Electrode Array System Research Articles

Galvanic Bipolar Electrode Arrays with Self-Driven Optical Readouts.

In this work, we report a bipolar electrode (BPE) array system with self-driven optical readouts of the faradic current flowing through the BPEs. The BPE array system is based on the spontaneous redox reactions that are respectively occurring at opposite poles of the BPEs with appropriate electrocatalysts on the poles; this system is analogous to one consisting of galvanic electrochemical cells. The galvanic BPE array system operates in a self-powered mode that requires there to be neither a direct electrical connection nor external electrical polarization to each BPE. Importantly, the appropriate electrocatalysts on the poles play a critical role in the galvanic BPE array system to induce the spontaneous redox reactions occurring at the poles of BPEs. Moreover, the galvanic BPE array system provides self-driven optical readouts, including fluorometric and colorimetric ones, to report the faradaic current resulting from the spontaneous redox reactions on the BPE poles. Based on the unique benefits that the galvanic BPE array system has over conventional BPEs, we demonstrated the promising potential of galvanic BPE arrays for the simple yet rapid and quantitative screening of electrocatalysts for the oxygen reduction reaction as well as sensitive sensing of H2O2 in parallel.

Self-powered triboelectric nanogenerator driven nanowires electrode array system for the urine sterilization

Urine is the primary source of pathogens (viruses, fungi, and bacteria) in urban sewage. The epidemic spread of these pathogens has a severe threat to human health and the ecological environment. The traditional sewage sterilization methods usually produce harmful by-products and have high energy consumption. These weaknesses restrict the quality of the purified water and economic benefits. Herein, we elaborately fabricated a triboelectric nanogenerator driving nanowires electrode array (T-NEA) system for removing bacteria in the urine. An irreversible electroporation damage results in high-efficiency bacteria inactivation. The sterilization efficiency of T-NEA system is more than 99.9999% in artificial urine contaminated by Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Klebsiella pneumoniae (K. pneumoniae), Pseudomonas aeruginosa (P. aeruginosa). Those bacteria could cause epidemic infection in hospital. The electroporation effect on the bacterial membrane was confirmed by SEM imaging and confocal laser scanning microscopy. In addition, it was demonstrated that the radical oxygen species accompanied by T-NEA working could degrade the organic components in artificial urine. After being treated by T-NEA for 30 mins, the reduction rates of the total organic carbon and total nitrogen in the artificial urine reached up to 30.41% and 33.79%. Meanwhile, the degradation degree of urea, uric acid, and creatinine reached 37.39%, 30.50%, 6.25%, respectively. And the degradation mechanism of organic materials in urine was also investigated. This work provided an effective self-powered system which could totally remove the hazardous bacteria and degrade the organics in the urine.

Flexible Tongue Electrode Array System for In Vivo Mapping of Electrical Signals of Taste Sensation.

Tongue is a unique organ that senses tastes, and the scientific puzzle about whether electricity can evoke taste sensations and how the sensations have been distributed on the tongue has not been solved. Investigations on tongue stimulation by electricity might benefit the developments of techniques for clinical neuromodulation, tissue activation, and a brain-tongue-machine interface. To solve the scientific puzzle of whether electrical stimulation induces taste-related sensations, a portable flexible tongue electrode array system (FTEAS) was developed, which can synchronously provide electrical stimulation and signal mapping at each zone of the tongue. Utilizing the FTEAS to perform tests on the rat tongue in vivo, specific electrical signals were observed to be evoked by chemical and electrical stimulations. The features and distributions of the electric signals evoked during the rat tongue tests were systematically studied and comprehensively analyzed. The results show that an appropriate electrical stimulation can induce multiple sensations simultaneously, while the distribution of each sensation was not significantly distinguished among different zones of the tongue, and at the same time, this taste-related electrical signal can be recorded by the FTEAS. This work establishes a promising platform to solve the scientific puzzle of how sensations are activated chemically and electrically on the tongue and may provide advanced noninvasive oral-electrotherapy and a brain-tongue-machine interface.

Reactive Exercises with Interactive Objects: Interim Analysis of a Randomized Trial on Task-Driven NMES Grasp Rehabilitation for Subacute and Early Chronic Stroke Patients.

