緒方 元気 (オガタ ゲンキ)

Ogata, Genki



理工学研究科 (矢上)




学位 【 表示 / 非表示

  • 博士(学術), 九州工業大学, 課程, 2007年03月


研究分野 【 表示 / 非表示

  • ライフサイエンス / 神経科学一般

  • ライフサイエンス / 薬理学

  • ライフサイエンス / 生体医工学

研究キーワード 【 表示 / 非表示

  • Neuroscience

  • ダイヤモンド電極

  • 神経科学


著書 【 表示 / 非表示

  • Diamond electrodes : fundamentals and applications

    Ogata G., Sawamura S., Asai K., Kusuhara H., Einaga Y., Hibino H., Diamond Electrodes: Fundamentals and Applications, 2022年03月

    担当範囲: In Vivo Real-Time Measurement of Drugs.,  担当ページ: 227-236


    Drugs play a key role in the treatment of patients with various diseases. A compound, when administered systemically, shows differential spatial and temporal distribution patterns not only in the body but also within each organ. In response to an increase or decrease in local concentrations in the organ, the activity of the cell population expressing the drug’s target protein(s) changes over time. Therefore, real time, simultaneous detection of kinetics of the drug and its pharmacological effects in in vivo microenvironments is essential for evaluating the efficacy of medicines. Although such challenging dual-mode measurement has not yet been addressed by any conventional methods, it has been successfully achieved via a microsensing system that we recently developed. The system consists of two different sensors: A needle-type boron-doped diamond microelectrode for monitoring the drug and a glass microelectrode for tracking electrophysiological activity of the target cells. This state-of-the-art approach is applicable to various drugs in terms of “local” pharmacokinetic and pharmacodynamic assays in vivo and may contribute to the development of next-generation therapeutic interventions.

論文 【 表示 / 非表示

  • A strategy for low-cost portable monitoring of plasma drug concentrations using a sustainable boron-doped-diamond chip.

    Saiki T, Ogata G, Sawamura S, Asai K, Razvina O, Watanabe K, Kato R, Zhang Q, Akiyama K, Madhurantakam S, Ahmad NB, Ino D, Nashimoto H, Matsumoto Y, Moriyama M, Horii A, Kondo C, Ochiai R, Kusuhara H, Saijo Y, Einaga Y, Hibino H

    Heliyon (Elsevier {BV})  9 ( 5 ) e15963 - e15963 2023年05月

    査読有り,  ISSN  2405-8440


    On-site monitoring of plasma drug concentrations is required for effective therapies. Recently developed handy biosensors are not yet popular owing to insufficient evaluation of accuracy on clinical samples and the necessity of complicated costly fabrication processes. Here, we approached these bottlenecks via a strategy involving engineeringly unmodified boron-doped diamond (BDD), a sustainable electrochemical material. A sensing system based on a ∼1 cm2 BDD chip, when analysing rat plasma spiked with a molecular-targeting anticancer drug, pazopanib, detected clinically relevant concentrations. The response was stable in 60 sequential measurements on the same chip. In a clinical study, data obtained with a BDD chip were consistent with liquid chromatography–mass spectrometry results. Finally, the portable system with a palm-sized sensor containing the chip analysed ∼40 μL of whole blood from dosed rats within ∼10 min. This approach with the ‘reusable’ sensor may improve point-of-monitoring systems and personalised medicine while reducing medical costs.

  • Calcium/calmodulin-dependent protein kinase II associates with the K<sup>+</sup> channel isoform Kv4.3 in adult rat optic nerve

    Ogata G., Partida G.J., Fasoli A., Ishida A.T.

