217 results on '"Akihiko Ishida"'
Search Results
2. A case of retractable helix lead auto‐retraction: A possible cause of deep septal lead dislodgement
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Keisuke Suzuki, Eiji Sato, Yoshihiro Yamashina, Akihiko Ishida, and Tetsuo Yagi
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complication ,deep septal pacing ,lead dislodge ,pacemaker ,self‐retracted lead ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2023
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3. Simple Approach for Fluorescence Signal Amplification Utilizing a Poly(vinyl alcohol)-Based Polymer Structure in a Microchannel
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Keine Nishiyama, Masatoshi Maeki, Akihiko Ishida, Hirofumi Tani, Hideaki Hisamoto, and Manabu Tokeshi
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Chemistry ,QD1-999 - Published
- 2021
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4. Real-Time Measurement of Protein Crystal Growth Rates within the Microfluidic Device to Understand the Microspace Effect
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Masatoshi Maeki, Shohei Yamazaki, Reo Takeda, Akihiko Ishida, Hirofumi Tani, and Manabu Tokeshi
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Chemistry ,QD1-999 - Published
- 2020
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5. Preparation of size-tunable sub-200 nm PLGA-based nanoparticles with a wide size range using a microfluidic platform
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Yi Bao, Masatoshi Maeki, Akihiko Ishida, Hirofumi Tani, and Manabu Tokeshi
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Medicine ,Science - Abstract
The realization of poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) from laboratory to clinical applications remains slow, partly because of the lack of precise control of each condition in the preparation process and the rich selectivity of nanoparticles with diverse characteristics. Employing PLGA NPs to establish a large range of size-controlled drug delivery systems and achieve size-selective drug delivery targeting remains a challenge for therapeutic development for different diseases. In this study, we employed a microfluidic device to control the size of PLGA NPs. PLGA, poly (ethylene glycol)-methyl ether block poly (lactic-co-glycolide) (PEG-PLGA), and blend (PLGA + PEG-PLGA) NPs were engineered with defined sizes. Blend NPs exhibit the widest size range (40–114 nm) by simply changing the flow rate conditions without changing the precursor (polymer molecular weight, concentration, and chain segment composition). A model hydrophobic drug, paclitaxel (PTX), was encapsulated in the NPs, and the PTX-loaded NPs maintained a large range of controllable NP sizes. Furthermore, size-controlled NPs were used to investigate the effect of particle size of sub-200 nm NPs on tumor cell growth. The 52 nm NPs showed higher cell growth inhibition than 109 nm NPs. Our method allows the preparation of biodegradable NPs with a large size range without changing polymer precursors as well as the nondemanding fluid conditions. In addition, our model can be applied to elucidate the role of particle sizes of sub-200 nm particles in various biomedical applications, which may help develop suitable drugs for different diseases.
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- 2022
6. Rapid, Sensitive, and Selective Detection of H5 Hemagglutinin from Avian Influenza Virus Using an Immunowall Device
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Kenia Chávez Ramos, Keine Nishiyama, Masatoshi Maeki, Akihiko Ishida, Hirofumi Tani, Toshihiro Kasama, Yoshinobu Baba, and Manabu Tokeshi
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Chemistry ,QD1-999 - Published
- 2019
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7. Label-Free Electrochemical Sensor for Ochratoxin A Using a Microfabricated Electrode with Immobilized Aptamer
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Donny N. Mazaafrianto, Akihiko Ishida, Masatoshi Maeki, Hirofumi Tani, and Manabu Tokeshi
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Chemistry ,QD1-999 - Published
- 2018
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8. Development of the iLiNP Device: Fine Tuning the Lipid Nanoparticle Size within 10 nm for Drug Delivery
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Niko Kimura, Masatoshi Maeki, Yusuke Sato, Yusuke Note, Akihiko Ishida, Hirofumi Tani, Hideyoshi Harashima, and Manabu Tokeshi
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Chemistry ,QD1-999 - Published
- 2018
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9. Understanding the formation mechanism of lipid nanoparticles in microfluidic devices with chaotic micromixers.
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Masatoshi Maeki, Yuka Fujishima, Yusuke Sato, Takao Yasui, Noritada Kaji, Akihiko Ishida, Hirofumi Tani, Yoshinobu Baba, Hideyoshi Harashima, and Manabu Tokeshi
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Medicine ,Science - Abstract
Lipid nanoparticles (LNPs) or liposomes are the most widely used drug carriers for nanomedicines. The size of LNPs is one of the essential factors affecting drug delivery efficiency and therapeutic efficiency. Here, we demonstrated the effect of lipid concentration and mixing performance on the LNP size using microfluidic devices with the aim of understanding the LNP formation mechanism and controlling the LNP size precisely. We fabricated microfluidic devices with different depths, 11 μm and 31 μm, of their chaotic micromixer structures. According to the LNP formation behavior results, by using a low concentration of the lipid solution and the microfluidic device equipped with the 31 μm chaotic mixer structures, we were able to produce the smallest-sized LNPs yet with a narrow particle size distribution. We also evaluated the mixing rate of the microfluidic devices using a laser scanning confocal microscopy and we estimated the critical ethanol concentration for controlling the LNP size. The critical ethanol concentration range was estimated to be 60-80% ethanol. Ten nanometer-sized tuning of LNPs was achieved for the optimum residence time at the critical concentration using the microfluidic devices with chaotic mixer structures. The residence times at the critical concentration necessary to control the LNP size were 10, 15-25, and 50 ms time-scales for 30, 40, and 50 nm-sized LNPs, respectively. Finally, we proposed the LNP formation mechanism based on the determined LNP formation behavior and the critical ethanol concentration. The precise size-controlled LNPs produced by the microfluidic devices are expected to become carriers for next generation nanomedicines and they will lead to new and effective approaches for cancer treatment.
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- 2017
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10. His-Purkinje system-related incessant ventricular tachycardia arising from the left coronary cusp
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Eiji Sato, MD, Tetsuo Yagi, MD, PhD, Akio Namekawa, MD, Akihiko Ishida, MD, Yoshiaki Mibiki, MD, PhD, Yoshihiro Yamashina, MD, PhD, Hirokazu Sato, MD, PhD, Takashi Nakagawa, MD, Manjirou Sakuramoto, MD, Jyuri Komatsu, MD, and Tomoyuki Yambe, MD, PhD
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Catheter ablation ,Coronary cusp ,His-Purkinje system ,Idiopathic left ventricular tachycardia ,Ventricular arrhythmia ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
We describe the case of a 23-year-old woman who had His-Purkinje system-related incessant ventricular tachycardia with a narrow QRS configuration. The ventricular tachycardia was ablated successfully in the left coronary cusp where the earliest endocardial activation had been recorded. We hypothesize that a remnant of the subaortic conducting tissue was the source of the ventricular arrhythmias.
