1
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Sakaibara M, Yamamoto H, Murota H, Monma N, Sato S, Hirano-Iwata A. Enhanced responses to inflammatory cytokine interleukin-6 in micropatterned networks of cultured cortical neurons. Biochem Biophys Res Commun 2024; 695:149379. [PMID: 38159413 DOI: 10.1016/j.bbrc.2023.149379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 12/09/2023] [Indexed: 01/03/2024]
Abstract
Cortical neurons in dissociated cultures are an indispensable model system for pharmacological research that provides insights into chemical responses in well-defined environments. However, cortical neurons plated on homogeneous substrates develop an unstructured network that exhibits excessively synchronized activity, which occasionally masks the consequences induced by external substances. Here, we show that hyperactivity and excessive synchrony in cultured cortical networks can be effectively suppressed by growing neurons in microfluidic devices. These devices feature a hierarchically modular design that resembles the in vivo network. We focused on interleukin-6, a pro-inflammatory cytokine, and assessed its acute and chronic effects. Fluorescence calcium imaging of spontaneous neural activity for up to 20 days of culture showed detectable modulation of collective activity events and neural correlation in micropatterned neurons, which was not apparent in neurons cultured on homogeneous substrates. Our results indicate that engineered neuronal networks provide a unique platform for detecting and understanding the fundamental effects of biochemical compounds on neuronal networks.
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Affiliation(s)
- Mamoru Sakaibara
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan; Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Hideaki Yamamoto
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan; Graduate School of Engineering, Tohoku University, Sendai, Japan.
| | - Hakuba Murota
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan; Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Nobuaki Monma
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan; Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Shigeo Sato
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan; Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Ayumi Hirano-Iwata
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan; Graduate School of Engineering, Tohoku University, Sendai, Japan; Advanced Institute for Materials Research, Tohoku University, Sendai, Japan; Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
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2
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Mokudai T, Kawada M, Tadaki D, Hirano-Iwata A, Kanetaka H, Fujimori H, Takemoto E, Niwano M. Radical generation and bactericidal activity of nanobubbles produced by ultrasonic irradiation of carbonated water. Ultrason Sonochem 2024; 103:106809. [PMID: 38364483 PMCID: PMC10879770 DOI: 10.1016/j.ultsonch.2024.106809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 02/04/2024] [Accepted: 02/13/2024] [Indexed: 02/18/2024]
Abstract
Our previous study showed that nanobubbles (NBs) encapsulating CO2 gas have bactericidal activity due to reactive oxygen species (ROS) (Yamaguchi et al., 2020). Here, we report that bulk NBs encapsulating CO2 can be efficiently generated by ultrasonically irradiating carbonated water using a piezoelectric transducer with a frequency of 1.7 MHz. The generated NBs were less than 100 nm in size and had a lifetime of 500 h. Furthermore, generation of ROS in the NB suspension was investigated using electron spin resonance spectroscopy and fluorescence spectrometry. The main ROS was found to be the hydroxyl radical, which is consistent with our previous observations. The bactericidal activity lasted for at least one week. Furthermore, a mist generated by atomizing the NB suspension with ultrasonic waves was confirmed to have the same bactericidal activity as the suspension itself. We believe that the strong, persistent bactericidal activity and radical generation phenomenon are unique to NBs produced by ultrasonic irradiation of carbonated water. We propose that entrapped CO2 molecules strongly interact with water at the NB interface to weaken the interface, and high-pressure CO2 gas erupts from this weakened interface to generate ROS with bactericidal activity.
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Affiliation(s)
- Takayuki Mokudai
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan; Joining and Welding Research Institute, Osaka University, Osaka 567-0047, Japan
| | - Michi Kawada
- Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Daisuke Tadaki
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Hiroyasu Kanetaka
- Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Hiroshi Fujimori
- Planning & Development Department, Takemoto Yohki Co., Ltd., Tokyo 111-0036, Japan
| | - Emiko Takemoto
- Planning & Development Department, Takemoto Yohki Co., Ltd., Tokyo 111-0036, Japan
| | - Michio Niwano
- Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan; Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan.
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3
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Niwano M, Ma T, Iwata K, Tadaki D, Yamamoto H, Kimura Y, Hirano-Iwata A. Two-dimensional water-molecule-cluster layers at nanobubble interfaces. J Colloid Interface Sci 2023; 652:1775-1783. [PMID: 37678082 DOI: 10.1016/j.jcis.2023.08.173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 08/18/2023] [Accepted: 08/27/2023] [Indexed: 09/09/2023]
Abstract
HYPOTHESIS Bulk nanobubbles (NBs) have high surface charge densities and long lifetimes. Despite several attempts to understand the lifetime of NBs, their interfacial layer structure remains unknown. It is hypothesized that a specific interfacial layer exists with a hydrogen bond network that stabilizes NBs. EXPERIMENTS In situ infrared reflectance-absorption spectroscopy and density functional theory were used to determine the interfacial layer structure of NBs. Furthermore, nuclear magnetic resonance spectroscopy was used to examine the interfacial layer hardness of bubbles filled with N2, O2, and CO2, which was expected to depend on the encapsulated gas species. FINDINGS The interfacial layer was composed of three-, four-, and five-membered ring clusters of water molecules. An interface model was proposed in which a two-dimensional layer of clusters with large electric dipole moments is oriented toward the endohedral gas, and the hydrophobic surface is adjacent to the free water. The interfacial layer hardness was dependent on the interaction with the gas (N2 > O2 > CO2), which supports the proposed interface model. These findings can be generalized to the structure of water at gas-water interfaces.
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Affiliation(s)
- Michio Niwano
- Laboratory for Nano-electronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi 980-8577, Japan.
| | - Teng Ma
- Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Kazuki Iwata
- Faculty of Comprehensive Management, Tohoku Fukushi University, Sendai, Miyagi 989-3201, Japan
| | - Daisuke Tadaki
- Laboratory for Nano-electronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Hideaki Yamamoto
- Laboratory for Nano-electronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Yasuo Kimura
- Department of Electric and Electronic Engineering, Tokyo University of Technology, Hachioji, Tokyo 192-0983, Japan
| | - Ayumi Hirano-Iwata
- Laboratory for Nano-electronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi 980-8577, Japan; Faculty of Comprehensive Management, Tohoku Fukushi University, Sendai, Miyagi 989-3201, Japan
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4
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Sato M, Hariyama M, Komiya M, Suzuki K, Tozawa Y, Yamamoto H, Hirano-Iwata A. Model-free idealization: Adaptive integrated approach for idealization of ion-channel currents. Biophys J 2023; 122:3959-3975. [PMID: 37634080 PMCID: PMC10560676 DOI: 10.1016/j.bpj.2023.08.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 04/21/2023] [Accepted: 08/24/2023] [Indexed: 08/28/2023] Open
Abstract
Single-channel electrophysiological recordings provide insights into transmembrane ion permeation and channel gating mechanisms. The first step in the analysis of the recorded currents involves an "idealization" process, in which noisy raw data are classified into two discrete levels corresponding to the open and closed states of channels. This provides valuable information on the gating kinetics of ion channels. However, the idealization step is often challenging in cases of currents with poor signal-to-noise ratios and baseline drifts, especially when the gating model of the target channel is not identified. We report herein on a highly robust model-free idealization method for achieving this goal. The algorithm, called adaptive integrated approach for idealization of ion-channel currents (AI2), is composed of Kalman filter and Gaussian mixture model clustering and functions without user input. AI2 automatically determines the noise reduction setting based on the degree of separation between the open and closed levels. We validated the method on pseudo-channel-current datasets that contain either computed or experimentally recorded noise. We also investigated the relationship between the noise reduction parameter of the Kalman filter and the cutoff frequency of the low-pass filter. The AI2 algorithm was then tested on actual experimental data for biological channels including gramicidin A, a voltage-gated sodium channel, and other unidentified channels. We compared the idealization results with those obtained by the conventional methods, including the 50%-threshold-crossing method.
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Affiliation(s)
- Madoka Sato
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi, Japan
| | - Masanori Hariyama
- Graduate School of Information Sciences, Tohoku University, Sendai, Miyagi, Japan.
| | - Maki Komiya
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, Japan
| | - Kae Suzuki
- Graduate School of Science and Engineering, Saitama University, Saitama, Japan; Epsilon Molecular Engineering, Inc, Open Innovation Center in Saitama University, Saitama, Japan
| | - Yuzuru Tozawa
- Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Hideaki Yamamoto
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, Japan
| | - Ayumi Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi, Japan; Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, Japan; Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, Miyagi, Japan.
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5
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Yamamoto H, Spitzner FP, Takemuro T, Buendía V, Murota H, Morante C, Konno T, Sato S, Hirano-Iwata A, Levina A, Priesemann V, Muñoz MA, Zierenberg J, Soriano J. Modular architecture facilitates noise-driven control of synchrony in neuronal networks. Sci Adv 2023; 9:eade1755. [PMID: 37624893 PMCID: PMC10456864 DOI: 10.1126/sciadv.ade1755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 07/21/2023] [Indexed: 08/27/2023]
Abstract
High-level information processing in the mammalian cortex requires both segregated processing in specialized circuits and integration across multiple circuits. One possible way to implement these seemingly opposing demands is by flexibly switching between states with different levels of synchrony. However, the mechanisms behind the control of complex synchronization patterns in neuronal networks remain elusive. Here, we use precision neuroengineering to manipulate and stimulate networks of cortical neurons in vitro, in combination with an in silico model of spiking neurons and a mesoscopic model of stochastically coupled modules to show that (i) a modular architecture enhances the sensitivity of the network to noise delivered as external asynchronous stimulation and that (ii) the persistent depletion of synaptic resources in stimulated neurons is the underlying mechanism for this effect. Together, our results demonstrate that the inherent dynamical state in structured networks of excitable units is determined by both its modular architecture and the properties of the external inputs.
