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Yusuke OKAWA, Yoshinori SAKAI, Fumiyuki SHIBA
2008 年 76 巻 8 号 p.
522-524
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
A novel electrochemical biosensor for hydrogen peroxide with high electron transfer efficiency was developed using a nanocomplex composed of horseradish peroxidase and Au-nanoparticle. The nanocomplex was prepared through adsorption of horseradish peroxidase on an Au-nanoparticle. The nanocomplexes were easily coagulated and immobilized on an ITO electrode as a monolayer film by simply casting the nanocomplex dispersion and drying below 10°C. The electrode worked as a hydrogen peroxide biosensor featuring high electron transfer efficiency without any soluble mediator at a mild electrode potential of +0.15 V vs. Ag/AgCl.
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Kumi Y. INOUE, Tomoyuki YASUKAWA, Hitoshi SHIKU, Tomokazu MATSUE
2008 年 76 巻 8 号 p.
525-528
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
We developed a cell-based assay device for the detection of endotoxin, the potentially toxic compound that induces septic shock. Genetically-engineered cells that secrete alkaline phosphatase (SEAP) on exposure to endotoxin were cultured in an electrochemical cell device in medium containing
p-aminophenyl phosphate and various concentrations of endotoxin. After 24 hr incubation,
p-aminophenol (pAP), generated by SEAP-catalyzed hydrolysis, was detected by amperometry at +0.35 V. The amperometric response increased with the concentration of endotoxin in the range of 0.01–1 ng/ml.
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Masayasu MIE, Masafumi MANABE, Eiry KOBATAKE
2008 年 76 巻 8 号 p.
529-531
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
Electrical stimulation has various effects on cellular functions. We previously reported a combined effect of electrical stimulation and cisplatin treatment on HeLa cell death. The present study investigates the signaling pathway behind this phenomenon. Decreased viability of HeLa cells after electrical stimulation plus cisplatin treatment was suppressed by addition of the caspase inhibitor zVAD-FMK. This showed that HeLa cell death induced by combining electrical stimulation and cisplatin treatment was caused by increased caspase activity. Moreover, mitochondrial cytochrome c release and c-Jun N-terminal kinases (JNK) activities were enhanced by this combined treatment. These results indicated that combined treatment-induced apoptosis was caused by increasing caspase activity via the JNK signal pathway.
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Matsuhiko NISHIZAWA, Takahiro KITAZUME, Hirokazu KAJI
2008 年 76 巻 8 号 p.
532-534
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
An electrode was coated by double layer of electrodeposited polypyrroles (PPy). The inner thicker PPy was doped with p-toluene sulfonate to ensure larger electrical capacity that is required for less-invasive stimulation of neural cells. The outer thinner PPy was doped with polyacrylate to present carboxyl group on the surface. Nerve Growth Factor was immobilized by utilizing the carboxyl groups, and successfully induced the differentiation of neuronal PC12 cells and their neurite growth. The present layered structure is one of effective approach to modify the high capacity PPy-based stimulation electrode with biomolecules for controlling cellular functions.
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Yuko NAKANE, Izumi KUBO
2008 年 76 巻 8 号 p.
535-537
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
For detection of endocrine disrupting chemicals (EDCs), a novel biosensor based on the degradation of cell membrane model by EDCs is proposed. As a cell membrane model, liposome cluster was prepared from cationic liposome and membrane protein bacteriorhodopsin. We fabricated a biosensor to detect EDCs by immobilization of the cluster on quartz crystal microbalance (QCM) through ionic alkyl thiol. Nonylphenol was examined as representative EDCs and the sensor detected nonylphenol at the range of 1.0 ppb-1.0 ppm.
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Masato TOMINAGA, Shoichiro NAGAISHI, Etsuko KUMAGAI, Shinji HARADA, Is ...
2008 年 76 巻 8 号 p.
538-540
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
Alternating electrical potentials consisting rectangular pulse waves of 0∼+1.0 V (vs. Ag/AgCl/Sat’d KCl) at 100 Hz were loaded onto MAGI/CCR5 (HeLa-CD4-LTR-β-gal) cells cultured on an ITO electrode. The ratio of cell membrane damage due to electrical potential loading increased with the expansion time of the potential loading, with a positive potential of more than +0.85 V. Furthermore, the induction of cell damage was very sensitive to the temperature of the potential loading. The membrane damage induced by the potential loading was irreversible.
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Izumi KUBO, Reo SHOJI, Yusuke FUCHIWAKI, Hiroaki SUZUKI
2008 年 76 巻 8 号 p.
