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Goda T, Yamada E, Katayama Y, Tabata M, Matsumoto A, Miyahara Y. Potentiometric responses of ion-selective microelectrode with bovine serum albumin adsorption. Biosens Bioelectron 2016; 77:208-14. [DOI: 10.1016/j.bios.2015.09.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 08/07/2015] [Accepted: 09/10/2015] [Indexed: 11/29/2022]
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2
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Xu Z, Oleschuk RD. A fluorous porous polymer monolith photo-patterned chromatographic column for the separation of a flourous/fluorescently labeled peptide within a microchip. Electrophoresis 2013; 35:441-9. [DOI: 10.1002/elps.201300365] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/15/2013] [Accepted: 10/15/2013] [Indexed: 11/12/2022]
Affiliation(s)
- Zhenpo Xu
- Department of Chemistry; Queen's University; Kingston Ontario Canada
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3
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Kano T, Kakinuma C, Wada S, Morimoto K, Ogihara T. Enhancement of Drug Solubility and Absorption by Copolymers of 2-Methacryloyloxyethyl Phosphorylcholine and n-Butyl Methacrylate. Drug Metab Pharmacokinet 2011; 26:79-86. [DOI: 10.2133/dmpk.dmpk-10-rg-070] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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4
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Xu Y, Takai M, Ishihara K. Phospholipid Polymer Biointerfaces for Lab-on-a-Chip Devices. Ann Biomed Eng 2010; 38:1938-53. [DOI: 10.1007/s10439-010-0025-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Accepted: 03/22/2010] [Indexed: 01/09/2023]
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MASADOME T, NAKAMURA K, IIJIMA D, HORIUCHI O, TOSSANAITADA B, WAKIDA SI, IMATO T. Microfluidic Polymer Chip with an Embedded Ion-Selective Electrode Detector for Nitrate-Ion Assay in Environmental Samples. ANAL SCI 2010; 26:417-23. [DOI: 10.2116/analsci.26.417] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Takashi MASADOME
- Department of Applied Chemistry, Faculty of Engineering, Shibaura Institute of Technology
| | - Kazuki NAKAMURA
- Department of Applied Chemistry, Faculty of Engineering, Shibaura Institute of Technology
| | - Daisuke IIJIMA
- Department of Applied Chemistry, Faculty of Engineering, Shibaura Institute of Technology
| | - Osamu HORIUCHI
- Department of Applied Chemistry, Faculty of Engineering, Shibaura Institute of Technology
| | - Benjaporn TOSSANAITADA
- Department of Applied Chemistry, Faculty of Engineering, Shibaura Institute of Technology
| | - Shin-ichi WAKIDA
- Health Device Research Institute, Human Stress Signal Research Center (HSS), National Institute of Advanced Industrial Science and Technology (AIST)
| | - Toshihiko IMATO
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University
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Xu Y, Takai M, Ishihara K. Suppression of Protein Adsorption on a Charged Phospholipid Polymer Interface. Biomacromolecules 2008; 10:267-74. [DOI: 10.1021/bm801279y] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yan Xu
- Department of Materials Engineering, School of Engineering, and Center for NanoBio Integration, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Madoka Takai
- Department of Materials Engineering, School of Engineering, and Center for NanoBio Integration, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kazuhiko Ishihara
- Department of Materials Engineering, School of Engineering, and Center for NanoBio Integration, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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Masadome T, Ishikawa M, Wakida S. Fabrication and Characterization of Polymer‐Based Microchip Integrated with NH4+‐ISFET Using a Small Diameter Wire as a Template of Channel. ANAL LETT 2007. [DOI: 10.1081/al-120028613] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Ren L, Escobedo-Canseco C, Li D. A new method of evaluating the average electro-osmotic velocity in microchannels. J Colloid Interface Sci 2007; 250:238-42. [PMID: 16290656 DOI: 10.1006/jcis.2002.8299] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2001] [Accepted: 02/12/2002] [Indexed: 11/22/2022]
Abstract
A new and simple method to evaluate the average electro-osmotic flow velocity in microchannels is presented in this paper. In this method, the average electro-osmotic flow velocity is determined by using the slope of the measured current-time relationship during the electro-osmotic flow of one solution replacing another similar solution. The two solutions have the same electrolyte and a small difference in ionic concentration. Careful experiments were conducted to measure the electrical current change with time during such a displacing process under a constant applied electrical field. KCl and LaCl3 electrolyte solutions and 10-cm-long polyamide-coated silica capillary tubes of 100 and 200 microm in internal diameter were used in this study. The average velocities were determined by using the slope method. A numerical model was also developed to predict the average velocity of such an electro-osmotic flow. An excellent agreement in the average velocities between the slope method and the model predictions was found.