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- 2014
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11. Particle Accumulation by AC Electroosmosis in Microfluidic Device with Co-Planar Electrodes
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Akihiko ISHIDA, Hikaru TOKI, Masahiro MOTOSUKE, and Shinji HONAMI
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microfluidics ,ac electroosmosis ,micro-ptv ,particle accumulation ,Mechanical engineering and machinery ,TJ1-1570 ,Mechanics of engineering. Applied mechanics ,TA349-359 - Abstract
This paper reports a particle accumulation driven by alternating-current electroosmosis (ACEO) in a microfluidic device with co-planar electrode. Accumulation processes of particles in single- and double-gap electrode device were investigated. The flow field of ACEO and flow-induced particle accumulation process were measured by the micron-resolution particle tracking velocimetry and fluorescent intensity analysis, respectively. Particles in a solution are concentrated gradually from an electrode edge close to gap at the entrance and converged into a certain location downstream. Contribution of ACEO to particle transportation and eventual accumulation was discussed, and dependences of experimental parameters on the accumulating position were evaluated as well. The particle concentration behavior can be classified into two types; one has similar accumulating characteristics in both gap patterns, the other is the case in which particles are concentrated at the center span of the channel. Consequently, it is indicated from the results in this study that an estimation of the particle concentration is possible in a device with more complicated electrode geometry based on that in the single-gap device. The particle focusing method by ACEO can contribute to an improvement of detection sensitivity in the microfluidic system.
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- 2012
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12. Recent Microdevice-Based Aptamer Sensors
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Donny Nugraha Mazaafrianto, Masatoshi Maeki, Akihiko Ishida, Hirofumi Tani, and Manabu Tokeshi
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microdevice ,aptamer ,biosensor ,SELEX ,lab-on-chip ,point-of-care ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
Since the systematic evolution of ligands by exponential enrichment (SELEX) method was developed, aptamers have made significant contributions as bio-recognition sensors. Microdevice systems allow for low reagent consumption, high-throughput of samples, and disposability. Due to these advantages, there has been an increasing demand to develop microfluidic-based aptasensors for analytical technique applications. This review introduces the principal concepts of aptasensors and then presents some advanced applications of microdevice-based aptasensors on several platforms. Highly sensitive detection techniques, such as electrochemical and optical detection, have been integrated into lab-on-a-chip devices and researchers have moved towards the goal of establishing point-of-care diagnoses for target analyses.
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- 2018
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13. Advances in Microfluidic Paper-Based Analytical Devices for Food and Water Analysis
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Lori Shayne Alamo Busa, Saeed Mohammadi, Masatoshi Maeki, Akihiko Ishida, Hirofumi Tani, and Manabu Tokeshi
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μPADs ,food analysis ,water analysis ,point-of-need ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
Food and water contamination cause safety and health concerns to both animals and humans. Conventional methods for monitoring food and water contamination are often laborious and require highly skilled technicians to perform the measurements, making the quest for developing simpler and cost-effective techniques for rapid monitoring incessant. Since the pioneering works of Whitesides’ group from 2007, interest has been strong in the development and application of microfluidic paper-based analytical devices (μPADs) for food and water analysis, which allow easy, rapid and cost-effective point-of-need screening of the targets. This paper reviews recently reported μPADs that incorporate different detection methods such as colorimetric, electrochemical, fluorescence, chemiluminescence, and electrochemiluminescence techniques for food and water analysis.
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- 2016
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14. Understanding the effects of ethanol on the liposome bilayer structure using microfluidic-based time-resolved small-angle X-ray scattering and molecular dynamics simulations.
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Masatoshi Maeki, Niko Kimura, Yuto Okada, Kazuki Shimizu, Kana Shibata, Yusuke Miyazaki, Akihiko Ishida, Kento Yonezawa, Nobutaka Shimizu, Wataru Shinoda, and Manabu Tokeshi
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- 2024
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15. Development of an Absorbance Detection Module Using a Deep UV Light-Emitting Diode for a Portable Miniaturized Liquid Chromatograph
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Kaito KOYAMA, Takuma NISHINURA, Akihiko ISHIDA, Mitsue HIBINO, Masatoshi MAEKI, Hirofumi TANI, and Manabu TOKESHI
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absorbance detector ,flow cell ,portable liquid chromatograph ,UV-LED ,Analytical Chemistry - Abstract
In recent years, there has been increasing demand for miniaturized analytical instruments that allow immediate on-site analysis. We have been developing a portable HPLC system consisting of a column-integrated chip and a compact, low-power electroosmotic flow pump. This study aims to extend the versatility of the portable HPLC system with a further reduction of the overall system size, and thus we constructed a UV absorbance detection module that can be mounted to the column-integrated chip. For this detection module, a UV light-emitting diode (peak wavelength = 255 nm) and photodiode were used as a light source and photodetector, and a system to control their operation and process the signals was also constructed. The developed detection module exhibited excellent performances as an HPLC detector., 近年,サンプリングした現場で即時に分析が可能な小型分析装置の需要が高まっている.著者らは,小型・低電力の電気浸透流ポンプとカラム内蔵チップからなる小型HPLCシステムの開発に取り組んできた.本研究では,小型HPLCシステム全体のさらなる小型化を目指しながら検出における汎用性を拡張するため,カラム内蔵チップに適用可能で,汎用性が高い紫外吸光度検出モジュールを構築した.そのために光源及び受光器に深紫外発光ダイオード(ピーク発光波長255 nm)及びフォトダイオードを用いるとともに,これらの動作を制御し,信号を処理するシステムも構築した.さらに,検出モジュールが市販分光光度計並みの感度を持ち,良好にクロマトグラム測定ができることを実証した.
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- 2023
16. マイクロ流体デバイスを利用した下痢性貝毒オカダ酸の蛍光偏光免疫分析におけるブロッキング剤添加の影響
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Shunsuke CHIDA, Kazuki TAKAHASHI, Mao FUKUYAMA, Motohiro KASUYA, Masatoshi MAEKI, Akihiko ISHIDA, Hirofumi TANI, Koji SHIGEMURA, Anatoly V. ZHERDEV, Sergei A. EREMIN, Akihide HIBARA, and Manabu TOKESHI
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Analytical Chemistry - Published
- 2023
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17. Potential Risk of Jailed Balloon Technique in Left Main Bifurcation Lesions
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Tetsuya Yamamoto, Takayoshi Toba, Toshimitsu Ishii, and Akihiko Ishida
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Cardiology and Cardiovascular Medicine - Published
- 2023
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18. Effect of Organic Solvents on a Production of PLGA-Based Drug-Loaded Nanoparticles Using a Microfluidic Device
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Yi Bao, Masatoshi Maeki, Akihiko Ishida, Hirofumi Tani, and Manabu Tokeshi
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Amorphous materials ,Copolymers ,General Chemical Engineering ,Microfluidic devices ,Solvents ,Encapsulation ,General Chemistry - Abstract
The translation of nanoparticles (NPs) from laboratory to clinical settings is limited, which is not ideal. One of the reasons for this is that we currently have limited ability to precisely regulate various physicochemical parameters of nanoparticles. This has made it difficult to rapidly perform targeted screening of drug preparation conditions. In this study, we attempted to broaden the range of preparation conditions for particle size-modulated poly(lactic-co-glycolic-acid) (PLGA) NP to enhance their applicability for drug delivery systems (DDS). This was done using a variety of organic solvents and a glass-based microfluidic device. Furthermore, we compared the PDMS-based microfluidic device to the glass-based microfluidic device in terms of the possibility of a wider range of preparation conditions, especially the effect of different solvents on the size of the PLGA NPs. PLGA NPs with different sizes (sub-200 nm) were successfully prepared, and three different types of taxanes were employed for encapsulation. The drug-loaded NPs showed size-dependent cytotoxicity in cellular assays, regardless of the taxane drug used.