Enriched environments and tools are believed to promote grasp rehabilitation after stroke. We designed S2, an interactive grasp rehabilitation system consisting of smart objects, custom orthoses for selective grasp constraining, and an electrode array system for forearm NMES. Motor improvements and perceived usability of a new enriched upper limb training system for sub-acute stroke patients was assessed in this interim analysis. Inclusion criteria: sub-acute stroke patients with , ipsilesional , and contralesional . Effects of 30-min therapy supplements, conventional vs. S2 prototype, are compared through a parallel two-arms dose-matched open-label trial, lasting 27 sessions. Clinical centres: Asklepios Neurologische Klinik Falkenstein, Königstein im Taunus, Germany, and Clinica Villa Beretta, Costa Masnaga, Italy. Assessment scales: ARAT, System Usability, and Technology Acceptance. Methodology: 26 participants were block randomized, allocated to the study (control , experimental ) and underwent the training protocol. Among them, 11 participants with ARAT score at inclusion below 35, n = 6 in the experimental group, and n = 5 in the control group were analysed. Results: participants in the enriched treatment group displayed a larger improvement in the ARAT scale (+14.9 pts, ). Perceived usability differed between clinics. No adverse effect was observed in relation to the treatments. Trial status: closed. Conclusions: The S2 system, developed according to shared clinical directives, was tested in a clinical proof of concept. Variations of ARAT scores confirm the feasibility of clinical investigation for hand rehabilitation after stroke.

Rapid Discrimination of Beer Flavors Using Ion-Selective Electrode Array System Combined with Chemometrics

Rapid discrimination of beer with different flavors was performed by ion-selective electrode array and chemometrics. Ion-selective electrode array consisted of twelve ion-selective electrodes. Six varieties of beer 10 types of each with different flavors from Tsingtao Brewery were investigated. Potentiometric measurements were conducted in presence of beer to obtain the output potential values. Principal component analysis (PCA) was applied as a data compaction technique to reduce complexity of the potential data. Linear discriminant analysis (LDA) and least-squares support vector machine (LS-SVM) methods were used to develop discriminant models. The LS-SVM model achieved a more satisfying performance with an identification rate of 95.0% than the LDA model. For validating reliability, the developed method and sensory evaluation method were used for discriminating the beer samples. The LS-SVM model with an identification rate of 98.3% was better than the sensory evaluation method with an identification rate of 89.2%. The prepared sensor array can rapidly and accurately discriminate beer samples with different flavors and quality.

Wearable and chest size-adjusted 12-lead electrode array system to record electrocardiogram: A novel design

Background: Cardiovascular diseases are the leading cause of morbidity and mortality worldwide. Majority of human loss caused due to cardiovascular issues can be saved if diagnosed early and treated appropriately. Electrocardiogram (ECG) is the basic screening tool for cardiac ailments. Cumbersome technique, inconvenience to the patients and lack of trained workforce to obtain record, makes ECG a challenge, especially at peripheral rural health centers. Making ECG recording simpler, available, and recordable by even untrained persons can help cardiac patients get timely screened for needful treatment. Aims and Objectives: This study aims to design a wearable, 12-lead, electrode array system for ECG recording. Materials and Methods: Data of 250 adult men in the age group of 30–70 years were collected. We measured chest circumference and distance of points on chest wall from the midline (anterior chest wall), where chest lead electrodes need to be placed for ECG recording and correlated this value with the height, age, weight, and body mass index (BMI) of the subjects. Results: The mean distances (±standard deviation) of the chest lead electrodes from the midline (cm) were 2.8 ± 0.39 (right to the midline), 2.8 ± 0.39, 6.09 ± 0.59, 11.81 ± 1.43, 20.43 ± 2.38, and 25.10 ± 2.10 for V1, V2, V3, V4, V5, and V6, respectively. This distance was significantly correlating with subject’s weight and BMI. Conclusion: BMI and body weight of the individuals, irrespective of their age, can be considered to design different size wearable electrode array system. A prototype of the chest size-adjusted electrode array system to record ECG is developed.