    Frontiers in Neuroanatomy (Frontiers in Neuroanatomy)  16 2022年09月

    筆頭著者, 査読有り,  ISSN  16625129


    Spikes are said to exhibit “memory” in that they can be altered by spikes that precede them. In retinal ganglion cell axons, for example, rapid spiking can slow the propagation of subsequent spikes. This increases inter-spike interval and, thus, low-pass filters instantaneous spike frequency. Similarly, a K+ ion channel blocker (4-aminopyridine, 4AP) increases the time-to-peak of compound action potentials recorded from optic nerve, and we recently found that reducing autophosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII) does too. These results would be expected if CaMKII modulates spike propagation by regulating 4AP-sensitive K+ channels. As steps toward identifying a possible substrate, we test whether (i) 4AP alters optic nerve spike shape in ways consistent with reducing K+ current, (ii) 4AP alters spike propagation consistent with effects of reducing CaMKII activation, (iii) antibodies directed against 4AP-sensitive and CaMKII-regulated K+ channels bind to optic nerve axons, and (iv) optic nerve CaMKII co-immunoprecipitates with 4AP-sensitive K+ channels. We find that, in adult rat optic nerve, (i) 4AP selectively slows spike repolarization, (ii) 4AP slows spike propagation, (iii) immunogen-blockable staining is achieved with anti-Kv4.3 antibodies but not with antibodies directed against Kv1.4 or Kv4.2, and (iv) CaMKII associates with Kv4.3. Kv4.3 may thus be a substrate that underlies activity-dependent spike regulation in adult visual system pathways.

  • A rapid and simple electrochemical detection of the free drug concentration in human serum using boron-doped diamond electrodes.

    Moriyama H, Ogata G, Nashimoto H, Sawamura S, Furukawa Y, Hibino H, Kusuhara H, Einaga Y

    The Analyst (Analyst)  147 ( 20 ) 4442 - 4449 2022年09月

    筆頭著者, 査読有り,  ISSN  0003-2654


    Monitoring drug concentration in blood and reflecting this in the dosage are crucial for safe and effective drug treatment. Most drug assays are based on total concentrations of bound and unbound proteins in the serum, although only the unbound concentration causes beneficial and adverse events. Monitoring the unbound concentration alone is expected to provide a means for further optimisation of drug treatment. However, unbound concentration monitoring has not been routinely used for drug treatment due to the long analysis time and the high cost of conventional methods. Here, we have developed a rapid electrochemical method to determine the unbound concentration in ultrafiltered human serum using boron-doped diamond (BDD) electrodes. When the anticancer drug doxorubicin was used as the test drug, the catalytic doxorubicin-mediated reduction of dissolved oxygen provided a sensitive electrochemical signal, with a detection limit of 0.14 nM. In contrast, the sensitivity of glassy carbon (GC) was inferior under the same conditions due to interference from the dissolved oxygen reduction current. The signal background ratio (S/B) of BDD and GC was 11.5 (10 nM doxorubicin) and 1.1 (50 nM), respectively. The results show that a fast measurement time within ten seconds is possible in the clinical concentration range. Additionally, in the ultrafiltered human serum, the obtained values of unbound doxorubicin concentration showed good agreement with those quantified by conventional liquid chromatography-mass spectrometry. This approach has the potential for application in clinical settings where rapid and simple analysis methods would be beneficial.

  • Electrochemical detection of triamterene in human urine using boron-doped diamond electrodes.

    Ishii K, Ogata G, Einaga Y

    Biosensors & bioelectronics (Biosensors and Bioelectronics)  217   114666 - 114666 2022年09月

    査読有り,  ISSN  0956-5663


    Urine is one of the most used biological fluids for screening drug delivery and the resultant metabolites. In sports, the use of diuretics such as triamterene is considered a violation of anti-doping rules and is stipulated to be present at less than 79 nM in urine by the World Anti-Doping Agency (WADA). It is therefore important to develop effective rapid and low-cost tests for this diuretic. Here we apply electrochemical analysis using boron-doped diamond (BDD) electrodes, which have superior properties such as low background current, a wide potential window, and high resistance to deactivation. Since real urine samples show clear oxidation current peaks in the potential range more positive than 0.5 V (vs. Ag/AgCl) due to the presence of bio-components such as protein, uric acid, and ascorbic acid, to detect triamterene effectively, the electrochemical protocol was optimized towards a potential range where the other components have limited effect. Our results show that reduced triamterene exhibits an oxidation peak at 0.1 V (vs. Ag/AgCl) in 0.1 M phosphate buffer (PB) and at 0.2 V (vs. Ag/AgCl) in pooled human urine. The peak current value increased according to the triamterene concentration. The limit of detection (LOD) was 3.15 nM in the PB and 7.80 nM in pooled human urine. Finally, triamterene detection was attempted in individual urine samples. Triamterene was electrochemically detectable in individual urine samples, excluding urine samples containing an excess amount of ascorbic acid. The limit of detection (LOD) in individual urine samples was determined to be 20.8 nM.

  • Application of boron doped diamond electrodes to electrochemical gas sensor

    Triana Y., Ogata G., Einaga Y.