541-544
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
Atrazine is a widely used herbicide. The electrochemical sensing of atrazine was performed by the detection of its reductive current. In order to make the sensing system smaller and simpler, a gold electrode chip (detection area: 1.8×0.6 mm) was prepared and modified with an atrazine imprinted polymer layer, as the recognition element for atrazine. An atrazine sensing chip modified with molecularly imprinted polymer (MIP) layer was fabricated by spin-coating in this study. Using the atrazine-sensing chip, a cathodic current of atrazine was observed and the reductive current depended on the concentration of atrazine below 20 µM. The detection limit of the sensor was 50 nM (11 ppb). The atrazine-sensing chip was more selective to atrazine than other herbicides such as simazine, ametryn and MCC.
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Hitoshi MUGURUMA, Shunsuke YOSHIDA, Muneyuki URATA, Kohta FUJISAWA, Ya ...
2008 年 76 巻 8 号 p.
545-548
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
We report on an amperometric biosensor that is based on a nanocomposite of carbon nanotubes (CNT), a nano-thin plasma-polymerized film (PPF), and glucose dehydrogenase (GDH). A mixture of the GDH and a CNT film is sandwiched with 6-nm-thick acetonitrile PPFs. Under PPF layer was deposited onto a sputtered gold electrode. To facilitate the electrochemical communication between the CNT layer and GDH, CNT was treated with nitrogen plasma. The resulting device showed that the large oxidizing current response due to enzymatic reaction was observed at +0.4 V (vs. Ag/AgCl) polarized potential. This demonstrates that the CNT play a role as a catalysis for NADH oxidation caused by enzymatic reaction and as a electron transfer conductor. The optimized glucose biosensor showed sensitivity of 3.3 µA mM
−1 cm
−2 (correlation coefficient of 0.983, linear response range of 4.9–19 mM) and response of 7 s (reach 95% of maximum response).
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Seiya TSUJIMURA, Tomohiko ABO, Kazunobu MATSUSHITA, Yoshitaka ANO, Ken ...
2008 年 76 巻 8 号 p.
549-551
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
Direct electron transfer-type bioelectrocatalytic oxidation of
d-gluconate was observed with
d-gluconate 2-dehydrogenase (GADH, EC 1.1.99.3, from
Gluconobacter frateurii) at bare and thiols-modified gold electrodes. Thiols used have different charges and various lengths of the alkyl chains. The catalytic current at every electrode arose at −0.05 V, which would correspond to the formal potential of the heme
c site in GADH. The GADH-loading examined through quartz crystal microbalance measurements was practically independent of the surface properties. However, the current-potential curves were strongly affected by the electrode surface properties, and were interpreted in views of kinetics of enzymatic reaction and electrode reaction, and states of GADH on the electrode surface. The interfacial electron transfer rate constants of GADH depended on the alkane-chain lengths.
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Kenta IWASAWA, Mika EGUCHI, Katsuhiro UNO, Soichi YABUKI
2008 年 76 巻 8 号 p.
552-554
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
In order to detect lactate, high sensitivity lactate sensor was completed by attaching lactate oxidase (LOD) to the hydrogen peroxide sensor. The hydrogen peroxide sensor was prepared as follows; poly(4-styrenesulfonate), peroxidase (POD), ferrocene and poly-
l-lysine solutions were dropped on a glassy carbon electrode. After drying this electrode, LOD and glutaraldehyde solutions were dropped on the membrane to immobilize the enzyme. The electrode was immersed into a buffer solution (pH 6.5), and a potential of −0.2 V vs. Ag/AgCl was applied to detect the reduction current. Immediately after the addition of
l-lactate (10 µM) to the test solution, the reductive current increased and reached a plateau within 20 s. The lower detection limit was 1 µM (S/N=3), and the ratio of the response for the interferent to that for
l-lactate on the electrode was 0.18.
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Hirokazu KAJI, Masahiko HASHIMOTO, Soichiro SEKINE, Takeaki KAWASHIMA, ...
2008 年 76 巻 8 号 p.
555-558
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
We describe a method to create cell-adhesive regions and to position adherent cells on the newly created regions in sequence within a microfluidic channel. One of the microelectrodes fabricated at the channel wall was used for locally electrogenerating hypobromous acid that renders the opposite face of the channel protein-adsorptive. After the fibronectin was immobilized on the treated region, an ac voltage (1 MHz, 20 Vpp) was applied to the microelectrodes array in the presence of suspended HeLa cells. Since a repulsive force of negative dielectrophoresis (DEP) directs the cells toward the weakest region of the nonuniform electric field, the cells were positioned on the fibronectin-patterned region to allow the cell adhesion, even in the presence of fluid flow (<0.1 µL min
−1). By repeating the above process, two types of cells could be patterned in the microchannel.