317 - Glycolytic and redox control of neuronal excitability in vitro

Metabolic control of epilepsy is recognized in part due to the efficacy of ketogenic diets, which provide alternate fuels rather than glucose for neuronal activity. It is documented that glycolytic rates are acutely increased during epileptic seizures and inhibition of glycolysis with 2-deoxyglucose (2-DG) has anti-seizure effects. Work from our laboratory has shown that seizure activity increases the steady-state levels of reactive oxygen species (ROS) production and causes mitochondrial dysfunction. Here we determined the relationship between glycolysis, ROS production and neuronal excitability. Mixed rat primary cortical cultures treated with 4-Aminopyridine (4-AP), a potassium channel blocker, showed an increase in a) Extracellular Acidification Rate (ECAR) levels (measure of glycolytic rate in the Seahorse XF analyzer), b) ROS production, measured by Amplex Red and c) increased neuronal excitability, assessed by a multiple electrode array system (Axion Biosystems). Pre-treatment of mixed primary cortical cultures with compounds like 2-DG, Bromopyruvic acid (3BP), palmitate - an anaplerotic substrate (along with glycogenic substrate limitation), nicotinamide riboside (NR) – an NAD+ precursor, oxaloacetate (OA) - a TCA cycle intermediate, and mTOR inhibitor rapamycin decreased ECAR rates and neuronal hyperexcitability induced by 4-AP. Pre-treatment with a reduced B-nicotinamide adenine dinucleotide (NADH), Thiazolidinediones – an acute specific inhibitor of the mitochondrial pyruvate carrier, PI3K inhibitor wortmannin decreased 4-AP induced increase in glycolysis, without significantly altering neuronal hyperexcitability. Lastly, 2-DG also reversed ROS production produced by 4-AP. Taken together, these results suggest that glycolysis contributes to ROS production, which in turn increases neuronal hyperexcitability.

High-efficient preparation and screening of electrocatalysts using a closed bipolar electrode array system

High-efficient preparation and screening of electrocatalysts for oxygen reduction reaction (ORR) was realized by a three electrode driving closed bipolar electrode (BPE) array system. As high concentrations of Fe(CN)63−/4− (both 200 mM) existed in the anodic cell of the BPE system and same electrode material was adopted by the BPE anodic pole and driving electrode in anodic cell, the anodic cell performed similar to “good conductor” and the electrochemical behavior of the closed BPE system approximately equal to that of the three-electrode system in cathodic cell. Based on the above property and the parallel array, electrocatalysts containing bimetallic Pt Au and reduced graphene oxide (PtAu-rGO) with varying metal proportion were successfully prepared on the cathodic BPE poles by a two-step reduction process. Graphene oxide was firstly reduced to reduced graphene oxide (rGO) in each cathodic pole by cyclic voltammetry, and then Pt Au with different metal proportion were electrodeposited on the surface of rGO. Afterward, in-situ and high-throughput screening of these electrocatalysts for ORR was carried out based on the electrochemiluminescence (ECL) imaging on the corresponding anodic BPE poles. The screening results were consistent with those of the conventional electrochemical method by testing the catalytic performance one by one very well. This closed BPE array system with one potentiostat not only can prepare multiple catalyst candidates at the same time, but also can evaluate them, simultaneously, which is of great immediate significance to the field of fuel cell.

MAPPING OF SALTWATER INTRUSION AT IGBOKODA, SOUTHWESTERN, NIGERIA USING COMBINED GEOPHYSICAL AND CHEMICAL TECHNIQUES

<p>This research work was set out to map saltwater intrusion in Igbokoda area of Ilaje, Ondo State, Southwestern, Nigeria using combined geophysical and chemical techniques. Eight (8) Vertical Electrical sounding were carried out using the Schlumberger Electrode array system with maximum spread of (AB/2) 133 m and water samples were acquired and analysed using atomic absorption spectrometer. The VES data was interpreted by the method of partial curve matching and computer iteration technique using Winresist software. The result obtained revealed four geoelectric layers. The saltwater intrusion originated from movement of seawater into the freshwater aquifer coupled with human activities.</p>

MAPPING OF SALTWATER INTRUSION AT IGBOKODA, SOUTHWESTERN, NIGERIA USING COMBINED GEOPHYSICAL AND CHEMICAL TECHNIQUES

This research work was set out to map saltwater intrusion in Igbokoda area of Ilaje, Ondo State, Southwestern, Nigeria using combined geophysical and chemical techniques. Eight (8) Vertical Electrical sounding were carried out using the Schlumberger Electrode array system with maximum spread of (AB/2) 133 m and water samples were acquired and analysed using atomic absorption spectrometer. The VES data was interpreted by the method of partial curve matching and computer iteration technique using Winresist software. The result obtained revealed four geoelectric layers. The saltwater intrusion originated from movement of seawater into the freshwater aquifer coupled with human activities.