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- 2022
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19. ST-segment elevation myocardial infarction originating from the preceding spontaneous coronary artery dissection: a case report
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Tetsuya Yamamoto, Tomofumi Takaya, Toshimitsu Ishii, and Akihiko Ishida
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Radiology, Nuclear Medicine and imaging ,General Medicine ,Cardiology and Cardiovascular Medicine - Published
- 2022
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20. Determination of Deoxynivalenol in Wheat, Barley, Corn Meal, and Wheat-Based Products by Simultaneous Multisample Fluorescence Polarization Immunoassay Using a Portable Analyzer
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Mitsutoshi Aoyagi, Masatoshi Maeki, Mao Fukuyama, Akihide Hibara, Hirofumi Tani, Koji Shigemura, Ayano Nakamura, Akihiko Ishida, and Manabu Tokeshi
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Spectrum analyzer ,Chromatography ,Corn meal ,Chemistry (miscellaneous) ,Chemistry ,Organic Chemistry ,Fluorescence polarization immunoassay ,Food Science ,Analytical Chemistry - Published
- 2021
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21. Using a Paper-Based Analytical Device Designed for Remote Learning Environments to Achieve Simple Quantitative Colorimetry without Micropipettes
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Takeshi Komatsu, Akihiko Ishida, Hirofumi Tani, Manabu Tokeshi, Ryan Russel A. Gabatino, Masatoshi Maeki, and Harrienica Hofileña
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SIMPLE (military communications protocol) ,business.industry ,Computer science ,Sample (material) ,Pipette ,Remote learning ,General Chemistry ,Paper based ,Volume control ,Ascorbic acid ,Colorimetry (chemical method) ,Education ,Process engineering ,business - Abstract
The majority of chemical experiments conducted during educational programs are carried out in laboratories because they require instructors with special skills, in addition to large, expensive instruments. Recently, there has been an increasing demand for chemical experiments that can be carried out anywhere. Herein, we propose a novel type of paper-based analytical device (PAD) for enabling quantitative analysis without the requirement for a micropipette, since the PAD features a large sample loading zone and a waste zone, enabling accurate volume control of a liquid sample. We initially employed a micropipette to evaluate the PAD and demonstrate the quantitative analysis of ascorbic acid (AA) and pH using different loading volumes. Finally, we determined the AA concentrations and pH values of commercially available beverages using disposable plastic droppers, and the obtained results were in good agreement with those obtained through conventional methods. This PAD format can therefore be used as a novel educational tool for conducting certain chemical analyses in remote learning environments.
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- 2021
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22. Potential Risk of Jailed Balloon Technique in Left Main Bifurcation Lesions: Sandwiched Jailed Balloon Shaft
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Tetsuya, Yamamoto, Takayoshi, Toba, Toshimitsu, Ishii, and Akihiko, Ishida
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- 2022
23. Mass production system for RNA-loaded lipid nanoparticles using piling up microfluidic devices
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Masatoshi Maeki, Yuto Okada, Shuya Uno, Kaisei Sugiura, Yuichi Suzuki, Kento Okuda, Yusuke Sato, Masao Ando, Hiroyuki Yamazaki, Masaki Takeuchi, Akihiko Ishida, Hirofumi Tani, Hideyoshi Harashima, and Manabu Tokeshi
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mRNA vaccines ,Microfluidic device ,Lipid nanoparticles ,General Materials Science ,Mass production ,Microfabrication - Abstract
Microfluidic devices are widely used in lipid nanoparticle (LNP)-based vaccines and nanomedicine research. These devices should be stiff enough to withstand the high flow rate for the mass production of LNPs, and malleable enough to use when fabricating complicated microchannel or micromixer structures, such as stag-gering herringbone micromixers. Due to the limitations of the available fabrication methods, optimal micro -fluidic devices have not yet been developed. In this study, we report the development of a glass-based microfluidic device based on the invasive Lipid Nanoparticle Production (iLiNP) device (R) reported previously. The LNP size controllability of glass-based iLiNP device was similar to that of the poly(dimethylsiloxane) (PDMS)-based iLiNP device, and the glass-iLiNP device was used for mRNA-loaded LNP production with ionizable lipids used for COVID-19 mRNA vaccines. We also demonstrate a piling-and numbering-up strategy based on glass-iLiNP device. The iLiNP unit composed of five-layered microchannels was fabricated by piling-up each glass-iLiNP device followed by parallelization (numbering-up) for the mass production of LNPs. This iLiNP system can produce LNPs with sizes ranging between 20 and 60 nm at a flow rate of 20-50 mL/min, and its performance is comparable to that of the commercially available microfluidic system like NanoAssemblr (R).
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- 2023
24. TouchMe: An Augmented Reality Interface for Remote Robot Control.
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Sunao Hashimoto, Akihiko Ishida, Masahiko Inami, and Takeo Igarashi
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- 2013
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25. Simple Approach for Fluorescence Signal Amplification Utilizing a Poly(vinyl alcohol)-Based Polymer Structure in a Microchannel
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Akihiko Ishida, Hirofumi Tani, Keine Nishiyama, Masatoshi Maeki, Hideaki Hisamoto, and Manabu Tokeshi
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chemistry.chemical_classification ,Vinyl alcohol ,Analyte ,Microchannel ,Materials science ,business.industry ,Calibration curve ,General Chemical Engineering ,Noncovalent probes ,General Chemistry ,Polymer ,Molecules ,Fluorescence ,Signal ,Article ,Chemistry ,chemistry.chemical_compound ,chemistry ,Chemical structure ,Mixtures ,Optoelectronics ,business ,QD1-999 ,Biosensor - Abstract
Analytical methods with fluorescence detection are in widespread use for detecting low abundance analytes. Here, we report a simple method for fluorescence signal amplification utilizing a structure of an azide-unit pendant water-soluble photopolymer (AWP) in a microchannel. The AWP is a poly(vinyl alcohol)-based photocross-linkable polymer, which is often used in biosensors. We determined that the wall-like structure of the AWP (AWP-wall) constructed in a microchannel functioned as an amplifier of a fluorescence signal. When a solution of fluorescent molecules was introduced into the microchannel having the AWP-wall, the fluorescent molecules accumulated inside the AWP-wall by diffusion. Consequently, the fluorescence intensity inside the AWP-wall increased locally. Among the fluorescent molecules considered in this paper, 9H-(1,3-dichloro-9,9-dimethylacridin-2-one-7-yl) (DDAO) showed the highest efficiency of fluorescence signal amplification. We prepared a calibration curve for DDAO using the fluorescence intensity inside the AWP-wall, and the sensitivity was 5-fold that for the microchannel without the AWP-wall. This method realizes the improved sensitivity of fluorescence detection easily because the fluorescence signal was amplified only by injecting the solution into the microchannel having the AWP-wall. Furthermore, since this method is not limited to only the use of microchannel, we expect it to be applicable in various fields.