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Shinsuke NAITO, Yasuhiro TANAKA, Tatsuro ENDO, Yasuko YANAGIDA, Takesh ...
2008 年 76 巻 8 号 p.
559-562
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
The nano/micro-structured materials and solid substrates are novel and exciting field of research for biotechnology applications. Especially, the porous silicon (PSi) has many attractive characteristics and is expected to several applications and devices. In this study, influences of PSi with different surface structures for cell adhesion characteristics were investigated. For investigation of cell adhesion characteristics, different surface structures of PSi substrates were fabricated. Using these PSi substrates, evaluation of the cell adhesion characteristics were carried out. In addition, in this study, Hela and COS-7 cell strains were used for evaluation of the cell adhesive characteristics.
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Kenichi MURATA, Nobuhumi NAKAMURA, Hiroyuki OHNO
2008 年 76 巻 8 号 p.
563-565
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
An electrochemically oxidized carbon fiber paper (CFP) electrode was fabricated and the direct electrochemical oxidation of NADH was examined for a biofuel cell application. The Raman spectra of the oxidized CFP electrode indicated that edge plane sites were generated by electrochemical activation. On a cyclic voltammogram of the electrode at pH 7.0, an oxidation-reduction peak with a redox potential of about 0 mV (vs. Ag/AgCl) appeared. The electrocatalytic oxidation of NADH with an anodic peak at low potential (+50 mV) occurred and the current density reached as large as a few mA/cm
2. The quinoidal moieties which are generated at the edge plane site act as an electron transfer mediator. With NAD
+-dependent alcohol dehydrogenase (ADH), the ADH catalyzed bioanode could be constructed by entrapment with poly(diallyldimethylammonium chloride) on the oxidized CFP electrode.
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Isao SHITANDA, Koji ISHIZAKI, Masayuki ITAGAKI, Kunihiro WATANABE
2008 年 76 巻 8 号 p.
566-568
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
An electrochemical system equipped with dual electrodes was developed for the simultaneous monitoring of motility and phototaxis of immobilized single flagellate alga,
Volvox carteri. The flagellate alga was immobilized on a polyion complex membrane. Photoinduced behavior of flagellate alga was recorded as changes in the redox currents for a coexisting redox marker ([Fe(CN)
6]
3−). From the amperometric measurements, the immobilized alga possessed its flagellar activity on the polyion complex membrane. In addition, it was found that changes of algal flagellar movement induced by phototaxis gave rise to different current changes at each electrode.
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Isao SHITANDA, Masamitsu KONYA, Masayuki ITAGAKI, Kunihiro WATANABE, Y ...
2008 年 76 巻 8 号 p.
569-572
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
Polyamide microcapsule containing glucose oxidase (GOD) and tetrathiafulvalene (TTF) was prepared for the application to a molecular recognition element of screen-printed enzyme electrode. The microcapsules were entrapped in a polyion complex film or a carbon ink containing TTF, and then immobilized directly on the screenprinted carbon electrodes. The enzyme activity of the microcapsule was evaluated by the cyclic voltammetry in a phosphate buffer solution containing glucose. The enzyme electrodes were active to oxidize the dissolved glucose which is catalyzed by the entrapped GOD. In addition, the electroactive TTF molecules were proved to penetrate the polyamide membrane and to function as a mediator.
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Keiichi HATAKEYAMA, Tsuyoshi TANAKA, Masahiro SAWAGUCHI, Akihito IWADA ...
2008 年 76 巻 8 号 p.
573-575
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
This work describes a disposable DNA-arrayed thin film transistor (TFT) photosensor integrating a miniaturized reaction unit and a photoelectronic effect-based internal detection sensor. Single stranded DNA was chemically conjugated and arrayed on the TFT photosensor, which was fabricated by the semiconductor integrated circuit (IC) technology, for the detection of specific target DNA by DNA-DNA hybridization. The photosensor surface can be modified by various silane coupling reagents for the optimization of oligonucleotide immobilization conditions and single nucleotide polymorphism (SNP) detection was successfully employed using the TFT photosensor. A microfluidic channels were constructed on the TFT photosensor to improve the hybridization efficiency. The developed TFT photosensor will further promote the development of disposable photodetecting devices applicable in genetic diagnosis.
