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Journal Articles

Passive sweat collection and colorimetric analysis of biomarkers relevant to kidney disorders using a soft microfluidic system

Zhang, Y.*; Guo, H.*; Kim, S. B.*; Wu, Y.*; Ostojich, D.*; Park, S. H.*; Wang, X.*; Weng, Z.*; Li, R.*; Bandodkar, A. J.*; et al.

Lab on a Chip, 19(9), p.1545 - 1555, 2019/05

 Times Cited Count:11 Percentile:1.69(Biochemical Research Methods)

This paper introduces two important advances in recently reported classes of soft, skin-interfaced microfluidic systems for sweat capture and analysis: (1) a simple, broadly applicable means for collection of sweat that bypasses requirements for physical/mental exertion or pharmacological stimulation and (2) a set of enzymatic chemistries and colorimetric readout approaches for determining the concentrations of creatinine and urea in sweat, across physiologically relevant ranges. The results allow for routine, non-pharmacological capture of sweat across patient populations, such as infants and the elderly, that cannot be expected to sweat through exercise, and they create potential opportunities in the use of sweat for kidney disease screening/monitoring.

Journal Articles

Root-endophytic Chaetomium cupreum chemically enhances aluminium tolerance in $$Miscanthus sinensis$$ via increasing the aluminium detoxicants, chlorogenic acid and oosporein

Haruma, Toshikatsu*; Yamaji, Keiko*; Ogawa, kazuyoshi*; Masuya, Hayato*; Sekine, Yurina; Kozai, Naofumi

PLOS ONE (Internet), 14(2), p.e0212644_1 - e0212644_16, 2019/02

 Times Cited Count:2 Percentile:29.47(Multidisciplinary Sciences)

Miscanthus sinensis Andersson is a pioneer plant species that grows naturally at mining sites. $$Miscanthus sinensis$$ can detoxify aluminium (Al) by producing phytosiderophores. Root-endophytic Chaetomium cupreum, which produces microbial siderophores, enhances Al tolerance in M. sinensis. We identified the siderophore produced by C. cupreum as oosporein. It was revealed that oosporein could detoxify Al. Inoculation test of C. cupreum onto M. sinensis in acidic mine soil showed that C. cupreum promoted seedling growth, and enhanced Al tolerance.

Journal Articles

Battery-free, skin-interfaced microfluidic/electronic systems for simultaneous electrochemical, colorimetric, and volumetric analysis of sweat

Bandodkar, A. J.*; Gutruf, P.*; Choi, J.*; Lee, K.-H.*; Sekine, Yurina; Reeder, J. T.*; Jeang, W. J.*; Aranyosi, A. J.*; Lee, S. P.*; Model, J. B.*; et al.

Science Advances (Internet), 5(1), p.eaav3294_1 - eaav3294_15, 2019/01

 Times Cited Count:60 Percentile:0.14(Multidisciplinary Sciences)

Interest in advanced wearable technologies increasingly extends beyond systems for biophysical measurements to those that enable continuous, non-invasive monitoring of biochemical markers in biofluids. Here, we introduce battery-free, wireless microelectronic platforms that perform sensing via schemes inspired by the operation of biofuel cells. Combining these systems in a magnetically releasable manner with chrono-sampling microfluidic networks that incorporate assays based on colorimetric sensing yields thin, flexible, lightweight, skin-interfaced technologies with broad functionality in sweat analysis. A demonstration device allows simultaneous monitoring of sweat rate/loss, along with quantitative measurements of pH and of lactate, glucose and chloride concentrations using biofuel cell and colorimetric approaches.

Journal Articles

Nanoscopic structural investigation of nanogels for drug delivery application

Sekine, Yurina

Shiki, 41, P. 4, 2018/12

This article described the detailed structure of a nanogel formed by self-association of polysaccharides determined by contrast variation small-angle neutron scattering.

Journal Articles

Soft, skin-interfaced microfluidic systems with wireless, battery-free electronics for digital, real-time tracking of sweat loss and electrolyte composition

Kim, S. B.*; Lee, K.-H.*; Raj, M. S.*; Reeder, J. T.*; Koo, J.*; Hourlier-Fargette, A.*; Bandodkar, A. J.*; Won, S. M.*; Sekine, Yurina; Choi, J.*; et al.