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Affiliation(s)
- Hideaki Yamamoto
- Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Japan
- Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - F. Paul Spitzner
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Taiki Takemuro
- Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Japan
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Victor Buendía
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department of Computer Science, University of Tübingen, Tübingen, Germany
- Departamento de Electromagnetismo y Física de la Materia, Universidad de Granada, Granada, Spain
| | - Hakuba Murota
- Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Japan
- Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Carla Morante
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, Spain
- Universitat de Barcelona Institute of Complex Systems (UBICS), Barcelona, Spain
| | - Tomohiro Konno
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Shigeo Sato
- Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Japan
- Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Ayumi Hirano-Iwata
- Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Japan
- Graduate School of Engineering, Tohoku University, Sendai, Japan
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, Japan
| | - Anna Levina
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department of Computer Science, University of Tübingen, Tübingen, Germany
| | - Viola Priesemann
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
- Institute for the Dynamics of Complex Systems, University of Göttingen, Göttingen, Germany
| | - Miguel A. Muñoz
- Departamento de Electromagnetismo y Física de la Materia, Universidad de Granada, Granada, Spain
- Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, Granada, Spain
| | | | - Jordi Soriano
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, Spain
- Universitat de Barcelona Institute of Complex Systems (UBICS), Barcelona, Spain
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6
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Sumi T, Yamamoto H, Katori Y, Ito K, Moriya S, Konno T, Sato S, Hirano-Iwata A. Biological neurons act as generalization filters in reservoir computing. Proc Natl Acad Sci U S A 2023; 120:e2217008120. [PMID: 37307467 DOI: 10.1073/pnas.2217008120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 04/16/2023] [Indexed: 06/14/2023] Open
Abstract
Reservoir computing is a machine learning paradigm that transforms the transient dynamics of high-dimensional nonlinear systems for processing time-series data. Although the paradigm was initially proposed to model information processing in the mammalian cortex, it remains unclear how the nonrandom network architecture, such as the modular architecture, in the cortex integrates with the biophysics of living neurons to characterize the function of biological neuronal networks (BNNs). Here, we used optogenetics and calcium imaging to record the multicellular responses of cultured BNNs and employed the reservoir computing framework to decode their computational capabilities. Micropatterned substrates were used to embed the modular architecture in the BNNs. We first show that the dynamics of modular BNNs in response to static inputs can be classified with a linear decoder and that the modularity of the BNNs positively correlates with the classification accuracy. We then used a timer task to verify that BNNs possess a short-term memory of several 100 ms and finally show that this property can be exploited for spoken digit classification. Interestingly, BNN-based reservoirs allow categorical learning, wherein a network trained on one dataset can be used to classify separate datasets of the same category. Such classification was not possible when the inputs were directly decoded by a linear decoder, suggesting that BNNs act as a generalization filter to improve reservoir computing performance. Our findings pave the way toward a mechanistic understanding of information representation within BNNs and build future expectations toward the realization of physical reservoir computing systems based on BNNs.
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Affiliation(s)
- Takuma Sumi
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
- Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Hideaki Yamamoto
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
- School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Yuichi Katori
- Graduate School of Systems Information Science, Future University Hakodate, Hakodate 041-8655, Japan
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan
| | - Koki Ito
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
- School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Satoshi Moriya
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Tomohiro Konno
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Shigeo Sato
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
- School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Ayumi Hirano-Iwata
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
- Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579, Japan
- School of Engineering, Tohoku University, Sendai 980-8579, Japan
- World Premier International Research Center Initiative-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
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7
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Sato Y, Yamamoto H, Kato H, Tanii T, Sato S, Hirano-Iwata A. Microfluidic cell engineering on high-density microelectrode arrays for assessing structure-function relationships in living neuronal networks. Front Neurosci 2023; 16:943310. [PMID: 36699522 PMCID: PMC9868575 DOI: 10.3389/fnins.2022.943310] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 11/29/2022] [Indexed: 01/11/2023] Open
Abstract
Neuronal networks in dissociated culture combined with cell engineering technology offer a pivotal platform to constructively explore the relationship between structure and function in living neuronal networks. Here, we fabricated defined neuronal networks possessing a modular architecture on high-density microelectrode arrays (HD-MEAs), a state-of-the-art electrophysiological tool for recording neural activity with high spatial and temporal resolutions. We first established a surface coating protocol using a cell-permissive hydrogel to stably attach a polydimethylsiloxane microfluidic film on the HD-MEA. We then recorded the spontaneous neural activity of the engineered neuronal network, which revealed an important portrait of the engineered neuronal network-modular architecture enhances functional complexity by reducing the excessive neural correlation between spatially segregated modules. The results of this study highlight the impact of HD-MEA recordings combined with cell engineering technologies as a novel tool in neuroscience to constructively assess the structure-function relationships in neuronal networks.
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Affiliation(s)
- Yuya Sato
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan,Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Hideaki Yamamoto
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan,*Correspondence: Hideaki Yamamoto,
| | - Hideyuki Kato
- Faculty of Science and Technology, Oita University, Oita, Japan
| | - Takashi Tanii
- Faculty of Science and Engineering, Waseda University, Tokyo, Japan
| | - Shigeo Sato
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
| | - Ayumi Hirano-Iwata
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan,Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan,Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
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8
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Kageyama H, Ma T, Sato M, Komiya M, Tadaki D, Hirano-Iwata A. New Aspects of Bilayer Lipid Membranes for the Analysis of Ion Channel Functions. Membranes (Basel) 2022; 12:membranes12090863. [PMID: 36135882 PMCID: PMC9501126 DOI: 10.3390/membranes12090863] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/26/2022] [Accepted: 08/31/2022] [Indexed: 05/30/2023]
Abstract
The bilayer lipid membrane (BLM) is the main structural component of cell membranes, in which various membrane proteins are embedded. Artificially formed BLMs have been used as a platform in studies of the functions of membrane proteins, including various ion channels. In this review, we summarize recent advances that have been made on artificial BLM systems for the analysis of ion channel functions. We focus on two BLM-based systems, cell-membrane mimicry and four-terminal BLM systems. As a cell-membrane-mimicking system, an efficient screening platform for the evaluation of drug side effects that act on a cell-free synthesized channel has been developed, and its prospects for use in personalized medicine will be discussed. In the four-terminal BLMs, we introduce "lateral voltage" to BLM systems as a novel input to regulate channel activities, in addition to the traditional transmembrane voltages. Such state-of-the-art technologies and new system setups are predicted to pave the way for a variety of applications, in both fundamental physiology and in drug discovery.
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Affiliation(s)
- Hironori Kageyama
- Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Teng Ma
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Madoka Sato
- Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Maki Komiya
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Daisuke Tadaki
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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9
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Albrecht T, Cao XE, Chen D, Corva M, Edwards MA, Ewing A, Fornasaro S, Gooding JJ, Gundry L, Hirano-Iwata A, Jeffcoat G, Kamali AR, Kanoufi F, Lemay SG, Limani N, Linfield S, Liu X, Lu SM, Meloni GN, Tian Z, Tschulik K, Vakamulla Raghu SN, Wei H, Ying YL. Electrochemical data mining: from information to knowledge: general discussion. Faraday Discuss 2022; 233:58-76. [PMID: 35302149 DOI: 10.1039/d2fd90001g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Buckingham MA, Cao XE, Chang S, Chen HY, Chen Q, Chinnathambi S, Edwards MA, Fornasaro S, Gooding J, Hill C, Hirano-Iwata A, Kamali AR, Kanoufi F, Krause S, Kurihara K, Lemay SG, Linfield S, Liu X, Long YT, Lu SM, Ma H, Mao BW, Meloni GN, Menkin S, Minteer S, O'Neill S, Pandey P, Ren H, Slater B, Tian Z, Unwin P, Valavanis D, Walcarius A, Willets KK, Wu Y, Xiao L, Xu W, Yang W, Ying YL, Zhang Z. Emerging electrochemical methods at the nanointerface: general discussion. Faraday Discuss 2022; 233:257-282. [PMID: 35302154 DOI: 10.1039/d2fd90003c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Ma T, Sato M, Komiya M, Kanomata K, Watanabe T, Feng X, Miyata R, Tadaki D, Hirose F, Tozawa Y, Hirano-Iwata A. Lateral voltage as a new input for artificial lipid bilayer systems. Faraday Discuss 2021; 233:244-256. [PMID: 34874047 DOI: 10.1039/d1fd00045d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we propose lateral voltage as a new input for use in artificial lipid bilayer systems in addition to the commonly used transmembrane voltage. To apply a lateral voltage to bilayer lipid membranes, we fabricated electrode-equipped silicon and Teflon chips. The Si chips could be used for photodetector devices based on fullerene-doped lipid bilayers, and the Teflon chips were used in a study of the ion channel functions in the lipid bilayer. The findings indicate that the lateral voltage effectively regulates the transmembrane current, in both ion-channel-incorporated and fullerene-incorporated lipid bilayer systems, suggesting that the lateral voltage is a practicable and useful additional input for use in lipid bilayer systems.
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Affiliation(s)
- Teng Ma
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. .,Core Research Cluster, Tohoku University, 2-1-1 Katahirano, Aoba-ku, Sendai 980-8577, Japan
| | - Madoka Sato
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.,Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Maki Komiya
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Kensaku Kanomata
- Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan
| | - Takaya Watanabe
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.,Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Xingyao Feng
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Ryusuke Miyata
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.,Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Daisuke Tadaki
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Fumihiko Hirose
- Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan
| | - Yuzuru Tozawa
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama-shi, Saitama 338-8570, Japan
| | - Ayumi Hirano-Iwata
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. .,Core Research Cluster, Tohoku University, 2-1-1 Katahirano, Aoba-ku, Sendai 980-8577, Japan.,Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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12
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Yamaguchi M, Ma T, Tadaki D, Hirano-Iwata A, Watanabe Y, Kanetaka H, Fujimori H, Takemoto E, Niwano M. Bactericidal Activity of Bulk Nanobubbles through Active Oxygen Species Generation. Langmuir 2021; 37:9883-9891. [PMID: 34339599 DOI: 10.1021/acs.langmuir.1c01578] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We investigated the bactericidal activity of bulk nanobubbles (NBs) using E. coli, a model bacterium. Bulk NBs were produced by forcing gas through a porous alumina membrane with an ordered arrangement of nanoscale straight holes in contact with water. NBs with different gas contents, including CO2, O2, and N2, were generated and evaluated for their bactericidal effects. The survival rate of E. coli was significantly reduced in a suspension of CO2-containing NB (CO2-NB water). The N2-NB water demonstrated a small amount of bactericidal behavior, but its impact was not as significant as that of CO2-NB water. When E. coli was retained in O2-NB water, the survival rate was even higher than that in pure water (PW). We investigated the generation of reactive oxygen species (ROS) in NB suspensions by electron spin resonance spectroscopy. The main ROS generated in the NB water were hydroxyl radicals and OH·, and the production of ROS was the strongest in CO2-NB water, which was consistent with the results of the bactericidal effect measurements. We assumed that NB mediated by ROS would exhibit bactericidal behavior and proposed a kinetic model to explain the retention time variation of the survival rate. The results calculated based on the proposed model matched closely with the experimental results.
