Graphic summary
  • Show / hide key
  • Information


Scientific and technological production
  •  

1 to 50 of 262 results
  • An FPGA-based frequency response analyzer for multisine and stepped sine measurements on stationary and time-varying impedance

     Sánchez Terrones, Benjamín; Fernandez Espiga, Xavier; Reig Quiroga, Sergi; Bragos Bardia, Ramon
    Measurement science and technology
    Date of publication: 2014-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    We report the development of a field programmable gate array (FPGA) based frequency response analyzer (FRA) for impedance frequency response function (FRF) measurements using periodic excitations, i.e. sine waves and multisines. The stepped sine measurement uses two dedicated hardware-built digital embedded multiplier blocks to extract the phase and quadrature components of the output signal. The multisine FRF measurements compute the fast Fourier transform (FFT) of the input/output signals. In this paper, we describe its design, implementation and performance evaluation, performing electrical impedance spectroscopy (EIS) measurements on phantoms. The stepped sine accuracy is 1.21% at 1 k Omega (1%), the precision is 35 m Omega and the total harmonic distortion plus noise (THD+N) is -120 dB. As for the multisine impedance FRF measurements, the magnitude and phase precision are, respectively, 0.23 Omega at 48.828 kHz and 0.021 deg at 8.087 MHz when measuring a resistor 505 Omega (1%). The magnitude accuracy is 0.55% at 8.087 MHz while the phase accuracy is 0.17 deg at 6.54 MHz. In all, the stepped sine signal-to-noise ratio (SNR) is 84 dB and 65 dB at frequencies below and above 1 MHz respectively. The SNR for the multisine FRF measurements is above 65 dB (30 kHz-10 MHz). The FRA bandwidth is 610.4 mHz-12.5 MHz and the maximum FRF measurement rate exciting with multisines starting at 30 kHz is 200 spectra s(-1). Based on its technical specifications and versatility, the FRA presented can be used in many applications, e.g. for getting insight quickly into the instantaneous impedance FRF of the time-varying impedance under test.

  • A new measuring and identification approach for time-varying bioimpedance using multisine electrical impedance spectroscopy

     Sánchez Terrones, Benjamín; Louarroudi, Ebrahim; Jorge-Herrero, Eduardo; Cinca Cosculluela, Juan; Bragos Bardia, Ramon; Pintelon, R.
    Physiological measurement
    Date of publication: 2013-03
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The bioimpedance measurement/identification of time-varying biological systems Z(omega, t) by means of electrical impedance spectroscopy (EIS) is still a challenge today. This paper presents a novel measurement and identification approach, the so-called parametric-in-time approach, valid for time-varying (bio-) impedance systems with a (quasi) periodic character. The technique is based on multisine EIS. Contrary to the widely used nonparametric-in-time strategy, the (bio-) impedance Z(omega, t) is assumed to be time-variant during the measurement interval. Therefore, time-varying spectral analysis tools are required. This new parametric-in-time measuring/identification technique has experimentally been validated through three independent sets of in situ measurements of in vivo myocardial impedance. We show that the time-varying myocardial impedance Z(omega, t) is dominantly periodically time varying (PTV), denoted as Z(PTV)(omega, t)...

  • Harmonic impedance spectra identification from time-varying bioimpedance : Theory and validation

     Sánchez Terrones, Benjamín; Louarroudi, Ebrahim; Bragos Bardia, Ramon; Pintelon, Rik
    Physiological measurement
    Date of publication: 2013-10
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The harmonic impedance spectra (HIS) of a time-varying bioimpedance Z(¿, t) is a new tool to better understand and describe complex time-varying biological systems with a distinctive periodic character as, for example, cardiovascular and respiratory systems. In this paper, the relationship between the experimental setup and the identification framework for estimating Z(¿, t) is set up. The theory developed applies to frequency response based impedance measurements from noisy current-voltage observations. We prove theoretically and experimentally that a voltage source (VS) and a current source (CS) analogue front end-based measurement lead, respectively, to a closed-loop and an open-loop HIS identification problem. Next, we delve into the estimation of the HIS by treating Z(¿, t), on the one hand, as a linear time-invariant (LTI) system within a short time window; and, on the other hand, as a linear periodically time-varying (PTV) system within the entire measurement interval. The LTI approach is based on the short-time Fourier transform (STFT), while the PTV approach relies on the information that is present in the skirts of the voltage and/or current spectra. In addition, direct and indirect methods are developed for estimating the HIS by using simple as well as more sophisticated techniques. Ultimately, the HIS and their uncertainty bounds are estimated from real measurements conducted on a periodically varying dummy impedance. © 2013 Institute of Physics and Engineering in Medicine.

    The harmonic impedance spectra (HIS) of a time-varying bioimpedance Z(ω, t ) is a new tool to better understand and describe complex time-varying biological systems with a distinctive periodic character as, for example,cardiovascular and respiratory systems. In this paper, the relationship between the experimental setup and the identification framework for estimating Z(ω, t )is set up. The theory developed applies to frequency response based impedance measurements from noisy current–voltage observations.We prove theoretically and experimentally that a voltage source (VS) and a current source (CS)analogue front end-based measurement lead, respectively, to a closed-loop and an open-loop HIS identification problem. Next, we delve into the estimation of the HIS by treating Z(ω, t ), on the one hand, as a linear time-invariant (LTI) system within a short time window; and, on the other hand, as a linear periodically time-varying (PTV) system within the entiremeasurement interval. The LTI approach is based on the short-time Fourier transform (STFT), while the PTV approach relies on the information that is present in the skirts of the voltage and/or current spectra. In addition, direct and indirect methods are developed for estimating the HIS by using simple as well as more sophisticated techniques.Ultimately, theHIS and their uncertainty bounds are estimated from real measurements conducted on a periodically varying dummy impedance.

  • Novel approach of processing electrical bioimpedance data using differential impedance analysis

     Sánchez Terrones, Benjamín; Bandarenka, Aliaksandr S.; Vandersteen, Gerd; Schoukens, Johan; Bragos Bardia, Ramon
    Journal of biomedical engineering
    Date of publication: 2013-04
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The goal of this manuscript is to present a new methodology for real time analysis of time-varying electrical bioimpedance data. The approach assumes that the Fricke¿Morse model of living tissues is meaningful and valid within the measured frequency range (10 kHz to 1 MHz). The parameters of this model are estimated in the whole frequency range with the presented method based on differential impedance analysis (DIA). The numerical accuracy of the developed approach has been validated and compared to complex nonlinear least square (CNLS) approach through simulations and also with experimental data from in vivo time-varying human lung tissue bioimpedance. The new developed method has demonstrated a promising performance for fast and easily interpretable information in real time.