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Affiliation(s)
- Liqing Ren
- Department of Mechanical & Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, M5S 3G8, Canada
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9
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Cytocompatible biointerface on poly(lactic acid) by enrichment with phosphorylcholine groups for cell engineering. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2007. [DOI: 10.1016/j.msec.2006.05.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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10
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Masadome T, Yada K, Wakida SI. Microfluidic Polymer Chip Integrated with an ISFET Detector for Cationic Surfactant Assay in Dental Rinses. ANAL SCI 2006; 22:1065-9. [PMID: 16896243 DOI: 10.2116/analsci.22.1065] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A cationic surfactant ion-selective field-effect transistor (cationic surfactant-ISFET) has been developed based on the tetraphenylborate derivative known as sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate. The cationic surfactant-ISFET shows an almost Nernstian response to tetradecyldimethylbenzylammonium chloride (Zephiramine) over a concentration range between 1.0 x 10(-6) M and 1.0 x 10(-3) M, with a slope of 58.5 +/- 1.7 mV/decade. The cationic surfactant-ISFET can be used over a range of pH values, between pH 3 and 9. The cationic surfactant-ISFET shows excellent selectivity for Zephiramine over small inorganic cations, but shows similar selectivity for other cationic surfactants, such as hexadecyltrimethylammonium and stearyltrimethylammonium ions. A microfluidic polymer chip was integrated with the cationic surfactant-ISFET, and this was fabricated using polystyrene plates and stainless wires as a template for the channel. Cationic surfactant-ISFETs used in a batch system and microchips integrated with cationic surfactant-ISFETs showed very similar performance in terms of low detection limits, slope sensitivity and the stability of the potential response. The microfluidic polymer chip was then applied to the determination of cationic surfactants in dental rinses.
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Affiliation(s)
- Takashi Masadome
- Department of Applied Chemistry, Faculty of Engineering, Shibaura Institute of Technology, Tokyo, Japan
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Omasu F, Nakano Y, Ichiki T. Measurement of the electrophoretic mobility of sheep erythrocytes using microcapillary chips. Electrophoresis 2005; 26:1163-7. [PMID: 15704247 DOI: 10.1002/elps.200410182] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cell electrophoretic mobility (EPM) can be used to characterize individual cells. The purpose of this study is to establish reproducible and reliable cell EPM values obtained using microcapillary electrophoresis (microCE) chips. We studied cell electrophoresis on microCE chips through the comprehensive measurement of EPM and zeta potential. The inner wall of microchannels in microCE chips was coated with three kinds of reagents, namely bovine serum albumin (BSA), gelatin, and 2-methacryloyloxyethylphosphorylcholine (MPC) polymer to prevent nonspecific adhesion and interaction between cells and the inner wall. Electrophoresis was conducted in phosphate-buffered saline (pH 4-9) using erythrocytes extracted from sheep whole blood. Electroosmotic flow (EOF) mobility was measured using noncharged particles, and then the true EPM was calculated by subtracting the EOF mobility from the electromigration. MPC polymer coatings in microCE chips reduced the zeta potential of the inner wall and fully prevented nonspecific adhesion. EPM data obtained using microCE chips were almost the same and reproducible over a wide range of pH irrespective of the coating reagent used. In conclusion, reliability in the measurement of cell EPM using microCE chips was realized.
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Affiliation(s)
- Fumihiro Omasu
- Department of Public Health, National Defense Medical College, 3-2 Namiki, Tokoro-zawa, Saitama 359-8513,Japan.