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Affiliation(s)
| | - Teng Ma
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan
| | - Daisuke Tadaki
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | | | - Hiroyasu Kanetaka
- Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Hiroshi Fujimori
- Planning & Development Department, Takemoto Yohki Co., Ltd., Tokyo 111-0036, Japan
| | - Emiko Takemoto
- Planning & Development Department, Takemoto Yohki Co., Ltd., Tokyo 111-0036, Japan
| | - Michio Niwano
- Tohoku Fukushi University, Sendai 989-3201, Japan
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
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13
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Ma T, Sato M, Komiya M, Feng X, Tadaki D, Hirano-Iwata A. Advances in Artificial Bilayer Lipid Membranes as a Novel Biosensing Platform: From Drug-screening to Self-assembled Devices. CHEM LETT 2021. [DOI: 10.1246/cl.200764] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Teng Ma
- Advanced Institute for Materials Research (WPI-AIMR), 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Madoka Sato
- Research Institute of Electrical Communication (RIEC), 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Maki Komiya
- Research Institute of Electrical Communication (RIEC), 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Xingyao Feng
- Research Institute of Electrical Communication (RIEC), 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Daisuke Tadaki
- Research Institute of Electrical Communication (RIEC), 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Advanced Institute for Materials Research (WPI-AIMR), 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
- Research Institute of Electrical Communication (RIEC), 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
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14
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Yoshino T, Yamaura D, Komiya M, Sugawara M, Mitsumori Y, Niwano M, Hirano-Iwata A, Edamatsu K, Sadgrove M. Optical transport of sub-micron lipid vesicles along a nanofiber. Opt Express 2020; 28:38527-38538. [PMID: 33379421 DOI: 10.1364/oe.411124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
Enhanced manipulation and analysis of bio-particles using light confined in nano-scale dielectric structures has proceeded apace in the last several years. Small mode volumes, along with the lack of a need for bulky optical elements give advantages in sensitivity and scalability relative to conventional optical manipulation. However, manipulation of lipid vesicles (liposomes) remains difficult, particularly in the sub-micron diameter regime. Here we demonstrate the optical trapping and transport of sub-micron diameter liposomes along an optical nanofiber using the nanofiber mode's evanescent field. We find that nanofiber diameters below a nominal diffraction limit give optimal results. Our results pave the way for integrated optical transport and analysis of liposome-like bio-particles, as well as their coupling to nano-optical resonators.
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15
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Yamaguchi M, Abe H, Ma T, Tadaki D, Hirano-Iwata A, Kanetaka H, Watanabe Y, Niwano M. Bactericidal Activity of TiO 2 Nanotube Thin Films on Si by Photocatalytic Generation of Active Oxygen Species. Langmuir 2020; 36:12668-12677. [PMID: 33105996 DOI: 10.1021/acs.langmuir.0c02225] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The photocatalytic bactericidal activity of titanium dioxide (TiO2) thin films has been extensively studied. In this study, we investigated the bactericidal activities of TiO2 nanotube (NT) thin films using Escherichia coli and Staphylococcus aureus cells as the model bacteria. Metallic titanium (Ti) thin films were anodized on a silicon (Si) wafer substrate to form TiO2 NT thin films. To evaluate the bactericidal activity of the TiO2 NT thin films, bacteria on the TiO2 NT thin films were irradiated with near-ultraviolet light (UV-A) at a wavelength of 365 nm. The bactericidal activity was estimated by the survival rate derived from the number of live cells, which form colonies on the cell culture medium. We demonstrated that the survival rate of the two types of bacteria investigated in this study was significantly reduced by UV light irradiation and that there was a difference in the temporal change in the survival rate between the two types of bacteria. Furthermore, we investigated the generation of reactive oxygen species (ROSs) by UV light irradiation of TiO2 NT thin films using electron spin resonance spectroscopy and fluorescence analysis. We found that the main ROS generated on the surface of the TiO2 NT film was the hydroxyl radical, OH•. In addition, the generation of ROSs increased with an increase in the UV irradiation time. We proposed a kinetic model that reproduces the dependence of bacterial viability on the UV light irradiation time by considering the temporal change in the amount of ROSs generated by UV light irradiation. A comparison of the calculated and experimental results revealed that the bactericidal effect consisted of the direct photolysis of bacteria and the photocatalysis via the generation of hydroxyl radicals, with the latter exhibiting a stronger bactericidal effect than the former.
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Affiliation(s)
- Masato Yamaguchi
- Kansei Fukushi Research Institute, Tohoku Fukushi University, Sendai 989-3201, Japan
| | - Hiroyuki Abe
- Industrial Technology Institute, Miyagi Prefectural Government, Sendai 981-3206, Japan
| | - Teng Ma
- Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
| | - Daisuke Tadaki
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Hiroyasu Kanetaka
- Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Yoshihiko Watanabe
- Kansei Fukushi Research Institute, Tohoku Fukushi University, Sendai 989-3201, Japan
| | - Michio Niwano
- Kansei Fukushi Research Institute, Tohoku Fukushi University, Sendai 989-3201, Japan
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16
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Hattori K, Hayakawa T, Nakanishi A, Ishida M, Yamamoto H, Hirano-Iwata A, Tanii T. Contribution of AMPA and NMDA receptors in the spontaneous firing patterns of single neurons in autaptic culture. Biosystems 2020; 198:104278. [PMID: 33075473 DOI: 10.1016/j.biosystems.2020.104278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 10/11/2020] [Accepted: 10/14/2020] [Indexed: 10/23/2022]
Abstract
Single neurons in an autaptic culture exhibit various types of firing pattern with different firing durations and rhythms. However, a neuron with autapses has often been modeled as an oscillator providing a monotonic firing pattern with a constant periodicity because of the lack of a mathematical model. In the work described in this study, we use computational simulation and whole-cell patch-clamp recording to elucidate and model the mechanism by which such neurons generate various firing pattens. In the computational simulation, three types of spontaneous firing pattern, i.e., short, long-lasting, and periodic burst firing patterns are realized by changing the combination ratio of N-methyl-d-aspartate (NMDA) to α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) conductance. These three types of firing patterns are also observed in the experiments where neurons are cultured in isolation on micropatterned substrates. Using the AMPA and NMDA current models, we discuss that, in principle, autapses can regulate rhythmicity and information selection in neuronal networks.
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Affiliation(s)
- Kouhei Hattori
- Waseda University, Faculty of Science and Engineering, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.
| | - Takeshi Hayakawa
- Tohoku University, Research Institute of Electrical Communication, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| | - Akira Nakanishi
- Waseda University, Faculty of Science and Engineering, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
| | - Mihoko Ishida
- Waseda University, Faculty of Science and Engineering, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
| | - Hideaki Yamamoto
- Tohoku University, Research Institute of Electrical Communication, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Tohoku University, Research Institute of Electrical Communication, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan; Tohoku University, WPI-Advanced Institute for Materials Research (WPI-AIMR), 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| | - Takashi Tanii
- Waseda University, Faculty of Science and Engineering, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
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17
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Suzuki K, Inoue H, Matsuoka S, Tero R, Hirano-Iwata A, Tozawa Y. Establishment of a cell-free translation system from rice callus extracts. Biosci Biotechnol Biochem 2020; 84:2028-2036. [PMID: 32543982 DOI: 10.1080/09168451.2020.1779024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Eukaryotic in vitro translation systems require large numbers of protein and RNA components and thereby rely on the use of cell extracts. Here we established a new in vitro translation system based on rice callus extract (RCE). We confirmed that RCE maintains its initial activity even after five freeze-thaw cycles and that the optimum temperature for translation is around 20°C. We demonstrated that the RCE system allows the synthesis of hERG, a large membrane protein, in the presence of liposomes. We also showed that the introduction of a bicistronic mRNA based on 2A peptide to RCE allowed the production of two distinct proteins from a single mRNA. Our new method thus facilitates laboratory-scale production of cell extracts, making it a useful tool for the in vitro synthesis of proteins for biochemical studies.
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Affiliation(s)
- Kakeru Suzuki
- Graduate School of Science and Engineering, Saitama University , Saitama, Japan
| | - Haruka Inoue
- Graduate School of Science and Engineering, Saitama University , Saitama, Japan
| | - Satoshi Matsuoka
- Graduate School of Science and Engineering, Saitama University , Saitama, Japan
| | - Ryugo Tero
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology , Toyohashi, Japan
| | - Ayumi Hirano-Iwata
- Advanced Institute for Materials Research, Tohoku University , Sendai, Japan
| | - Yuzuru Tozawa
- Graduate School of Science and Engineering, Saitama University , Saitama, Japan
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18
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Ma T, Kimura Y, Yamamoto H, Feng X, Hirano-Iwata A, Niwano M. Characterization of Bulk Nanobubbles Formed by Using a Porous Alumina Film with Ordered Nanopores. J Phys Chem B 2020; 124:5067-5072. [DOI: 10.1021/acs.jpcb.0c02279] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Teng Ma
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Yasuo Kimura
- Faculty of Engineering, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo 192-0914, Japan
| | - Hideaki Yamamoto
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Xingyao Feng
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Michio Niwano
- Kansei Fukushi Research Institute, Tohoku Fukushi University, 149-1 Kunimi-ga-oka, Aoba-ku, Sendai 989-3201, Japan
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19
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Feng X, Ma T, Tadaki D, Hirano-Iwata A. Self-Assembly of Hybrid Lipid Membranes Doped with Hydrophobic Organic Molecules at the Water/Air Interface. J Vis Exp 2020. [PMID: 32421002 DOI: 10.3791/60957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Because of their unique properties, including an ultrathin thickness (3-4 nm), ultrahigh resistivity, fluidity and self-assembly ability, lipid bilayers can be readily functionalized and have been used in various applications such as bio-sensors and bio-devices. In this study, we introduced a planar organic molecule: copper (II) 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (CuPc) to dope lipid membranes. The CuPc/lipid hybrid membrane forms at the water/air interface by self-assembly. In this membrane, the hydrophobic CuPc molecules are located between the hydrophobic tails of lipid molecules, forming a lipid/CuPc/lipid sandwich structure. Interestingly, an air-stable hybrid lipid bilayer can be readily formed by transferring the hybrid membrane onto a Si substrate. We report a straightforward method for incorporating nanomaterials into a lipid bilayer system, which represents a new methodology for the fabrication of biosensors and biodevices.