  • In vivo electrical bioimpedance characterization of human lung tissue during the bronchoscopy procedure. A feasibility study

     Sánchez Terrones, Benjamín; Vandersteen, Gerd; Martín Robles, Irene; Castillo Villegas, Diego; Torrego Fernández, Alfons; Riu Costa, Pere Joan; Schoukens, Johan; Bragos Bardia, Ramon
    Medical engineering and physics
    Date of publication: 2013-07
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Lung biopsies form the basis for the diagnosis of lung cancer. However, in a significant number of cases bronchoscopic lung biopsies fail to provide useful information, especially in diffuse lung disease, so more aggressive procedures are required. Success could be improved using a guided electronic biopsy based on multisine electrical impedance spectroscopy (EIS), a technique which is evaluated in this paper. The theoretical basis of the measurement method and the instrument developed are described, characterized and calibrated while the performance of the instrument is assessed by experiments to evaluate the noise and nonlinear source of errors from measurements on phantoms. Additional preliminary results are included to demonstrate that it is both feasible and safe to monitor in vivo human lung tissue electrical bioimpedance (EBI) during the bronchoscopy procedure. The time required for performing bronchoscopy is not extended because the bioimpedance measurements, present no complications, tolerance problems or side effects among any of the patients measured.

    Lung biopsies form the basis for the diagnosis of lung cancer. However, in a significant number of cases bronchoscopic lung biopsies fail to provide useful information, especially in diffuse lung disease, so more aggressive procedures are required. Success could be improved using a guided electronic biopsy based on multisine electrical impedance spectroscopy (EIS), a technique which is evaluated in this paper. The theoretical basis of the measurement method and the instrument developed are described, characterized and calibrated while the performance of the instrument is assessed by experiments to evaluate the noise and nonlinear source of errors from measurements on phantoms. Additional preliminary results are included to demonstrate that it is both feasible and safe to monitor in vivo human lung tissue electrical bioimpedance (EBI) during the bronchoscopy procedure. The time required for performing bronchoscopy is not extended because the bioimpedance measurements, present no complications, tolerance problems or side effects among any of the patients measured.

  • Monitoring cell monolayers during electroporation: Electrical impedance spectroscopy measurements

     Garcia Sanchez, Tomas; Guitart, Maria; Sánchez Terrones, Benjamín; Rosell Ferrer, Francisco Javier; Gomez Foix, Anna Maria; Bragos Bardia, Ramon
    Symposium on Measurements of Electrical Quantities
    Presentation's date: 2013-07
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Electroporation or electropermeabilization is a phenomenon observed when lipid bilayers, generally cell membranes, are exposed to high electric field pulses becoming transiently permeable to molecules that under regular conditions are not able to penetrate through them. This change in molecular permeability is believed to be produced by transient aqueous pores created in the lipidic structure and can be monitored by changes in the electrical conductivity of these membranes. The aim of this study is to use fast electrical impedance spectroscopy to measure the process of electroporation applied on cell monolayers growing attached to standard multiwell plates. The frequency response of the impedance can provide useful information about the extent of permeabilization in the cell membranes exposed to high electric fields and also the time dynamics of creation and resealing of these pores. For this study we used a microelectrode assembly specifically designed for in situ performance of both electroporation and impedance measurements. The design of the microelectrodes is based on a spiral geometry conceived to improve the uniformity of the electric field applied and to perform impedance measurements in a four-electrode configuration.

  • Contactless electrical bioimpedance system for monitoring ventilation. A biodevice for vehicle environment

     Macias Macias, Raul; Garcia Gonzalez, Miquel Angel; Ramos Castro, Juan Jose; Bragos Bardia, Ramon; Fernandez Chimeno, Mireya
    International Conference on Biomedical Electronics and Devices
    Presentation's date: 2013-02
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Nowadays, automotive companies are focused in improving road traffic safety. For that, not only the vehicle performance is improved but also the driver behavior is monitored. This could be done in many ways. One of them is to monitor a specific physiological parameter using a biodevice. That device should be reliable enough to use in a very noisy environment like a vehicle is. Furthermore, because long-term monitoring is required, any invasive and annoying method should be avoided. Therefore, an electrical bioimpedance device capable of monitoring driver ventilation using several textiles electrodes has been designed and implemented.

  • Access to the full text
    Towards an accurate bioimpedance identification  Open access

     Sánchez Terrones, Benjamín; Louarroudi, Ebrahim; Bragos Bardia, Ramon; Pintelon, Rik
    International Conference on Electrical Bio-impedance
    Presentation's date: 2013-04
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    This paper describes the local polynomial method (LPM) for estimating the time-invariant bioimpedance frequency response function (FRF) considering both the output-error (OE) and the errors-in-variables (EIV) identification framework and compare it with the traditional cross - and autocorrelation spectral analysis techniques. The bioimpedance FRF is measured with the multisine electrical impedance spectroscopy (EIS) technique. To show the overwhelming accuracy of the LPM approach, both the LPM and the classical cross - and autocorrelation spectral analysis technique are evaluated through the same experimental data coming from a nonsteady-state measurement of time-varying in vivo myocardial tissue. The estimated error sources at the measurement frequencies due to noise, Zn, and the stochastic nonlinear distortions, ZNL, have been converted to and plotted over the bioimpedance spectrum for each framework. Ultimately, the impedance spectra have been fitted to a Cole impedance model using both an unweighted and a weighted complex nonlinear least square (CNLS) algorithm. A table is provided with the relative standard errors on the estimated parameters to reveal the importance of which system identification frameworks should be used.

    This paper describes the local polynomial method (LPM) for estimating the time- invariant bioimpedance frequency response function (FRF) considering both the output-error (OE) and the errors-in-variables (EIV) identi cation framework and compare it with the traditional cross and autocorrelation spectral analysis techniques. The bioimpedance FRF is measured with the multisine electrical impedance spectroscopy (EIS) technique. To show the overwhelming accuracy of the LPM approach, both the LPM and the classical cross and autocorrelation spectral analysis technique are evaluated through the same experimental data coming from a nonsteady-state measurement of time-varying in vivo myocardial tissue. The estimated error sources at the measurement frequencies due to noise, n Z, and the stochastic nonlinear distortions, NL Z , have been converted to and plotted over the bioimpedance spectrum for each framework. Ultimately, the impedance spectra have been tted to a Cole impedance model using both an unweighted and a weighted complex nonlinear least square (CNLS) algorithm. A table is provided with the relative standard errors on the estimated parameters to reveal the importance of which system identi cation frameworks should be used.

  • Access to the full text
    Ventilation and heart rate monitoring in drivers using a contactless electrical bioimpedance system  Open access

     Macias Macias, Raul; Garcia Cabezas, Maria de la Cruz; Ramos Lara, Rafael Ramon; Bragos Bardia, Ramon; Fernandez Chimeno, Mireya
    International Conference on Electrical Bio-impedance
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Nowadays, the road safety is one of the most important priorities in the automotive industry. Many times, this safety is jeopardized because of driving under inappropriate states, e.g. drowsiness, drugs and/or alcohol. Therefore several systems for monitoring the behavior of subjects during driving are researched. In this paper, a device based on a contactless electrical bioimpedance system is shown. Using the four-wire technique, this system is capable of obtaining the heart rate and the ventilation of the driver through multiple textile electrodes. These textile electrodes are placed on the car seat and the steering wheel. Moreover, it is also reported several measurements done in a controlled environment, i.e. a test room where there are no artifacts due to the car vibrations or the road state. In the mentioned measurements, the system response can be observed depending on several parameters such as the placement of the electrodes or the number of clothing layers worn by the driver.