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Katsuhiko NISHIYAMA, Sayaka OKA, Kengo SHIMAMURA, Toshihiko SAKURAI, I ...
2008 年 76 巻 8 号 p.
576-578
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
We synthesized an α-helix forming polypeptide (CK30) and a random-coiled peptide (CdlK30) in order to clear the effect of secondary structure of the modifier on the electrochemical reaction in solution. By changing the surface structure of the CK30 from random-coil to α-helix, the electrochemical reaction of Fe(CN)
64− was suppressed. In contrast, on the CdlK30 modified electrode, the oxidation and reduction peak currents of the cyclic voltammogram increased.
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Naoyoshi EGASHIRA, Takashi HIRATA, Emi HIFUMI, Tami OHTA, Taizo UDA
2008 年 76 巻 8 号 p.
579-582
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
An immunoliposome encapsulating a Ru complex with two aminobutyl moieties was prepared to rapidly detect bovine serum albumin (BSA) protein. The detection was carried out within 80 min by electrochemiluminescence (ECL) from the Ru complex adsorbed on Au electrodes after immunoreaction. The adsorption of the complex is a key-step of this procedure in order to increase its sensitivity. Under optimal conditions, the present method can detect BSA in the concentration range from about 1×10
−9 g/mL to 1×10
−6 g/mL, with almost the same sensitivity as that obtained by conventional ELISA.
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Tomoo HOMMA, Keiji HIRAI, Soonil KWON, Hisashi KATSURAGI, Hiroki HAMAD ...
2008 年 76 巻 8 号 p.
583-585
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
Actions of capsaicin glucosides transformed by using the cultured cells of
Phytolacca americana on intestinal transport in rats were investigated. Transient increase in the transmural short-circuit current (Isc) related with intestinal transport were observed when capsaicin glucosides (50 µM) were applied to the mucosal side at jejunum and ileum, but capsaicin induced no Isc changes at jejunum and Isc decrease at ileum. Compared with actions of capsaicin, different action manners and lesser Isc changes by capsaicin glucosides against intestinal transport suggest the possibility of the use of capsaicin glucosides as food ingredients.
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Chikashi NAKAMURA, Hideki KAMIISHI, Noriyuki NAKAMURA, Jun MIYAKE
2008 年 76 巻 8 号 p.
586-589
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
An influx of calcium ions into a living cell occurs when the cell is deformed mechanically by compressing, indenting or stretching. The calcium ions are taken up through mechanosensitive channels sensing deforming signals. The calcium ion is a key trigger for the reformation of cytoskeletal structure. Indentation of a capillary to a cell during microinjection causes influx of calcium ions, as does a typical AFM tip. A nanoneedle, which is a sharpened needle shaped AFM tip of 200 nm in diameter does not cause any influx of calcium ions when it is inserted into a cell. The mechanical stress from the nanoneedle insertion is negligible and its invasiveness is low.
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Tomohiko YAMAZAKI, Shigenori OHTA, Koji SODE
2008 年 76 巻 8 号 p.
590-593
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
We have previously reported the development of an artificial enzyme catalysing hydrolytic oxidation reaction of fructosyl-valine (Fru-val). The enzyme was prepared by molecularly imprinting a catalytic polymer composed of vinyl imidazole to form a molecular imprinting catalyst (MIC). In this study, we have attempted to improve both the selectivity and sensitivity of the MIC-based Fru-val sensor by altering the operational conditions. Assuming that the hydrophobic interaction between the valine residue of Fru-val and the cross-linker in the polymer increases with increasing ionic strength of the buffer solution, and that the hydrophilic interaction between N-epsilon-substituted fructosyl-lysine (Fru-ε-lys) and the polymer decreases, we have used a higher concentration of the buffer solution for sensor operation. The sensitivity towards Fru-val increased, whereas the sensitivity towards Fru-ε-lys decreased when a 100 mM potassium phosphate buffer was used for sensor operation instead of a 10 mM buffer. The selectivity of the MIC towards Fru-val against Fru-ε-lys increased drastically from 1.9 to 5.7. In addition, the sensor was able to measure a glycated peptide, fructosyl valyl histidyl, which is a characteristic of the N-terminal structure of glycated hemoglobin.
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Kenji ISHIBASHI, Seiya TSUJIMURA, Kenji KANO
2008 年 76 巻 8 号 p.
