BUNSEKI KAGAKU
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Volume 53, Issue 5
Displaying 1-9 of 9 articles from this issue
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Review
  • Bioassay using living cells integrated on a chip
    Yu-suke TORISAWA, Hitoshi SHIKU, Tomoyuki YASUKAWA, Tomokazu MATSUE
    2004 Volume 53 Issue 5 Pages 367-382
    Published: 2004
    Released on J-STAGE: September 13, 2004
    DOIhttps://doi.org/10.2116/bunsekikagaku.53.367
    JOURNAL FREE ACCESS
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    A living cell-based assay is widely used for the characterization of various cellular functions, screening of drugs and environmental monitoring. Recent progress in cell culture and microfabrication technologies has attracted the integration of cell culture and sensors on a chip. A bioassay using a cell chip makes it possible to evaluate small-volume samples with multitudinous characterizations, and is applicable for a rapid and simple detection system. This paper reviews cell-based bioassay using living cells integrated on a chip. The cell patterning and three-dimensional cell culture facilitates the integration of cell culture technology. These in vitro culture technologies are appropriate for the recapitulation of in vivo-like cell behavior, because of the potential to control the cell differentiation and polarity. Alternatively, the evaluation methods, such as cellular acidification, oxygen consumption and impedance measurements, are principally non-invasive, and are especially expected in the field of anticancer drug sensitivity test using a biopsy tumor.
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  • Nucleobase recognition by hydrogen bond forming ligands and its use for fluorescence detection of single-nucleotide polymorphisms
    Seiichi NISHIZAWA, Keitaro YOSHIMOTO, Takehiro SEINO, Chun-Yan XU, Nor ...
    2004 Volume 53 Issue 5 Pages 383-391
    Published: 2004
    Released on J-STAGE: September 13, 2004
    DOIhttps://doi.org/10.2116/bunsekikagaku.53.383
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    In combination with abasic site (AP site)-containing oligodeoxynucleotides (ODNs), we demonstrate the potential use of hydrogen bond-forming ligands, 2-amino-7-methyl-1,8-naphthyridine (AMND) and 2-amino-4-oxopteridine (pterin), for the recognition of nucleobases in the aqueous phase. Our strategy is based on the construction of an AP site in ODN duplexes, which allows small synthetic and/or biotic ligands to strongly bind to target nucleobases; an AP site-containing ODN is hybridized with a target ODN so as to place the AP site toward a target nucleobase, by which hydrophobic microenvironments are provided for ligands to recognize target nucleobases through hydrogen-bonding. From an examination of the binding behaviors by melting temperature (Tm), fluorescence and circular dichroism spectra measurements, it has been found that AMND selectively binds to a cytosine base with a 1 : 1 binding constant of > 106 M−1, while pterin shows selectivity for a guanine base (K11 = 1.2 × 104 M−1) over other nucleobases. The observed high stabilities of 1 : 1 complexes can be explained by a cooperative binding event, i.e., hydrogen-bonding with target nucleobases and stacking with nucleobases flanking the AP site. The potential use of these ligands is also presented for the fluorescence detection of single-nucleotide polymorphisms (SNPs) of the cancer repression gene p53.
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  • Plasma-polymerized thin film for biosensors of a new generation
    Hitoshi MUGURUMA, Atsunori HIRATSUKA
    2004 Volume 53 Issue 5 Pages 393-409
    Published: 2004
    Released on J-STAGE: September 13, 2004
    DOIhttps://doi.org/10.2116/bunsekikagaku.53.393
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    A biosensor is a device that converts information on the concentration of chemical or biochemical substances into a quantifiable electronic signal. The typical structure of a biosensor is an integrated product utilizing biological components and transducers. We have indicated that plasma-polymerized thin films have potential for use in the interfacial design between these two components for biosensors. A plasma-polymerized film was achieved in a plasma in the vapor phase. The properties of the film are that they: (i) are extremely thin (< 1 μm), (ii) provide good adhesion to the substrate, (iii) are pin-hole free and present a flat surface structure, (iv) are mechanically and chemically stable because of the highly branched and cross-linked structure in the polymer, and (v) allow for large amount of biological components, such as enzymes and antibodies, to be loaded onto the surface of the film. Recently, the trend in biosensors can be addressed concerning two main aspects. One is a micro total analytical system and/or a micro electro mechanical system, which is an analytical system integrated into one chip in order to reduce the solvent, the amount of the sample, and the time and cost of analysis, The other is a post genome research tool, such as a DNA or a protein chip; the former allows an easy and rapid analysis for gene expression and single-nucleotide polymorphism; the latter allows proteome analysis e.g., a capillary electrophoresis chip and analysis for biospecific interaction. In this article, we stress the usefulness of plasma-polymerized films and/or a process for a new generation of biosensers.
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Research Paper
  • Simple and rapid determination of estrogens and bisphenol A in water samples by high-performance liquid chromatography with electrochemical detection
    Takashi ISHIYAMA, Teruyuki SHIMADU, Chieko NUDESHIMA, Junya HOSHI, Yuk ...
