Publications by authors named "Yoshihiko Murakami"

Most drug carriers used in pulmonary administration are microparticles with diameters over 1 µm. Only a few examples involving nanoparticles have been reported because such small particles are readily exhaled. Consequently, the development of microparticles capable of encapsulating nanoparticles and a wide range of compounds for pulmonary drug-delivery applications is an important objective.

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Porous particles with controllable surface and internal morphologies were successfully prepared by a "one-step mechanical emulsification" technique via the control of spontaneous emulsification where self-emulsification is followed by mechanical emulsification. The morphological changes in the porous particles were determined not by the preparation conditions of the water-in-oil-in-water (w/o/w) emulsion but by the proportion of solvents that favors the stabilization of the spontaneously prepared water-in-oil (w/o) emulsion droplets acting as porogens. The proposed method for controlling the morphology of the porous particles could be applied to all particle-preparation systems based on emulsion-solvent evaporation using organic solvents.

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In the present study, we demonstrated zeolites' potential contribution to establish a method for preparing successfully refolded and reassembled PEGylated protein nanoparticles without the use of protein denaturants through the proteins' reassembly process. At first, the PEGylated nanoparticles are disassembled into identical PEGylated protein subunits by means of protein denaturants, and then the denatured subunits are adsorbed to zeolites. After the complete removal of denaturants, high-molecular-weight poly(ethylene glycol) (PEG) molecules are added to a solution where the zeolites suspend.

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In the present study, by spin-coating a solution containing w/o (water-in-oil) emulsions and hydrophobic polymers, we obtained sheets possessing uniformly dispersed w/o emulsions. We performed release experiments for more than 100 days and clarified the effects of the number of layers, the sheet-forming polymers (polylactide (PLA), poly(lactic--glycolic acid (PLGA)), the ratio of organic solvent to water, and the composition of block copolymers on the release properties of the sheets. For a variety of sheets, we successfully achieved the sustained release of compounds from the sheets for 100⁻150 days.

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Signs of aging in facial skin correlate with lifespan and chronic disease; however, the health of aging skin has not been extensively studied. In healthy young skin, the dermis forms a type III collagen-rich dermal papilla, where capillary vessels supply oxygen and nutrients to basal epidermal cells. Chicken eggshell membranes (ESMs) have been used as traditional medicines to promote skin wound healing in Asian countries for many years.

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We prepared the "sheet-type hydrogel" (gel sheet), a sheet consisting of PEG-grafted chitosan and cross-linkable polymeric micelles, that were expected to be used for wound healing. We optimized the PEG-modification process, evaluated the strain-dependence of the gel's properties to obtain flexible gel sheets, and evaluated the drug-release properties of the gel sheets. Finally, we succeeded in observing that the release of the antibiotic tetracycline (TET) from the gel sheet in which TET existed only in the cross-linkers was lower than the release of TET from the sheet in which TET was dispersed in the polymer networks.

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Wound-dressing sheet biomaterials can cover wound sites and enhance wound healing. In this study, a detailed evaluation of the factors affecting both the PEG modification percentage (PMP) in poly(ethylene glycol) (PEG)-grafted chitosan synthesis and the gelation properties of PEG-grafted chitosan was presented for constructing our novel hybrid hydrogel sheet consisting of PEG-grafted chitosan (a gel-forming polymer) and a reactive polymeric micelle (a crosslinker). It was confirmed that various factors (i.

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In the present study, by using a newly developed one-step emulsification technique, we tried to prepare porous PLGA particles having a proper diameter and surface morphology in order to achieve both a high efficient delivery of the particles to the lungs and a phagocytosis-avoidance ability. We found that our porous particles have the very low tapped density of 0.04g/cm.

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Inflammatory activation of macrophages is a key factor in chronic inflammatory diseases such as ulcerative colitis. The excessive production of reactive oxygen species (ROS)/reactive nitrogen species (RNS) by macrophages causes oxidative stress during the inflammatory response and exaggerates inflammatory lesions in ulcerative colitis. Inhibition of the inflammatory activation of macrophages is a promising treatment for chronic inflammatory diseases.

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We developed a hollow PEGylated encapsulin nanoparticle from Rhodococcus erythropolis N771. The hollow engineered encapsulin nanoparticles with His-Tag and Lys residues on the surface were constructed by means of genetic recombination. The Lys residues on the particle surface were successfully PEGylated with a PEG derivative, methoxy-PEG-SCM.

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In the present study, we designed hydrogels for dual drug release: the hydrogels that covalently contained the polymeric micelles that possess different drug release properties. The hydrogels that were formed from polymeric micelles possessing a tightly packed (i.e.

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RAFT polymerization is attractive for its reliability, facile operation, and high tolerance to a wide variety of monomers, functional groups, solvents, and temperatures. Herein, we report the RAFT-based synthesis of well-defined polymers bearing hydroxyl groups at two terminals by using various monomers. We found that the molecular weight of obtained polymers was half that of a target value when a trithiocarbonate-type chain transfer agent (CTA) was used, suggesting that the polymers unexpectedly cleaved at the middle of the polymer chain as the reaction was proceeding.