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Affiliation(s)
- Xingyao Feng
- Research Institute of Electrical Communication, Tohoku University
| | - Teng Ma
- Advanced Institute for Materials Research, Tohoku University;
| | - Daisuke Tadaki
- Research Institute of Electrical Communication, Tohoku University
| | - Ayumi Hirano-Iwata
- Research Institute of Electrical Communication, Tohoku University; Advanced Institute for Materials Research, Tohoku University
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20
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Sumi T, Yamamoto H, Hirano-Iwata A. Suppression of hypersynchronous network activity in cultured cortical neurons using an ultrasoft silicone scaffold. Soft Matter 2020; 16:3195-3202. [PMID: 32096811 DOI: 10.1039/c9sm02432h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The spontaneous activity pattern of cortical neurons in dissociated culture is characterized by burst firing that is highly synchronized among a wide population of cells. The degree of synchrony, however, is excessively higher than that in cortical tissues. Here, we employed polydimethylsiloxane (PDMS) elastomers to establish a novel system for culturing neurons on a scaffold with an elastic modulus resembling brain tissue, and investigated the effect of the scaffold's elasticity on network activity patterns in cultured rat cortical neurons. Using whole-cell patch clamp to assess the scaffold effect on the development of synaptic connections, we found that the amplitude of excitatory postsynaptic current, as well as the frequency of spontaneous transmissions, was reduced in neuronal networks grown on an ultrasoft PDMS with an elastic modulus of 0.5 kPa. Furthermore, the ultrasoft scaffold was found to suppress neural correlations in the spontaneous activity of the cultured neuronal network. The dose of GsMTx-4, an antagonist of stretch-activated cation channels (SACs), required to reduce the generation of the events below 1.0 event per min on PDMS substrates was lower than that for neurons on a glass substrate. This suggests that the difference in the baseline level of SAC activation is a molecular mechanism underlying the alteration in neuronal network activity depending on scaffold stiffness. Our results demonstrate the potential application of PDMS with biomimetic elasticity as cell-culture scaffold for bridging the in vivo-in vitro gap in neuronal systems.
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Affiliation(s)
- Takuma Sumi
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
| | - Hideaki Yamamoto
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. and WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. and WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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21
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Ma T, Feng X, Ohori T, Miyata R, Tadaki D, Yamaura D, Deguchi T, Komiya M, Kanomata K, Hirose F, Niwano M, Hirano-Iwata A. Modulation of Photoinduced Transmembrane Currents in a Fullerene-Doped Freestanding Lipid Bilayer by a Lateral Bias. ACS Omega 2019; 4:18299-18303. [PMID: 31720530 PMCID: PMC6844088 DOI: 10.1021/acsomega.9b02336] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/10/2019] [Indexed: 06/01/2023]
Abstract
We report on a novel lipid bilayer system, in which a lateral bias can be applied in addition to a conventional transmembrane voltage. Freestanding bilayer lipid membranes (BLMs) doped with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) were formed in a microaperture, around which metal electrodes were deposited. Using this system, it was possible to modulate and amplify photoinduced transmembrane currents by applying a lateral bias along the BLM. The results indicate that the microfabricated Si chip with embedded electrodes is a promising platform for the formation of transistor-like devices based on PCBM-doped BLMs and have potential for use in a wide variety of nanohybrid devices.
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Affiliation(s)
- Teng Ma
- Advanced
Institute for Materials Research (WPI-AIMR) and Research Institute
of Electrical Communication, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Xingyao Feng
- Advanced
Institute for Materials Research (WPI-AIMR) and Research Institute
of Electrical Communication, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Takeshi Ohori
- Advanced
Institute for Materials Research (WPI-AIMR) and Research Institute
of Electrical Communication, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Ryusuke Miyata
- Advanced
Institute for Materials Research (WPI-AIMR) and Research Institute
of Electrical Communication, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Daisuke Tadaki
- Advanced
Institute for Materials Research (WPI-AIMR) and Research Institute
of Electrical Communication, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Daichi Yamaura
- Advanced
Institute for Materials Research (WPI-AIMR) and Research Institute
of Electrical Communication, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Takafumi Deguchi
- Advanced
Institute for Materials Research (WPI-AIMR) and Research Institute
of Electrical Communication, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Maki Komiya
- Advanced
Institute for Materials Research (WPI-AIMR) and Research Institute
of Electrical Communication, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Kensaku Kanomata
- Graduate
School of Science and Engineering, Yamagata
University, 4-3-16 Jonan, Yonezawa 992-8510, Japan
| | - Fumihiko Hirose
- Graduate
School of Science and Engineering, Yamagata
University, 4-3-16 Jonan, Yonezawa 992-8510, Japan
| | - Michio Niwano
- Kansei
Fukushi Research Institute, Tohoku Fukushi
University, 6-149-1 Kunimi-ga-oka, Aoba-ku, Sendai, Miyagi 989-3201, Japan
| | - Ayumi Hirano-Iwata
- Advanced
Institute for Materials Research (WPI-AIMR) and Research Institute
of Electrical Communication, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
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22
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Feng X, Ma T, Yamaura D, Tadaki D, Hirano-Iwata A. Formation and Characterization of Air-Stable Lipid Bilayer Membranes Incorporated with Phthalocyanine Molecules. J Phys Chem B 2019; 123:6515-6520. [PMID: 31280566 DOI: 10.1021/acs.jpcb.9b05135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bilayer lipid membranes (BLMs) are used as basic frameworks for biosensors and biohybrid devices due to their unique properties, which include ultrathin thickness, ultrahigh resistivity, and self-assembling ability. However, BLMs can only form and maintain their structure in aqueous environments, which pose significant limitations to their use. In this work, we report on the formation of highly uniform hybrid BLMs at a water/air interface through self-assembly by simply doping the BLMs with a functional organic molecule, copper(II) 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (CuPc). By transferring the membrane onto substrates, we were able to produce stable hybrid BLMs under anhydrous conditions. Atomic force microscopy and X-ray diffraction measurements confirmed that the hybrid membranes were composed of single, highly uniform BLMs or stacks of BLMs. Fluorescence resonance energy transfer measurements indicated that the CuPc molecules were located between the hydrophobic tails of lipid molecules, forming a sandwich structure in the hybrid membranes. The hybrid BLMs fabricated by this method substantially expand the range of applications of BLMs to solid-state devices.
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23
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Yamamoto H, Grob L, Sumi T, Oiwa K, Hirano-Iwata A, Wolfrum B. Ultrasoft Silicone Gel as a Biomimetic Passivation Layer in Inkjet-Printed 3D MEA Devices. ACTA ACUST UNITED AC 2019; 3:e1900130. [PMID: 32648655 DOI: 10.1002/adbi.201900130] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 06/25/2019] [Indexed: 12/15/2022]
Abstract
Multielectrode arrays (MEAs) are versatile tools that are used for chronic recording and stimulation of neural cells and tissues. Driven by the recent progress in understanding of how neuronal growth and function respond to scaffold stiffness, development of MEAs with a soft cell-to-device interface has gained importance not only for in vivo but also for in vitro applications. However, the passivation layer, which constitutes the majority of the cell-device interface, is typically prepared with stiff materials. Herein, a fabrication of an MEA device with an ultrasoft passivation layer is described, which takes advantage of inkjet printing and a polydimethylsiloxane (PDMS) gel with a stiffness comparable to that of the brain. The major challenge in using the PDMS gel is that it cannot be patterned to expose the sensing area of the electrode. This issue is resolved by printing 3D micropillars at the electrode tip. Primary cortical neurons are grown on the fabricated device, and effective stimulation of the culture confirms functional cell-device coupling. The 3D MEA device with an ultrasoft interface provides a novel platform for investigating evoked activity and drug responses of living neuronal networks cultured in a biomimetic environment for both fundamental research and pharmaceutical applications.
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Affiliation(s)
- Hideaki Yamamoto
- WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.,Institute for Advanced Study, Technische Universität München, Lichtenbergstraße 2a, 85748, Garching, Germany
| | - Leroy Grob
- Munich School of BioengineeringDepartment of Electrical and Computer Engineering, Technische Universität München, Boltzmannstraße 11, 85748, Garching, Germany
| | - Takuma Sumi
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Kazuhiro Oiwa
- Advanced ICT Research Institute, National Institute of Information and Communication Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Ayumi Hirano-Iwata
- WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.,Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Bernhard Wolfrum
- Munich School of BioengineeringDepartment of Electrical and Computer Engineering, Technische Universität München, Boltzmannstraße 11, 85748, Garching, Germany
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24
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Kanomata K, Deguchi T, Ma T, Haseyama T, Miura M, Yamaura D, Tadaki D, Niwano M, Hirano-Iwata A, Hirose F. Photomodulation of electrical conductivity of a PCBM-doped free-standing lipid bilayer in buffer solution. J Electroanal Chem (Lausanne) 2019. [DOI: 10.1016/j.jelechem.2018.10.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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25
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Moriya S, Yamamoto H, Akima H, Hirano-Iwata A, Kubota S, Sato S. Mean-field analysis of directed modular networks. Chaos 2019; 29:013142. [PMID: 30709116 DOI: 10.1063/1.5044689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
We considered a modular network with a binomial degree distribution and related the analytical relationships of the network properties (modularity, average clustering coefficient, and small-worldness) with structural parameters that define the network, i.e., number of nodes, number of modules, average node degree, and ratio of intra-modular to total connections. Even though modular networks are universally found in real-world systems and are consequently of broad interest in complex network science, the relationship between network properties and structural parameters has not yet been formulated. Here, we show that a series of equations for predicting the network properties can be related using a mean-field connectivity matrix that is defined on the basis of the structural parameters in the network generation algorithm. The theoretical results are then compared with values calculated numerically using the original connectivity matrix and are found to agree well, except when the connections between modules are sparse. Representation of the structure of the network using simple parameters is expected to be conducive for elucidating the structure-dynamics relationship.
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Affiliation(s)
- Satoshi Moriya
- Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Hideaki Yamamoto
- WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Hisanao Akima
- Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Shigeru Kubota
- Graduate School of Science and Engineering, Yamagata University, Yonezawa, Yamagata 992-8510, Japan
| | - Shigeo Sato
- Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi 980-8577, Japan
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26
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Yamamoto H, Moriya S, Ide K, Hayakawa T, Akima H, Sato S, Kubota S, Tanii T, Niwano M, Teller S, Soriano J, Hirano-Iwata A. Impact of modular organization on dynamical richness in cortical networks. Sci Adv 2018; 4:eaau4914. [PMID: 30443598 PMCID: PMC6235526 DOI: 10.1126/sciadv.aau4914] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/16/2018] [Indexed: 05/02/2023]
Abstract
As in many naturally formed networks, the brain exhibits an inherent modular architecture that is the basis of its rich operability, robustness, and integration-segregation capacity. However, the mechanisms that allow spatially segregated neuronal assemblies to swiftly change from localized to global activity remain unclear. Here, we integrate microfabrication technology with in vitro cortical networks to investigate the dynamical repertoire and functional traits of four interconnected neuronal modules. We show that the coupling among modules is central. The highest dynamical richness of the network emerges at a critical connectivity at the verge of physical disconnection. Stronger coupling leads to a persistently coherent activity among the modules, while weaker coupling precipitates the activity to be localized solely within the modules. An in silico modeling of the experiments reveals that the advent of coherence is mediated by a trade-off between connectivity and subquorum firing, a mechanism flexible enough to allow for the coexistence of both segregated and integrated activities. Our results unveil a new functional advantage of modular organization in complex networks of nonlinear units.