    2004 Volume 53 Issue 5 Pages 411-417
    Published: 2004
    Released on J-STAGE: September 13, 2004
    DOIhttps://doi.org/10.2116/bunsekikagaku.53.411
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    A selective and sensitive method was developed for the determination of estrogens and bisphenol A by high-performance liquid chromatography with electrochemical detection. A mixing solution consisting 45 vol% acetonitrile and 55 vol% water containing 0.07 mol l−1 sodium perchlorate at pH 2.7 was used as a mobile phase. The electrolytic oxidation of estrogens and bisphenol A was performed on a glassy carbon working electrode at 1.05 V vs. Ag/AgCl. The calibration curves (peak area vs. concentration) were linear (correlation coefficient≥0.999) in the range from 10 ng ml−1 to at least 1000 ng ml−1, and passed through the origin with a relative standard deviation of 0.6 to 2% for 100 ng ml−1 (n = 5). This method was applied to the simultaneous determination of these compounds at ng l−1 level in river water and the discharge water of a sewage treatment plant. Interference from humic compounds could be avoided by using a clean-up technique with a 45 vol% methanol solution at pH 9 to 10, and a stable background current was obtained. The detection limits calculated from the S/N ratio (S/N = 3) were ca. 5 ng l−1. The time required for an analysis after solid-phase extraction was within 40 min. The proposed method without any troublesome and time-consuming pretreatment process, such as derivatization, is more simple and rapid compared with conventional methods.
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  • Determination of phosphate ion by adhesion of a precipitate of ammonium phosphomolybdate onto a one-electrode-separated piezoelectric quartz crystal in a flow system
    Keisuke EGUCHI, Teruo HINOUE, Toshiaki NOMURA
    2004 Volume 53 Issue 5 Pages 419-427
    Published: 2004
    Released on J-STAGE: September 13, 2004
    DOIhttps://doi.org/10.2116/bunsekikagaku.53.419
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    Utilizing the adhesion of a precipitate of ammonium phosphomolybdate onto a piezoelectric quartz crystal (PQC), phosphate ions in water could be determined as a frequency change of the PQC. The precipitate was formed in the tubing of the flow system by a precipitation reaction between phosphate and hexaammonium heptamolybdate ions, and adhered onto the PQC. The adhesion of the precipitate was largely dependent on a surface condition of the PQC. That is, the adhesion proceeded smoothly with time on a surface pretreated by coating with the precipitate of ammonium phosphomolybdate, although not smoothly on a clean surface. In order to obtain optimal conditions for the determination of phosphate ions, the effects of the composition, acid concentration and flow rate of the carrier solution, and the length of the reaction coil on the frequency change were examined by using a PQC pretreated by coating with the precipitate. Under the optimal conditions, the frequency change was proportional to the concentration of phosphate ions to 30 μmol dm−3. Phosphate ions in river and lake water samples were actually determined by the proposed method using a PQC. Results for the determination by the standard addition method were in fairly good agreement with those determined by spectrophotometry, i.e. a molybdenum-blue method. It is therefore suggested that the proposed method is applicable to the determination of phosphate ions in natural water.
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  • Continuous extraction of iron for the determination of trace elements in steel
    Tetsuo UCHIDA, Eri TSUZUKI, Yusuke TAKAHASHI, Utako INOUE
    2004 Volume 53 Issue 5 Pages 429-433
    Published: 2004
    Released on J-STAGE: September 13, 2004
    DOIhttps://doi.org/10.2116/bunsekikagaku.53.429
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    A simple, rapid and contamination-free method of iron removal was developed for the determination of trace elements in steel by ICP-AES. A 200 mg sample was dissolved in HCl, HNO3 and HF containing Y as an internal standard, and evaporated to dryness. The residue was dissolved in 10 ml of 6 M HCl, then transferred to a Teflon test tube. Under vigorous stirring, MIBK was introduced at a flow rate of 1 ml/min through a Teflon tube inserted in the bottom, and the upper MIBK layer was suctioned off. This continuous extraction enabled the removal of 200 mg of iron using only 6 ml of MIBK. After evaporating the resulting aqueous layer(∼8 ml) in an evaporation chamber, the residue was dissolved in 12 ml of 0.1 M HCl, and then used for an ICP-AES measurement of trace elements. The proposed method was applied to analyses of Certified Reference Materials prepared by the Japan Iron and Steel Federation. The analytical results for Mn, Ni, Cr, Cu, V, Co, Ti, Al and Ca agreed with the certified values.
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Technical Paper
  • Fluorimetric determination of aluminum in human serum and whole blood
    Tomoko TAMADA
    2004 Volume 53 Issue 5 Pages 435-440
    Published: 2004
    Released on J-STAGE: September 13, 2004
    DOIhttps://doi.org/10.2116/bunsekikagaku.53.435
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    The determination of trace amounts of aluminum in blood is problematic due to the great amount and complicated composition of organic and inorganic matrices. Therefore, most previous studies have investigated only serum or plasma samples, and there have been few studies on whole blood samples. In this study, organic matter in serum and whole blood samples was digested by microwave heating with acid, and then inorganic matter, such as iron, was removed using solvent extraction; finally, aluminum was fluorimetrically determined by the lumogallion method. Because the interference from matrices was markedly reduced, especially in whole blood samples, it enabled the determination of aluminum in serum and whole blood samples by the same operation. From the values in healthy human serum and whole blood, it also allowed an estimation of the aluminum concentration in erythrocytes; the distribution ratio of aluminum between serum and erythrocytes was also obtained.
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