    Nowadays, the road safety is one of the most important priorities in the automotive industry. Many times, this safety is jeopardized because of driving under inappropriate states, e.g. drowsiness, drugs and/or alcohol. Therefore several systems for monitoring the behavior of subjects during driving are researched. In this paper, a device based on a contactless electrical bioimpedance system is shown. Using the four-wire technique, this system is capable of obtaining the heart rate and the ventilation of the driver through multiple textile electrodes. These textile electrodes are placed on the car seat and the steering wheel. Moreover, it is also reported several measurements done in a controlled environment, i.e. a test room where there are no artifacts due to the car vibrations or the road state. In the mentioned measurements, the system response can be observed depending on several parameters such as the placement of the electrodes or the number of clothing layers worn by the driver.

  • Access to the full text
    Minimal implementation of an AFE4300-based spectrometer for electrical impedance spectroscopy measurements  Open access

     Sánchez Terrones, Benjamín; Praveen, A.; Bartolome, E.; Soundarapandian, K.; Bragos Bardia, Ramon
    International Conference on Electrical Bio-impedance
    Presentation's date: 2013-04
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The AFE4300 is a new low-cost on-chip impedance spectrometer developed by Texas Instruments able to handle multiple four electrode interface measurements. In this work, we present a brief description and characterization of this device and, besides its interesting features as a body-composition impedancemeter system; we evaluate its potential to develop minimal implementations for other biomedical applications. As the case study presented in this paper, its use to monitor ventilatory time-varying bioimpedance.

    The AFE4300 is a new low-cost on-chip impedance spectrometer developed by Texas Instruments able to handle multiple four electrode interface measurements. In this work, we present a brief description and characterization of this device and, besides its interesting features as a body-composition impedancemeter system; we evaluate its potential to develop minimal implementations for other biomedical applications. As the case study presented in this paper, its use to monitor ventilatory time-varying bioimpedance.

  • Access to the full text
    Designing CDIO capstone projects: a systems thinking approach  Open access

     Alarcon Cot, Eduardo Jose; Bou Balust, Elisenda; Camps Carmona, Adriano Jose; Bragos Bardia, Ramon; Oliveras Verges, Albert; Pegueroles Valles, Josep Rafel; Sayrol Clols, Elisa; Marques Acosta, Fernando
    International CDIO Conference
    Presentation's date: 2013-06-10
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Given the all-pervasiveness of Systems thinking -which consists of thinking about things as systems- as a way of reasoning, in this work we will describe its application to make an interpretation of how to conceive and design a final year CDIO capstone course. Both the student teamwork structure as well as the complex engineering system itself addressed in the project are described in terms of entities, links, form and function, thereby pointing out their formal and functional interaction. The ultimate goal of the Systems thinking perspective is, given the necessary ingredients, to try maximizing the chances of the emergence of a fruitful capstone course, namely a culminating project that yields a set of students qualified to CDIO complex engineering systems.

    Given the all-pervasiveness of Systems thinking -which consists of thinking about things as systemsas a way of reasoning, in this work we will describe its application to make an interpretation of how to conceive and design a final year CDIO capstone course. Both the student teamwork structure as well as the complex engineering system itself addressed in the project are described in terms of entities, links, form and function, thereby pointing out their formal and functional interaction. The ultimate goal of the Systems thinking perspective is, given the necessary ingredients, to try maximizing the chances of the emergence of a fruitful capstone course, namely a culminating project that yields a set of students qualified to CDIO complex engineering systems.

  • Electrical impedance spectroscopy cell monitoring in a miniaturized bioreactor

     Martinez Teruel, Jesus; Garcia Sanchez, Tomas; Fontova, Andreu; Bragos Bardia, Ramon
    Symposium on Measurements of Electrical Quantities
    Presentation's date: 2013-07
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Electrical impedance spectroscopy measurement of biologic materials provides information about viable cell density as well as cell size and shape homogeneity. Several experimental and even commercial biomass density probes have been developed both for cell suspensions and monolayer cell cultures in the last twenty years. This communication describes the development of a set of electrodes and circuits designed to add viable biomass density measurement capability to a set of single-use miniaturized bioreactors. Two applications: adherent animal cultures and generic cell suspension cultures drive to the need of providing two electrode sets and two measurement systems with different frequency ranges.

  • Textile electrode characterization: Dependencies in the skin-clothing-electrode interface

     Macias Macias, Raul; Fernandez Chimeno, Mireya; Bragos Bardia, Ramon
    International Conference on Electrical Bio-impedance
    Presentation's date: 2013-04
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Given the advances in the technology known as smart textiles, the use of textile electrodes is more and more common. However this kind of electrodes presents some differences regarding the standard ones as the Ag-AgCl electrodes. Therefore to characterize them as best as possible is required. In order to make the characterization reproducible and repetitive, a skin dummy made of agar-agar and a standardized measurement set-up is used in this article. Thus, some dependencies in the skin-electrode interface are described. These dependencies are related to the surface of the textile electrode, the conductive material and the applied pressure. Furthermore, the dependencies on clothing in the skin-textile electrode interface are also analyzed. Thus, based on some parameters such as textile material, width and number of layers, the behavior of the interface made up by the skin, the textile electrode and clothing is depicted.

  • Modeling the non-stationary behaviour of time-varying electrical bioimpedance

     Sánchez Terrones, Benjamín; Louarroudi, Ebrahim; Pintelon, Rik; Bragos Bardia, Ramon
    Symposium on Measurements of Electrical Quantities
    Presentation's date: 2013-07
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The electrical bioimpedance (EBI) measurement of varying biological systems Z(¿,t) (e.g. the heart, the lungs,.) by means of electrical impedance spectroscopy (EIS) remains an open challenge today. Briefly stated, the bioimpedance is widely assumed to be time-invariant when it is measured with the frequency sweep EIS approach. Hence, time-varying changes are thus ignored or treated as a noise source. In this work, we attempt to model the time-variant effects and obtain a simple (periodically) time-varying [(P)TV)] electrical circuit model with (P)TV parameters from experimental in vivo EBI data using the model proposed by Fricke- Morse. The aim is then to illustrate that a limited number of harmonic components of the electrical circuit parameters, which corresponds to an integer number of the bio-system periodicity, can be used to have a realistic evolution of the bioimpedance over time as well as in frequency.

  • Gene transfer to adherent cells by in situ electroporation with a spiral microelectrode assembly

     Garcia Sanchez, Tomas; Guitart, Maria; Rosell Ferrer, Francisco Javier; Gomez Foix, Anna Maria; Bragos Bardia, Ramon
    Mediterranean Conference on Medical and Biological Engineering and Computing
    Presentation's date: 2013-09-26
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In this study, in situ electroporation is applied to adherent cell monolayers growing on standard multiwell plates. A new microelectrode assembly based on spiral geometry and fabricated using standard PCB tecnology with slight modifications is used. The system was tested in the electroporation of two different cell lines (CHO and HEK 293). A fluorescent probe was initially used to test the extent of permeabilization and adjust experimental conditions. Subsequently, plasmid DNA encoding green fluorescent protein (GFP) was transfered by electroporation. Together with these experiments, cell viability was studied. We show for permeabilization experiments up to 70 % of fluorescent cells detected in both cells lines. Successful gene electrotransfer was obtained with more than 9 % and 15 % for CHO and HEK 293 respectively. In this work we prove how our device can be used for electroporation of adherent cells under the same standard laboratory conditions as regular biochemical treatments.