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- 2021
26. Dip-Type Paper-Based Analytical Device for Straightforward Quantitative Detection without Precise Sample Introduction
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Masatoshi Maeki, Manabu Tokeshi, Takeshi Komatsu, Akihiko Ishida, Hirofumi Tani, and Ryoga Maeda
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Fluid Flow and Transfer Processes ,Detection limit ,Reproducibility ,Materials science ,Chromatography ,Calibration curve ,Process Chemistry and Technology ,Coefficient of variation ,Homogeneity (statistics) ,010401 analytical chemistry ,Pipette ,Reproducibility of Results ,Bioengineering ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Ascorbic acid ,01 natural sciences ,0104 chemical sciences ,Limit of Detection ,Calibration ,Colorimetry ,0210 nano-technology ,Instrumentation - Abstract
The development of low-cost, user-friendly paper-based analytical devices (PADs) that can easily measure target chemicals is attracting attention. However, most PADs require manipulation of the sample using sophisticated micropipettes for quantitative analyses, which restricts their user-friendliness. In addition, immobilization of detection molecules to cellulose fibers is essential for achieving good measuring ability as it ensures the homogeneity of color development. Here, we have described a dip-type PAD that does not require pipette manipulation for sample introduction and immobilization of detection molecules to cellulose fibers and its application to ascorbic acid (AA) and pH assays. The PAD consisted of a dipping area and two channels, each with two detection zones. The developed PADs show color distribution in the two detection zones depending on the sample flow from the dipping area. In comparison with a PAD that has one detection zone at the end of the channel, our developed device achieved higher sensitivity (limit of detection (LOD), 0.22 mg/mL) and reproducibility (maximum coefficient of variation (CV), 2.4%) in AA detection. However, in pH detection, the reproducibility of the PAD with one detection zone at the end of the channel (maximum CV, 21%) was worse than that with two zones (maximum CV, 11%). Furthermore, a dipping time over 3 s did not affect color formation or calibration curves in AA detection: LODs at 3 and 30 s dipping time were 18 and 5.8 μg/mL, respectively. The simultaneous determination of AA and pH in various beverages was performed with no significant difference compared to results of the conventional method.
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- 2021
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27. Non-competitive fluorescence polarization immunoassay for detection of H5 avian influenza virus using a portable analyzer
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Akihiko Ishida, Keine Nishiyama, Mao Fukuyama, Koji Shigemura, Haruko Ogawa, Akihide Hibara, Manabu Tokeshi, Hirofumi Tani, Yohei Takeda, Masatoshi Maeki, and Kazuki Takahashi
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Spectrum analyzer ,Avian influenza ,Rapid diagnosis ,02 engineering and technology ,medicine.disease_cause ,Polymerase Chain Reaction ,Sensitivity and Specificity ,01 natural sciences ,Biochemistry ,Virus ,Analytical Chemistry ,Fluorescence Polarization Immunoassay ,medicine ,Animals ,Virus detection ,Chromatography ,Avian influenza virus ,Influenza A Virus, H5N1 Subtype ,medicine.diagnostic_test ,Chemistry ,Communication ,010401 analytical chemistry ,021001 nanoscience & nanotechnology ,Influenza A virus subtype H5N1 ,0104 chemical sciences ,Influenza in Birds ,Immunoassay ,Fluorescence polarization immunoassay ,0210 nano-technology ,Chickens ,Fluorescence anisotropy - Abstract
Nowadays, the diagnosis of viral infections is receiving broad attention. We have developed a non-competitive fluorescence polarization immunoassay (NC-FPIA), which is a separation-free immunoassay, for a virus detection. H5 subtype avian influenza virus (H5-AIV) was used as a model virus for the proof of concept. The fluorescein-labeled Fab fragment that binds to H5 hemagglutinin was used for NC-FPIA. The purified H5-AIV which has H5 hemagglutinin was mixed with the fluorescein-labeled Fab fragment. After that, the degree of fluorescence polarization was measured with a portable FPIA analyzer. H5-AIV was successfully detected with an incubation time of 15 min. In addition, the portable FPIA analyzer enables performance of on-site NC-FPIA with a sample volume of 20 μL or less. This is the first research of detecting a virus particle by FPIA. This NC-FPIA can be applied to rapid on-site diagnosis of various viruses. Supplementary Information The online version contains supplementary material available at 10.1007/s00216-021-03193-y.
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- 2021
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28. Rapid, sensitive universal paper-based device enhances competitive immunoassays of small molecules
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Masatoshi Maeki, Akihiko Ishida, Hirofumi Tani, Yuki Sato, Takeshi Komatsu, and Manabu Tokeshi
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Immunoassay ,Detection limit ,Chemistry ,010401 analytical chemistry ,Biotin ,02 engineering and technology ,Paper based ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Small molecule ,Antibodies ,0104 chemical sciences ,Analytical Chemistry ,Layered structure ,Limit of Detection ,Environmental Chemistry ,Competitive immunoassay ,Indicators and Reagents ,Color formation ,0210 nano-technology ,Biological system ,Spectroscopy - Abstract
Competitive immunoassays comprise the standard means of detecting small molecules. However, conventional methods using microwells are difficult to apply during point-of-care tests (POCT) because they require complicated handling and are time consuming. Although paper-based analytical devices (PAD) have received considerable focus because of their rapid and straightforward operation, only a few devices have been proposed for competitive immunoassays. Herein, we describe a novel universal PAD format with a 3-dimensional configuration for competitive immunoassays that rapidly and sensitively detects small molecules. The proposed device comprised a layered structure with uniform color formation and high capture efficiency between antigen and antibody that results in rapid and reproducible results. The device rapidly (90 s) assayed biotin as a model target, with a limit of detection (LOD) of 5.08 ng mL−1, and detected progesterone with an LOD of 84 pg mL−1 within 5 min. Moreover, sample volumes and reagent consumption rates were minimized. Thus, our device could be applied to competitive immunoassays of various small molecules in POCT.
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- 2021
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29. One-Step Production Using a Microfluidic Device of Highly Biocompatible Size-Controlled Noncationic Exosome-like Nanoparticles for RNA Delivery
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Masatoshi Maeki, Manabu Tokeshi, Akihiko Ishida, Niko Kimura, and Hirofumi Tani
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Microfluidics ,Biomedical Engineering ,Nanoparticle ,Biocompatible Materials ,One-Step ,Exosomes ,Exosome ,Biomaterials ,chemistry.chemical_compound ,Lab-On-A-Chip Devices ,Materials Testing ,Tumor Cells, Cultured ,Humans ,Particle Size ,RNA, Small Interfering ,Gene ,Chemistry ,Biochemistry (medical) ,Cationic polymerization ,RNA ,General Chemistry ,Biophysics ,Nanoparticles ,lipids (amino acids, peptides, and proteins) ,DNA ,HeLa Cells - Abstract
Size-controlled lipid nanoparticle (LNP)-based DNA/RNA delivery is a leading technology for gene therapies. For DNA/RNA delivery, typically, a cationic lipid is used to encapsulate DNA/RNA into LNPs. However, the use of the cationic lipid leads to cytotoxicity. In contrast, noncationic NPs, such as exosomes, are ideal nanocarriers for DNA/RNA delivery. However, the development of a simple one-step method for the production of size-controlled noncationic NPs encapsulating DNA/RNA is still challenging because of the lack of electrostatic interactions between the cationic lipid and negatively charged DNA/RNA. Herein, we report a microfluidic-based one-step method for the production of size-controlled noncationic NPs encapsulating small interfering RNA (siRNA). Our microfluidic device, named iLiNP, enables the efficient encapsulation of siRNA, as well as control over the NP size, by varying the flow conditions. We applied this method to produce size-controlled exosome-like NPs. The siRNA-loaded exosome-like NPs did not show in vitro cytotoxicity at a high siRNA dosage. In addition, we investigated the effect of the size of the exosome-like NPs on the target gene silencing and found that the 40-50 nm-sized NPs suppressed target protein expression at a dose of 20 nM siRNA. The iLiNP-based one-step production method for size-controlled noncationic-NP-encapsulated RNA is a promising method for the production of artificial exosomes and functionally modified exosomes for gene and cell therapies.
