Design and synthesis of thermoresponsive aliphatic polyethers with a tunable phase transition temperature

This paper describes a comprehensive study of the lower critical solution temperature (LCST)-type thermoresponsive properties of various poly(glycidyl ether) homopolymers with a varying side chain structure, molecular weight, and main chain tacticity, as well as their copolymers with a varying monomer composition and monomer sequence. For the initial screening, we prepared nine kinds of poly(glycidyl ether)s by the phosphazene base-catalyzed ring-opening polymerization of glycidyl methyl ether (MeGE), ethyl glycidyl ether (EtGE), glycidyl isopropyl ether (iPrGE), 2-methoxyethyl glycidyl ether (MeEOGE), 2-ethoxyethyl glycidyl ether (EtEOGE), 2-propoxyethyl glycidyl ether (PrEOGE), 2-(2- methoxyethoxy) ethyl glycidyl ether (MeEO(2)GE), 2-(2-ethoxyethyl) ethyl glycidyl ether (EtEO(2)GE), and 2-(2-(2-methoxyethoxy) ethoxy) ethyl glycidyl ether (MeEO(3)GE). Among them, poly(MeGE), poly(EtGE), poly(MeEOGE), poly(EtEOGE), and poly(MeEO(2)GE) (M-n = ca. 5000 g mol(-1)) were found to exhibit a LCST-type phase transition in water at 65.5 degrees C, 10.3 degrees C, 91.6 degrees C, 41.3 degrees C, and 58.2 degrees C, respectively. Although the molecular weight and main chain tacticity had little impact on the phase transition temperature, the side chain structure, i.e., the number of oxyethylene units and terminal alkyl groups, significantly affected the transition temperature. The statistical copolymers composed of MeEOGE and EtEOGE revealed that the transition temperature of the polymer can be desirably customized in between those of the homopolymers by varying the monomer composition. On the other hand, we found that the block copolymer composed of MeEOGE and EtEOGE exhibited a complex thermoresponsive behavior due to its ability to form a micellar aggregate

Self-Assembly of Maltoheptaose- block -polycaprolactone Copolymers: Carbohydrate-Decorated Nanoparticles with Tunable Morphology and Size in Aqueous Media

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Synthesis, Thermal Properties, and Morphologies of Amphiphilic Brush Block Copolymers with Tacticity-Controlled Polyether Main Chain

A series of brush block copolymers (BBCPs) consisting of poly­(decyl glycidyl ether) (PDGE) and poly­(10-hydroxyldecyl glycidyl ether) (PHDGE) blocks, having four different types of chain tacticities, i.e., [<i>at</i>-PDGE]-<i>b</i>-[<i>at</i>-PDEGE], [<i>at</i>-PDGE]-<i>b</i>-[<i>it</i>-PDEGE], [<i>it</i>-PDGE]-<i>b</i>-[<i>at</i>-PDEGE], and [<i>it</i>-PDGE]-<i>b</i>-[<i>it</i>-PDEGE], where the <i>it</i> and <i>at</i> represent the isotactic and atactic chains, respectively, were prepared by <i>t</i>-Bu-P₄-catalyzed sequential anionic ring-opening polymerization of glycidyl ethers followed by side-chain modification. The corresponding homopolymers, i.e., <i>at</i>-PDGE, <i>it</i>-PDGE, <i>at</i>-PHDGE, and <i>it</i>-PHDGE, were also prepared for comparison with the BBCPs. The PDGE homopolymers were significantly promoted in the phase transitions and morphological structure formation by the isotacticity formation. In particular, <i>it</i>-PDGE was found to form only a horizontal multibilayer structure with a monoclinic lattice in thin films, which was driven by the bristles’ self-assembling ability and enhanced by the isotacticity. However, the PHDGE homopolymers were found to reveal somewhat different behaviors in the phase transitions and morphological structure formation by the tacticity control due to the additional presence of a hydroxyl group in the bristle end as an H-bonding interaction site. The H-bonding interaction could be enhanced by the isotacticity formation. The <i>it</i>-PHDGE homopolymer formed only the horizontal multibilayer structure, which was different from the formation of a mixture of horizontal and tilted multibilayer structures in <i>at</i>-PHDGE. The structural characteristics were further significantly influenced by the diblock formation and the tacticity of the counterpart block. Because of the strong self-assembling characteristics of the individual block components, all the BBCPs formed separate crystals rather than cocrystals. The isotacticity always promoted the formation of better quality morphological structures in terms of their lateral ordering and orientation

MANTA, an integrative database and analysis platform that relates microbiome and phenotypic data.