  • An implantable bioimpedance monitor using 2.45 GHz band for telemetry

     Bogonez Franco, Francisco; Nescolarde Selva, Lexa Digna; Gálvez Montón, Carolina; Bragos Bardia, Ramon; Rosell Ferrer, Francisco Javier
    Physiological measurement
    Date of publication: 2013-01
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Development of in-vitro µ-channel devices for continous long-term monitoring of neuron circuit development  Open access

     Riss, Michael Martin
    Defense's date: 2013-07-08
    Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    In this thesis various methods are presented towards long-term electrophysiological monitoring of in-vitro neuron cultures in µ-channel devices. A new µ-channel device has been developed. The StarPoM device offers multiple culture chambers connected with µ-channels allowing to study communication between neuron populations. For its fabrication an advanced multi level SU-8 soft-lithography master was developed that can mold µ-channels and culture wells simultaneously. The problem of aligning features across a thick SU-8 layer has been solved by integrating a chrome mask into the substrate and then using backside exposure through the chrome mask. A long-term monitoring of neuron electrophysiological activity has been conducted continuously during 14 days in the StarPoM device. For the analysis of the recorded dataset a new software tool-chain has been created with the goal of high processing performance. The two most advanced components - O1Plot and ISI viewer - offer high performance visualization of time series data with event or interval annotation and visualization of inter-spike interval histograms for fast discovery of correlations between spike units on a device. The analysis of the 14 day recording revealed that signals can be recorded from day 4/5 onwards. While maximum spike amplitudes in kept rising during the 14 days and reached up to 3.16 mV, the average spike amplitudes reached their maximum of 0.1-0.3 mV within 6 to 8 days and then kept the amplitudes stable. To better understand the biophysics of signal generation in µ-channels, the influence of µ-channel length on signal amplitude was studied. A model based on the passive cable theory was developed showing that spike amplitude rises with channel length for µ-channels < 250 µm. In longer µ-channels, further growth of spike amplitude is inhibited by cancellation of positive and negative spike phase. Also, clogging of the µ-channel entrances by cells and debris helps to enhance signal amplification.

  • DESARROLLO DE TECNOLOGÍAS AVANZADAS DE PRODUCCIÓN Y VALIDACIÓN DE UN PRODUCTO CELULAR

     Bragos Bardia, Ramon
    Participation in a competitive project

     Share

  • Access to the full text
    Automatic system for electroporation of adherent cells growing in standard multi-well plates*  Open access

     Garcia Sanchez, Tomas; Guitart, Maria; Rosell Ferrer, Francisco Javier; Gomez Foix, Anna Maria; Bragos Bardia, Ramon
    IEEE Engineering in Medicine and Biology Society
    Presentation's date: 2012-08-28
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    In this study an automatic system is presented to perform electroporation, also known as electropermeabilization, on adherent cells. It is an intention of this system to apply electric field pulses directly to cells growing in standard multiwell plates as a step forward to include this technique in standard laboratory protocols. An interdigitated microelectrode assembly constructed with Printed Circuit Board (PCB) is placed closely above the cell monolayer, and in order to avoid direct contact with cells, small micro-separators were included in the structure. Additionally, distribution of current density was modified by filling the gap between adjacent electrodes with a non conductive material as predicted by electric field simulations. This modification helps to concentrate the electric field intensity in the region where cells are present. The device was tested using C2C12 cell line growing adhered in 24 multiwell plates and fluorescent labeled dextran FD20S as the molecule to be delivered. Successful transfection was observed with minimal invasiveness of the operation reducing the stress caused to cells.

  • Influence of electrical stimulation on 3D-cultures of Adipose Tissue Derived Progenitor Cells (ATDPCs) behavior  awarded activity

     Castells-Sala, C.; Sánchez, Benjamín; Recha-Sancho, L.; Puig, V.; Bragos Bardia, Ramon; Semino, C.E.
    IEEE Engineering in Medicine and Biology Society
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Tissue engineering has a fundamental role in regenerative medicine. Still today, the major motivation for cardiac regeneration is to design a platform that enables the complete tissue structure and physiological function regeneration of injured myocardium areas. Although tissue engineering approaches have been generally developed for two-dimensional (2D) culture systems, three-dimensional (3D) systems are being spotlighted as the means to mimic better in vivo cellular conditions. This manuscript examines the influence of electrical stimulation on 3D cultures of adipose tissue-derived progenitor cells (ATDPCs). ATDPCs cells were encapsulated into a self-assembling peptide nanoscaffold (RAD16-I) and continuously electro stimulated during 14-20 days with 2-ms pulses of 50mV/cm at a frequency of 1 Hz. Good cellular network formation and construct diameter reduction was observed in electro stimulated samples. Importantly, the process of electro stimulation does not disrupt cell viability or connectivity. As a future outlook, differentiation studies to cardiomyocytes-like cells will be performed analyzing gene profile and protein expression.

  • Access to the full text
    Towards on line monitoring the evolution of the myocardium infarction scar with an implantable electrical impedance spectrum monitoring system.  Open access

     Sánchez, Benjamín; Guasch, Assumpció; Bogonez Franco, Francisco; Gálvez-Montón, C.; Puig, V.; Prat-Vidal, C.; Semino, C.E.; Bayés-Genis, Antoni; Bragos Bardia, Ramon
    IEEE Engineering in Medicine and Biology Society
    Presentation's date: 2012-08-29
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The human heart tissue has a limited capacity for regeneration. Tissue and cellular therapies based on the use of stem cells may be useful alternatives to limit the size of myocardial infarction. In this paper, the preliminary results from an experimental campaign for on-line monitoring of myocardium scar infarction are presented. This study has been carried out under a research project that has as main objective the development and application of a bioactive patch implant for regeneration of myocardial infarction. Electrical Impedance Spectroscopy (EIS) has been chosen as a tissue state monitoring technique. What is presented in this communication is the first results of an implantable EIS measurement system which has been implanted in a subset of the animals corresponding to the control group, along one month. In all the animals, the myocardial infarction was induced by the ligation of the first circumflex marginal artery. In the animal group presented,the bioactive patch scaffold and the electrodes were implanted without the stem cells load. The scaffold is a piece of decellularized human pericardium, lyophilized and rehydrated with hydrogel RAD16-I. Nanogold particles were also placed near the electrodes to improve the electrode area conductivity. The results presented correspond to the subset of animals (n = 5), which had implanted the bioimpedance system monitoring the electrical impedance spectrum in vivo during 1 month. Two electrodes were connected to the bioactive patch implant. A total of 14 logarithmically spaced frequencies were measured every 5 minutes, from 100 Hz to 200 kHz. Results show a convergence of low-frequency and high frequency impedance magnitudes along the measurement period, which is coherent with the scar formation.