Simultaneous determination of copper and zinc in brass samples by PCR and PLS1 methods using a multiple ion-selective electrode array

A method was developed to determine copper and zinc simultaneously in brass sample using a multiple ion-selective electrode array system and multivariate calibration techniques. The multiple ion-selective electrode array system was consisted of one pH electrode and eight ion selective electrodes which were formed using commercial ionophores and which are mainly sensitive copper and zinc. PCR, PLS1 which are multivariate calibration techniques were used to calibrate the multiple ion-selective electrode array system using five level multivariate calibration design and PCR method was selected as most suitable method. The measurements were performed at pH 10 in ammonia-ammonium chloride buffer. Copper and zinc content of a brass sample were determined by the calibrated multiple ion-selective electrode array system and the composition of brass sample was also determined by gravimetric method. The percentage amount of copper and zinc in brass sample were 64 ± 1 and 26 ± 2, respectively using the gravimetric method. The percentage results obtained in brass samples for copper and zinc were 63 ± 3 and 24 ± 3 by PCR method and 60 ± 5 and 20 ± 7 by PLS1 method, respectively. The obtained results were calculated for a 95% confidence level.

Investigation of root signaling under heterogeneous salt stress: A case study for Cucumis sativus L.

To sense, respond and adapt to the constantly changing environmental conditions, plants have developed sophisticated signaling mechanisms. In this study, plant signaling under heterogeneous salt conditions was investigated. A split root system was established in which one half of the root apparatus (HR1) was treated with salt. The impact of the salt on the electrical signals as the initial response of the plant to exterior stimulus was measured in the other half of the root system (HR2) with a Multi Electrode Array (MEA) system. Duration and amplitude of the recorded electrical signals increased compared to the control. In order to identify the nature of the signal traveling from HR1 to HR2, H+ and K+ fluxes were measured in HR2 by using ion-selective microelectrodes (vibrating probe technique). A net potassium influx was observed after the treatment while no change in proton flux was detected. By corona sodium green and confocal microscopy we confirmed that changes in electrical signals and fluxes are not simply associated with apoplastic diffusion of sodium from HR1 to HR2. The activation of salt stress marker genes was also examined: the modulation of CsGOL-like expression seems to have systemic response, while ERF109 and aspartate oxidase showed localized responses.

Evaluation of micro Electroretinograms Recorded with Multiple Electrode Array to Assess Focal Retinal Function.

Full-field electroretinograms (ERGs) are used to objectively assess the mass function of the retina, whereas focal ERGs are used to evaluate the focal retinal function. The purpose of this study was to determine the usefulness of a multiple electrode array (MEA) system for recording ex vivo micro ERGs (mERGs) together with multiunit spike responses of the retinal ganglion cells (RGCs) to assess focal retinal function in isolated mouse retinas. The a- and b-waves of the full-field ERGs were present in the mERG. The b-wave was blocked by L-AP4, an inhibitor of the mGluR6 receptor, and the OFF-component was blocked by exposure to PDA, an antagonist of ionotropic glutamate receptors, with a corresponding RGC responses. mERGs were also recorded from mice with progressive retinal degeneration, the C57BL/6J-Pde6brd1-2J/J (rd1) mice, from which conventional full-field ERGs are non-recordable. A blockade of the glutamate receptors indicated that the negative wave of rd1 mice do not originate from the photoreceptors but from the second or third order neurons. This technique of recording mERGs will be useful in assessing the focal properties of the retinas obtained from eyes with pathology and also to follow the recovery of the physiology of the retina in regenerative studies.

Numerically controlled atmospheric-pressure plasma sacrificial oxidation using electrode arrays for improving silicon-on-insulator layer uniformity

Silicon-on-insulator (SOI) wafers are important semiconductor substrates in high-performance devices. In accordance with device miniaturization requirements, ultrathin and highly uniform top silicon layers (SOI layers) are required. A novel method involving numerically controlled (NC) atmospheric-pressure plasma sacrificial oxidation using an electrode array system was developed for the effective fabrication of an ultrathin SOI layer with extremely high uniformity. Spatial resolution and oxidation properties are the key factors controlling ultraprecision machining. The controllability of plasma oxidation and the oxidation properties of the resulting experimental electrode array system were examined. The results demonstrated that the method improved the thickness uniformity of the SOI layer over one-sixth of the area of an 8-in. wafer area.