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- 2021
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30. Non-competitive fluorescence polarization immunosensing for CD9 detection using a peptide as a tracer
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Kazuki Takahashi, Shunsuke Chida, Thanawat Suwatthanarak, Mikiko Iida, Min Zhang, Mao Fukuyama, Masatoshi Maeki, Akihiko Ishida, Hirofumi Tani, Takao Yasui, Yoshinobu Baba, Akihide Hibara, Mina Okochi, and Manabu Tokeshi
- Subjects
Fluorescence Polarization Immunoassay ,Biomedical Engineering ,Humans ,Bioengineering ,Fluorescence Polarization ,General Chemistry ,Peptides ,Biochemistry ,Tetraspanin 29 ,HeLa Cells - Abstract
This paper is the first report of a non-competitive fluorescence polarization immunoassay (NC-FPIA) using a peptide as a tracer. The NC-FPIA can easily and quickly quantify the target after simply mixing them together. This feature is desirable for point-of-need applications such as clinical diagnostics, infectious disease screening, on-site analysis for food safety
- Published
- 2022
31. Impact of post physiological assessment after treatment for de novo coronary lesions using drug-coated balloons
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Tetsuya Yamamoto, Toshimitsu Ishii, and Akihiko Ishida
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Fractional Flow Reserve, Myocardial ,Cardiac Catheterization ,Percutaneous Coronary Intervention ,Treatment Outcome ,Coronary Stenosis ,Humans ,Coronary Artery Disease ,Angioplasty, Balloon, Coronary ,Cardiology and Cardiovascular Medicine ,Coronary Angiography - Abstract
Acute physiological changes after balloon angioplasty are very important because of acute recoil and dissection. However, serial physiological assessments after drug-coated balloons (DCB) have not been investigated.This prospective observational single-center study evaluated 50 lesions that underwent optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) with DCB and a 9-months angiographical and OCT follow-up. Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) were measured immediately (FFR0m and, iFR0m) and 15 min (FFR15m and iFR15m) after DCB, and the difference (dif-FFR and, dif-iFR) was calculated. The iFR gradients during lesions treated with DCB were measured. For OCT and quantitative coronary angiography (QCA) data, delta values were calculated.At index PCI, three lesions were needed for bailout stenting. At follow-up, 47 lesions were divided into two groups according to the delta minimal lumen area (MLA) on OCT: late lumen enlargement (LLE) (n = 29) and non-LLE (n = 18). In LLE group, FFR15m and iFR15m were significantly high (0.90 ± 0.03 vs. 0.85 ± 0.07, p 0.001, 0.97 ± 0.02 vs. 0.92 ± 0.10, p = 0.008, respectively) and %AS on OCT, dif-FFR and dif-iFR were significantly low (38.5% (33.6, 42.3) vs. 45.1% (38.9, 54.6), p = 0.03, -0.001 ± 0.006 vs. 0.036 ± 0.032, p 0.001, -0.002 ± 0.008 vs. 0.019 ± 0.017, p 0.001, respectively) compared with non-LLE group. However, there were no significant differences in FFR0m, iFR0m, or any other OCT or QCA data.Post-physiological assessment and a decrease in physiological indices in the first 15 min after PCI are important for treating de novo lesions using the DCB strategy.
- Published
- 2022
32. Production of siRNA-Loaded Lipid Nanoparticles using a Microfluidic Device
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Manabu Tokeshi, Hirofumi Tani, Akihiko Ishida, Ayuka Niwa, Shuya Uno, Yuto Okada, and Masatoshi Maeki
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General Immunology and Microbiology ,General Chemical Engineering ,General Neuroscience ,Lab-On-A-Chip Devices ,Liposomes ,COVID-19 ,Humans ,Nanoparticles ,Tissue Distribution ,RNA, Small Interfering ,Lipids ,General Biochemistry, Genetics and Molecular Biology - Abstract
The development of functional lipid nanoparticles (LNPs) is one of the major challenges in the field of drug delivery systems (DDS). Recently, LNP-based RNA delivery systems, namely, RNA-loaded LNPs have attracted attention for RNA therapy. In particular, mRNA-loaded LNP vaccines were approved to prevent COVID-19, thereby leading to the paradigm shift toward the development of next-generation nanomedicines. For the LNP-based nanomedicines, the LNP size is a significant factor in controlling the LNP biodistribution and LNP performance. Therefore, a precise LNP size control technique is indispensable for the LNP production process. Here, we report a protocol for size controlled LNP production using a microfluidic device, named iLiNP. siRNA loaded LNPs are also produced using the iLiNP device and evaluated by in vitro experiment. Representative results are shown for the LNP size, including siRNA-loaded LNPs, Z-potential, siRNA encapsulation efficiency, cytotoxicity, and target gene silencing activity.
- Published
- 2022
33. Development of a Paper-based Analytical Chip for the Detection of Bacterial 16S rRNA in Wastewater Samples
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Manabu Tokeshi, Akihiko Ishida, Hisashi Satoh, and Meri Nakajima
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colorimetric method ,Wastewater ,Chemistry ,Colloidal gold ,Bacterial 16S rRNA ,gold nanoparticles ,Paper based ,Pulp and paper industry ,Chip ,hybridization ,Analytical Chemistry - Abstract
Analysis of bacteria in the sewage wastewater treatment process is essential for process stabilization and upgrading. Although bacteria are currently being analyzed by molecular biology techniques targeting the 16S rRNA gene, there is a problem that they are time-consuming and labor-intensive. In this study, we developed a paper-based analytical chip by using two types of DNA molecules that specifically bind to bacterial 16S rRNA. We optimized the fabrication method of the detection probe and the paper-based analytical chip, and then detected synthetic DNA having a nucleotide sequence that hybridizes with the designed DNA molecules and bacterial 16S rRNA extracted from an activated sludge sample. We evaluated the amount of nucleic acids quantitatively by taking images of the detection line on the paper-based analytical chip with a smartphone and analyzing its brightness with an open-source image processing program, ImageJ. Our method was able to detect 85 nM of bacterial 16S rRNA concentration in the extract. Nucleic acids that did not hybridize with either of the designed DNA molecules were not detected, demonstrating high selectivity of our method.
- Published
- 2020
34. Silica Nanopillar Arrays for Monitoring Diffraction-Based Label-Free Biomolecule Separation
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Manabu Tokeshi, Junji Nishii, Akihiko Ishida, Yoshinobu Baba, Taiga Ajiri, Takao Yasui, Hirofumi Tani, and Masatoshi Maeki
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chemistry.chemical_classification ,Diffraction ,Bioanalysis ,Materials science ,chemistry ,Optical diffraction ,Biomolecule ,General Materials Science ,Nanofluidics ,Nanotechnology ,Label free ,Nanopillar - Abstract
Recent studies on nanopillar arrays, one type of nanofluidic device, have demonstrated various tools for bioanalysis. When carrying out nanopillar array-based separation, it is indispensable to obs...