With an ever-increasing interest in understanding the relationships between the microbiota and the host, more tools to map, analyze and interpret these relationships have been developed. Most of these tools, however, focus on taxonomic profiling and comparative analysis among groups, with very few analytical tools designed to correlate microbiota and the host phenotypic data. We have developed a software program for creating a web-based integrative database and analysis platform called MANTA (Microbiota And pheNoType correlation Analysis platform). In addition to storing the data, MANTA is equipped with an intuitive user interface that can be used to correlate the microbial composition with phenotypic parameters. Using a case study, we demonstrated that MANTA was able to quickly identify the significant correlations between microbial abundances and phenotypes that are supported by previous studies. Moreover, MANTA enabled the users to quick access locally stored data that can help interpret microbiota-phenotype relations. MANTA is available at https://mizuguchilab.org/manta/ for download and the source code can be found at https://github.com/chenyian-nibio/manta

Synthesis of Linear, Cyclic, Figure-Eight-Shaped, and Tadpole-Shaped Amphiphilic Block Copolyethers via <i>t</i>‑Bu‑P₄‑Catalyzed Ring-Opening Polymerization of Hydrophilic and Hydrophobic Glycidyl Ethers

This paper describes the synthesis of systematic sets of figure-eight- and tadpole-shaped amphiphilic block copolyethers (BCPs) consisting of poly­(decyl glycidyl ether) and poly­[2-(2-(2-methoxyethoxy)­ethoxy)­ethyl glycidyl ether], together with the corresponding cyclic counterparts, via combination of the <i>t</i>-Bu-P₄-catalyzed ring-opening polymerization (ROP) and click cyclization. The clickable linear BCP precursors, with precisely controlled azido and ethynyl group placements as well as a fixed molecular weight and monomer composition (degree of polymerization for each block was adjusted to be around 50), were prepared by the <i>t</i>-Bu-P₄-catalyzed ROP with the aid of functional initiators and terminators. The click cyclization of the precursors under highly diluted conditions produced a series of cyclic, figure-eight-, and tadpole-shaped BCPs with narrow molecular weight distributions of less than 1.06. Preliminary studies of the BCPs self-assembly in water revealed the significant variation in their cloud points depending on the BCP architecture, though there were small architectural effects on their critical micelle concentration and morphology of the aggregates

Self-Assembly of Maltoheptaose-<i>block</i>-polycaprolactone Copolymers: Carbohydrate-Decorated Nanoparticles with Tunable Morphology and Size in Aqueous Media

This paper describes the systematic investigation into the aqueous self-assembly of a series of block copolymers (BCPs) consisting of maltoheptaose (MH; as the A block) and poly­(ε-caprolactone) (PCL; as the B block), i.e., linear AB-type diblock copolymers with varied PCL molecular weights (MH-<i>b</i>-PCL_{(2.5k,3.3k,5k,10k)}), AB_<i>y</i>-type (<i>y</i> = 2, MH-<i>b</i>-(PCL_5k)₂; <i>y</i> = 3, MH-<i>b</i>-(PCL_3.3k)₃), A₂B₂-type ((MH)₂-<i>b</i>-(PCL_5k)₂), and A_<i>x</i>B-type miktoarm star polymers (<i>x</i> = 2, (MH)₂-<i>b</i>-PCL_10k; <i>x</i> = 3, (MH)₃-<i>b</i>-PCL_10k), which had been precisely synthesized via the combination of the living ring-opening polymerization and click reaction. Under similar conditions, the nanoprecipitation method was employed to self-assemble them in an aqueous medium. Imaging and dynamic light scattering techniques indicated the successful formation of the carbohydrate-decorated nanoparticles via self-assembly. The MH-<i>b</i>-PCLs formed regular core–shell micellar nanoparticles with the hydrodynamic radius (<i>R</i>_h) of 17–43 nm. MH-<i>b</i>-(PCL_5k)₂ and MH-<i>b</i>-(PCL_3.3k)₃, which have an <i>N</i>_PCL comparable to MH-<i>b</i>-PCL_10k, were found to form large compound micelles with relatively large radii (<i>R</i>_h of 49 and 56 nm, respectively). On the other hand, (MH)₂-<i>b</i>-(PCL_5k)₂, (MH)₂-<i>b</i>-PCL_10k, and (MH)₃-<i>b</i>-PCL_10k predominantly formed the regular core–shell micellar nanoparticles (<i>R</i>_h = 29–39 nm) with a size smaller than that of MH-<i>b</i>-PCL_10k (<i>R</i>_h = 43 nm)

Dietary Vitamin B1 Intake Influences Gut Microbial Community and the Consequent Production of Short-Chain Fatty Acids

The gut microbiota is closely related to good health; thus, there have been extensive efforts dedicated to improving health by controlling the gut microbial environment. Probiotics and prebiotics are being developed to support a healthier intestinal environment. However, much work remains to be performed to provide effective solutions to overcome individual differences in the gut microbial community. This study examined the importance of nutrients, other than dietary fiber, on the survival of gut bacteria in high-health-conscious populations. We found that vitamin B1, which is an essential nutrient for humans, had a significant effect on the survival and competition of bacteria in the symbiotic gut microbiota. In particular, sufficient dietary vitamin B1 intake affects the relative abundance of Ruminococcaceae, and these bacteria have proven to require dietary vitamin B1 because they lack the de novo vitamin B1 synthetic pathway. Moreover, we demonstrated that vitamin B1 is involved in the production of butyrate, along with the amount of acetate in the intestinal environment. We established the causality of possible associations and obtained mechanical insight, through in vivo murine experiments and in silico pathway analyses. These findings serve as a reference to support the development of methods to establish optimal intestinal environment conditions for healthy lifestyles