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Affiliation(s)
- Hideaki Yamamoto
- WPI–Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan
- Corresponding author. (H.Y.); (J.S.)
| | - Satoshi Moriya
- Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Katsuya Ide
- Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Takeshi Hayakawa
- Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Hisanao Akima
- Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Shigeo Sato
- Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Shigeru Kubota
- Graduate School of Science and Engineering, Yamagata University, Yamagata 992-8510, Japan
| | - Takashi Tanii
- Faculty of Science and Engineering, Waseda University, Tokyo 169-8555, Japan
| | - Michio Niwano
- Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Sara Teller
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Catalonia, Spain
- Universitat de Barcelona Institute of Complex Systems (UBICS), Barcelona 08028, Catalonia, Spain
| | - Jordi Soriano
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Catalonia, Spain
- Universitat de Barcelona Institute of Complex Systems (UBICS), Barcelona 08028, Catalonia, Spain
- Corresponding author. (H.Y.); (J.S.)
| | - Ayumi Hirano-Iwata
- WPI–Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan
- Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577, Japan
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27
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Matsumura R, Yamamoto H, Hayakawa T, Katsurabayashi S, Niwano M, Hirano-Iwata A. Dependence and Homeostasis of Membrane Impedance on Cell Morphology in Cultured Hippocampal Neurons. Sci Rep 2018; 8:9905. [PMID: 29967389 PMCID: PMC6028398 DOI: 10.1038/s41598-018-28232-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 06/20/2018] [Indexed: 11/09/2022] Open
Abstract
The electrical impedance of cell membranes is important for excitable cells, such as neurons, because it strongly influences the amount of membrane potential change upon a flow of ionic current across the membrane. Here, we report on an investigation of how neuronal morphology affects membrane impedance of cultured hippocampal neurons. Microfabricated substrates with patterned scaffolding molecules were used to restrict the neurite growth of hippocampal neurons, and the impedance was measured via whole-cell patch-clamp recording under the inhibition of voltage-dependent ion channels. Membrane impedance was found to depend inversely on the dendrite length and soma area, as would be expected from the fact that its electrical property is equivalent to a parallel RC circuit. Moreover, we found that in biological neurons, the membrane impedance is homeostatically regulated to impede changes in the membrane area. The findings provide direct evidence on cell-autonomous regulation of neuronal impedance and pave the way towards elucidating the mechanism responsible for the resilience of biological neuronal networks.
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Affiliation(s)
- Ryosuke Matsumura
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-aza Aoba, Aoba-ku, Sendai, 980-8578, Japan.
- WPI-AIMR, Tohoku University, Sendai, Japan.
| | - Takeshi Hayakawa
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Shutaro Katsurabayashi
- Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan
| | - Michio Niwano
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- Kansei Fukushi Research Institute, Tohoku Fukushi University, 6-149-1 Kunimigaoka, Aoba-ku, Sendai, 989-3201, Japan
| | - Ayumi Hirano-Iwata
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
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28
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Ito K, Ogawa Y, Yokota K, Matsumura S, Minamisawa T, Suga K, Shiba K, Kimura Y, Hirano-Iwata A, Takamura Y, Ogino T. Host Cell Prediction of Exosomes Using Morphological Features on Solid Surfaces Analyzed by Machine Learning. J Phys Chem B 2018; 122:6224-6235. [PMID: 29771528 DOI: 10.1021/acs.jpcb.8b01646] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Exosomes are extracellular nanovesicles released from any cells and found in any body fluid. Because exosomes exhibit information of their host cells (secreting cells), their analysis is expected to be a powerful tool for early diagnosis of cancers. To predict the host cells, we extracted multidimensional feature data about size, shape, and deformation of exosomes immobilized on solid surfaces by atomic force microscopy (AFM). The key idea is combination of support vector machine (SVM) learning for individual exosome particles and their interpretation by principal component analysis (PCA). We observed exosomes derived from three different cancer cells on SiO2/Si, 3-aminopropyltriethoxysilane-modified-SiO2/Si, and TiO2 substrates by AFM. Then, 14-dimensional feature vectors were extracted from AFM particle data, and classifiers were trained in 14-dimensional space. The prediction accuracy for host cells of test AFM particles was examined by the cross-validation test. As a result, we obtained prediction of exosome host cells with the best accuracy of 85.2% for two-class SVM learning and 82.6% for three-class one. By PCA of the particle classifiers, we concluded that the main factors for prediction accuracy and its strong dependence on substrates are incremental decrease in the PCA-defined aspect ratio of the particles with their volume.
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Affiliation(s)
- Kazuki Ito
- Yokohama National University , 79-5, Tokiwadai , Hodogaya-ku, Yokohama 240-8501 , Japan
| | - Yuta Ogawa
- Yokohama National University , 79-5, Tokiwadai , Hodogaya-ku, Yokohama 240-8501 , Japan
| | - Keiji Yokota
- Yokohama National University , 79-5, Tokiwadai , Hodogaya-ku, Yokohama 240-8501 , Japan
| | - Sachiko Matsumura
- Japanese Foundation for Cancer Research , 3-8-31 Ariake , Koto-ku, Tokyo 135-8550 , Japan
| | - Tamiko Minamisawa
- Japanese Foundation for Cancer Research , 3-8-31 Ariake , Koto-ku, Tokyo 135-8550 , Japan
| | - Kanako Suga
- Japanese Foundation for Cancer Research , 3-8-31 Ariake , Koto-ku, Tokyo 135-8550 , Japan
| | - Kiyotaka Shiba
- Japanese Foundation for Cancer Research , 3-8-31 Ariake , Koto-ku, Tokyo 135-8550 , Japan
| | - Yasuo Kimura
- Tokyo University of Technology , 1404-1, Katakura-Cho , Hachioji 192-0914 , Japan
| | - Ayumi Hirano-Iwata
- Tohoku University , 2-1-1, Katahira , Aoba-ku, Sendai , Miyagi 980-8577 , Japan
| | - Yuzuru Takamura
- Japan Advanced Institute of Science and Technology , 1-1, Asahi-Dai , Nomi , Ishikawa 923-1292 , Japan
| | - Toshio Ogino
- Yokohama National University , 79-5, Tokiwadai , Hodogaya-ku, Yokohama 240-8501 , Japan.,Japan Advanced Institute of Science and Technology , 1-1, Asahi-Dai , Nomi , Ishikawa 923-1292 , Japan
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29
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Yamaura D, Tadaki D, Araki S, Yoshida M, Arata K, Ohori T, Ishibashi KI, Kato M, Ma T, Miyata R, Yamamoto H, Tero R, Sakuraba M, Ogino T, Niwano M, Hirano-Iwata A. Amphiphobic Septa Enhance the Mechanical Stability of Free-Standing Bilayer Lipid Membranes. Langmuir 2018; 34:5615-5622. [PMID: 29664647 DOI: 10.1021/acs.langmuir.8b00747] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Artificial bilayer lipid membranes (BLMs) provide well-defined systems for investigating the fundamental properties of membrane proteins, including ion channels, and for screening the effect of drugs that act on them. However, the application of this technique is limited due to the low stability and low reconstitution efficiency of the process. We previously reported on improving the stability of BLM based on the fabrication of microapertures having a tapered edge in SiO2/Si3N4 septa and efficient ion channel incorporation based on vesicle fusion accelerated by a centrifugal force. Although the BLM stability and incorporation probability were dramatically improved when these approaches were used, some BLMs were ruptured when subjected to a centrifugal force. To further improve the BLM stability, we investigated the effect of modifying the surface of the SiO2/Si3N4 septa on the stability of BLM suspended in the septa. The modified surfaces were characterized in terms of hydrophobicity, lipophobicity, and surface roughness. Diffusion coefficients of the lipid monolayers formed on the modified surfaces were also determined. Highly fluidic lipid monolayers were formed on the amphiphobic substrates that had been modified with long-chain perfluorocarbons. Free-standing BLMs formed in amphiphobic septa showed a much higher mechanical stability, including tolerance to water movement and applied centrifugal forces with and without proteoliposomes, than those formed in the septa that had been modified with a short alkyl chain. These results demonstrate that highly stable BLMs are formed when the surface of the septa has amphiphobic properties. Because highly fluidic lipid monolayers that are formed on the septa seamlessly connect with BLMs in a free-standing region, the high fluidity of the lipids contributes to decreasing potential damage to BLMs when mechanical stresses are applied. This approach to improve the BLM stability increases the experimental efficiency of the BLM systems and will contribute to the development of high-throughput platforms for functional assays of ion channel proteins.
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Affiliation(s)
| | | | | | | | | | | | - Ken-Ichi Ishibashi
- Hang-Ichi Corporation , 1-7-315 Honcho , Naka-ku, Yokohama , Kanagawa 231-0005 , Japan
| | | | | | | | - Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences , Tohoku University , 6-3 Aramaki-Aza-Aoba , Aoba-ku, Sendai , Miyagi 980-8578 , Japan
| | - Ryugo Tero
- Department of Environmental and Life Sciences , Toyohashi University of Technology , Toyohashi , Aichi 441-8580 , Japan
| | | | - Toshio Ogino
- The Instrumental Analysis Center , Yokohama National University , Tokiwadai 79-5 , Hodogaya-ku, Yokohama , Kanagawa 240-8501 , Japan
| | - Michio Niwano
- Kansei Fukushi Research Institute , Tohoku Fukushi University , 6-149-1 Kunimi-ga-oka , Aoba-ku, Sendai , Miyagi 989-3201 , Japan
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30
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Yamamoto H, Kubota S, Shimizu FA, Hirano-Iwata A, Niwano M. Effective Subnetwork Topology for Synchronizing Interconnected Networks of Coupled Phase Oscillators. Front Comput Neurosci 2018; 12:17. [PMID: 29643771 PMCID: PMC5882810 DOI: 10.3389/fncom.2018.00017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 03/06/2018] [Indexed: 11/13/2022] Open
Abstract
A system consisting of interconnected networks, or a network of networks (NoN), appears diversely in many real-world systems, including the brain. In this study, we consider NoNs consisting of heterogeneous phase oscillators and investigate how the topology of subnetworks affects the global synchrony of the network. The degree of synchrony and the effect of subnetwork topology are evaluated based on the Kuramoto order parameter and the minimum coupling strength necessary for the order parameter to exceed a threshold value, respectively. In contrast to an isolated network in which random connectivity is favorable for achieving synchrony, NoNs synchronize with weaker interconnections when the degree distribution of subnetworks is heterogeneous, suggesting the major role of the high-degree nodes. We also investigate a case in which subnetworks with different average natural frequencies are coupled to show that direct coupling of subnetworks with the largest variation is effective for synchronizing the whole system. In real-world NoNs like the brain, the balance of synchrony and asynchrony is critical for its function at various spatial resolutions. Our work provides novel insights into the topological basis of coordinated dynamics in such networks.