- Published
- 2020
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35. Paper-Based Device for the Facile Colorimetric Determination of Lithium Ions in Human Whole Blood
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Takeshi Komatsu, Akihiko Ishida, Hirofumi Tani, Manabu Tokeshi, and Masatoshi Maeki
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Paper ,Materials science ,Coefficient of variation ,chemistry.chemical_element ,Bioengineering ,02 engineering and technology ,Lithium ,01 natural sciences ,Ion ,chemistry.chemical_compound ,Humans ,Colorimetry ,Instrumentation ,Whole blood ,Ions ,Fluid Flow and Transfer Processes ,Detection limit ,Reproducibility ,Chromatography ,Process Chemistry and Technology ,010401 analytical chemistry ,Lithium carbonate ,Reproducibility of Results ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,0210 nano-technology - Abstract
Lithium carbonate is an effective medicine for the treatment of the bipolar disorder, but the concentration of lithium in the patient's blood must be frequently monitored because of its toxicity. To date, no colorimetric methods of lithium ion detection in whole blood without pretreatment have been reported. Here, we report a colorimetric paper-based device that allows point-of-care testing in one step. This device is composed of two paper-based elements linked to each other: a blood cell separation unit and a colorimetric detection unit. After a portion of whole blood has been placed on the end of the separation unit, plasma in the sample is automatically transported to the detection unit, which displays a diagnostic color. The key feature of this device is its simple, user-friendly operation. The limit of detection is 0.054 mM and the coefficient of variance is below 6.1%, which are comparable to those of conventional instruments using the same colorimetric reaction. Furthermore, we achieved high recovery (>90%) and reproducibility (
- Published
- 2020
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36. Paper-Based Analytical Device for the On-Site Detection of Nerve Agents
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Hajime Miyaguchi, Akinori Yamaguchi, Akihiko Ishida, and Manabu Tokeshi
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Paper ,Computer science ,Biochemistry (medical) ,Biomedical Engineering ,General Chemistry ,Paper based ,Biomaterials ,Lab-On-A-Chip Devices ,medicine ,Biological Assay ,Colorimetry ,Nerve Agents ,Biomedical engineering ,Nerve agent ,medicine.drug - Abstract
We report a colorimetric paper-based microfluidic device based on an enzyme inhibition assay that allows the on-site detection of nerve agents by sampling and wicking. The sample and reagents are automatically transported through the channel where an enzyme inhibition reaction is conducted, followed by an enzyme-substrate reaction and a color reaction. This device can detect 0.1 μg/mL of the nerve agent VX in a 2.5 μL drop and is nerve agent selective and robust against temperature, pH, and several liquids. We confirmed that sampling procedures (dilution and wiping) are applicable to this device. Furthermore, the fabrication procedure is easy, and the cost is at most a few tens of cents. Thus, the present device provides a practical method for the urgent detection of nerve agents in suspected chemical terrorism incidents.
- Published
- 2022
37. Microfluidic paper-based analytical devices for cancer diagnosis
- Author
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Ahmed A. Shalaby, Chia-Wen Tsao, Akihiko Ishida, Masatoshi Maeki, and Manabu Tokeshi
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Materials Chemistry ,Metals and Alloys ,Electrical and Electronic Engineering ,Condensed Matter Physics ,Instrumentation ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2023
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38. A fabrication technique for paper-based analytical devices via two-sided patterning with thermal-transfer printer and laminator
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Takuya Monju, Manabu Hirakawa, Satoshi Kuboyama, Rikuro Saiki, and Akihiko Ishida
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Materials Chemistry ,Metals and Alloys ,Electrical and Electronic Engineering ,Condensed Matter Physics ,Instrumentation ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2023
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39. Healed plaque erosion as a cause of recurrent vasospastic angina: a case report
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Tetsuya Yamamoto, Akihiko Ishida, and Ishii Toshimitsu
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medicine.medical_specialty ,Acute coronary syndrome ,Healed plaque ,Optical coherence tomography ,business.industry ,Chest pain ,medicine.disease ,Vasospastic angina ,Stenosis ,Nifedipine ,Internal medicine ,Coronary vasospasm ,Case report ,medicine ,Isosorbide mononitrate ,Cardiology ,AcademicSubjects/MED00200 ,cardiovascular diseases ,medicine.symptom ,Thrombus ,Cardiology and Cardiovascular Medicine ,Nicorandil ,business ,medicine.drug - Abstract
Background Recurrent vasospastic angina sometimes occurs. Fresh thrombi have been known to arise without plaque rupture at coronary spasm sites due to blood flow stagnation and intimal erosion caused by vasospasms. The relationship between recurrence of vasospastic angina and thrombus formation remains unclear. Case summary A 67-year-old man presented with sudden chest pain at rest. Electrocardiography and coronary angiography indicated vasospastic angina. His chest pain persisted despite the administration of benidipine, isosorbide mononitrate, nicorandil, and nifedipine. Coronary angiography performed one month after initial presentation showed stenosis refractory to isosorbide administration. Optical coherence tomography revealed a healed plaque, and a stent was deployed. The patient remained symptom-free at 1-year follow-up. Discussion Prolonged coronary vasospasm with limited coronary blood flow could induce total occlusion of the coronary artery, and acute thrombus formation, which resulted in healed plaque erosion. When vasospastic angina cannot be controlled, rapidly progressive stenosis caused by healed plaque erosion could be its underlying cause and mechanism. This report indicates that antiplatelet therapy may be a preventive option for future recurrent vasospastic angina, especially in those caused by healed plaques.
- Published
- 2021
40. Successful Cryoablation for Parahissian Right Midseptal Accessory Pathway with Atrioventricular Block during Radiofrequency Ablation
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Yoshiaki Mibiki, Keisuke Suzuki, Tetsuo Yagi, Akihiko Ishida, Kousuke Aoki, Hirokazu Sato, Eiji Sato, Takashi Nakagawa, Takuma Izutsu, and Yoshihiro Yamashina
- Subjects
medicine.medical_specialty ,business.industry ,Radiofrequency ablation ,medicine.medical_treatment ,Cryoablation ,Accessory pathway ,medicine.disease ,law.invention ,law ,Internal medicine ,medicine ,Cardiology ,business ,Atrioventricular block - Published
- 2019
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41. Rapid, Sensitive, and Selective Detection of H5 Hemagglutinin from Avian Influenza Virus Using an Immunowall Device
- Author
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Yoshinobu Baba, Keine Nishiyama, Manabu Tokeshi, Akihiko Ishida, Kenia Chávez Ramos, Toshihiro Kasama, Hirofumi Tani, and Masatoshi Maeki
- Subjects
Detection limit ,Avian influenza virus ,medicine.diagnostic_test ,General Chemical Engineering ,virus diseases ,Outbreak ,General Chemistry ,Biology ,medicine.disease_cause ,Virology ,Article ,Influenza A virus subtype H5N1 ,Virus ,Chemistry ,Immunoassay ,Pandemic ,medicine ,biology.protein ,Antibody ,QD1-999 - Abstract
Avian influenza virus (AIV) infection, caused by influenza virus type A, is an infectious, acute respiratory disease of birds related to influenza outbreaks worldwide. The highly pathogenic AIV subtype H5N1 has crossed species barriers to infect mammals, including humans, with fatal outcomes and has received attention as a potential pandemic threat. A rapid and timely detection in poultry is vitally important to prevent the virus spread. Despite their great sensitivity, conventional detection methods such as real-time reverse transcription-polymerase chain reaction and the agar gel precipitation test are time-consuming and labor-intensive and require special training. In this work, an immunowall device was evaluated as an easier and faster way for detecting AIV H5-hemagglutinin (AIV H5-HA). For detection, fluorescence-labeled or enzyme-labeled antibody was employed as a labeling antibody in a sandwich immunoassay. Both were shown in this paper to be easier and faster assays for detection compared with the conventional enzyme-linked immunosorbent assay (ELISA) kit. In addition, high selectivity was achieved for AIV H5-HA detection after the evaluation of other different HA virus subtypes. The limit of detection was 0.23 ng/mL for the enzyme-labeled antibody. This value was equivalent to that of the conventional ELISA kit but 8 times faster (31 min compared to 260 min). The detection range was 0.23-100 ng/mL. The immunowall device with the enzyme-labeled antibody offers a rapid, sensitive, selective, and simple immunoassay system for future H5 AIV real sample detection.