  • Minimally invasive in vivo human lung tissue bioimpedance measurements during the bronchoscopy procedure

     Sánchez, Benjamín; Vandersteen, Gerd; Martin, I.; Castillo, David; Torrego, A.; Riu Costa, Pere Joan; Schoukens, Johan; Bragos Bardia, Ramon
    IEEE Engineering in Medicine and Biology Society
    Presentation's date: 2012-08-28
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Respiratory diseases, which include diseases of the lung, pleura, bronchial tree, trachea, upper respiratory tract and of the respiratory muscles and nerves, are a common and important cause of illness and death among the population. Experimental evidences have shown that tissue lesions have different electrical properties compared with normal tissue. Therefore, lung tissues lesions may be differentiated from lung normal tissue by comparing the tissue passive electrical properties. The manuscript reports a feasibility study for minimally invasive in vivo human lung tissue tetrapolar bioimpedance measurements using a catheter during the bronchoscopy procedure based on multisine Electrical Impedance Spectroscopy (EIS) at 10 kHz - 1 MHz.

  • Interoperability platform for virtual and remote laboratories

     Fernández Ruzafa, Jose; Bragos Bardia, Ramon; Cabrera Bean, Margarita Asuncion; Abello Gamazo, Alberto; Arroyo Luna, Neus; Gonzalez Lareo, Daniel; Garofano, Francesc; Cortes, Antonia; Fabra, Alex
    International Conference on Remote Engineering and Virtual Instrumentation
    Presentation's date: 2012-07-06
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • iLabRS : A remote laboratory for science & technology in secondary education

     Garófano, F.; Gallardo Casals, Jorge; Guasch Martinez, Aleix; Sánchez Terrones, Benjamín; Bragos Bardia, Ramon
    International Conference on Remote Engineering and Virtual Instrumentation
    Presentation's date: 2012
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Electrical impedance spectroscopy measurements using a four-electrode configuration improve on-line monitoring of cell concentration in adherent animal cell cultures

     Sarró Casanovas, Enric; Lecina, M.; Fontova, A.; Solà, C.; Godia, Francesc; Cairo, Jordi Joan; Bragos Bardia, Ramon
    Biosensors and bioelectronics
    Date of publication: 2012-01-15
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    On the calculation of the D-optimal multisine excitation power spectrum for broadband impedance spectroscopy measurements  Open access

     Sánchez Terrones, Benjamín; Rojas, C.R.; Vandersteen, Gerd; Bragos Bardia, Ramon; Schoukens, Johan
    Measurement science and technology
    Date of publication: 2012-08
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The successful application of impedance spectroscopy in daily practice requires accurate measurements for modeling complex physiological or electrochemical phenomena in a single frequency or several frequencies at different (or simultaneous) time instants. Nowadays, two approaches are possible for frequency domain impedance spectroscopy measurements: (1) using the classical technique of frequency sweep and (2) using (non-)periodic broadband signals, i.e. multisine excitations. Both techniques share the common problem of how to design the experimental conditions, e.g. the excitation power spectrum, in order to achieve accuracy of maximum impedance model parameters from the impedance data modeling process. The original contribution of this paper is the calculation and design of the D-optimal multisine excitation power spectrum for measuring impedance systems modeled as 2R-1C equivalent electrical circuits. The extension of the results presented for more complex impedance models is also discussed. The influence of the multisine power spectrum on the accuracy of the impedance model parameters is analyzed based on the Fisher information matrix. Furthermore, the optimal measuring frequency range is given based on the properties of the covariance matrix. Finally, simulations and experimental results are provided to validate the theoretical aspects presented.

  • Development of a simple disposable six minibioreactor system for suspension mammalian cell culture

     Soley, A.; Fontova, A.; Gálvez, Jordi; Sarró Casanovas, Enric; Lecina, M.; Bragos Bardia, Ramon; Cairo, Jordi Joan; Godia, Francesc
    Process biochemistry
    Date of publication: 2012-04
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    A simple disposable six minibioreactor system has been developed in order to perform multiple cell culture experiments in parallel, as a tool to accelerate experimentation in cell culture optimization. The system consists of a fixed part containing all instrumentation, sensors and actuators, and a disposable part, a compact unit with six minibioreactors with 10–15 mL of working volume each. This single-use unit is made of transparent biocompatible plastic material (polystyrene). Each one of the minibioreactors is equipped with agitation, headspace aeration supply and two optical probes, one for total cells measurement and pH, and another for dissolved oxygen measurement (and consequently the evaluation of Oxygen Uptake Rate, OUR). As an example of application, the performance of the system is successfully demonstrated for the culture of hybridoma cells growing in suspension under different conditions. The results allowed confirming the reproducibility of the system, and the feasibility to follow-up continuously the differences in cell growth, pH, pO2 and OUR evolution when hybridoma cells are cultured in different experimental conditions. For this, three different sets of experiments are considered. First, the use of the same culture medium DMEM supplemented with 10% fetal calf serum in all six minibioreactors. Second, the use of DMEM supplemented with three different FCS percentages (0, 1 and 10%) in two minibioreactors each. Third, the use of two different media (DMEM supplemented with 10% FCS and a chemically defined medium) in three minibioreactors each.

  • Design and implementation of a microelectrode assembly for use on noncontact in situ electroporation of adherent cells

     Garcia Sanchez, Tomas; Sanchez Ortiz, Beatriz; Vila, Ingrid; Guitart, Maria; Rosell Ferrer, Francisco Javier; Gomez Foix, Anna Maria; Bragos Bardia, Ramon
    Journal of membrane biology
    Date of publication: 2012-10
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In situ electroporation of adherent cells provides significant advantages with respect to electroporation systems for suspension cells, such as causing minimal stress to cultured cells and simplifying and saving several steps within the process. In this study, a new electrode assembly design is shown and applied to in situ electroporate adherent cell lines growing in standard multiwell plates. We designed an interdigitated array of electrodes patterned on copper with printed circuit board technology and covered with nickel/gold. Small interelectrode distances were used to achieve effective electroporation with low voltages. Epoxy-based microseparators were constructed to avoid direct contact with the cells and to create more uniform electric fields. The device was successful in the electropermeabilization of two different adherent cell lines, C2C12 and HEK 293, as assessed by the intracellular delivery of the fluorescent dextran FD20S. Additionally, as a collateral effect, we observed cell electrofusion in HEK 293 cells, thus making this device also useful for performing cell fusion. In summary, we show the effectiveness of this minimally invasive device for electroporation of adherent cells cultured in standard multiwell plates. The cheap technologies used in the fabrication process of the electrode assembly indicate potential use as a low-cost, disposable device.

  • BROADBAND ELECTRICAL IMPEDANCE SPECTROSCOPY FOR DYNAMIC ELECTRICAL BIO-IMPEDANCE CHARACTERIZATION

     Sánchez Terrones, Benjamín
    Defense's date: 2012-01-13
    Department of Electronic Engineering, Universitat Politècnica de Catalunya
    Theses

     Share Reference managers Reference managers Open in new window

  • Desarrollo de bioimplantes para la regeneración cardiaca con células progenitoras derivadas de la grasa cardiaca, biomateriales y..

