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Journal Articles

Magnetically navigated protein transduction in vivo using iron oxide-nanogel chaperone hybrid

Kawasaki, Riku*; Sasaki, Yoshihiro*; Nishimura, Tomoki*; Katagiri, Kiyofumi*; Morita, Keiichi*; Sekine, Yurina; Sawada, Shinichi*; Mukai, Sadaatsu*; Akiyoshi, Kazunari*

Advanced Healthcare Materials, 10(9), p.2001988_1 - 2001988_8, 2021/05

 Times Cited Count:6 Percentile:62.81(Engineering, Biomedical)

Systems for "protein transduction", the intracellular delivery of functional proteins, are needed to address the deliverability challenges of protein therapy, but protein transfer in vivo remains difficult. In this study, we have developed a magnetically induced in vivo protein transfection system using a magnetic nanogel chaperone (MC) composed of iron oxide nanoparticles and polysaccharide nanogels. Experiments using an oral cancer model have shown that this MC system is useful for cancer treatment.

Journal Articles

Structural analysis of DDS nanocarriers by neutron and X-ray small-angle scattering measurements

Nishimura, Tomoki*; Akiyoshi, Kazunari*; Sekine, Yurina

Hamon, 30(2), p.102 - 105, 2020/05

The development of drug delivery systems (DDS) that enable encapsulation of drugs, selective delivery to target tissues or organs has improved therapeutic effect and reduced side effects. DDS carriers are mainly based on the self-assembled nanoparticles, and their size and shape have significant influences on the therapeutic effect and side effects. However, their small sizes preclude from obtaining structural data with high accuracy by using conventional structural analysis techniques. We thus have analyzed the structures of supramolecular assemblies under the same conditions in actual use by neutron and synchrotron radiation small-angle X-ray scattering. Here, we review our recent studies on the structural analysis of supramolecular assemblies, including nanogels and polymer vesicles using contrast-variation neutron scattering and X-ray small-angle scattering measurements.

Journal Articles

Calcium-deficient hydroxyapatite as a potential sorbent for strontium

Sekine, Yurina; Motokawa, Ryuhei; Kozai, Naofumi; Onuki, Toshihiko; Matsumura, Daiju; Tsuji, Takuya; Kawasaki, Riku*; Akiyoshi, Kazunari*

Scientific Reports (Internet), 7(1), p.2064_1 - 2064_8, 2017/05

 Times Cited Count:34 Percentile:75.84(Multidisciplinary Sciences)

A calcium (Ca)-deficient hydroxyapatite was investigated for its potential to remove Sr$$^{2+}$$ from environmentally relevant water. We conducted sorption tests on solutions having Mg$$^{2+}$$ and Ca$$^{2+}$$ as competing cations at the Sr$$^{2+}$$ concentration of 0.05 mmol/L. The Ca-deficient hydroxyapatite maintained its high Sr$$^{2+}$$ sorption ratio: the sorption ratio was above 80% in the presence of Mg$$^{2+}$$ and Ca$$^{2+}$$ in the concentrations between 0.1 to 1.0 mmol/L, whereas stoichiometric hydroxyapatite showed a lower ratio even in the presence of small amounts of Mg$$^{2+}$$ and Ca$$^{2+}$$. The bonding states of Sr$$^{2+}$$ onto the Ca-deficient hydroxyapatite were evaluated by extended X-ray absorption fine structure measurements. The results indicated that there are specific sorption sites in Ca-deficient hydroxyapatite where Sr$$^{2+}$$ could be stably and preferentially immobilized.

Journal Articles

Nanoscopic structural investigation of physically cross-linked nanogels formed from self-associating polymers

Sekine, Yurina; Endo, Hitoshi*; Iwase, Hiroki*; Takeda, Shigeo*; Mukai, Sadaatsu*; Fukazawa, Hiroshi; Littrell, K. C.*; Sasaki, Yoshihiro*; Akiyoshi, Kazunari*

Journal of Physical Chemistry B, 120(46), p.11996 - 12002, 2016/11

 Times Cited Count:10 Percentile:27.43(Chemistry, Physical)

The detailed structure of a nanogel formed by self-association of cholesterol-bearing pullulans (CHP) was determined by contrast variation small-angle neutron scattering. The decomposition of scattering intensities into partial scattering functions of each CHP nanogel component, i.e., pullulan, cholesterol, and the cross-term between the pullulan and the cholesterol allows us to investigate the internal structure of the nanogel. The effective spherical radius of the skeleton formed by pullulan chains was found to be about 8.1 nm. In the CHP nanogel, there are about 19 cross-linking points where a cross-linking point is formed by aggregation of trimer cholesterol molecules with the spatially inhomogeneous distribution of the mass fractal dimension of 2.6. The average radius of the partial chains can also be determined to be 1.7 nm. As the result, the complex structure of the nanogels is coherently revealed at the nanoscopical level.