Universal principles of topology governing both of structural and effective connectivity

Event Abstract Back to Event Universal principles of topology governing both of structural and effective connectivity Masanori Shimono1* and John Beggs2 1 University of Tokyo, Japan 2 Indiana University, United States Since the era of Hebb, the importance and mysterious role that neuronal ensembles play in has been a main concern of the neuroscience [Hebb, 1949]. Recently, much work using structural connectivity has revealed patterns of synaptic connections in neuron ensembles [Bock et al., 2011]. Structural connectivity information is extremely valuable, as it indicates pathways through which one neuron could possibly influence spiking in another. In contrast, effective connectivity aims to describe the pathways through which influence actually occurs. The concept of effective connectivity was initially described in regard to local neuronal networks [Aertsen et al., 1989]. However, almost all research on effective connectivity has been done in macroscopic dynamics recorded using fMRI, MEG, and EEG [Friston, 1994]. Furthermore, even out of the studies on microcircuits, almost no work has been done on effective connectivity in local cortical networks at the timescale of typical synaptic delays within the cortex (1-20 ms). This is unfortunate, as direct influence between neurons would be expected to occur at these time delays. Structural connectivity studies have shown that groups of 3-7 cortical neurons are more likely than chance to be synaptically connected to each other if they have synapses onto a common neighbor neuron [Perin et al., 2011]. This led to the question whether effective connectivity also shows this pattern. In order to investigate these topics, we used a 512 electrode array system to record spontaneous activity in 9 slice cultures that included neocortex and portions of hippocampus. On average, we recorded over ~120 neurons from each culture for 1 hr or more. Although many metrics of effective connectivity have been proposed, we selected transfer entropy because several studies found it to compare favorably in accuracy to other metrics. In the comparison between the topological properties of structural neuronal networks and the topological properties of the reconstructed effective connectivities, we could find universal principles of topology governing both of structural and effective connectivity. Keywords: Large scale modeling, structural connectivity, effective connectivity, topology, neuronal networks Conference: 5th INCF Congress of Neuroinformatics, Munich, Germany, 10 Sep - 12 Sep, 2012. Presentation Type: Poster Topic: Neuroinformatics Citation: Shimono M and Beggs J (2014). Universal principles of topology governing both of structural and effective connectivity. Front. Neuroinform. Conference Abstract: 5th INCF Congress of Neuroinformatics. doi: 10.3389/conf.fninf.2014.08.00119 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 21 Mar 2013; Published Online: 27 Feb 2014. * Correspondence: Dr. Masanori Shimono, University of Tokyo, unset, Japan, shimono@brain.k.u-tokyo.ac.jp Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Masanori Shimono John Beggs Google Masanori Shimono John Beggs Google Scholar Masanori Shimono John Beggs PubMed Masanori Shimono John Beggs Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

2P198 多電極電位計測システムを用いた薬剤試験を行うための培地条件の探索(12. 細胞生物的課題,ポスター,第52回日本生物物理学会年会(2014年度))

2P198 多電極電位計測システムを用いた薬剤試験を行うための培地条件の探索(12. 細胞生物的課題,ポスター,第52回日本生物物理学会年会(2014年度))

2P197 多電極電位計測システムを用いた薬剤の催不整脈性の検出(12. 細胞生物的課題,ポスター,第52回日本生物物理学会年会(2014年度))

2P197 多電極電位計測システムを用いた薬剤の催不整脈性の検出(12. 細胞生物的課題,ポスター,第52回日本生物物理学会年会(2014年度))

The effects of exposure to traumatic stressors on inhibitory control in police officers: A dense electrode array study using a Go/NoGo continuous performance task