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In the present paper, we clarify the effects that the composition of three types of sheets-the PCL sheet, the PCL-BC (PCL-block copolymer composite) sheet, and the PCL-PM (PCL-polymeric micelle composite) sheet-can have on (1) the sheets' inner structure, (2) the dispersity of hydrophilic compounds in the sheets, (3) the sheets' mechanical properties, and (4) the sheets' degradability. Our results show that (1) the PCL-PM sheet can disperse hydrophilic compounds uniformly, (2) the molecular state (free or micellar) of a co-existing compound (PEG-b-PCL block copolymers) affects the strength and the inner structures of the sheets, whereas the presence of a co-existing compound affects the flexibility of the sheets, and (3) according to our degradation experiment, hard-to-handle PCL having extremely low hydrolysis could serve as materials with a controllable surface morphology by the effective use of co-existing compounds. The results obtained in this paper show that the PCL-CM sheet, with its uniformly dispersed polymeric micelles providing hydrophilic spaces, could be an effective biomaterial platform for incorporating hydrophilic polymers.

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Objective: To characterize clinical features of polymyositis/dermatomyositis (PM/DM) patients with different anti-aminoacyl transfer RNA synthetase (ARS) antibodies and their association with anti-Ro52.

Methods: Autoantibodies in sera from 97 Japanese patients (36 PM, 56 DM, and 5 clinically amyopathic DM), who satisfied Bohan and Peter or modified Sontheimer's criteria, were characterized by immunoprecipitation and enzyme-linked immunosorbent assay. Clinical information was from medical records.

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Sheets have several advantages over conventional gel- or particle-type drug carriers. Sheets have several notable attributes: sheets' size and shape are easily adjustable, sheets are highly accessible in surgery, and sheets have a large contact area relative to drug-targeting sites. However, it is difficult to incorporate hydrophilic proteins into hydrophobic sheets and to release the proteins over the long term in a sustained manner.

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The patient was a 63-year-old woman who presented with slowness of speech after cerebral infarction. Diffusion-weighted MR images and investigations of cerebrospinal fluid showed abnormal values, and the patient was diagnosed as having sporadic Creutzfeldt-Jakob disease(CJD). This is an intractable disease and affects one in one million people; it progresses relatively rapidly, eventually resulting in death.

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The encapsulin nanocompartment from Rhodococcus erythropolis N771 (Reencapsulin) was expressed and purified in wild-type and C-terminally His-tagged forms. Negative-stained transmission electron microscopy, field-flow fractionation combined with multi-angle light scattering and dynamic light scattering analyses showed that 60 Reencapsulin monomers were assembled as a spherical particle with a diameter of 28 nm. Heterogeneous guest proteins such as EGFP and firefly luciferase were packaged into the internal cavity of the Reencapsulin nanocompartment by fusing the C-terminal 37-amino-acid sequence of the R.

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We found that porous particles were unexpectedly obtained in a "one-step" manner only by mixing an organic solvent and water under "low-energy-input" (i.e., low-homogenization-rate) conditions.

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Thermoresponsive hybrids consisting of synthetic polymers and microtubules (MTs), i.e., assemblies of tubulins, were prepared by bonding MTs covalently to a few reactive units in a macromolecular strand.

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In this study, we successfully prepared a novel "sheet-shaped" chitosan hydrogel for wound healing consisting of both PEG-g-chitosan and a crosslinkable polymeric micelle. The study's findings clarify that the PEG modification percentage (PMP) of PEG-g-chitosan increased proportionally as the weight ratio of PEG/chitosan increased. Furthermore, the positive second virial coefficient of PEG-g-chitosans from a Debye plot strongly suggests that the PEG modification greatly improved the solubility of the water-insoluble chitosan.

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A new class of solvent-free room temperature liquid fullerenes was synthesized by attaching a single substituent of 1,3,5-tris(alkyloxy)benzene unit to C60 or C70 under the Prato conditions. Although the C60 monoadducts were single components after chromatographic purification, the C70 monoadducts were isomeric mixtures due to the prolate spheroidal π-chromophore. The alkyl chain length of the substituents significantly affected both melting points and rheological behavior of the fullerene derivatives.

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Sheet-shaped materials with a large contact area relative to the drug targeting site lead to advantages over conventional particle-shaped drug carriers and have several advantages for their biomedical applications. The present study proposes a methodology for preparing a novel sheet-shaped "hydrophobic" and biocompatible biomaterial in which polymeric micelles are uniformly dispersed for the incorporation of "hydrophilic" compounds into the sheet. The methoxy-terminated poly(ethylene glycol)-block-poly(lactic acid) block copolymer (CH(3)O-PEG-b-PLA) was successfully synthesized by means of the anionic ring-opening polymerization of both ethylene oxide and dl-lactide.

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Inorganic/organic hybrids were obtained by the sol-gel type organic modification reaction of Laponite sidewalls with poly(ethylene glycol) (PEG) bearing alkoxysiloxy terminal functionality. By casting an aqueous dispersion of the hybrid, the flexible and transparent hybrid films were obtained. Regardless of the inorganic/organic component ratio, the hybrid film had the ordered structure of Laponite in-plane flat arrays.

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We developed a novel "spray dry-based" method for preparing surface-modified particle via "block copolymer-assisted" emulsification/evaporation for pulmonary drug delivery. The method included three steps: (1) o/w emulsion containing both hydrophobic polymers and amphiphilic block copolymers was obtained by emulsification of water and a polymer-containing organic solvent, (2) the o/w emulsion was misted with a nebulizer, and (3) the emulsion mists were dried by a heater. In this way, the hydrophobic polymers and the hydrophobic part of the amphiphilic block copolymers gradually tangled during the evaporation of organic solvents from the o/w emulsion.

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We have developed a novel macromolecular assembly, trilayered polymeric micelle, which can incorporate hydrophilic compounds. The micelle can be prepared from the amphiphilic block copolymers without regard to their properties such as the copolymer's charges and the homogeneity of the copolymers forming the micelle's inner and outer parts. In this study, we investigated the optimal condition for the preferential formation of the trilayered polymeric micelle.

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