IMSE Publications

Found results matching for:

Author: Pablo Pérez García
Year: Since 2002

Journal Papers


A Plethysmography Capacitive Sensor for Real-Time Monitoring of Volume Changes in Acute Heart Failure
E. Rando, P. Perez, S. Fernandez-Scagliusi, F.J. Medrano, G. Huertas and A. Yufera
Journal Paper · IEEE Transactions on Instrumentation and Measurement, vol. 70, article 4005912, 2021
abstract      doi      

A small, wearable, low-weight, and low-power-consumption device for plethysmography capacitive sensing is proposed herein. The device allows carrying out real-time monitoring of leg volume changes in patients suffering from heart failure (HF) conditions. The dynamic of fluid overload in patients with acute HF serves as a prognosis marker for this type of severe disease and, consequently, these patients can benefit from a wearable monitoring system to measure their body volume evolution during and after hospitalization. Our approach is based on contactless capacitive wearable structures implemented by two different sensor realizations located in the ankle: 180°-parallel capacitor plates (two modes of operations are compared, with the patient’s body connected to ground and to the average voltage between plates) and planar-parallel capacitor plates whose overlapped surface varies with the volume of the patient’s leg. Both realizations exhibit good sensitivity to leg volume changes. The acquisition of capacitance values is performed via a simple circuit that achieves notable performance in simulated volume analysis. A preliminary pilot clinical prototype is described as well.

A computer-aided design tool for biomedical OBT sensor tuning in cell-culture assays
P. Pérez, J.A. Serrano, M.E. Martín, P. Daza, G. Huertas and A. Yúfera
Journal Paper · Computer Methods and Programs in Biomedicine, vol. 200, article 105840, 2021
abstract      doi      

It is proposed a computer program for system design of biosensors applied to monitoring cell culture dynamics. The program allows obtaining confident system information by electrical stimulation. All system components (electrodes, cell culture and test circuits) are properly modelled. The employed procedure can be applied to any other 2D electrode layout or alternative circuit technique for ECIS test. Finally, deep insight information on cell size, number, and time-division can be extracted from the comparison with real cell culture assays in the future.

Alternative General Fitting Methods for Real-Time Cell-Count Experimental Data Processing
J.A. Serrano, P. Perez, G. Huertas and A. Yufera
Journal Paper · IEEE Sensors Journal, vol. 20, no. 24, pp 15177-15184, 2020
abstract      doi      

This paper reports two general methods for extraction of cell-electrode electrical model parameters in cell culture (CC) assays. The presented approaches can be applied to CC assays based on electrical cell-substrate impedance spectroscopy (ECIS) technique for real-time supervision, providing the cell number per square centimeter, i.e., the cell density, as main result. Both of the proposed methods - minimization of system equations and data predictive model - search, during the experiment, the optimum values of the electrical model parameters employed for the electrode-cell model. The results of this search enable a fast and efficient calculation of the involved cell-electrode model parameters and supply real-time information on the cell number. For the sake of experimental validation, we applied the proposed methods to practical CCs in cell growth assays with a cell line of AA8 Chinese hamster ovarian fibroblasts and the Oscillation Based Test technique for bioimpedance measurements. These methods can be easily extrapolated to any general cell lines and/or other bioimpedance test methodologies.

3D-printed sensors and actuators in cell culture and tissue engineering: Framework and research challenges
P. Pérez, J.A. Serrano and A. Olmo
Journal Paper · Sensors, vol. 20, no. 19, article 5617, 2020
abstract      doi      pdf

Three-dimensional printing technologies have been recently proposed to monitor cell cultures and implement cell bioreactors for different biological applications. In tissue engineering, the control of tissue formation is crucial to form tissue constructs of clinical relevance, and 3D printing technologies can also play an important role for this purpose. In this work, we study 3D-printed sensors that have been recently used in cell culture and tissue engineering applications in biological laboratories, with a special focus on the technique of electrical impedance spectroscopy. Furthermore, we study new 3D-printed actuators used for the stimulation of stem cells cultures, which is of high importance in the process of tissue formation and regenerative medicine. Key challenges and open issues, such as the use of 3D printing techniques in implantable devices for regenerative medicine, are also discussed.