Small, 14(45), p.1802876_1 - 1802876_9, 2018/11

 Times Cited Count:16 Percentile:11.46(Chemistry, Multidisciplinary)

Excretion of sweat from eccrine glands is a dynamic physiological process that varies with body position, activity level, and health status. Information content embodied in sweat rate and chemistry can be used to assess health status and athletic performance. This paper presents a thin, miniaturized, skin-interfaced microfluidic technology that includes a reusable, battery-free electronics module for measuring sweat conductivity and rate in real-time using wireless power from and data communication with capabilities in near field communications (NFC). Systematic studies of these combined microfluidic/electronic systems, accurate correlations of measurements performed with them to those of laboratory standard instrumentation, and field tests on human subjects establish the key operational features and their utility in sweat analytics.

Journal Articles

A Fluorometric skin-interfaced microfluidic device and smartphone imaging module for ${{it in situ}}$ quantitative analysis of sweat chemistry

Sekine, Yurina; Kim, S. B.*; Zhang, Y.*; Bandodkar, A. J.*; Xu, S.*; Choi, J.*; Irie, Masahiro*; Ray, T. R.*; Kohli, P.*; Kozai, Naofumi; et al.

Lab on a Chip, 18(15), p.2178 - 2186, 2018/08

The rich composition of solutes and metabolites in sweat and its relative ease of collection upon excretion from skin pores make this class of biofluid an attractive candidate for point of care analysis. Here, we present a complementary approach that exploits fluorometric sensing modalities integrated into a soft, skin-interfaced microfluidic system which, when paired with a simple smartphone-based imaging module, allows for in-situ measurement of important biomarkers in sweat. A network array of microchannels and a collection of microreservoirs pre-filled with fluorescent probes that selectively react with target analytes in sweat (e.g. probes), enable quantitative, rapid analysis. Field studies on human subjects demonstrate the ability to measure the concentrations of chloride, sodium and zinc in sweat, with accuracy that matches that of conventional laboratory techniques.

Journal Articles

Super-absorbent polymer valves and colorimetric chemistries for time-sequenced discrete sampling and chloride analysis of sweat via skin-mounted soft microfluidics

Kim, S. B.*; Zhang, Y.*; Won, S. M.*; Bandodkar, A. J.*; Sekine, Yurina; Xue, Y.*; Koo, J.*; Harshman, S. W.*; Martin, J. A.*; Park, J. M.*; et al.

Small, 14(12), p.1703334_1 - 1703334_11, 2018/03

 Times Cited Count:26 Percentile:5.63(Chemistry, Multidisciplinary)

Journal Articles

Experience note of John Rogers Laboratory in Northwestern University

Sekine, Yurina

Hoshasen To Sangyo, (143), p.51 - 54, 2017/12

The author reports experience note of John Rogers laboratory in Northwestern University from January in 2017.

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:12 Percentile:27.13(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:8 Percentile:62.28(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.

Journal Articles

Neutron diffraction of ice and water in hydrogels

Sekine, Yurina; Kobayashi, Riki*; Chi, S.*; Fernandez-Baca, J. A.*; Suzuya, Kentaro; Fujisaki, Fumika*; Ikeda, Kazutaka*; Otomo, Toshiya*; Fukazawa, Tomoko*; Yamauchi, Hiroki; et al.

JPS Conference Proceedings (Internet), 8, p.033009_1 - 033009_6, 2015/09

Neutron diffraction profiles of low-D$$_{2}$$O-content poly-N,N,-dimethylacrylamide (PDMAA) hydrogels were measured from 100 to 300 K to investigate the structure and properties of water in hydrogels. A broad diffraction observed at temperatures lower than 220 K indicates the existence of amorphous ice in the hydrogels at low temperatures. During the heating process, diffraction peaks from ice crystals appear in the profiles. These peaks indicate that cubic ice and hexagonal ice exist at T $$geq$$ 220 K. We refined the structure parameters of these ices in the hydrogel, which indicate the existence of low-density ice in the hydrogel.

Journal Articles

Fly to the world Episode 1

Sekine, Yurina

Hamon, 25(2), P. 179, 2015/05

no abstracts in English

Journal Articles

Dependence of structure of polymer side chain on water structure in hydrogels

Sekine, Yurina; Takagi, Hajime*; Sudo, Sayoko*; Kajiwara, Yutaro*; Fukazawa, Hiroshi; Fukazawa, Tomoko*

Polymer, 55(24), p.6320 - 6324, 2014/11

 Times Cited Count:12 Percentile:44.83(Polymer Science)

To investigate the effects of structure of polymer side chains on structure of water in hydrogels, Raman spectra of polyacrylamide (PAA) and poly-$$N$$,$$N$$-dimethylacrylamide (PDMAA) hydrogels were measured. PAA and PDMAA have similar chemical structures, except for the side chain structure. The result shows that the frequency of the OH stretching mode for the PAA hydrogel decreases as the water content decreases, while that for the PDMAA hydrogel increases. We conclude that most of the bound water molecules in the PAA hydrogel form four strong hydrogen bonds with the hydrophilic groups in the side chain of PAA, whereas those in the PDMAA hydrogel form weak hydrogen bonds with surrounding water molecules. The water structure is an important factor governing the physical and chemical properties of gel materials.