- Published
- 2019
42. An Electrochemical Sensor Based on Structure Switching of Dithiol-modified Aptamer for Simple Detection of Ochratoxin A
- Author
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Masatoshi Maeki, Donny Nugraha Mazaafrianto, Hirofumi Tani, Akihiko Ishida, and Manabu Tokeshi
- Subjects
Aptamer ,Biosensing Techniques ,02 engineering and technology ,Electrochemistry ,01 natural sciences ,Signal ,Analytical Chemistry ,chemistry.chemical_compound ,microfabricated device ,Limit of Detection ,signal-on ,Dithiol ,Detection limit ,Base Sequence ,Chemistry ,010401 analytical chemistry ,aptamer ,Aptamers, Nucleotide ,021001 nanoscience & nanotechnology ,Ochratoxins ,Combinatorial chemistry ,0104 chemical sciences ,Electrochemical gas sensor ,Dissociation constant ,electrochemical detection ,Electrode ,methylene blue ,0210 nano-technology ,ochratoxin A ,Toluene - Abstract
In this study, we developed an electrochemical sensor for ochratoxin A (OTA) by using an aptamer having a dithiol-based anchor, which exhibited higher stability on a gold electrode than a monothiol-based aptamer because of its two anchors. The sensor was also based on a signal-on scheme that produces a signal current resulting from structure-switching of the aptamer upon interaction with OTA. For simple fabrication of this sensor, the non-covalent interaction of methylene blue with the aptamer was also employed as an electrochemical indicator. In this study, the performance of the sensor, including the dissociation constant of the aptamer-OTA complex, was characterized. The proposed sensor exhibited high reproducibility and enough sensitivity to detect the minimum amount of OTA required for the analysis of real food samples with a limit of detection of 113 pM.
- Published
- 2019
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43. A Concentric Ring Electrode for a Wall‐jet Cell in a Microfluidic Device
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Koki Hoshikawa, Masatoshi Maeki, Keine Nishiyama, Hirofumi Tani, Manabu Tokeshi, and Akihiko Ishida
- Subjects
Jet (fluid) ,Materials science ,business.industry ,Electrode ,Microfluidics ,Electrochemistry ,Optoelectronics ,business ,Concentric ring ,Analytical Chemistry - Published
- 2019
- Full Text
- View/download PDF
44. Sensitive fluorescent polarization immunoassay by optimizing synchronization mismatch condition
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Hirofumi Tani, Akihiko Ishida, Osamu Wakao, Masatoshi Maeki, Manabu Tokeshi, and Akihide Hibara
- Subjects
Image sampling ,Materials science ,Dynamic range ,System of measurement ,Fluorescent polarization ,Metals and Alloys ,Image processing ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Synchronization ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Liquid crystal ,Materials Chemistry ,Electrical and Electronic Engineering ,Image sensor ,0210 nano-technology ,Biological system ,Instrumentation - Abstract
Fluorescence polarization (FP) is a one of the measurement techniques to study molecular interactions. We previously developed our own FP measurement system based on synchronization detection that uses a liquid crystal layer and an image sensor. The measurement cycle was fixed to 100 without any theoretical considerations, however, the influence of the synchrony and measurement cycles for FP values should be considered. In the present paper, we carried out an experimental and theoretical investigation into the influence of the synchrony between liquid crystal operation and image sampling for FP values of our system. When there was synchronization mismatch, the experimental FP values obtained using fluorescein ethylene glycol solution and the theoretical FP values changed according to the number of measurement cycles. Additionally, we measured the FP immunoassay for a physiologically active substance under synchronization mismatch. The synchronization mismatch influenced the measurement performance of the system, indicating that optimization of the number of image samplings was necessary to improve the measurement performance. For instance, the Mismatch 0.99 case, the measurement cycle should be 50 cycle judging from its dynamic range and R-square (R2). From the investigation, we obtained theoretical and experimental knowledge on FP response to facilitate further applications of our FP system.
- Published
- 2019
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- View/download PDF
45. Ultrasensitive detection of disease biomarkers using an immuno-wall device with enzymatic amplification
- Author
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Masatoshi Maeki, Toshihiro Kasama, Yoshinobu Baba, Daisuke Onoshima, Koya Ishikawa, Akihiko Ishida, Keine Nishiyama, Manabu Tokeshi, Seiya Nakamata, Hirofumi Tani, and Hiroshi Yukawa
- Subjects
Streptavidin ,02 engineering and technology ,01 natural sciences ,Biochemistry ,Analytical Chemistry ,Mice ,chemistry.chemical_compound ,Limit of Detection ,Lab-On-A-Chip Devices ,Electrochemistry ,medicine ,Animals ,Humans ,Environmental Chemistry ,Spectroscopy ,Fluorescent Dyes ,Immunoassay ,Detection limit ,Microchannel ,Chromatography ,biology ,medicine.diagnostic_test ,Chemistry ,Goats ,010401 analytical chemistry ,Microfluidic Analytical Techniques ,Alkaline Phosphatase ,021001 nanoscience & nanotechnology ,Orders of magnitude (mass) ,0104 chemical sciences ,C-Reactive Protein ,Biotinylation ,biology.protein ,Acridines ,Biomarker (medicine) ,Rabbits ,Antibody ,0210 nano-technology ,Antibodies, Immobilized ,Biomarkers - Abstract
We present an ultrasensitive immunoassay system for disease biomarkers utilizing the immuno-wall device and an enzymatic amplification reaction. The immuno-wall device consisted of 40 microchannels, each of which contained an antibody-modified wall-like structure along the longitudinal axis of the microchannel. The wall was fabricated with a water-soluble photopolymer containing streptavidin by photolithography, and biotinylated capture antibodies were immobilized on the sides through streptavidin-biotin interaction. For an assay, introducing the target biomarker and secondary and labeled antibodies produced a sandwich complex anchored on the sides of the wall. A conventional immuno-wall device uses a fluorescence-labeled antibody as a labeling antibody. To achieve an ultrasensitive detection of a trace biomarker, we used an enzyme label and amplified the signal with the enzymatic reaction with a fluorogenic substrate in the microchannel. The highest signal/background ratio was obtained by using alkaline phosphatase-labeled antibody and 9H-(1,3-dichloro-9,9-dimethylacridin-2-one-7-yl) phosphate. To evaluate the device performance, we detected human C-reactive protein (CRP) as a model biomarker. The detection limit (LOD) of CRP in phosphate-buffered saline was 2.5 pg mL-1 with a sample volume of 0.25 μL. This LOD was approximately 3 orders of magnitude lower than that obtained with fluorescent-dye (DyLight 650)-labeled antibody. In addition, the present device provided a wide detection range of 0.0025-10 ng mL-1 for CRP. We successfully developed an ultrasensitive immunoassay system with simple operation and only a small sample volume.