Electrical modeling of the growth and differentiation of skeletal myoblasts cell cultures for tissue engineering
A. Olmo, Y. Yuste, J.A. Serrano, A. Maldonado-Jacobi, P. Pérez, G. Huertas, S, Pereira, A. Yufera and F. de la Portilla
Journal Paper · Sensors, vol. 20, no. 11, article 3152, 2020
abstract      doi      pdf

In tissue engineering, of utmost importance is the control of tissue formation, in order to form tissue constructs of clinical relevance. In this work, we present the use of an impedance spectroscopy technique for the real-time measurement of the dielectric properties of skeletal myoblast cell cultures. The processes involved in the growth and differentiation of these cell cultures in skeletal muscle are studied. A circuit based on the oscillation-based test technique was used, avoiding the use of high-performance circuitry or external input signals. The effect of electrical pulse stimulation applied to cell cultures was also studied. The technique proved useful for monitoring in real-time the processes of cell growth and estimating the fill factor of muscular stem cells. Impedance spectroscopy was also useful to study the real-time monitoring of cell differentiation, obtaining different oscillation amplitude levels for differentiated and undifferentiated cell cultures. Finally, an electrical model was implemented to better understand the physical properties of the cell culture and control the tissue formation process.

Evaluation of Implanted Stent Occlusion Status Based on Neointimal Tissue Bioimpedance Simulations
J.M. Portillo-Anaya, P. Perez, A. Olmo, G. Huertas and A. Yufera
Journal Paper · Journal of Sensors, vol. 2019, article 7167186, 2019
abstract      doi      

This paper describes the characterization of the light hole, also known as the lumen, in implanted stents affected by restenosis processes using bioimpedance (BI) as a biomarker. The presented approach will enable real-time monitoring of lumens in implanted stents. The basis of the work hereby reported is the fact that neointimal tissues involved in restenosis can be detected and measured through their impedance properties, namely, conductivity and permittivity. To exploit these properties, a 4-electrode setup for BI measurement is proposed. This setup allows study of the influence of the various tissues involved in restenosis fat, muscle, fibre, and endothelium, together with the blood, on the BI value at several frequencies. In addition, BI simulation tests were performed using the electric physics module available in COMSOL Multiphysics®. Interestingly, fat constitutes the most influential layer on the value of impedance (measured in kΩ/μm-magnitude change per micrometre of lumen occlusion). A case study using a standard stent is also presented. In this study, where the involved tissues and blood were simultaneously considered, we conducted an analysis for stable and vulnerable plaques in restenosis test situations. In this regard, the proposed method is useful to test the stent obstruction and detect potential dangerous cases due to nonstable fat accumulation.

Data-Analytics Modeling of Electrical Impedance Measurements for Cell Culture Monitoring
E. García, P. Pérez, A. Olmo, R. Díaz, G. Huertas and A. Yúfera
Journal Paper · Sensors, vol. 19, no. 21, art. 4639, 2019
abstract      doi      pdf

High-throughput data analysis challenges in laboratory automation and lab-on-a-chip devices´ applications are continuously increasing. In cell culture monitoring, specifically, the electrical cell-substrate impedance sensing technique (ECIS), has been extensively used for a wide variety of applications. One of the main drawbacks of ECIS is the need for implementing complex electrical models to decode the electrical performance of the full system composed by the electrodes, medium, and cells. In this work we present a new approach for the analysis of data and the prediction of a specific biological parameter, the fill-factor of a cell culture, based on a polynomial regression, data-analytic model. The method was successfully applied to a specific ECIS circuit and two different cell cultures, N2A (a mouse neuroblastoma cell line) and myoblasts. The data-analytic modeling approach can be used in the decoding of electrical impedance measurements of different cell lines, provided a representative volume of data from the cell culture growth is available, sorting out the difficulties traditionally found in the implementation of electrical models. This can be of particular importance for the design of control algorithms for cell cultures in tissue engineering protocols, and labs-on-a-chip and wearable devices applications.