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Affiliation(s)
- Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Shigeru Kubota
- Graduate School of Science and Engineering, Yamagata University, Yamagata, Japan
| | - Fabio A Shimizu
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
| | - Ayumi Hirano-Iwata
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan.,Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
| | - Michio Niwano
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
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31
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Tero R, Fukumoto K, Motegi T, Yoshida M, Niwano M, Hirano-Iwata A. Formation of Cell Membrane Component Domains in Artificial Lipid Bilayer. Sci Rep 2017; 7:17905. [PMID: 29263355 PMCID: PMC5738377 DOI: 10.1038/s41598-017-18242-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 12/07/2017] [Indexed: 12/31/2022] Open
Abstract
The lipid bilayer environment around membrane proteins strongly affects their structure and functions. Here, we aimed to study the fusion of proteoliposomes (PLs) derived from cultured cells with an artificial lipid bilayer membrane and the distribution of the PL components after the fusion. PLs, which were extracted as a crude membrane fraction from Chinese hamster ovary (CHO) cells, formed isolated domains in a supported lipid bilayer (SLB), comprising phosphatidylcholine (PC), phosphatidylethanolamine (PE), and cholesterol (Chol), after the fusion. Observation with a fluorescence microscope and an atomic force microscope showed that the membrane fusion occurred selectively at microdomains in the PC + PE + Chol-SLB, and that almost all the components of the PL were retained in the domain. PLs derived from human embryonic kidney 293 (HEK) cells also formed isolated domains in the PC + PE + Chol-SLB, but their fusion kinetics was different from that of the CHO-PLs. We attempted to explain the mechanism of the PL-SLB fusion and the difference between CHO- and HEK-PLs, based on a kinetic model. The domains that contained the whole cell membrane components provided environments similar to that of natural cell membranes, and were thus effective for studying membrane proteins using artificial lipid bilayer membranes.
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Affiliation(s)
- Ryugo Tero
- Department of Environmental and Life Sciences, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan. .,Electronics-Inspired Interdisciplinary Research Institute, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan.
| | - Kohei Fukumoto
- Department of Environmental and Life Sciences, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan
| | - Toshinori Motegi
- Electronics-Inspired Interdisciplinary Research Institute, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan.,Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma, 376-8515, Japan
| | - Miyu Yoshida
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, 980-8577, Japan
| | - Michio Niwano
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, 980-8577, Japan.,Kansei Fukushi Research Institute, Tohoku Fukushi University, Sendai, Miyagi, 989-3201, Japan
| | - Ayumi Hirano-Iwata
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, 980-8577, Japan.,Advanced Institute for Materials Research, Tohoku University, Sendai, Miyagi, 980-8577, Japan
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32
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Tadaki D, Yamaura D, Araki S, Yoshida M, Arata K, Ohori T, Ishibashi KI, Kato M, Ma T, Miyata R, Tozawa Y, Yamamoto H, Niwano M, Hirano-Iwata A. Mechanically stable solvent-free lipid bilayers in nano- and micro-tapered apertures for reconstitution of cell-free synthesized hERG channels. Sci Rep 2017; 7:17736. [PMID: 29255199 PMCID: PMC5735097 DOI: 10.1038/s41598-017-17905-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/01/2017] [Indexed: 01/08/2023] Open
Abstract
The self-assembled bilayer lipid membrane (BLM) is the basic component of the cell membrane. The reconstitution of ion channel proteins in artificially formed BLMs represents a well-defined system for the functional analysis of ion channels and screening the effects of drugs that act on them. However, because BLMs are unstable, this limits the experimental throughput of BLM reconstitution systems. Here we report on the formation of mechanically stable solvent-free BLMs in microfabricated apertures with defined nano- and micro-tapered edge structures. The role of such nano- and micro-tapered structures on the stability of the BLMs was also investigated. Finally, this BLM system was combined with a cell-free synthesized human ether-a-go-go-related gene channel, a cardiac potassium channel whose relation to arrhythmic side effects following drug treatment is well recognized. Such stable BLMs as these, when combined with a cell-free system, represent a potential platform for screening the effects of drugs that act on various ion-channel genotypes.
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Affiliation(s)
- Daisuke Tadaki
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Daichi Yamaura
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Shun Araki
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Miyu Yoshida
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Kohei Arata
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Takeshi Ohori
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Ken-Ichi Ishibashi
- Hang-Ichi Corporation, 1-7-315 Honcho, Naka-ku, Yokohama, Kanagawa, 231-0005, Japan
| | - Miki Kato
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Teng Ma
- Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Ryusuke Miyata
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Yuzuru Tozawa
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, Saitama, 338-8570, Japan
| | - Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Michio Niwano
- Kansei Fukushi Research Institute, Tohoku Fukushi University, 6-149-1 Kunimi-ga-oka, Aoba-ku, Sendai, Miyagi, 989-3201, Japan
| | - Ayumi Hirano-Iwata
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan. .,Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan.
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33
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Kawano H, Oyabu K, Yamamoto H, Eto K, Adaniya Y, Kubota K, Watanabe T, Hirano-Iwata A, Nabekura J, Katsurabayashi S, Iwasaki K. Astrocytes with previous chronic exposure to amyloid β-peptide fragment 1-40 suppress excitatory synaptic transmission. J Neurochem 2017; 143:624-634. [PMID: 29076533 DOI: 10.1111/jnc.14247] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/27/2017] [Accepted: 10/13/2017] [Indexed: 11/28/2022]
Abstract
Synaptic dysfunction and neuronal death are responsible for cognitive and behavioral deficits in Alzheimer's disease (AD). It is well known that such neurological abnormalities are preceded by long-term exposure of amyloid β-peptide (Aβ) and/or hyperphosphorylated tau prior. In addition to the neurological deficit, astrocytes as a major glial cell type in the brain, significantly participate in the neuropathogenic mechanisms underlying synaptic modulation. Although astrocytes play a significant key role in modulating synaptic transmission, little is known on whether astrocyte dysfunction caused by such long-term Aβ exposure affects synapse formation and function. Here, we show that synapse formation and synaptic transmission are attenuated in hippocampal-naïve neurons co-cultured with astrocytes that have previously experienced chronic Aβ1-40 exposure. In this abnormal astrocytic condition, hippocampal neurons exhibit decrements of evoked excitatory post-synaptic currents (EPSCs) and miniature EPSC frequency. Furthermore, size of readily releasable synaptic pools and number of excitatory synapses were also significantly decreased. Contrary to these negative effects, release probability at individual synapses was significantly increased in the same astrocytic condition. Taken together, our data indicate that lower synaptic transmission caused by astrocytes previously, and chronically, exposed to Aβ1-40 is attributable to a small number of synapses with higher release probability.
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Affiliation(s)
- Hiroyuki Kawano
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Kohei Oyabu
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aoba-ku, Sendai, Japan
| | - Kei Eto
- Division of Homeostatic Development, Department of Fundamental Neuroscience, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Physiological Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Yuna Adaniya
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Kaori Kubota
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan.,A.I.G. Collaborative Research Institute for Aging and Brain Sciences, Fukuoka University, Fukuoka, Japan
| | - Takuya Watanabe
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan.,A.I.G. Collaborative Research Institute for Aging and Brain Sciences, Fukuoka University, Fukuoka, Japan
| | - Ayumi Hirano-Iwata
- Advanced Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, Japan.,Research Institute of Electrical Communication, Tohoku University, Aoba-ku, Sendai, Japan
| | - Junichi Nabekura
- Department of Physiological Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan.,Division of Homeostatic Development, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Japan.,CREST, Japan Science and Technology Agency (JST), Kawaguchi, Japan
| | - Shutaro Katsurabayashi
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Katsunori Iwasaki
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan.,A.I.G. Collaborative Research Institute for Aging and Brain Sciences, Fukuoka University, Fukuoka, Japan
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Hirano-Iwata A, Ishinari Y, Yoshida M, Araki S, Tadaki D, Miyata R, Ishibashi K, Yamamoto H, Kimura Y, Niwano M. Reconstitution of Human Ion Channels into Solvent-free Lipid Bilayers Enhanced by Centrifugal Forces. Biophys J 2017; 110:2207-15. [PMID: 27224486 DOI: 10.1016/j.bpj.2016.04.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 04/11/2016] [Accepted: 04/11/2016] [Indexed: 12/26/2022] Open
Abstract
Artificially formed bilayer lipid membranes (BLMs) provide well-defined systems for functional analyses of various membrane proteins, including ion channels. However, difficulties associated with the integration of membrane proteins into BLMs limit the experimental efficiency and usefulness of such BLM reconstitution systems. Here, we report on the use of centrifugation to more efficiently reconstitute human ion channels in solvent-free BLMs. The method improves the probability of membrane fusion. Membrane vesicles containing the human ether-a-go-go-related gene (hERG) channel, the human cardiac sodium channel (Nav1.5), and the human GABAA receptor (GABAAR) channel were formed, and the functional reconstitution of the channels into BLMs via vesicle fusion was investigated. Ion channel currents were recorded in 67% of the BLMs that were centrifuged with membrane vesicles under appropriate centrifugal conditions (14-55 × g). The characteristic channel properties were retained for hERG, Nav1.5, and GABAAR channels after centrifugal incorporation into the BLMs. A comparison of the centrifugal force with reported values for the fusion force revealed that a centrifugal enhancement in vesicle fusion was attained, not by accelerating the fusion process but by accelerating the delivery of membrane vesicles to the surface of the BLMs, which led to an increase in the number of membrane vesicles that were available for fusion. Our method for enhancing the probability of vesicle fusion promises to dramatically increase the experimental efficiency of BLM reconstitution systems, leading to the realization of a BLM-based, high-throughput platform for functional assays of various membrane proteins.