Journal Articles

Neutron diffraction of ice in hydrogels

Sekine, Yurina; Fukazawa, Tomoko*; Aizawa, Mamoru*; Kobayashi, Riki*; Chi, S.*; Fernandez-Baca, J. A.*; Yamauchi, Hiroki; Fukazawa, Hiroshi

Journal of Physical Chemistry B, 118(47), p.13453 - 13457, 2014/08

 Times Cited Count:1 Percentile:97.47(Chemistry, Physical)

Neutron diffraction patterns for deuterated poly-$$N$$,$$N$$,-dimethylacrylamide (PDMAA) hydrogels were measured from 10 to 300 K to investigate the structure and properties of water in the gels. Diffraction peaks observed below 250 K indicate the existence of ice in the hydrogels. Some diffraction peaks from the ice are at lower diffraction angles than those in ordinary hexagonal ice (Ih). These shifts in peaks indicate that the lattice constants of the $$a$$ and $$c$$ axes in the ice are about 0.29% and 0.3% higher than those in ice Ih, respectively. The results show that bulk low-density ice can exist in PDMAA hydrogels. The distortions in the lattice structure of ice imply significant interactions between water molecules and the surrounding polymer chains, which play an important role in the chemical and mechanical properties of the hydrogel.

Journal Articles

Oak Ridge National Laboratory trip report

Sekine, Yurina

Photon Factory News, 31(4), p.45 - 46, 2014/02

Oak Ridge National Laboratory is a science and technology national laboratory managed for the United States Department of Energy by IT-Battelle. ORNL is located in Oak Ridge, Tennessee, near Knoxville in United States. I had my first neutron experiment in ORNL last year. The neutron diffraction measurements were performed using Wide Angle Neutron Diffractometer (WAND). From the result, we found that structure of water molecules in hydrogels different from that of ordinary water.

Journal Articles

Structural changes of water in poly(vinyl alcohol) hydrogel during dehydration

Kudo, Kushi*; Ishida, Junichi*; Syuu, G.*; Sekine, Yurina; Fukazawa, Tomoko*

Journal of Chemical Physics, 140(4), p.044909_1 - 044909_8, 2014/01

 Times Cited Count:22 Percentile:21.76(Chemistry, Physical)

To investigate the mechanism of structural changes of water and polymer networks with drying and swelling, we measured the Raman spectra of a physically cross-linked poly(vinyl alcohol) (PVA) hydrogel synthesized using the freezing thawing method. On the basis of the dependence of the frequency shifts on the PVA concentration of the original solution, it was found that the structure of the polymer network in the reswollen hydrogel becomes inhomogeneous due to shrinkage of the polymer network with drying. Furthermore, to investigate the effects of the cross-linking structure on the drying process, these results were compared with those of a chemically cross-linked PVA hydrogel synthesized using glutaraldehyde as a cross-linker. The results show that the structures of the polymer network and water change with the gel preparation process, cross-linking method, and drying and reswelling processes.

Journal Articles

Effects of crosslinker density on the polymer network structure in poly-$$N$$,$$N$$-dimethylacrylamide hydrogels

Fukazawa, Tomoko*; Ikeda, Naohiro*; Tabata, Mayu*; Hattori, Masataka*; Aizawa, Mamoru*; Yunoki, Shunji*; Sekine, Yurina

Journal of Polymer Science, Part B; Polymer Physics, 51(13), p.1017 - 1027, 2013/07

 Times Cited Count:20 Percentile:31.82(Polymer Science)

Oral presentation

The Existence of dense ferroelectric ice under high pressure

Sekine, Yurina; Fukazawa, Hiroshi; Arakawa, Masashi*; Abe, Jun; Hattori, Takanori; Sano, Asami; Utsumi, Wataru; Arima, Hiroshi*; Uwatoko, Yoshiya; Komatsu, Kazuki*; et al.

no journal, , 

Oral presentation

Water structure in a hydrogel

Sekine, Yurina; Fukazawa, Hiroshi; Songxue, C.*; Chakoumakos, B.*; Fernandez-Baca, J. A.*

no journal, , 

no abstracts in English

Oral presentation

Ice structure formed in saccharide solution

Sekine, Yurina; Fukazawa, Tomoko*; Kajiwara, Yutaro*; Ito, Yu*; Fukazawa, Hiroshi

no journal, , 

no abstracts in English

38 (Records 1-20 displayed on this page)