Electrical pulse stimulation of skeletal myoblasts cell cultures with simulated action potentials
P. Villanueva, S. Pereira, A. Olmo, P. Pérez, Y. Yuste, A. Yúfera and F. de la Portilla
Journal Paper · Journal of Tissue Engineering and Regenerative Medicine, vol. 13, no. 7, pp 1265-1269, 2019
abstract      doi      

Electrical pulse stimulation has an important effect on skeletal muscle development and maturation. However, the methodology for controlling these stimulation parameters to develop in vitro functional skeletal muscle tissues remains to be established. In this work, we have studied the effect of simulated action potentials on the growth and differentiation of skeletal myoblast cell cultures. A circuit simulating action potentials of 0.15 and 0.3 V/mm, at a frequency of 1 Hz and with a 4-ms pulse width, is proposed. Results show an important improvement of the growth rate and differentiation of myoblasts at a voltage of 0.15 V/mm. Parameters such as electrodes geometry or type of signals must be considered in the development of in vitro skeletal muscle.

Remote Cell Growth Sensing using Self-Sustained Bio-Oscillations
P. Pérez, G. Huertas, A. Olmo, A. Maldonado-Jacobi, J. Serrano, M. Martín, P. Daza and A. Yúfera
Journal Paper · Sensors, vol. 18, no. 8, art. 2550, 2018
abstract      doi      pdf

A smart sensor system for cell culture real-time supervision is proposed, allowing for a significant reduction in human effort applied to this type of assay. The approach converts the cell culture under test into a suitable "biological" oscillator. The system enables the remote acquisition and management of the "biological" oscillation signals through a secure web interface. The indirectly observed biological properties are cell growth and cell number, which are straightforwardly related to the measured bio-oscillation signal parameters, i.e., frequency and amplitude. The sensor extracts the information without complex circuitry for acquisition and measurement, taking advantage of the microcontroller features. A discrete prototype for sensing and remote monitoring is presented along with the experimental results obtained from the performed measurements, achieving the expected performance and outcomes.

An empirical-mathematical approach for calibration and fitting cell-electrode electrical models in bioimpedance tests
J.A. Serrano, G. Huertas, A. Maldonado-Jacobi, A. Olmo, P. Pérez, M.E. Martín, P. Daza and A. Yúfera
Journal Paper · Sensors, vol. 18, no. 7, article 2354, 2018
abstract      doi      pdf

This paper proposes a new yet efficient method allowing a significant improvement in the on-line analysis of biological cell growing and evolution. The procedure is based on an empirical-mathematical approach for calibration and fitting of any cell-electrode electrical model. It is valid and can be extrapolated for any type of cellular line used in electrical cell-substrate impedance spectroscopy (ECIS) tests. Parameters of the bioimpedance model, acquired from ECIS experiments, vary for each cell line, which makes obtaining results difficult and -to some extent-renders them inaccurate. We propose a fitting method based on the cell line initial characterization, and carry out subsequent experiments with the same line to approach the percentage of well filling and the cell density (or cell number in the well). To perform our calibration technique, the so-called oscillation-based test (OBT) approach is employed for each cell density. Calibration results are validated by performing other experiments with different concentrations on the same cell line with the same measurement technique. Accordingly, a bioimpedance electrical model of each cell line is determined, which is valid for any further experiment and leading to a more precise electrical model of the electrode-cell system. Furthermore, the model parameters calculated can be also used by any other measurement techniques. Promising experimental outcomes for three different cell-lines have been achieved, supporting the usefulness of this technique.