- Published
- 2019
- Full Text
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46. High-throughput fluorescence polarization immunoassay by using a portable fluorescence polarization imaging analyzer
- Author
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Masatoshi Maeki, Ayano Nakamura, Mikhail A. Proskurnin, Ken Sumiyoshi, Akihide Hibara, Fumio Kurosawa, Akihiko Ishida, Polina A. Galkina, Manabu Tokeshi, Keine Nishiyama, Koji Shigemura, Ken Satou, Osamu Wakao, and Hirofumi Tani
- Subjects
Spectrum analyzer ,Molecular interactions ,Materials science ,010401 analytical chemistry ,Biomedical Engineering ,Analytical chemistry ,Bioengineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Sample volume ,Independent samples ,Fluorescence polarization immunoassay ,0210 nano-technology ,Throughput (business) ,Fluorescence anisotropy - Abstract
High-throughput fluorescence polarization immunoassays (FPIAs) for mycotoxin were conducted using a portable FP analyzer with a microdevice. Simultaneous FPIA measurements for 8 different deoxynivalenol (DON) concentrations in 12 chambers (total of 96 samples) and high-throughput FPIA measurements for single DON concentrations in more than 500 chambers were conducted. The results indicated that simultaneous FPIAs for 96 independent samples and for 500 samples were possible by FP imaging. The FP analyzer has a size of 65 cm (W 35 cm × D 15 cm × H 15 cm) and costs less than $5000. The sample volume was 1 nL. Furthermore, it is expected that sample reaction and FP detection can be automatically conducted with the analyzer by changing the microdevice and the software. Its features such as low cost and portability will contribute to on-site measurement and point-of-care testing. Additionally, the high-throughput feature will contribute to the study of molecular interactions based on FP measurements.
- Published
- 2019
- Full Text
- View/download PDF
47. Active navigation landmarks for a service robot in a home environment.
- Author
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Kentaro Ishii, Akihiko Ishida, Greg Saul, Masahiko Inami, and Takeo Igarashi
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- 2010
- Full Text
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48. Three-dimensional, symmetrically assembled microfluidic device for lipid nanoparticle production
- Author
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Hideyoshi Harashima, Manabu Tokeshi, Kosuke Sasaki, Akihiko Ishida, Masatoshi Maeki, Yusuke Sato, Hirofumi Tani, and Niko Kimura
- Subjects
Preparation method ,Biodistribution ,Materials science ,Homogeneous ,General Chemical Engineering ,Drug delivery ,Slow rate ,Microfluidics ,Nanoparticle ,Nanotechnology ,General Chemistry ,Nanoparticle Production - Abstract
Sub 100 nm-sized lipid nanoparticles (LNPs) have been widely used in drug delivery systems (DDSs). The size of the LNPs is an important parameter for the DDS performance, such as biodistribution and gene silencing using siRNAs. However, the LNPs prepared by the conventional preparation method show a wide size distribution. To improve the LNP size distribution, we developed a microfluidic device, named the iLiNP™ device, in a previous study. This device could produce LNPs in the size range of 20 to 150 nm, but the size distribution of the large-sized LNPs needs to be further improved. From the viewpoint of the LNP formation process, a homogeneous and slow rate dilution of ethanol plays an important role in improving the large-size LNP size distribution. In this study, we developed a three-dimensional, symmetrically assembled microfluidic device named the 3D-iLiNP device with the aim of precise size control of large-sized LNPs. We designed the 3D-iLiNP device using a computational fluid dynamics simulation and demonstrated that the 3D-iLiNP device can improve the LNP size distribution. The gene silencing activity of four kinds of siRNA-loaded LNPs was investigated via in vitro and in vivo experiments to elucidate the effect of the LNP size distribution. The results revealed that the LNPs with a size between 90 and 120 nm showed higher gene silencing activity than those with other sizes. The 3D-iLiNP device is expected to improve DDS performance by precisely controlling the size of LNPs.
- Published
- 2020
49. Development of a Microfluidic-Based Post-Treatment Process for Size-Controlled Lipid Nanoparticles and Application to siRNA Delivery
- Author
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Yusuke Sato, Masatoshi Maeki, Hirofumi Tani, Manabu Tokeshi, Akihiko Ishida, Niko Kimura, and Hideyoshi Harashima
- Subjects
Liposome ,Mice, Inbred ICR ,Materials science ,Microscopy, Confocal ,Organic solvent ,Microfluidics ,Nanoparticle ,Nanotechnology ,Factor VII ,Transfection ,Lipids ,Mice ,Cholesterol ,Scientific method ,Hepatocytes ,Phosphatidylcholines ,Animals ,Nanoparticles ,General Materials Science ,RNA Interference ,Post treatment ,RNA, Small Interfering - Abstract
Microfluidic methodologies for preparation of lipid nanoparticles (LNPs) based on an organic solvent injection method enable precise size control of the LNPs. After preparation of LNPs, the organic solvent injection method needs some post-treatments, such as overnight dialysis or direct dilution with a buffer solution. LNP production using the microfluidic-based organic solvent injection method is dominated by kinetics rather than thermodynamics. Kinetics of ethanol removal from the inner and outer membranes of LNPs could induce a structural change in the membrane that could lead to fusion of LNPs. However, the effects of microfluidic post-treatment on the final size of LNPs have not been sufficiently understood. Herein, we investigated the effect of the post-treatment processes on the final product size of LNPs in detail. A simple baffle device and a model lipid system composed of a neutral phospholipid (1-palmitoyl-2-oleoyl
- Published
- 2020
50. Electrochemical enzyme-based blood ATP and lactate sensor for a rapid and straightforward evaluation of illness severity
- Author
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Hiroshi Kido, Ryohei Mizukami, Keine Nishiyama, Junji Chida, Akihiko Ishida, Shizuka Kuki, Hirofumi Tani, Manabu Tokeshi, and Masatoshi Maeki
- Subjects
chemistry.chemical_classification ,Immobilized enzyme ,Chemistry ,Patient Acuity ,Biomedical Engineering ,Biophysics ,Adenylate kinase ,Biosensing Techniques ,General Medicine ,Potentiostat ,chemistry.chemical_compound ,Adenosine Triphosphate ,Enzyme ,Biochemistry ,Intensive care ,Electrochemistry ,Pyruvate oxidase ,Humans ,Lactic Acid ,Hydrogen peroxide ,Electrodes ,Pyruvate kinase ,Biotechnology - Abstract
This study aimed to develop an electrochemical system for measuring blood ATP and lactate levels in a single format. The ratio of ATP to lactate levels was previously reported to provide an alternative illness severity score. Although severity evaluation is crucial to treat patients with acute disease admitted to intensive care units, no sensors are currently available to simply and rapidly measure ATP and lactate levels using the same detection method. Therefore, we constructed an integrated sensing system for ATP and lactate using enzymatic reactions and two sets of electrodes integrated into a chip connected to a single potentiostat operated by a microcontroller. The enzymatic system involves adenylate kinase, pyruvate kinase, and pyruvate oxidase for ATP, and lactate oxidase for lactate, both of which produce hydrogen peroxide. Multiplex enzyme-based reactions were designed to minimize the corresponding operations significantly without enzyme immobilization onto the electrodes. The system was robust in the presence of potentially interfering blood components, such as ascorbate, pyruvate, ADP, urate, and potassium ions. The ATP and lactate levels in the blood were successfully measured using the new sensor with good recoveries. The analytical results of blood samples obtained using our sensor were in good agreement with those using conventional methods. Integrating electrode-based analysis and a microcontroller-based system saved further operations, enabling the straightforward measurement of ATP and lactate levels within 5 min. The proposed sensor may serve as a useful tool in the management of serious infectious diseases.
- Published
- 2022
- Full Text
- View/download PDF
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