Exposure to psychologically stressful and traumatic experiences and the requirement of heightened attention to environmental stimuli are common in police work. Police officers are at increased risk for stress-related disorders such as Post-Traumatic Stress Disorder (PTSD). Traumatic experiences can result in changes to brain structure and function associated with attention and cognitive control processes (such as response inhibition). Despite the significance that these cognitive functions may have on job performance in police officers, few studies have examined the effects of exposure to traumatic events on top-down cognitive control functions in police. In the present study, a dense electrode array system was used to examined the N2 and P3 components of the event-related potential (ERP) during a Go/NoGo continuous performance task (Go/NoGo CPT) in trauma-exposed police officers who did not meet criteria for a current diagnosis of PTSD and in non-trauma exposed civilian controls. Amplitude and latency were obtained to Go, NoGo, and non-target trials. The major between-group findings were for P3 amplitude. There were no group effects for N2. Both groups had an enhanced fronto-central P3 amplitude to NoGo compared to Go trials. However, police had greater P3 amplitude compared to controls for all trial types (Go, NoGo, non-target). PTSD symptom scores in police officers were positively correlated with fronto-central NoGo P3 amplitude, but not with posterior NoGo amplitude. This study provides evidence of heightened attention and/or arousal in police officers as indicated by the generally greater P3 amplitude in police compared to controls during a task requiring sustained attention and inhibitory control. Greater PTSD symptom severity in trauma-exposed individuals may affect frontal cognitive control systems related to response inhibition.

Design, Fabrication and Characterization of a Low-Impedance 3D Electrode Array System for Neuro-Electrophysiology

Recent progress in patterned microelectrode manufacturing technology and microfluidics has opened the way to a large variety of cellular and molecular biosensor-based applications. In this extremely diverse and rapidly expanding landscape, silicon-based technologies occupy a special position, given their statute of mature, consolidated, and highly accessible areas of development. Within the present work we report microfabrication procedures and workflows for 3D patterned gold-plated microelectrode arrays (MEA) of different shapes (pyramidal, conical and high aspect ratio), and we provide a detailed characterization of their physical features during all the fabrication steps to have in the end a reliable technology. Moreover, the electrical performances of MEA silicon chips mounted on standardized connector boards via ultrasound wire-bonding have been tested using non-destructive electrochemical methods: linear sweep and cyclic voltammetry, impedance spectroscopy. Further, an experimental recording chamber package suitable for in vitro electrophysiology experiments has been realized using custom-design electronics for electrical stimulus delivery and local field potential recording, included in a complete electrophysiology setup, and the experimental structures have been tested on newborn rat hippocampal slices, yielding similar performance compared to commercially available MEA equipments.

Abstract 136: Novel Disease Analysis Using Long QT Syndrome-Specific Induced Pluripotent Stem Cells

[Background] Although previous reports have indicated that long QT syndrome-specific iPS cells (LQTS-iPSCs)-derived cardiomyocytes recapitulated disease phenotypes, those patients were previously diagnosed with mutated channel profiles. In reality, most patients have no such specific information. To address whether iPSCs could be used for personalized disease characterization, we generated iPSCs from a sporadic LQTS patient with unknown disease cause. [Methods and Results] 1 We generated iPSCs from control (n = 2) and a patient with LQTS, and differentiated into cardiomyocytes through embryoid body (EB) formation. 2 Electrophysiological analysis of the LQTS-iPSCs-derived EBs using multi electrode array system revealed that the duration of the field potential (FPD) was markedly prolonged compared with the control (388.9 ± 44.3 msec vs 202.3 ± 16.3 msec, P<0.01). 3 We tested several drugs affecting QT prolongation to clarify the electrophysiological properties. The IKr blocker E4031 significantly prolonged FPD (% change 1.21 ± 0.02, P<0.01) and induced frequent severe arrhythmia, not only early-after depolarization (n = 8/16 vs n = 1/16) but also torsades de pointes-like arrhythmia, only in LQTS (n = 4/16 vs n = 0/16). The IKs blocker, chromanol 293B did not prolong FPD in LQTS but it significantly prolonged FPD in the control (% change 1.09 ± 0.04, NS vs 1.44 ± 0.07, P<0.01), suggesting the involvement of IKs disturbance in the patient. Isoproterenol induced ventricular tachycardia-like arrhythmia only in LQTS, which was blocked by propranolol. These data strongly suggested a functional impairment in the patient’s IKs channel; genotype analysis for KCNQ1 gene revealed a novel heterozygous mutation, 1893delC. 4 Patch clamp analysis and immunostaining confirmed a dominant-negative role for 1893delC in IKs channel through a trafficking deficiency. [Conclusions] LQTS-iPSCs-derived cardiomyocytes recapitulated the disease phenotypes, and they can be utilized for identification of the disease cause and genotype. This study demonstrated that iPSCs could be useful to characterize the disease, drug responses, diagnosis and genotyping in patients with sporadic LQTS, which in turn may facilitate medical therapies in the clinical settings.