Sensing Cell-Culture Assays with Low-Cost Circuitry
P. Pérez, G. Huertas, A. Maldonado-Jacobi, M. Martín, J.A. Serrano, A. Olmo, P. Daza and A. Yúfera
Journal Paper · Scientific Reports, vol. 8, no. 1, article 8841, 2018
abstract      doi      pdf

An alternative approach for cell-culture end-point protocols is proposed herein. This new technique is suitable for real-time remote sensing. It is based on Electrical Cell-substrate Impedance Spectroscopy (ECIS) and employs the Oscillation-Based Test (OBT) method. Simple and straightforward circuit blocks form the basis of the proposed measurement system. Oscillation parameters - frequency and amplitude - constitute the outcome, directly correlated with the culture status. A user can remotely track the evolution of cell cultures in real time over the complete experiment through a web tool continuously displaying the acquired data. Experiments carried out with commercial electrodes and a well-established cell line (AA8) are described, obtaining the cell number in real time from growth assays. The electrodes have been electrically characterized along the design flow in order to predict the system performance and the sensitivity curves. Curves for 1-week cell growth are reported. The obtained experimental results validate the proposed OBT for cell-culture characterization. Furthermore, the proposed electrode model provides a good approximation for the cell number and the time evolution of the studied cultures.

Microcontroller-Based Sinusoidal Voltage Generation for Electrical Bio-Impedance Spectroscopy Applications
J.A. Castro, A. Olmo, P. Pérez and A. Yúfera
Journal Paper · Journal of Computer and Communications, vol. 4, no. 17, pp 51-58, 2016
abstract      doi      pdf

A sinusoidal voltage wave generator is proposed based on the use of micro-processor digital signals with programmable duty-cycles, with application to real-time Electrical Cell-substrate Impedance Spectroscopy (ECIS) assays in cell cultures. The working principle relies on the time convolution of the programmed microcontroller (μC) digital signals. The expected frequency is easily tuned on the bio-impedance spectroscopy range [100 Hz, 1 MHz] thanks to the μC clock frequency selection. This system has been simulated and tested on the 8 bits μC ArduinoTM Uno with ATmega328 version. Results obtained prove that only three digital signals are required to fit the general specification in ECIS experiments, below 1% THD accuracy, and show the appropriateness of the system for the real-time monitoring of this type of biological experiments.

Conferences


Modeling Edema Evolution with Electrical Bioimpedance: Application to Heart Failure Patients
M. Puertas, L. Giménez, A. Pérez, S.F. Scagliusi, P. Pérez, A. Olmo, G. Huertas, J. Medrano and A. Yúfera
Conference · Conference on Design of Circuits and Integrated Systems DCIS 2021
abstract     

This work presents a procedure to calculate the edema time-evolution in HF patients from bioimpedance (BI) measurements performed in their corresponding legs. The data for diagnosis are picked-up using a wearable device specifically developed for the application in accuted heart failure patients in the context of HF-VOLUM project. The main objective of the project is the calculus of the edema or volume evaluation in legs as a consequence of liquid accumulation, basically, water, as a procedure to real time supervision of the patient health. For that, as an initial step, a calibration method is proposed to extract the extracellular volume component from bioimpedance measurements done in healthy subjects, and then, applied to unhealthy ones. In the method, intra and extra cellular resistances are calculated from fitted Cole-Cole model parameters derived from BI spectroscopy measurements, and employed for the calculus of the extracellular resistance. Results obtained in a small pilot assay, with four healthy subject and two heart failure subjects, show sensitivities in the ranges of -5.2 to -1.94 ml/Ω in leg volume for healthy people, and -122.4 to -41.47 ml/Ω in unhealthy people. Measurements taken at test point of 50 kHz frequency show comparable sensitivities. We expect to extend this pilot to a wider sample to further validation and confirmation of the proposed calibration method for wearable device here described.

Effects of Electrical Fields on Neuroblastoma (N2A) Cell Differentiation: Preliminary Results
D. Martin-Fernández, P. Pérez-García, M.E. Martín, P. Daza, J.A. Serrano-Viseas, G. Huertas and A. Yúfera
Conference · International Conference on Biomedical Electronics and Devices BIODEVICES 2021
abstract     

This work describes Electrical Stimulations (ES) assays on stem cells. The neuroblastoma (N2A) cell linage was submitted to several electrical fields to enable and enhance its differentiation toward neurons. Both Direct Current (DC) and Alternated Current (AC) time dependent electric field protocols were applied to N2A cell culture under differentiation conditions, obtaining different responses. Control and electrically excited samples’ number of differentiated cells and neurite lengths were measure after differentiation. Results showed that DC fields have a strong influence on N2A differentiation since the percentage of differentiated cells and the neurites lengths were the highest. In addition, a significant alignment of neurites measured with the applied electrical field has been detected, which demonstrates the high sensitivity of differentiation processes to electrical field polarity.

