Columnar Stacks of Star- and Tadpole-Shaped Polyoxazolines Having Triphenylene Moiety and Their Applications for Synthesis of Wire-Assembled Gold Nanoparticles

Characterization of 2,3,6,7,10,11-hexahydroxytriphenylene and its effects on cell viability in human cancer cell lines

We synthesized 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP), characterized it by electrochemistry, spectroelectrochemistry, and electron paramagnetic resonance techniques, and evaluated its cytotoxicity to human cancer cell lines. The results revealed that HHTP has accessible higher-oxidation states, especially the tris-semiquinone monoradical. This species is stable and is formed after being stored for months. HHTP exhibited cytotoxic effects on 5 human cancer cell lines, including glioma and lung cancer cells. The cytotoxic effect was evaluated based on the decrease in cell viability, increases in the percentage of cells with fragmented DNA, and elevated numbers of annexin V–PI-positive cells after HHTP treatment.

Star-shaped Poly(2-oxazoline)s by Dendrimer Endcapping

The synthesis of star-shaped poly(2-ethyl-2-oxazoline) is reported by direct end-capping of the living polymer chains with dendritic multiamines. The end-capping kinetics after addition of a first generation polypropylenimine dendrimer are discussed based on monitoring by size exclusion chromatography, revealing less efficient end-capping with larger poly(2-ethyl-2-oxazoline) chains and increasing dendrimer generation. In addition, it is demonstrated that the solution viscosity and cloud point temperature of the star-shaped polymers are much less affected by chain length compared with their linear analogues.

Chemically responsive supramolecular assemblies of pyrene-beta-cyclodextrin dimer

We report supramolecular assemblies of a beta-cyclodextrin dimer linked at both ends of a fluorescent phenylethynylpyrene moiety (Py-beta-CD dimer). The Py-beta-CD dimer formed supramolecular associations in aqueous media due to the pi-pi stacking of the hydrophobic phenylethynylpyrene moiety. From tapping mode atomic force microscopy measurements, the Py-beta-CD dimer formed wire-shaped assemblies in aqueous media. By adding sodium adamantane carboxylate to the supramolecular assemblies, the structural change to J-type assemblies was observed. In contrast, upon addition of the electron-deficient guest, the electron transfer from the electron rich phenylethynylpyrene moiety of the supramolecular assemblies to the electron-deficient guest took place.