594-596
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
Pentacyanoferrate-polymer (PVI[Fe
III(CN)
5]) was synthesized from potassium hexacyanoferrate (II) and a backbone polymer, poly(1-vinylimidazole) (PVI). Bilirubin oxidase (BOD) from
Myrothecium verrucaria and PVI[Fe(CN)
5] were cross-linked with poly(ethylene glycol) diglycidyl ether. BOD-PVI[Fe(CN)
5]-modified glassy carbon electrode showed a sigmoidal wave of a catalytic four-electron reduction of dioxygen (O
2) with a half-wave potential of 0.2 V vs. Ag|AgCl|KCl(sat.) in rotating disk voltammetry. The current density as high as 15 mA cm
−2 was achieved by immobilization of BOD-PVI[Fe(CN)
5] on carbon paper electrodes at 4000 rpm under O
2-saturated conditions.
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Keisuke SASAKURA, Shintaro KUBOTA, Jun ONISHI, Shunsuke OZAKI, Kenji K ...
2008 年 76 巻 8 号 p.
597-599
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
The ion transport from one aqueous (W1) to another (W2) across a bilayer lipid membrane (BLM) in the presence of a hydrophobic ion, dipicrylaminate (DPA
−), was investigated by cyclic voltammetry when the hydrophilic salt such as LiCl, NaCl, KCl or CsCl was used as a supporting electrolyte. Voltammograms for the ion transport at a lower scan rate than 10 mV s
−1 were in steady state and showed sigmoid curves. The magnitude of the ion transport current density at a given potential was proportional to the hydrophobicity of the counter cation. The result supports our proposed mechanism that the hydrophobic ion serves as a carrier compound in the BLM for the ion transfer of the hydrophilic counter ion in the presence of the membrane potential gradient.
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Ryosuke YAMADA, Nobutaka FUJIEDA, Maiko TSUTSUMI, Seiya TSUJIMURA, Osa ...
2008 年 76 巻 8 号 p.
600-602
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
Histamine dehydrogenase (HmDH) from
Nocardioides simplex was used in constructing mediated bioelectrochemical systems for histamine oxidation using Os complexes as mediators. Amperometric histamine sensor was prepared by immobilizing a mixture of HmDH and a mediator, poly(1-vinylimidazole) complexed with [Os(2,2′-dipyridylamine)
2Cl], with a crosslinker, poly(ethylene glycol) diglycidyl ether on a glassy carbon electrode. The electrode responded linearly to histamine over the range from 2 to 30 µmol dm
−3, became free from the substrate inhibition observed in solution, and was almost insensitive to ascorbate at pH 7.0. On the other hand, the charge in coulometry using carbon felt electrodes was proportional to the histamine amount over the range from 0.1 to 5 nmol and the slope indicates a 4-electron oxidation (2-electron in the enzyme reaction and 2-electron in follow-up electrochemical reaction).
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Haruko TAKEYAMA, Takeyuki SUZUKI, Yoshiko OKAMURA, Tetsushi MORI, Tada ...
2008 年 76 巻 8 号 p.
603-605
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
To elucidate the mechanism of the electrochemical killing, the global gene expression of synchronously cultured
Saccharomyces cerevisiae exposed to electrochemical stimulus was analyzed using DNA microarray. By applying a potential of 1.0 V vs. saturated calomel electrode (SCE), oxidative stress related genes were expressed after only 5 minutes. The gene for
cta1 exhibited the highest expression level, while ROS gradually accumulated inside the cells. Genes for signal transduction which may be related to cellular apoptosis were also seen expressed.
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Masato SAITO, Masaaki KITSUNAI, Minhaz Uddin AHMED, Shigeru SUGIYAMA, ...
2008 年 76 巻 8 号 p.
606-609
発行日: 2008/08/05
公開日: 2012/03/22
ジャーナル
フリー
Here we are reporting a new and rapid immunoassay for the food allergen using disposable screen printed carbon electrode (SPCE) in connection with the differential pulse voltammetry (DPV). Changes in the current signals due to antibody-antigen interaction provide the basis for an immunoassay on the SPCE surface which is simple, rapid, and cost effective. Casein, which is one of the most potent allergens in milk, was utilized as the model target in our experiment. After the immobilization of the anti-casein antibody on the pre-treated SPCE surface, sample solution contained casein was applied on the electrode surface and measured with DPV. Peak current due to casein was comparable while with bovine serum albumin (BSA) in solution. Our protocol is readily transferable for application to other immunological tests of food testing, because of this system is derived from utilizing the intrinsic electrochemical activity of antibody and antigen.
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