    Current Opinion in Electrochemistry (Current Opinion in Electrochemistry)  36   101113 - 101113 2022年08月

    査読有り,  ISSN  2451-9103


    Boron-doped diamond (BDD) electrodes have been attracting attention as superior electrode materials for electrochemical sensing applications. Here, we focused on applications of the BDD electrodes to electrochemical gas sensing especially dissolved gas in aqueous solution. This article discusses arsine, hydrogen sulfide, nitrogen dioxide gas for environmental sensing, and oxygen in the blood for biomedical sensing. The analytical performances suggest that BDD electrodes are more than adequate for determining the concentration of these gas species.

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総説・解説等 【 表示 / 非表示

  • ダイヤモンド電極による緑内障点眼薬の電気化学リアルタイム計測

    栄長 泰明, 米田 真央, 緒方 元気, 山岸 麗子, 本庄 恵, 相原 一

    日本眼薬理学会プログラム・抄録集 (日本眼薬理学会)  42回   63 - 63 2022年10月

  • 研究者の最新動向 針状ダイヤモンド電極を駆使した脳の薬物モニタリングシステムの創出

    澤村 晴志朗, 緒方 元気, 栄長 泰明, 日比野 浩

    Precision Medicine ((株)北隆館)  5 ( 7 ) 645 - 647 2022年07月

    ISSN  2434-3625



  • ダイヤモンド電極を用いた電気化学測定による薬物血中濃度の迅速測定

    齋木琢郎, 齋木琢郎, 緒方元気, 澤村晴志朗, ラズビナ オリガ, 渡邊航太, 加藤里都, 浅井開, 松本吉史, 森山雅人, 西條康夫, 楠原洋之, 栄長泰明, 日比野浩

    日本生理学雑誌(Web) ((一社)日本生理学会)  83 ( 2 ) 25 - 26 2021年

    ISSN  0031-9341

  • 血漿パゾパニブ濃度の迅速・簡便測定を目指した計測システムの構築

    緒方元気, 齋木琢郎, 齋木琢郎, 澤村晴志朗, RAZVINA Olga, 渡邉航太, 加藤理都, 浅井開, 花輪藍, 松本吉史, 森山雅人, 西條康夫, 楠原洋之, 栄長泰明, 日比野浩

    日本生体医工学会大会プログラム・抄録集(Web) 60th 2021年

  • がんオーダーメイド治療に貢献するポータブル血中「薬物」濃度測定器の創出

    緒方 元気, 椎木 弘, 高井 まどか, 楠原 洋之, 栄長 泰明, 日比野 浩

    福田記念医療技術振興財団情報 ((公財)福田記念医療技術振興財団)   ( 33 ) 97 - 104 2020年12月



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競争的研究費の研究課題 【 表示 / 非表示

  • ダイヤモンド電極法を用いた血中薬物濃度測定に基づくパゾパニブ服用患者の観察研究


    日本学術振興会, 科学研究費助成事業 基盤研究(C), 齋木 琢郎, 西條 康夫, 日比野 浩, 緒方 元気, 栄長 泰明, 西條 康夫, 日比野 浩, 緒方 元気, 栄長 泰明, 基盤研究(C), 研究分担者


    現在,血漿サンプル量: ~100 &#181;L,測定時間: ~35秒,簡単なボタン操作のみで測定可能な系を確立した.今後,動物血漿検体を用い,迅速性,簡便性,測定感度のさらなる向上を目指し,電極装置,サンプル処理法などの最適化を進める.

  • 針状ダイヤモンドセンサを用いたノンラベリング緑内障点眼薬のリアルタイムin vivo測定法の創出


    公益財団法人 武田科学振興財団, 2022年度ライフサイエンス研究助成, 研究代表者

  • がんオーダーメイド治療に貢献するダイヤモンドセンサを用いた血漿中の分子標的薬の迅速測定法の開発


    公益財団法人 持田記念医学薬学振興財団, 2022年度 研究助成金, 研究代表者

  • 極微量血液からのポータブル迅速薬物測定システムの創出


    公益財団法人内藤記念科学振興財団, 第 54 回(2022 年度) 内藤記念科学奨励金・研究助成, 研究代表者

  • 極微量血液からの迅速薬物モニタリングを実現するハンディシステムの構築


    新潟大学, 科学研究費助成事業 基盤研究(B), 緒方 元気, 基盤研究(B), 補助金,  研究代表者



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