     Rosell Ferrer, Francisco Javier; Sánchez Terrones, B.; Macías Macías, Raul; Balleza, Marco; Bragos Bardia, Ramon
    Participation in a competitive project

     Share

  • Basics of broadband impedance spectroscopy measurements using periodic excitations

     Sánchez Terrones, Benjamín; Vandersteen, Gerd; Bragos Bardia, Ramon; Schoukens, Johan
    Measurement science and technology
    Date of publication: 2012-08-21
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Measuring the impedance frequency response of systems by means of frequency sweep electrical impedance spectroscopy (EIS) takes time. An alternative based on broadband signals enables the user to acquire simultaneous impedance response data collection. This is directly reflected in a short measuring time compared to the frequency sweep approach. As a result of this increase in the measuring speed, the accuracy of the impedance spectrum is compromised. The aim of this paper is to study how the choice of the broadband signal can contribute to mitigate this accuracy loss. A review of the major advantages and pitfalls of four different periodic broadband excitations suitable to be used in EIS applications is presented. Their influence on the instrumentation and impedance spectrum accuracy is analyzed. Additionally, the signal processing tools to objectively evaluate the quality of the impedance spectrum are described. In view of the experimental results reported, the impedance spectrum signalto- noise ratio (SNR Z) obtained with multisine or discrete interval binary sequence signals is about 20-30 dB more accurate than maximum length binary sequence or chirp signals. © 2012 IOP Publishing Ltd.

  • Electrode assembly for generating electric field pulses to perform electroporation to a biological sample

     Garcia Sanchez, Tomas; Rosell Ferrer, Francisco Javier; Bragos Bardia, Ramon; Gomez Foix, Anna Maria; Guitart de la Rosa, Maria; Sanchez Ortiz, Beatriz
    Date of request: 2012-05-11
    Invention patent

     Share Reference managers Reference managers Open in new window

  • Methods and devices for mechanical and electrical stimulation of stem cell monolayer and 3d cultures for tissue engineering applications

     Rosell Ferrer, Francisco Javier; Sánchez Terrones, Benjamín; Bragos Bardia, Ramon; Bayés Genís, Antonio; Llucía Valldeperas, Aida
    Date of request: 2012-06-13
    Invention patent

     Share Reference managers Reference managers Open in new window

  • Implementación y primeros resultados de la asignatura de introducción a la ingeniería en los nuevos grados de la ETSETB-UPC

     Bragos Bardia, Ramon; Pegueroles Valles, Josep Rafel; Alarcon Cot, Eduardo Jose; Camps Carmona, Adriano Jose; Sarda Ferrer, Joan; Consolacion Segura, Carolina Maria; Mussons Selles, Jaume; Pons Peregort, Olga; Oliveras Verges, Albert; Garcia Hernandez, Miguel Jesus; Onrubia Ibañez, Raul; Sayrol Clols, Elisa
    Conferencia Internacional de Fomento e Innovación con Nuevas Tecnologías en la Docencia de la Ingeniería
    Presentation's date: 2011-05-05
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    En este trabajo se describe la asignatura "Introducción a la Ingeniería de las TIC" que, basándose en restricciones y especificaciones iniciales, ha sido concebida, diseñada e implementada en la ETSETB de la UPC. Es la primera de una serie de cuatro asignaturas de proyectos distribuidas a lo largo de los grados. Está organizada en tres itinerarios paralelos que cubren la visión de sistema TIC complejo, los conceptos básicos de economía, empresa y gestión de proyectos y la realización física de un proyecto. En los primeros 5 años este proyecto se lleva a cabo sobre la plataforma SeaPerch, un pequeño robot subacuático desarrollado en el MIT Sea Grant, sobre el que se diseñan y construyen sistemas de medida y comunicaciones. Después de probarla con grupos pequeños durante dos cuatrimestres, se acomete su explotación con una previsión de 250 estudiantes en el cuatrimestre de primavera de este año.

  • Learning to conceive, design, implement and operate circuits and systems

     Alarcon Cot, Eduardo Jose; Bragos Bardia, Ramon; Sayrol Clols, Elisa
    IEEE International Symposium on Circuits and Systems
    Presentation's date: 2011
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The type of transversal competences and skills to be acquired by EE students is in open debate. It is argued in this paper that beyond core technical skills and soft skills, the competences of Conceiving, Designing, Implementing and Operating Circuits and Systems are key for a comprehensive electrical engineering education. CAS-centric learning activities and methodologies oriented to expose the student to such skills are discussed. This description is carried out both at curriculum architecture level as well as at course level, in the framework of the CDIO approach, an engineering education methodology which considers design-oriented analysis techniques included in an integral project-based learning methodology.

  • Implementation and first results of the Introduction to Engineering course in the ETSETB-UPC new degrees

     Bragos Bardia, Ramon; Pergueroles, Josep; Alarcon Cot, Eduardo Jose; Camps Carmona, Adriano Jose; Sarda Ferrer, Joan; Consolacion Segura, Carolina Maria; Mussons Selles, Jaume; Pons Peregort, Olga; Oliveras Verges, Albert; García, Miguel; Onrubia Ibañez, Raul; Sayrol Clols, Elisa
    Conferencia Internacional de Fomento e Innovación con Nuevas Tecnologías en la Docencia de la Ingeniería
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This paper describes the new course "Introduction to ICT Engineering" which has been conceived, designed and implemented at Telecom-BCN (ETSETB-UPC) from initial specifications and restrictions. It is the first of a series of four project subjects distributed throughout the new curricula. It is organized in three parallel paths covering the systemic vision of complex ICT systems, the basic concepts of economics, business and project management and the physical realization of a design-build project. In the first 5 years, this project is beling performed using the SeaPerch platform, a small underwater robot developed at MIT Sea Grant. A payload which includes measurement and communications subsystems is designed and built. After testing with small groups for two semesters, the course will be undertaken with around 250 students in the spring semester of this year.

  • Influence of the multisine excitation amplitude design for biomedical applications using impedance spectroscopy

     Sánchez, Benjamín; Bragos Bardia, Ramon; Vandersteen, Gerd
    IEEE Engineering in Medicine and Biology Society
    Presentation's date: 2011-08-30
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Electrical Impedance Spectroscopy (EIS) is a powerful tool to collect data from many biological materials in a wide variety of applications. Body composition fluid or tissue and organ state monitoring are just some examples of these applications. While the classical EIS is based on frequency sweep, the EIS technique using broadband excitations allows to acquire simultaneous impedance spectrum data. The strength and weakness of broadband EIS relies on the fact that it enables multiple Electrical Bio-Impedance (EBI) data collection in a short measuring time but at the cost of losing impedance spectrum accuracy. In general, there is a relationship between the broadband excitation time/frequency properties and the final EBI's accuracy obtained. This paper studies the influence of the multisine broadband excitation amplitude's design over the EBI accuracy by means of the resultant Noise-to-Signal Ratio (NSR) obtained when measuring with a custom impedance analyzer. Theory has been supported by a set of validation experiments.

