Sonodynamic Therapeutic Effects of Sonosensitizers with Different Intracellular Distribution Delivered by Hollow Nanocapsules Exhibiting Cytosol Specific Release

Sonodynamic therapy (SDT) is a novel promising noninvasive therapy involving utilization of low‐intensity ultrasound and sonosensitizer, which can generate reactive oxygen species (ROS) by sonication. In SDT, a high therapeutic effect is achieved by intracellular delivery and accumulation at the target sites of sonosensitizer followed by oxidative damage of produced ROS by sonication. Here, pH‐ and redox‐responsive hollow nanocapsules are prepared through the introduction of disulfide cross‐linkages to self‐assembled polymer vesicles formed from polyamidoamine dendron‐poly(l‐ lysine) for the efficient delivery of sonosensitizer. As sonosensitizer, doxorubicin (DOX), an anticancer drug accumulating into cell nucleus, is selected. Also, the conjugate of DOX and triphenylphosphonium (TPP‐DOX) is synthesized as sonosensitizer with mitochondrial targeting ability. DOX and TPP‐DOX are delivered to nucleus and mitochondria by nanocapsules. Furthermore, DOX‐ or TPP‐DOX‐loaded nanocapsules exhibit in vitro sonodynamic therapeutic effect to HeLa cells with sonication, which might be through oxidative damage to nucleus and mitochondria.     

Rate of Convergence to Barenblatt Profiles for the Fast Diffusion Equation

We study the asymptotic behaviour of positive solutions of the Cauchy problem for the fast diffusion equation as t approaches the extinction time. We find a continuum of rates of convergence to a self-similar profile. These rates depend explicitly on the spatial decay rates of the initial data.     

Oligoresorcinols fold into double helices in water

We report the first double helices with a controlled helicity in water based on oligoresorcinols as a new, simplest water-soluble structural motif. The molecular strands of the oligoresorcinols self-assemble into double helices with the aid of aromatic interactions in water as characterized by 1H NMR and absorption spectroscopies together with the X-ray crystallographic study of the pentamer. The double helix formation is sensitive to the chain length, solvent composition, and temperature. Moreover, a bias in the screw sense of the double helices was achieved by covalently attaching chiral substituents to both ends of the molecular strands.     

Two-dimensional surface chirality control by solvent-induced helicity inversion of a helical polyacetylene on graphite

We report the direct evidence for the macromolecular helicity inversion of a helical poly(phenylacetylene) bearing l- or d-alanine pendants with a long alkyl chain in different solvents by atomic force microscopy observations of the diastereomeric helical structures. The diastereomeric helical poly(phenylacetylene)s induced in polar and nonpolar solvents self-assembled into ordered, two-dimensional helix bundles with controlled molecular packing, helical pitch, and handedness on graphite upon exposure of each solvent. The macromolecular helicity deposited on graphite from a polar solvent further inverted to the opposite handedness by exposure to a specific nonpolar solvent, and these changes in the surface chirality based on the inversion of helicity could be visualized by atomic force microscopy with molecular resolution, and the results were quantified by X-ray diffraction of the oriented liquid crystalline, diastereomeric helical polymer films.     

Nanosphere and nanonetwork formations of [60]fullerene-end-capped stereoregular poly(methyl methacrylate)s through stereocomplex formation combined with self-assembly of the fullerenes

We report a novel and versatile method for constructing a supramolecular nanosphere and nanonetwork based on isotactic and syndiotactic C60-end-capped poly(methyl methacrylate)s (it- and st-PMMA-C60's) through their stereocomplex formation combined with self-assembly of the terminal C60. The stereoregular PMMA-C60's with a precisely controlled structure including molecular weight, its distribution, tacticity, and the chain-end structure were synthesized by the stereospecific anionic living polymerizations of methyl methacrylate followed by end-capping with C60, and their structures were proven by size exclusion chromatography, NMR, UV-vis, and MALDI-TOF-MS analyses. The stereoregular PMMA-C60's self-assembled to form a core-shell aggregate with C60 as the core and the PMMA chains as the shell in H2O/CH3CN (1/9, v/v) due to the solvophobic interaction of the C60 units. These it- and st-PMMA-C60 aggregates further supramolecularly assembled through iterative stereocomplex formation into nanonetworks in which the self-assembled C60 clusters were robustly connected with two- and three-dimensional arrangements. In addition, when the it- and st-PMMA-C60's were simultaneously mixed, self-assembly of the C60 units and stereocomplex formation of the it- and st-PMMA chains took place at once, resulting in the formation of uniformly sized spherical nanoparticles with resistance to heat. Similar nanonetwork architectures can be produced using it-PMMA-C60 clusters and st-PMMA prepolymers as the binder.     