Oral presentation

Structure of physically cross-linked nanogels investigated by means of contrast variation small-angle neutron scattering

Sekine, Yurina; Endo, Hitoshi*; Iwase, Hiroki*; Fukazawa, Hiroshi; Mukai, Sadaatsu*; Akiyoshi, Kazunari*

no journal, , 

Cholesterol-bearing pullulan (CHP) spontaneously forms stable nanogel of ca. 30 nm in size in water. Because the CHP nanogels can trap various proteins spontaneously and release them in their native form to environment, they are valuable for use in protein delivery systems, particularly for cancer vaccines, and so on. The distribution and position of cross-linking domain are important factor determining the properties of nanogels. The aim of this study is to investigate the distribution and position of cross-linking domain of nanogels by means of contrast variation small-angle neutron scattering (CV-SANS). We had the CV-SANS measurement of the CHP nanogel dispersed in complex solvent of D$$_{2}$$O/H$$_{2}$$O to clarify the microscopic structure of cross-linking domain of CHP nanogels. In this presentation, we will discuss the detailed structure of the CHP nanogel analyzed from the result of CV-SANS.

Oral presentation

Structure of self-assembled nanogels investigated by means of contrast variation small-angle neutron scattering

Sekine, Yurina; Fukazawa, Hiroshi; Endo, Hitoshi*; Iwase, Hiroki*; Mukai, Sadaatsu*; Littrell, K. C.*; Fernandez-Baca, J. A.*; Akiyoshi, Kazunari*

no journal, , 

Cholesterol-bearing pullulan (CHP) spontaneously forms stable nanogel of ca. 30 nm in size in water. Because the CHP nanogels can trap various proteins spontaneously and release them in their native form to environment, they are valuable for use in protein delivery systems. The aim of this study is to investigate the distribution and position of cross-linking domain of nanogels by means of contrast variation small-angle neutron scattering (CV-SANS). We had SANS measurement of the CHP nanogel dispersed in complex solvent of D$$_{2}$$O/H$$_{2}$$O to clarify the microscopic structure of cross-linking domain. The result shows that the particle radius of the pullulan and the cholesterol are 8.09 and 6.31 nm, respectively. The dispersion of the cross-linking domains might have important implications for the interactions of nanogels with other molecules.

Oral presentation

Nanoscopic structure of physically cross-linked nanogels investigated by small-angle neutron scattering

Sekine, Yurina; Endo, Hitoshi*; Iwase, Hiroki*; Takeda, Shigeo*; Mukai, Sadaatsu*; Fukazawa, Hiroshi; Sasaki, Yoshihiro*; Akiyoshi, Kazunari*

no journal, , 

Cholesterol-bearing pullulan (CHP) forms stable nanogel of 20 nm in size in water. The CHP nanogels can trap various proteins spontaneously. Owing to their characteristics, nanogels can be used in protein delivery systems, particularly for cancer vaccines. The spatial distribution and detailed structure of the cross-linking points are important factor determining their chemical and physical functions. The aim of this study is to investigate the structure of the nanogels by means of contrast variation small-angle neutron scattering (CV-SANS), which enables us to determine quantitative complex structure at nanometer scale. In this presentation, we will discuss the detailed structure of the CHP nanogel.

Oral presentation

Nanoscopic structure of nanogels formed from self-associating polymers

Sekine, Yurina; Endo, Hitoshi*; Akiyoshi, Kazunari*

no journal, , 

Nanogels, which have characteristic properties of both hydrogels and nanoparticles are attracting growing interest in the fields of material science and nanotechnology. Although the spatial distribution of cross-linking points in the nanogels would be highly related to their properties, no clear nanoscopic information has been obtained so far due to the complex structure with the multi components. The detailed internal structure of a nanogel formed by self-association of cholesterol-bearing pullulans (CHP) was investigated by contrast variation small-angle neutron scattering (CV-SANS), which enables us to determine quantitative complex structure at nanometer scale. In this presentation, I will discuss the detailed structure of the nanogels.

Oral presentation

Structural investigation of various nanogels by contrast variation small-angle neutron scattering method

Sekine, Yurina; Endo, Hitoshi*; Akiyoshi, Kazunari*

no journal, , 

Hydrogel nano-particles (nanogels) show characteristic properties of both hydrogels and nano-particles and are attracting growing interest in the fields of material science and nanotechnology. Although the spatial distribution of cross-linking points in the nanogels would be highly related to their properties, no clear nanoscopic information has been obtained due to the complex structure with the multi components. We have been studied about the detailed internal structure of a nanogel formed by self-association of cholesterol-bearing pullulans (CHP) by using contrast variation small-angle neutron scattering (CV-SANS). In this presentation, I will discuss the detailed structure of nanogels and the dependence of the chemical components on the structure.

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