technique [40] is a unique method for immobilization of bilayer membranes with polymers. Water-insoluble complex is precipitated as the polyion complex when an aqueous solution of the charged bilayer membrane is mixed with a water solution of the counter charged polyelectrolyte. Stoichiometric ion pair formation is often found. Aging of the precipitate in a hot mixture kept above phase transition temperature of the bilayer membrane completes the ion exchange reaction [41], Chloroform solution of the polyion complex is washed by water several times to remove water soluble components [42]. 

Scheme 3. Anionic polymers used for polyion complex formation.

Figure 25. Schematic models of spacer effect of polymer main chain on molecular ordering of polyion complex films.

Spectral change of polyion complex films due to thermal and photochemical phase transition. 

Figure 27. Polymer effect on isothermal spectral transition induced by moisture treatment of polyion complex films, (relative humidity = 62%)...

Photochemically induced phase transition is also found in the polyion complex films. Transient behavior of the cis isomer formation is more apparent in the complex films with polymer 6 and 7. 

Figure 28. Spectral change of annealed polyion complex films of CgAzoCioN+ Br by photoirradiation, (a) with polymer 7, (b) with polymer 6.

Photochemical switching of the phase transition is also found in the polyion complex film. Figure 29 shows reversible cycles of the absorption at 370nm by the coupling of the thermal and photoinduced phase transition of the complex film with carboxymethylcellulose 8. In conclusion, we indicate that the immobilized bilayer membranes containing the azobenzene chromophore are available to the erasable memory materials based on the phase transition triggered by thermal and photochemical processes. The polyion complex technique is clearly shown to be a very useful method for materialization of the immobilized bilayer membranes. 

Figure 29. Reversible cycles of spectral change of polyion complex film by coupling of heating (higher absorbance) and photoirradiation (lower absorbance). 

RA and transmission techniques [3], and applied it to the studies of LB films of cadmium stearate [3], azobenzene-containing long-chain fatty acids and their barium salts [4], dipalmitoylphosphatidylcholine (DPPC) [5], and polyion complexes [6]. Furthermore, we explored the relationship between the molecular orientation evaluated by this method and pyroelectricity in alternating (noncentrosymmetric) Y-type LB films consisting of a phenylpyrazine-containing long-chain fatty acid and deuterated stearic acid and of their barium salts [7]. 

Figure 30. The K-A isotherms of Compound II (solid line barium salt, broken line polyion complex with PAA dotted line polyion complex with PDDA).

Phase separation in polyion complexed mixed monolayers containing HC cationic and anionic surfactants and a FC anionic surfactant studied by SPMs and SIMS... 

Tb clarify the effect of addition of a cationic HC surfactant on phase separation behavior in the mixed monolayers of anionic HC and FC surfactants polyion complexed with cationic polymers, the mixed monolayers containing three amphiphilic components complexed with PVA were transferred on various substrate plates and studied by AFM, FFM, SSPM, and SIMS. As a cationic surfactant, ODTMAC was examined. 

Figure 10. (a) AFM, (b) FFM, and (c) SSPM images of an SA-PFECA-ODTMAC (1 1 1) mixed monolayer polyion complexed with PVA deposited on Si(100). 

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