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Affiliation(s)
- Ayumi Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan.
| | - Yutaka Ishinari
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Miyu Yoshida
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Shun Araki
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Daisuke Tadaki
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Ryusuke Miyata
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | | | - Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aoba, Sendai, Japan
| | - Yasuo Kimura
- Department of Electric and Electronic Engineering, School of Engineering, Tokyo University of Technology, Hachioji, Tokyo, Japan
| | - Michio Niwano
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan; Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba, Sendai, Japan
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Sakaguchi N, Kimura Y, Hirano-Iwata A, Ogino T. Fabrication of Au-Nanoparticle-Embedded Lipid Bilayer Membranes Supported on Solid Substrates. J Phys Chem B 2017; 121:4474-4481. [PMID: 28414450 DOI: 10.1021/acs.jpcb.7b00500] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We fabricated gold nanoparticle (Au-NP)-embedded supported lipid bilayers (SLBs) by two methods. In the vesicle-vesicle fusion method, vesicles with hydrophobized Au-NPs are ruptured and fused on SiO2/Si substrates. In the vesicle-membrane fusion method, SLBs without Au-NPs were preformed on the substrate and then vesicles with Au-NPs were fused into the preformed membranes. In the former method, Au-NP incorporation into the SLBs was observed as an increase in the membrane thickness in atomic force microscopy (AFM) images and directly observed by transmission electron microscopy. In the latter method, fusion of vesicles into the preformed membranes was confirmed by the fluorescent color change in the preformed membranes, and Au-NP incorporation was also confirmed by an increase in the membrane thickness in the AFM images. Key techniques for the successful vesicle-membrane fusion are hydrophobization of Au-NPs, approach control of vesicles by mixing the charged lipids, and destabilization of the lipid bilayers by adding lipids with a small polar headgroup.
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Affiliation(s)
- Naotoshi Sakaguchi
- Yokohama National University , 79-1, Tokiwadai, Hodogaya, Yokohama 240-8501, Japan
| | - Yasuo Kimura
- Tokyo University of Technology , 1404-1, Katakura, Hachioji, Tokyo 192-0982, Japan
| | | | - Toshio Ogino
- Yokohama National University , 79-1, Tokiwadai, Hodogaya, Yokohama 240-8501, Japan
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Ma T, Zhang Q, Tadaki D, Hirano-Iwata A, Niwano M. Fabrication and Characterization of High-Quality Perovskite Films with Large Crystal Grains. J Phys Chem Lett 2017; 8:720-726. [PMID: 28128959 DOI: 10.1021/acs.jpclett.6b03037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Solution-processable organometal perovskite materials have been widely used in various kinds of devices. In these devices, the perovskite materials normally act as active layers. Grain boundaries and structural disorder in the perovskite layer would interfere the charge transport and increase recombination probability. Here we proposed a novel fabrication method to dramatically increase the crystal size by more than 20 times as compared with previously reported values. Exceptional structural order in the large crystals is illustrated by nanoscale surface morphology and a simple recrystallization method. Because of reduced grain boundaries and increased crystal order in perovskite layers, the lateral charge transport is significantly improved, as demonstrated by conductive atomic-force microscopy and performance of photodetectors. This deposition technology paves the way for future high-performance devices based on perovskite thin films.
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Affiliation(s)
- Teng Ma
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 Japan
- CREST, Japan Science and Technology Agency (JST) , 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Qiwu Zhang
- School of Resources and Environmental Engineering, Wuhan University of Technology , Luoshi Road 122, Wuhan, Hubei 430070, China
| | - Daisuke Tadaki
- CREST, Japan Science and Technology Agency (JST) , 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Graduate School of Biomedical Engineering, Tohoku University , 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Ayumi Hirano-Iwata
- CREST, Japan Science and Technology Agency (JST) , 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Graduate School of Biomedical Engineering, Tohoku University , 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Michio Niwano
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 Japan
- CREST, Japan Science and Technology Agency (JST) , 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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Kono S, Yamamoto H, Kushida T, Hirano-Iwata A, Niwano M, Tanii T. Live-Cell, Label-Free Identification of GABAergic and Non-GABAergic Neurons in Primary Cortical Cultures Using Micropatterned Surface. PLoS One 2016; 11:e0160987. [PMID: 27513933 PMCID: PMC4981301 DOI: 10.1371/journal.pone.0160987] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 07/28/2016] [Indexed: 12/21/2022] Open
Abstract
Excitatory and inhibitory neurons have distinct roles in cortical dynamics. Here we present a novel method for identifying inhibitory GABAergic neurons from non-GABAergic neurons, which are mostly excitatory glutamatergic neurons, in primary cortical cultures. This was achieved using an asymmetrically designed micropattern that directs an axonal process to the longest pathway. In the current work, we first modified the micropattern geometry to improve cell viability and then studied the axon length from 2 to 7 days in vitro (DIV). The cell types of neurons were evaluated retrospectively based on immunoreactivity against GAD67, a marker for inhibitory GABAergic neurons. We found that axons of non-GABAergic neurons grow significantly longer than those of GABAergic neurons in the early stages of development. The optimal threshold for identifying GABAergic and non-GABAergic neurons was evaluated to be 110 μm at 6 DIV. The method does not require any fluorescence labelling and can be carried out on live cells. The accuracy of identification was 98.2%. We confirmed that the high accuracy was due to the use of a micropattern, which standardized the development of cultured neurons. The method promises to be beneficial both for engineering neuronal networks in vitro and for basic cellular neuroscience research.
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Affiliation(s)
- Sho Kono
- Graduate School of Fundamental Science and Engineering, Waseda University, Tokyo, Japan
- Japan Society for the Promotion of Science (JSPS), Tokyo, Japan
| | - Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Takatoshi Kushida
- Graduate School of Fundamental Science and Engineering, Waseda University, Tokyo, Japan
| | - Ayumi Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Michio Niwano
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
| | - Takashi Tanii
- Graduate School of Fundamental Science and Engineering, Waseda University, Tokyo, Japan
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38
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Yamamoto H, Matsumura R, Takaoki H, Katsurabayashi S, Hirano-Iwata A, Niwano M. Unidirectional signal propagation in primary neurons micropatterned at a single-cell resolution. Appl Phys Lett 2016; 109:043703. [PMID: 27746482 PMCID: PMC5030838 DOI: 10.1063/1.4959836] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 07/14/2016] [Indexed: 05/04/2023]
Abstract
The structure and connectivity of cultured neuronal networks can be controlled by using micropatterned surfaces. Here, we demonstrate that the direction of signal propagation can be precisely controlled at a single-cell resolution by growing primary neurons on micropatterns. To achieve this, we first examined the process by which axons develop and how synapses form in micropatterned primary neurons using immunocytochemistry. By aligning asymmetric micropatterns with a marginal gap, it was possible to pattern primary neurons with a directed polarization axis at the single-cell level. We then examined how synapses develop on micropatterned hippocampal neurons. Three types of micropatterns with different numbers of short paths for dendrite growth were compared. A normal development in synapse density was observed when micropatterns with three or more short paths were used. Finally, we performed double patch clamp recordings on micropatterned neurons to confirm that these synapses are indeed functional, and that the neuronal signal is transmitted unidirectionally in the intended orientation. This work provides a practical guideline for patterning single neurons to design functional neuronal networks in vitro with the direction of signal propagation being controlled.
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Affiliation(s)
- H Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University , 6-3 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - R Matsumura
- Graduate School of Biomedical Engineering, Tohoku University , 6-6 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - H Takaoki
- Research Institute of Electrical Communication, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - S Katsurabayashi
- Faculty of Pharmaceutical Sciences, Fukuoka University , 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| | - A Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University , 6-6 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - M Niwano
- Research Institute of Electrical Communication, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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Yamamoto H, Kubota S, Chida Y, Morita M, Moriya S, Akima H, Sato S, Hirano-Iwata A, Tanii T, Niwano M. Size-dependent regulation of synchronized activity in living neuronal networks. Phys Rev E 2016; 94:012407. [PMID: 27575164 DOI: 10.1103/physreve.94.012407] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Indexed: 06/06/2023]
Abstract
We study the effect of network size on synchronized activity in living neuronal networks. Dissociated cortical neurons form synaptic connections in culture and generate synchronized spontaneous activity within 10 days in vitro. Using micropatterned surfaces to extrinsically control the size of neuronal networks, we show that synchronized activity can emerge in a network as small as 12 cells. Furthermore, a detailed comparison of small (∼20 cells), medium (∼100 cells), and large (∼400 cells) networks reveal that synchronized activity becomes destabilized in the small networks. A computational modeling of neural activity is then employed to explore the underlying mechanism responsible for the size effect. We find that the generation and maintenance of the synchronized activity can be minimally described by: (1) the stochastic firing of each neuron in the network, (2) enhancement in the network activity in a positive feedback loop of excitatory synapses, and (3) Ca-dependent suppression of bursting activity. The model further shows that the decrease in total synaptic input to a neuron that drives the positive feedback amplification of correlated activity is a key factor underlying the destabilization of synchrony in smaller networks. Spontaneous neural activity plays a critical role in cortical information processing, and our work constructively clarifies an aspect of the structural basis behind this.
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Affiliation(s)
- Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Shigeru Kubota
- Graduate School of Science and Engineering, Yamagata University, Yamagata 992-8510, Japan
| | - Yudai Chida
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Mayu Morita
- School of Fundamental Science and Engineering, Waseda University, Tokyo 169-8555, Japan
| | - Satoshi Moriya
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Hisanao Akima
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Shigeo Sato
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University, 980-8579 Sendai, Japan
| | - Takashi Tanii
- School of Fundamental Science and Engineering, Waseda University, Tokyo 169-8555, Japan
| | - Michio Niwano
- Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan
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Matsumura R, Yamamoto H, Niwano M, Hirano-Iwata A. An electrically resistive sheet of glial cells for amplifying signals of neuronal extracellular recordings. Appl Phys Lett 2016; 108:023701. [PMID: 27703279 PMCID: PMC5035130 DOI: 10.1063/1.4939629] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 12/24/2015] [Indexed: 06/06/2023]
Abstract
Electrical signals of neuronal cells can be recorded non-invasively and with a high degree of temporal resolution using multielectrode arrays (MEAs). However, signals that are recorded with these devices are small, usually 0.01%-0.1% of intracellular recordings. Here, we show that the amplitude of neuronal signals recorded with MEA devices can be amplified by covering neuronal networks with an electrically resistive sheet. The resistive sheet used in this study is a monolayer of glial cells, supportive cells in the brain. The glial cells were grown on a collagen-gel film that is permeable to oxygen and other nutrients. The impedance of the glial sheet was measured by electrochemical impedance spectroscopy, and equivalent circuit simulations were performed to theoretically investigate the effect of covering the neurons with such a resistive sheet. Finally, the effect of the resistive glial sheet was confirmed experimentally, showing a 6-fold increase in neuronal signals. This technique feasibly amplifies signals of MEA recordings.