Designing bioimpedance based sensors for cell cultures test
P. Perez, A. Yúfera, J.A. Serrano and G. Huertas
Conference · Conference on Design of Circuits and Integrated Systems DCIS 2020
abstract     

This work presents a procedure to improve biomedical sensor design flow by including information taken from sensor technical specifications and data from its biomedical dynamics, in our case, the system described is sensing cell culture assays. The main structural components of a biosensor for cell culture with real-time monitoring are analyzed, modelled and incorporated into the system design flow in such a way that the resulting sensor designed by the procedure will engender analysis of the circuits' constraints and cell sensitivity, together with the dynamics imposed by the living cells. The time evolution for general cell cultures is reproduced, and an image processing approach is applied to transduce the cell increments to the cell-electrode parameters as previously defined. The proposed tool is applied to the Electrical Cell-Substrate Sensing (ECIS) technique for cell culture test using herein the Oscillation Based Test (OBT) as a bioimpedance testing method. Other bioimpedance test techniques could be directly implemented into the proposed tool to profit similar results. The aforementioned tool, that fully models a cell-culture assay, was experimentally tested using the AA8 cell line, and the results presented in this paper validating the tool predictions.

A plethysmographic sensor for monitoring volumen changes in cardiovascular pathologies
E. Rando, P. Pérez, G. Huertas and A. Yúfera
Conference · Conference on Design of Circuits and Integrated Systems DCIS 2019
abstract     

This paper presents a capacitive system capable of performing leg volume change monitorization in patients suffering from Heart Failure (HF) conditions. The body volume evolution serves as a prognosis marker for this kind of patients, such patients can benefit from a wearable monitorization system. The proposal is based on a contactless capacitive wearable structure implemented by a two-plate plane-parallel capacitor geometry. The system exhibits sensitivity to leg volume change and the sensor curves are provided. A 2.5x2.5cm capacitive electrode design will generate capacitive values within the range [1-2] pF. Acquisition of the capacitance value is performed via an electronic differentiator implemented using op-amps, illustrating good results in simulated volume analysis implemented using pspice.

A 32 Input Multiplexed Channel Analog Front-End with Spatial Delta Encoding Technique and Differential Artifacts Compression
N. Pérez-Prieto, R. Fiorelli, J.L. Valtierra, P. Pérez-García, M. Delgado-Restituto and A. Rodríguez-Vázquez
Conference · IEEE Biomedical Circuits and Systems Conference BioCAS 2019
abstract     

This paper describes a low-noise, low-power and high dynamic range analog front-end intended for sensing neural signals. In order to reduce interface area, a 32-channel multiplexer is implemented on circuit input. Furthermore, a spatial delta encoding is proposed to compress the signal range. A differential artifact compression algorithm is implemented to avoid saturation in the signal path, thus enabling reconstruct or suppressing artifacts in digital domain. The proposed design has been implemented using 0.18 μm TSMC technology. Experimental results shows a power consumption per channel of 1.0 μW, an input referred noise of 1.1 μVrms regarding the bandwidth of interest and a dynamic range of 91 dB.