  • In-cycle myocardium tissue electrical impedance monitoring using broadband impedance spectroscopy

     Sánchez, Benjamín; Vandersteen, Gerd; Rosell Ferrer, Francisco Javier; Cinca Cosculluela, Juan; Bragos Bardia, Ramon
    IEEE Engineering in Medicine and Biology Society
    Presentation's date: 2011
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Optimal multisine excitation design for broadband electrical impedance spectroscopy

     Sánchez Terrones, Benjamín; Bragos Bardia, Ramon; Vandersteen, Gerd; Schoukens, Johan
    Measurement science and technology
    Date of publication: 2011-11
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Simple voltage-controlled current source for wideband electrical bioimpedance spectroscopy: circuit dependences and limitations

     Seoane, F.; Macías Macías, Raul; Bragos Bardia, Ramon; Lindecrantz, K.
    Measurement science and technology
    Date of publication: 2011
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In this work, the single Op-Amp with load-in-the-loop topology as a current source is revisited. This circuit topology was already used as a voltage-controlled current source (VCCS) in the 1960s but was left unused when the requirements for higher frequency arose among the applications of electrical bioimpedance (EBI). The aim of the authors is not only limited to show that with the currently available electronic devices it is perfectly viable to use this simple VCCS topology as a working current source for wideband spectroscopy applications of EBI, but also to identify the limitations and the role of each of the circuit components in the most important parameter of a current for wideband applications: the output impedance. The study includes the eventual presence of a stray capacitance and also an original enhancement, driving with current the VCCS. Based on the theoretical analysis and experimental measurements, an accurate model of the output impedance is provided, explaining the role of the main constitutive elements of the circuit in the source's output impedance. Using the topologies presented in this work and the proposed model, any electronic designer can easily implement a simple and efficient current source for wideband EBI spectroscopy applications, e.g. in this study, values above 150 kΩ at 1 MHz have been obtained, which to the knowledge of the authors are the largest values experimentally measured and reported for a current source in EBI at this frequency.

  • Microchannel enhanced neuron-computer interface: design, fabrication, biophysics of signal generation, signal strength optimization, and its applications to ion-channel screening and basic neuroscience research  Open access

     Wang, Ling
    Defense's date: 2011-12-15
    Department of Automatic Control, Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    En el presente trabajo, utilizamos técnicas de microfabricación, simulaciones numéricas, experimentos de electrofisiología para explorar la viabilidad en me- jorar la interface ordenador-neurona a través de microcanales, y la biofísica para la generación de señales en los dispositivos con microcanales. También demos- tramos que los microcanales pueden ser usados como una técnica prometedora con alto rendimiento en el muestreo automático de canales iónicos a nivel subce- lular. Finalmente, se ha diseñado, fabricado y probado el micropozo-microcanal como modificación adicional a los arreglos de multielectrodos, permitiendo una alta ganancia en la relación señal/ ruido (en inglés Signal to Noise Ratio SNR), y el registro de múltiples-lugares en poblaciones de baja densidad de redes neu- ronales del hipocampo in vitro. Primero, demostramos que son de alto rendimiento los microcanales de bajo costo con interface neurona-electrodo, para el registro extracelular de la activi- dad neuronal con baja complexidad, por periodos estables de larga duración y con alta ganancia SNR. En seguida, se realiza un estudio mediante experimentos y simulaciones nu- méricas de la biofísica para la generación de las señales obtenidas de los dispositi- vos con microcanales. Basados en los resultados, racionalizamos y demostramos como es que la longitud del canal (siendo 200 μm) y la sección transversal del microcanal (siendo 12 μm2) canaliza a los potenciales de acción para estar dentro del rango de milivolts. A pesar del bajo grado de complexidad envuelto en la fabricación y aplicación, los dispositivos con microcanales otorgan una sola media de valor SNR de 101 76, lo cual es favorablemente comparable con la SNR que se obtiene de desarrollos recientes que emplean electrodos curados con CNT y Si-NWFETs. Más aún, nosotros demostramos que el microcanal es una técnica promete- dora para el alto rendimiento del muestro automático de canales iónicos a nivel subcelular: (1) Información experimental y simulaciones numéricas sugieren que las señales registradas sólo afectan los parches membranales localizados dentro del microcanal o alrededor de 100 μm de las entradas del microcanal. (2) La transferencia de masa de los componentes químicos en los microcanales fue ana- lizada por experimentos y simulaciones FEM. Los resultados muestran que los microcanales que contienen glía y tejido neuronal pueden funcionar como barre- ra de fluido/química. Los componentes químicos pueden ser solamente aplicados a diferentes compartimentos a nivel subcelular. Finalmente, basado en simulaciones numéricas y resultados experimentales, se propone que del micropozo-microcanal, obtenido de la modificación de MEA (MWMC-MEA), la longitud óptima del canal debe ser 0,3 mm y la posición 1 óptima del electrodo intracanal, hacia la entrada más cercana del microcanal, debe ser 0,1 mm. Nosotros fabricamos un prototipo de MWMC-MEA, cuyo hoyo pasante sobre las películas de Polydimethylsiloxane (PDMS) fue microtrabajado a través de la técnica de grabados reactivos de plasma de iones. La baja densidad del cultivo (57 neuronas /mm2) en el MWMC-MEAs permitió que las neuronas vivieran al menos 14 días, con lo que la señal neuronal con la máxima SNR obtenida fue de 142. 2

    In this present work, we used microfabrication techniques, numerical simulations, electrophysiological experiments to explore the feasibility of enhancing neuron-computer interfaces with microchannels and the biophysics of the signal generation in microchannel devices. We also demonstrate the microchannel can be used as a promising technique for high-throughput automatic ion-channel screening at subcellular level. Finally, a microwell-microchannel enhanced multielectrode array allowing high signal-to-noise ratio (SNR), multi-site recording from the low-density hippocampal neural network in vitro was designed, fabricated and tested. First, we demonstrate using microchannels as a low-cost neuron-electrode interface to support low-complexity, long-term-stable, high SNR extracellular recording of neural activity, with high-throughput potential. Next, the biophysics of the signal generation of microchannel devices was studied by experiments and numerical simulations. Based on the results, we demonstrate and rationalize how channels with a length of 200 μm and channel cross section of 12 μm2 yielded spike sizes in the millivolt range. Despite the low degree of complexity involved in their fabrication and use, microchannel devices provided a single-unit mean SNR of 101 76, which compares favourably with the SNR obtained from recent developments employing CNT-coated electrodes and Si-NWFETs. Moreover, we further demonstrate that the microchannel is a promising technique for high-throughput automatic ion-channel screening at subcellular level: (1) Experimental data and numerical simulations suggest that the recorded signals are only affected by the membrane patches located inside the microchannel or within 100 μm to the microchannel entrances. (2) The mass transfer of chemical compounds in microchannels was analyzed by experiments and FEM simulations. The results show that the microchannel threaded by glial and neural tissue can function as fluid/chemical barrier. Thus chemical compounds can be applied to different subcellular compartments exclusively. Finally, a microwell-microchannel enhanced MEA (MWMC-MEA), with the optimal channel length of 0.3 mm and the optimal intrachannel electrode position of 0.1 mm to the nearest channel entrance, was proposed based on numerical simulation and experiment results. We fabricated a prototype of the MWMCMEA, whose through-hole feature of Polydimethylsiloxane film (PDMS) was micromachined by reactive-ion etching. The low-density culture (57 neurons/mm2) were survived on the MWMC-MEAs for at least 14 days, from which the neuronal signal with the maximum SNR of 142 was obtained.