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Affiliation(s)
- R Matsumura
- Graduate School of Biomedical Engineering, Tohoku University , 6-6 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - H Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University , 6-3 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - M Niwano
- Research Institute of Electrical Communication, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - A Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University , 6-6 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
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Yamamoto H, Demura T, Sekine K, Kono S, Niwano M, Hirano-Iwata A, Tanii T. Photopatterning Proteins and Cells in Aqueous Environment Using TiO2 Photocatalysis. J Vis Exp 2015:e53045. [PMID: 26554338 PMCID: PMC4692672 DOI: 10.3791/53045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Organic contaminants adsorbed on the surface of titanium dioxide (TiO2) can be decomposed by photocatalysis under ultraviolet (UV) light. Here we describe a novel protocol employing the TiO2 photocatalysis to locally alter cell affinity of the substrate surface. For this experiment, a thin TiO2 film was sputter-coated on a glass coverslip, and the TiO2 surface was subsequently modified with an organosilane monolayer derived from octadecyltrichlorosilane (OTS), which inhibits cell adhesion. The sample was immersed in a cell culture medium, and focused UV light was irradiated to an octagonal region. When a neuronal cell line PC12 cells were plated on the sample, cells adhered only on the UV-irradiated area. We further show that this surface modification can also be performed in situ, i.e., even when cells are growing on the substrate. Proper modification of the surface required an extracellular matrix protein collagen to be present in the medium at the time of UV irradiation. The technique presented here can potentially be employed in patterning multiple cell types for constructing coculture systems or to arbitrarily manipulate cells under culture.
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Affiliation(s)
- Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University; CREST, Japan Science and Technology Agency;
| | - Takanori Demura
- School of Fundamental Science and Engineering, Waseda University
| | - Kohei Sekine
- School of Fundamental Science and Engineering, Waseda University
| | - Sho Kono
- School of Fundamental Science and Engineering, Waseda University
| | - Michio Niwano
- CREST, Japan Science and Technology Agency; Research Institute of Electrical Communication, Tohoku University
| | - Ayumi Hirano-Iwata
- CREST, Japan Science and Technology Agency; Graduate School of Biomedical Engineering, Tohoku University
| | - Takashi Tanii
- Faculty of Science and Engineering, Waseda University
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Hirano-Iwata A, Ishinari Y, Yamamoto H, Niwano M. Frontispiece: Micro- and Nano-Technologies for Lipid Bilayer-Based Ion-Channel Functional Assays. Chem Asian J 2015. [DOI: 10.1002/asia.201580661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ayumi Hirano-Iwata
- CREST (Japan) Science and Technology Agency (JST); 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
| | - Yutaka Ishinari
- CREST (Japan) Science and Technology Agency (JST); 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
| | - Hideaki Yamamoto
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
- Frontier Research Institute for Interdisciplinary Sciences; Tohoku University; 6-3 Aoba Aramaki, Aoba-ku Sendai 980-8578 Japan
| | - Michio Niwano
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
- Laboratory for Nanoelectronics and Spintronics; Research Institute of Electrical Communication; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
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Hirano-Iwata A, Ishinari Y, Yamamoto H, Niwano M. Micro- and Nano-Technologies for Lipid Bilayer-Based Ion-Channel Functional Assays. Chem Asian J 2015; 10:1266-74. [DOI: 10.1002/asia.201403391] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Ayumi Hirano-Iwata
- CREST (Japan) Science and Technology Agency (JST); 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
| | - Yutaka Ishinari
- CREST (Japan) Science and Technology Agency (JST); 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
| | - Hideaki Yamamoto
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
- Frontier Research Institute for Interdisciplinary Sciences; Tohoku University; 6-3 Aoba Aramaki, Aoba-ku Sendai 980-8578 Japan
| | - Michio Niwano
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
- Laboratory for Nanoelectronics and Spintronics; Research Institute of Electrical Communication; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
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Ikegami Y, Hozumi S, Shoji A, Hirano-Iwata A, Bliss T, Sugawara M. Real-time monitoring of extracellular l-glutamate levels released by high-frequency stimulation at region CA1 of hippocampal slices with a glass capillary-based l-glutamate sensor. Sensing and Bio-Sensing Research 2014. [DOI: 10.1016/j.sbsr.2014.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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45
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Oshima A, Hirano-Iwata A, Mozumi H, Ishinari Y, Kimura Y, Niwano M. Reconstitution of Human Ether-a-go-go-Related Gene Channels in Microfabricated Silicon Chips. Anal Chem 2013; 85:4363-9. [DOI: 10.1021/ac303484k] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Azusa Oshima
- Graduate School of Biomedical
Engineering, Tohoku University, 6-6 Aoba,
Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Ayumi Hirano-Iwata
- Graduate School of Biomedical
Engineering, Tohoku University, 6-6 Aoba,
Aramaki, Aoba-ku, Sendai 980-8579, Japan
- PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi,
Saitama 332-0012, Japan
| | - Hideki Mozumi
- Graduate School of Biomedical
Engineering, Tohoku University, 6-6 Aoba,
Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Yutaka Ishinari
- Graduate School of Biomedical
Engineering, Tohoku University, 6-6 Aoba,
Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Yasuo Kimura
- Laboratory
for Nanoelectronics
and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai,
Miyagi 980-8577, Japan
| | - Michio Niwano
- Graduate School of Biomedical
Engineering, Tohoku University, 6-6 Aoba,
Aramaki, Aoba-ku, Sendai 980-8579, Japan
- Laboratory
for Nanoelectronics
and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai,
Miyagi 980-8577, Japan
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Oshima A, Hirano-Iwata A, Nasu T, Kimura Y, Niwano M. Mechanically Stable Lipid Bilayers in Teflon-Coated Silicon Chips for Single-Channel Recordings. ACTA ACUST UNITED AC 2012. [DOI: 10.2174/1876402911204010002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Hozumi S, Ikezawa K, Shoji A, Hirano-Iwata A, Bliss T, Sugawara M. Simultaneous monitoring of excitatory postsynaptic potentials and extracellular L-glutamate in mouse hippocampal slices. Biosens Bioelectron 2010; 26:2975-80. [PMID: 21194919 DOI: 10.1016/j.bios.2010.11.052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 11/22/2010] [Accepted: 11/29/2010] [Indexed: 11/30/2022]
Abstract
Simultaneous monitoring of amperometric currents at a glass capillary sensor based on recombinant GluOx and field excitatory postsynaptic potentials (fEPSPs) were performed in region CA1 of mouse hippocampal slices. A transient increase in the glutamate current relative to the basal one at control stimulation (0.052Hz) was evoked by stimulation at 2 Hz for 2 min. The magnitude of the glutamate current was dependent on the intensity (current) of a 2 Hz stimulus and reflected the slope of the fEPSP. The in situ calibration of the L-glutamate sensor revealed that the extracellular concentration of L-glutamate released by 2 Hz stimulation before tetanus is in the range from 0.8 to 2.2 μM and it is enhanced after tetanic stimulation. The L-glutamate level at a test stimulus (0.052 Hz) was estimated to be 32 nM. The recombinant GluOx-based sensor exhibited weak responses to glutamine above 300 μM and L-aspartic acid above 200 μM. The potential use of a glass capillary sensor in combination with fEPSP measurements for electrophysiological study is discussed.
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Affiliation(s)
- Shizuko Hozumi
- Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajuosui, Setagayaku, Tokyo 156-8550, Japan
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Hirano-Iwata A, Aoto K, Oshima A, Taira T, Yamaguchi RT, Kimura Y, Niwano M. Free-standing lipid bilayers in silicon chips-membrane stabilization based on microfabricated apertures with a nanometer-scale smoothness. Langmuir 2010; 26:1949-1952. [PMID: 19799400 DOI: 10.1021/la902522j] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In the present study, we propose a method for preparing stable free-standing bilayer lipid membranes (BLMs). The BLMs were prepared in a microfabricated aperture with a smoothly tapered edge, which was prepared in a nanometer-thick Si(3)N(4) septum by the wet etching method. Owing to this structure, the stress on lipid bilayers at the contact with the septum was minimized, leading to remarkable membrane stability. The BLMs were not broken by applying a constant voltage of +/-1 V. The membrane lifetime was 15-45 h with and without an incorporated gramicidin channel. Gramicidin single-channel currents were recorded from the same BLM preparation when the aqueous solutions surrounding the BLM were repeatedly exchanged, demonstrating the tolerance of the present BLM to repetitive solution exchanges. Such stable membranes enable analysis of channel functions under various solution conditions from the same BLM, which will open up a variety of applications including a high throughput drug screening for ion channels.
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Affiliation(s)
- Ayumi Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan.
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50
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Okumura W, Moridera N, Kanazawa E, Shoji A, Hirano-Iwata A, Sugawara M. Visualizing L-glutamate fluxes in acute hippocampal slices with glutamate oxidase-immobilized coverslips. Anal Biochem 2008; 385:326-33. [PMID: 19026980 DOI: 10.1016/j.ab.2008.10.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 10/28/2008] [Accepted: 10/29/2008] [Indexed: 11/30/2022]
Abstract
We used a glutamate oxidase (GluOx)-immobilized glass coverslip for reducing diffusional blur and improving the temporal resolution of visualizing L-glutamate fluxes in acute brain slices. The immobilization of GluOx on an avidin modified glass coverslips was achieved by optimized the amine coupling method. The GluOx coverslip was applied to the imaging of L-glutamate fluxes in acute hippocampal slices under hypoxia and KCl stimulation. A slice from mouse brain was loaded with horseradish peroxidase (HRP) and substrate DA-64, and placed on the GluOx coverslip for stimulation. The regional distribution of hypoxia-induced L-glutamate fluxes was analyzed. The maximum flux at 3 min after the onset of hypoxia increased in the order CA1>CA3>DG. The time-courses of the L-glutamate fluxes at CA1 and DG were biphasic, while that at CA3 decreased monotonously. The KCl-stimulated release of L-glutamate in the presence of the DL-TBOA uptake inhibitor was imaged. While no noticeable change was observed in the absence of DL-TBOA, L-glutamate fluxes in the presence of the inhibitor increased in the order CA1>CA3>DG, reflecting the effect of uptake processes. The present approach suppressed diffusional blur of the glutamate signal and improved the temporal resolution as compared with the BSA-HRP membrane method described earlier.
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Affiliation(s)
- Wataru Okumura
- Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajousui, Setagaya, Tokyo, Japan
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