Characterization of Implanted Stents through Neointimal Tissue Bioimpedance Simulations
J.M. Portillo-Anaya, P. Pérez, G. Huertas, A. Olmo, J.A. Serrano, A. Maldonado-Jacobi and A. Yúfera
Conference · International Conference of the IEEE Engineering in Medicine and Biology Society EMBC2019
abstract     

This work describes how is possible the definition of the light hole or lumen in implanted stents affected by restenosis processes using the BioImpedance (BI) as biomarker. The main approach is based on the fact that neointimal tissues implied in restenosis can be detected and measured thanks to their respective conductivity and dielectric properties. For this goal, it is proposed a four-electrode setup for bioimpedance measurement. The influence of the several involved tissues in restenosis: fat, muscle, fiber, endothelium and blood, have been studied at several frequencies, validating the setup and illustrating the sensitivity of each one. Finally, a real example using a standard stent, has been analyzed for stable and vulnerable plaques in restenosis test cases, demonstrating that the proposed method is useful for the stent obstruction test. Bioimpedance simulation test has been performed using the electric physics module in COMSOL Multiphysics®.

Practical Characterization of Cell-Electrode Electrical Models in Bio-Impedance Assays
J.A. Serrano, P. Pérez, A. Maldonado, M. Martín, A. Olmo, P. Daza, G. Huertas and A. Yúfera
Conference · International Conference on Biomedical Electronics and Devices BIODEVICES 2018
abstract     

This paper presents the fitting process followed to adjust the parameters of the electrical model associated to a cell-electrode system in Electrical Cell-substrate Impedance Spectroscopy (ECIS) technique, to the experimental results from cell-culture assays. A new parameter matching procedure is proposed, under the basis of both, mismatching between electrodes and time-evolution observed in the system response, as consequence of electrode fabrication processes and electrochemical performance of electrode-solution interface, respectively. The obtained results agree with experimental performance, and enable the evaluation of the cell number in a culture, by using the electrical measurements observed at the oscillation parameters in the test circuits employed.

Monitoring Muscle Stem Cell Cultures with Impedance Spectroscopy
Y. Yuste, J.A. Serrano, A. Olmo, A. Maldonado-Jacobi, P. Pérez, G. Huertas, S. Pereira, F. de la Portilla and A. Yúfera
Conference · International Conference on Biomedical Electronics and Devices BIODEVICES 2018
abstract     

The aim of this work is to present a new circuit for the real-time monitoring the processes of cellular growth and differentiation of skeletal myoblast cell cultures. An impedance spectroscopy Oscillation-Based technique is proposed for the test circuit, converting the biological system into a voltage oscillator, and avoiding the use of very high performance circuitry or equipment. This technique proved to be successful in the monitoring of cell cultures growth levels and could be useful for determining the degree of differentiation achieved, of practical implications in tissue engineering.

A Tracking Algorithm For Cell Motility Assays in CMOS Systems
C. Martínez-Gómez, A. Olmo, G. Huertas, P. Pérez, A. Maldonado-Jacobi and A. Yúfera
Conference · International Conference of the IEEE Engineering in Medicine and Biology Society EMBC 2017
abstract     

This work proposes a method for the study and real-time monitorization of a single cell on a 2D electrode matrix, of great interest in cell motility assays and in the characterization of cancer cell metastasis. A CMOS system proposal for cell location based on occupation maps data generated from Electrical Cell-substrate Impedance Spectroscopy (ECIS) has been developed. From experimental assays data, an algorithm based on analysis of the eight nearest neighbours has been implemented to find the cell center of mass. The path followed by a cell, proposing a Brownian route, has been simulated with the proposed algorithm. The presented results give an accuracy over 95% in the determination of the coordinates (x, y) from the expected cell center of mass.

A CMOS Tracking System Approach for Cell Motility Assays
C. Martínez-Gómez, A. Olmo, G. Huertas, P. Pérez, A. Maldonado-Jacobi and A. Yufera
Conference · International Conference on Biomedical Electronics and Devices BIODEVICES 2017
abstract     

This work proposes a method for studying and monitoring in real-time a single cell on a 2D electrode matrix, of great interest in cell motility assays and in the characterization of cancer cell metastasis. A CMOS system proposal for cell location based on occupation maps data generated from Electrical Cell-substrate Impedance Spectroscopy (ECIS) has been developed. From this cell model, obtained from experimental assays data, an algorithm based on analysis of the 8 nearest neighbors has been implemented, allowing the evaluation of the cell center of mass. The path followed by a cell, proposing a Brownian route, has been simulated with the proposed algorithm. The presented results show the success of the approach, with accuracy over 95% in the determination of any coordinate (x, y) from the expected center of mass.