  • Transoesophageal bioimpedance analysis for the detection of graft rejection after cardiac transpantation

     Giovinazzo, Giuseppe
    Defense's date: 2011-02-25
    Department of Electronic Engineering, Universitat Politècnica de Catalunya
    Theses

     Share Reference managers Reference managers Open in new window

  • FP7-262029-DRYCHECK

     Rosell Ferrer, Francisco Javier; Riu Costa, Pere Joan; Guasch Martinez, Aleix; Bragos Bardia, Ramon
    Participation in a competitive project

     Share

  • DESARROLLO DE TECNOLOGÍAS AVANZADAS DE PRODUCCIÓN Y VALIDACIÓN DE UN PRODUCTO CELULAR

     Rosell Ferrer, Francisco Javier; Riu Costa, Pere Joan; Bragos Bardia, Ramon
    Participation in a competitive project

     Share

  • Novel estimation of the electrical bioimpedance using the local polynomial method. Application to in vivo real-time myocardium tissue impedance characterization during the cardiac cycle

     Sánchez Terrones, Benjamín; Schoukens, Johan; Bragos Bardia, Ramon; Vandersteen, Gerd
    IEEE transactions on biomedical engineering
    Date of publication: 2011-11-18
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Classicalmeasurements ofmyocardium tissue electrical impedance for characterizing the morphology of myocardium cells, as well as cell membranes integrity and intra/extra cellular spaces, are based on the frequency-sweep electrical impedance spectroscopy (EIS) technique. In contrast to the frequency-sweep EIS approach, measuring with broadband signals, i.e., multisine excitations, enables to collect, simultaneously, multiple myocardium tissue impedance data in a short measuring time. However, reducing the measuring time makes the measurements to be prone to the influence of the transients introduced by noise and the dynamic time-varying properties of tissue. This paper presents a novel approach for the impedance-frequency-response estimation based on the local polynomial method (LPM). The fast LPM version presented rejects the leakage error’s influence on the impedance frequency response when measuring electrical bioimpedance in a short time. The theory is supported by a set of validation measurements. Novel preliminary experimental results obtained from real-time in vivo healthy myocardium tissue impedance characterization within the cardiac cycle using multisine excitation are reported.

  • Mixed integration of CDIO skills into telecommunication engineering curricula

     Sayrol Clols, Elisa; Bragos Bardia, Ramon; Alarcon Cot, Eduardo Jose; Cabrera Bean, Margarita Asuncion; Calveras Auge, Ana M.; Comellas Colome, Jaume; O'callaghan Castella, Juan Manuel; Pegueroles Valles, Josep Rafel; Pla, E; Prat Viñas, Luis; Saez Moreno, German; Sardà ., J; Tallon Montoro, Carme
    Elektronika ir elektrotechnika
    Date of publication: 2010
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    GILABVIR: Virtual laboratories and remote laboratories in engineering. A teaching innovation group of interest  Open access

     Cabrera Bean, Margarita Asuncion; Bragos Bardia, Ramon; Pérez, Marimar; Mariño Acebal, Jose Bernardo; Rius Casals, Juan-manuel; Gomis Bellmunt, Oriol; Casañ Guerrero, Maria Jose; Gironella i Cobos, Framcesc Xavier
    IEEE Annual Engineering Education Conference
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    GILABVIR (Grup d’Interès en Laboratoris Virtuals i Remots) is a recently created Virtual and Remote Laboratory Group of Interest of UPC (Universitat Politècnica de Catalunya) and it is integrated in a more general teaching innovation project. RIMA [1], [2]. RIMA has been developed to promote research on the use of innovative learning methodologies applied to engineering education and it was specially created to assess in the new European higher education adaptation process.

  • Proceso de inversión de competencias genéricas en los nuevos planes de estudios de grado de la ETSETB de acuerdo con el modelo CDIO

     Bragos Bardia, Ramon; Alarcon Cot, Eduardo Jose; Cabrera Bean, Margarita Asuncion; Calveras Auge, Ana M.; Comellas Colome, Jaume; O'callaghan Castella, Juan Manuel; Pegueroles Valles, Josep Rafel; Prat Viñas, Luis; Saez Moreno, German; Sardà ., J; Sayrol Clols, Elisa
    Congreso de Tecnologías Aplicadas a la Enseñanza de la Electrónica
    Presentation's date: 2010-04-13
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    A remote laboratory to promote the interaction between university and secondary education  Open access

     Cabrera Bean, Margarita Asuncion; Bragos Bardia, Ramon; Pérez, Marimar; Sánchez Terrones, B.; Guasch Petit, Antonio; Garófano, F.; Gomis Bellmunt, Oriol; Rius Casals, Juan-manuel; Casañ Guerrero, Maria Jose
    IEEE Annual Engineering Education Conference
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    iLabRS is a remote laboratory developed in Telecom BCN, the Telecom and Electronics Engineering School of the UPC with the key participation of a Secondary Education Technology teacher. Students and teachers can access to real experiments in the electronics and physics areas using a web browser. The remote experiments have been designed to partially cover the technology curriculum in the last two high school years with a triple goal: (1) to enrich the set of laboratory experiences available in High Schools, (2) to provide a clear example of the possibilities of internet-based technologies and (3) to promote the interaction between University and Secondary Education. Currently, there are 13 different experiments available. A pilot evaluation experience was carried out, in collaboration with 7 High Schools and around 100 students participating. In the experience assessment, the students gave a mark of 3.8/5 and the teachers of 4.4/5.

  • Access to the full text
    Plataforma modular para el desarrollo de laboratorios remotos  Open access

     Bragos Bardia, Ramon; Gallardo Casals, Jordi; Amoros, J.G.; Sánchez Terrones, B.; Anton, D.; Tallon Montoro, Carme; Garófano, F.; Guasch Martinez, Aleix; Anton Cardona, Daniel
    Congreso de Tecnologías Aplicadas a la Enseñanza de la Electrónica
    Presentation's date: 2010-04-13
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Se presenta una plataforma modular de bajo coste que permite múltiples réplicas para el desarrollo de laboratorios remotos. A modo de resumen, las funcionalidades que ofrece son un sistema de adquisición, conexión a Ethernet y la opción de conectar distintas placas específicas para realizar los experimentos a distancia. El interfaz de usuario se realiza mediante paneles remotos de LabVIEW a los que el usuario accede a través de internet. Esta comunicación presenta iLabRS, el laboratorio remoto resultante basados en esta plataforma y las mejoras que se están llevando a cabo.