Control of the optical properties of quantum dots by surface coating with calix[n]arene carboxylic acids

A new method for the control of the optical properties of quantum dots (QDs) has been developed using calix[n]arene carboxylic acids (1-3) as surface coating agents for QDs. The calixarene coating of CdSe/ZnS QDs was easily performed in tetrahydrofuran at room temperature. Deprotonation of the carboxyl groups of the calixarene derivatives surrounding the QDs resulted in highly fluorescent water-soluble QDs. The emission peak of the calixarene-coated QDs shifted to longer wavelengths depending on the oligomer size of the calix[n]arene derivative used for the surface coating. Although the red shift of the emission peak decreases with the increase in the particle size of QDs, this surface coating method is useful for the preparation of multi-colored water-soluble QDs from a single-colored hydrophobic QD.     

A fluorescent lectin array using supramolecular hydrogel for simple detection and pattern profiling for various glycoconjugates

Because sugar and its derivatives play important roles in various biological phenomena, the rapid and high-throughput analysis of various glycoconjugates is keenly desirable. We describe herein the construction of a novel fluorescent lectin array for saccharide detection using a supramolecular hydrogel matrix. In this array, the fluorescent lectins were noncovalently fixed under semi-wet conditions to suppress the protein denaturation. It is demonstrated by fluorescence titration and fluorescence lifetime experiments that the immobilized lectins act as a molecular recognition scaffold in the hydrogel matrix, similar to that in aqueous solution. That is, a bimolecular fluorescence quenching and recovery (BFQR) method can successfully operate under both conditions. This enables one to fluorescently read-out a series of saccharides on the basis of the recognition selectivity and affinity of the immobilized lectins without tedious washing processes and without labeling the target saccharides. Simple and high-throughput sensing and profiling were carried out using the present lectin array for diverse glycoconjugates, which not only included a simple glucose, but also oligosaccharides, and glycoproteins, and, furthermore, the pattern recognition and profiling of several types of cell lysates were also accomplished.     

Studies on the constituents of Scutellaria species (XXII). Constituents of the roots of Scutellaria amabilis HARA

From the roots of Scutellaria amabilis HARA, eleven new flavonoids, 5,7,2'-trihydroxy-8-methoxyflavone 7-O-beta-D-glucopyranoside, 5,7,2'-trihydroxy-8-methoxyflavone 2'-O-beta-D-glucopyranoside, 5,7-dihydroxy-8,2'-dimethoxyflavone 7-O-beta-D-glucopyranoside, 5,7,2'-trihydroxyflavone 2'-O-beta-D-glucopyranoside, 5,7,2',5'-tetrahydroxyflavone 7-O-beta-D-glucuronopyranoside, (2S)-5,7,2',5'-tetrahydroxyflavanone, (2S)-5,7,2',5'-tetrahydroxyflavanone 7-O-beta-D-glucopyranoside, (2S)-5,7,2',5'-tetrahydroxyflavanone 7-O-beta-D-glucuronopyranoside, (2S)-7,2'-dihydroxy-5-methoxyflavanone 7-O-beta-D-glucuronopyranoside, (I-2S)-I-5,II-5,I-7,II-7,I-2',II-2',II-5'-heptahydroxy-[I-6,II-6']-flavanonylflavone and (I-2S)-I-5,II-5,I-7,II-7,I-2',II-2',I-5',II-5'-octahydroxy-[I-6,II-6']-flavanonylflavone, were isolated, together with ten known flavonoids, wogonin (5,7-dihydroxy-8-methoxyflavone), 5,7-dihydroxy-8,2'-dimethoxyflavone, (2S)-5,7,2'-trihydroxyflavanone, scutevulin (5,7,2'-trihydroxy-8-methoxyflavone), 5,7,4'-trihydroxy-8-methoxyflavone, alpinetin ((2S)-7-hydroxy-5-methoxyflavanone), 5,7,2'-trihydroxyflavone, 5,7,2',5'-tetrahydroxyflavone, (2S)-7,2'-dihydroxy-5-methoxyflavanone and 5,7-dihydroxy-8,2'-dimethoxyflavone 7-O-beta-D-glucuronopyranoside. The structures were determined on the basis of chemical and spectral data.     

Fabrication of highly porous and micropatterned SnO2 films by oxygen bubbles generated on the anode electrode

The fabrication process of highly porous SnO(2) thick film by reaction between tin ions and oxygen gas generated by an anodic applied potential on substrates in SnCl(2) aqueous solution is reported; moreover, we succeeded in forming porous SnO(2) micropatterns through site-selective deposition on a Pt-patterned F-doped SnO(2)(FTO) coated substrate .     

Ruthenium-catalyzed carbonylation of allene: direct synthesis of methacrylates and methacrylamides

Carbonylation reactions of allene in alcohols and amines in the presence of a ruthenium carbonyl catalyst under mild conditions gave methacrylates and methacrylamides, respectively, in good yields with an atom economy of 100%.