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A novel amphiphilic graft copolymer composed of poly(?-glutamic acid) (?-PGA) as a hydrophilic backbone and dodecylamine (DOA) as a hydrophobic side chain (?-PGA-DOA) was successfully synthesized by employing 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) as the coupling reagent. The grafting degree was stoichiometrically controlled by adjusting the feeding amounts of DOA and EDC in the reaction system. ?-PGA-DOA, with a grafting degree of 55%, self-assembled via hydrophobic interactions and formed microparticles (MPs; diameter of 13±3?µm) in an aqueous solution. These MPs possessed functional carboxylic groups and could be further modified with compounds such as drugs, proteins and peptides, and thus have great potential as vaccine carriers.

Novel amphiphilic graft copolymers composed of poly(?-glutamic acid) (?-PGA) as a hydrophilic backbone and enantiomeric poly(lactide) (PLA) as hydrophobic side chains were successfully synthesized by using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) as the coupling agent. The number of poly(L-lactide) (PLLA) or poly(D-lactide) (PDLA) chains grafted onto the ?-PGA main chain was enhanced by increasing the feed ratio of PLA to ?-PGA in the reaction system. Nanoparticles (NPs) self-assembled from ?-PGA-graft-PLLA, ?-PGA-graft-PDLA and equal molar mixtures of enantiomeric ?-PGA-graft-PLLA and ?-PGA-graft-PDLA copolymers were formed in aqueous solution. The mean diameters of the NPs formed by equal molar mixtures of enantiomeric ?-PGA-graft-PLLA and ?-PGA-graft-PDLA copolymers (stereocomplex NPs) were in the range from 150 to 250?nm, and these NPs with reactive functional groups would have great potential to be used as stable delivery vehicles for pharmaceutical and biomedical applications.

We demonstrated that positive polyelectrolyte multilayers (PEMs) have great potential for conventional enzyme-linked immunosorbent assay (ELISA) systems because of the induction protein enrichment on their surface. In this study, we developed a novel simple molecular detection system using a PEMs-modified cellulose acetate (CA) membrane filter (PEMs-CA), which achieved rapid detection without compromising sensitivity as compared with conventional ELISA systems. This rapid detection was carried out by the centrifugal permeation of the antigen solution, thus allowing the local condensation of the antigen molecule in the proximity of the primary antibody-enriched PEMs-CA membrane, which overcame molecular diffusion as the time-limiting factor as compared with conventional ELISA systems. Hence, on the permeation system, the incubation time required for the antigen–antibody reaction corresponded to just the permeation time, which was 1/20 shorten than the conventional ELISA system under optimized conditions for the centrifugal forces. Moreover, the calibration curve of PEMs-CA had wide range of concentration from 0.02 to 5?µg?ml-1and larger change in signal as compared with the bare CA membrane. We concluded that this centrifugal permeation system should be further developed for rapid, precise and simple systems in various immunosensors using PEMs-modified membrane filters.

Morphological changes of macromolecularly porous thin films during isotactic (it) poly(methyl methacrylate) (PMMA) crystallization and the subsequent syndiotactic (st) poly(methacrylic acid) (PMAA) incorporation are described herein. Porous it-PMMA thin films were prepared on a gold substrate by the selective extraction of st-PMAA from stereocomplex films composed of it-PMMA/st-PMAA using layer-by-layer assembly. it-PMMA crystallization occurred when the porous it-PMMA films were immersed in a mixed solvent of acetonitrile/water (4/6, v/v). Surface analyses of films were performed by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS) and static contact angles. Dotted aggregates of it-PMMA appeared on crystallized films, whereas networks composed of crystallized it-PMMA and the stereocomplex were observed on st-PMAA incorporated films. Gold substrate peaks were observed not on porous it-PMMA films, but on crystallized it-PMMA films by XPS, indicating that homogeneously broadened it-PMMA in porous films was localized because of its crystallization. The static contact angle of crystallized it-PMMA films was 36.5±1.6°, which was smaller than that of porous it-PMMA films (49.2±1.9°). This difference resulted from the surface morphology of the thin films. Dotted it-PMMA aggregates were also observed when spin-coated films were immersed in the mixed solvent.