Monitoring Tissue Evolution on Electrodes with Bio-Impedance Test
A. Maldonado, P. Pérez, G. Huertas, A. Yúfera, A. Rueda, and J.L. Huertas
Conference · Conference on Design of Circuits and Integrated Systems DCIS 2016
abstract     

A technique for real-time monitoring of bio-impedances using a Voltage Oscillation (VO) methodology is proposed. The main idea relies on connecting the bio-system in such a way that a suitable electrical oscillator, which only uses a DC power source, is built. Thanks to the employed electrical models, the oscillation parameters can be directly related to the biological test. System simulations show that the impedance values of a tissue, called herein Zx, can be determined by measuring the actual frequency and amplitude of the proposed VO system, being possible to select the frequency range to optimize the system sensitivity.

Cell-Culture Measurements using Voltage Oscillations
A. Maldonado, P. Pérez, G. Huertas, A. Yúfera, A. Rueda and J.L. Huertas
Conference · IEEE Latin American Symposium on Circuits and Systems LASCAS 2016
abstract     

A comprehensive system for real-time monitoring of a set of cell-cultures using a Voltage Oscillation (VO) methodology is proposed. The main idea is to connect the bioelectrical elements (electrodes&cell-culture) in such a way that sequentially a suitable electrical oscillator, which only uses a DC power source, is built. Using the employed electrical models given in [1, 2], the attained oscillation parameters (frequency and amplitude) can be directly related to the biological test. A digital circuitry is developed to pick-up the experimental measurements, which are gathered and shown in real-time in a web application.

From voltage oscillations to tissue-impedance measurements
A. Maldonado, P. Perez, G. Huertas, A. Yufera, A. Rueda and J.L. Huertas
Conference · IEEE Biomedical Circuits and Systems Conference BioCAS 2015
abstract     

A technique for real-time monitoring of bio-impedances using a Voltage Oscillation (VO) methodology is proposed. The main idea relies on connecting the bio-system in such a way that a suitable electrical oscillator, which only uses a DC power source, is built. Thanks to the employed electrical models, the oscillation parameters can be directly related to the biological test. System simulations show that the impedance values of a tissue, called herein Zx, can be determined by measuring the actual frequency and amplitude of the proposed VO system, being possible to select the frequency range to optimize the system sensitivity.

Towards Bio-Impedance Based Labs: A Review
P. Pérez, A. Maldonado, A. Yúfera, G. Huertas, A. Rueda and J.L. Huertas
Conference · Conference on Design of Circuits and Integrated Systems DCIS 2015
abstract     

Conference Paper

Books


No results

Book Chapters


Remote Sensing of Cell-Culture Assays
P. Pérez, A. Maldonado-Jacobi, A.J. López, C. Martínez, A. Olmo, G. Huertas and A. Yufera
Book Chapter · New Insights into Cell Culture Technology, pp 135-155, 2017
abstract      doi      

This chapter describes a full system developed to perform the remote sensing of cell-culture experiments from any access point with internet connection. The proposed system allows the real-time monitoring of cell assays thanks to bioimpedance measurement circuits developed to count the number of cell present in a culture. Cell-culture characterization is performed through the measurement of the increasing bioimpedance parameter over time. The circuit implementation is based on the oscillation-based test (OBT) methodology. Bioimpedance of cell cultures is measured in terms of the oscillation parameters (frequency, amplitude, phase, etc.) and used as empirical markers to carry out an appropriate interpretation in terms of cell size identification, cell counting, cell growth, growth rhythm, etc. The device is capable of managing the whole sensing task and performs wireless communication through a Bluetooth module. Data are interpreted and displayed on a computer or a mobile phone through a web application. The system has its practical application in drug development processes, offering a label-free, high-throughput, and high-content screening method for cellular research, avoiding the classical end-point techniques and a significant workload and cost material reduction.

Other publications


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