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Watanabe J, Ishihara K. Cell Engineering Biointerface Focusing on Cytocompatibility Using Phospholipid Polymer with an Isomeric Oligo(lactic acid) Segment. Biomacromolecules 2005; 6:1797-802. [PMID: 15877407 DOI: 10.1021/bm050138f] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Initial contact between a biological environment and a biomaterial ultimately decides the in vivo performance. Therefore, the fabrication of a delicate biointerface is important because it can be utilized as a platform for novel biomaterials. For the preparation of advanced biomedical devices such as biochips, nanoparticles, and cell engineering devices, the surface properties may be modified by the design of polymeric biomaterials. Anomalous phospholipid polymers with an isomeric oligo(lactic acid) segment were designed and evaluated as a biointerface. The phospholipid polymer containing 2-methacryloyloxyethyl phosphorylcholine was easily copolymerized with isomeric oligo(lactic acid) macromonomers, and the obtained polymer could easily form thin coating membranes as biointerfaces. The oligo(lactic acid) involves three kinds of isomers: dl-, d-, and l-forms. The favorable characteristic on the surface provides regulation of cell-material interactions on the biointerface. The oligo(lactic acid) segment could form hydrophobic domains, which were considered to be located on the interface, to enhance protein adsorption and cell adhesion. The most favorable characteristics on the biointerface were dual functions of cytocompatibility by the phospholipid polymer and cell adhesion property by the oligo(lactic acid) segment. In this study, we focused on the biological responses such as protein adsorption and cell adhesion by change in the oligo(lactic acid) component. The cell viability on the confluent stage was evaluated in terms of metabolic activity.
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Affiliation(s)
- Junji Watanabe
- Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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Development of healthcare chips checking life-style-related diseases. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2004. [DOI: 10.1016/j.msec.2004.08.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Sinton D, Escobedo-Canseco C, Ren L, Li D. Direct and indirect electroosmotic flow velocity measurements in microchannels. J Colloid Interface Sci 2002; 254:184-9. [PMID: 12702440 DOI: 10.1006/jcis.2002.8584] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
As microfluidic technologies mature, increasingly complex solutions are employed, and accurate methods for the measurement of electroosmotic flow rates are becoming increasingly important. The methodologies of both a direct method and an indirect method of flow rate measurement are presented here. The direct method involves flow visualization using trace amounts of a caged fluorescent dye. The indirect method is based on the change in current that occurs when one solution in the microchannel is replaced by another. The results of concurrent and independent measurements of electroosmotic velocities of Tris-acetate with EDTA (TAE) and Tris-borate with EDTA (TBE) at 1x concentration in fused silica capillaries are presented. Although these buffers are commonly used in biological chemistry, these mobilities have not previously been reported. Strong agreement among data collected with both methods establishes confidence in the electroosmotic mobility values obtained and indicates that the current-based method, which requires less infrastructure than the direct method, can provide accurate flow rate measurements under these conditions. Constant electroosmotic mobilities of 4.90 x 10(-8) m(2) V(-1) s(-1) for TAE and 3.10 x 10(-8) m(2) V(-1) s(-1) for TBE were determined by tests in a range of electrical field strengths from 5 to 20 kV/m. A linear flow rate increase with applied field strength indicated that constant mobility and negligible Joule heating effects were present. Applicability and limitations of both the measurement methods and these buffers are discussed in the context of microfluidic applications.
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Affiliation(s)
- David Sinton
- Department of Mechanical & Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, M5S 3G8, Canada
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Nam KW, Watanabe J, Ishihara K. Characterization of the spontaneously forming hydrogels composed of water-soluble phospholipid polymers. Biomacromolecules 2002; 3:100-5. [PMID: 11866561 DOI: 10.1021/bm015589o] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spontaneously forming hydrogels composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymers, poly(MPC-co-methacrylic acid) (PMA), and poly(MPC-co-n-butyl methacrylate) (PMB) were examined. The MPC copolymer hydrogel was observed to have a spontaneous gelation property. To determine the properties of the hydrogels and why the gelation takes place, we have studied the properties of the hydrogels by scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC). The morphologies of the hydrogels were spongelike with a homogeneous structure. By XPS analysis in terms of the molecular distributions in the hydrogels, it was observed that a stabilization time was required for the hydrogel to undergo chain rearrangement. DSC thermograms of the hydrogels were different from their components, PMA and PMB. For the hydrogel, a crystallization peak around -30 degrees C was observed. This result indicated that some ordered structures existed in the hydrogels. To determine the role of the MPC groups, aqueous solutions of poly(methacrylic acid) (PMAc) and PMB were mixed. The mixture of PMAc-PMB turned into a sol state, and the sol state remained for a week. When the mixture was cooled, a very weak hydrogel was prepared. This result suggested that the MPC groups were the dominant unit for spontaneously forming the hydrogels.
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Affiliation(s)
- Kwang Woo Nam
- Department of Materials Science, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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