Control predictivo aplicado al modelo macroscópico del tráfico en una ciudad

El trabajo consiste en la estimación de un modelo macroscópico del comportamiento del tráfico urbano (en especial de vehiculos eléctricos), y en la implementación en simulación de un control predictivo que maximice los beneficios de las estaciones de recarga.Universidad de Sevilla. Máster en Automática, Robótica y Telemátic

Sensing Cell-Culture Assays with Low-Cost Circuitry

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.España, Feder TEC2013-46242-C3-1-

Effects of electrical fields on neuroblastoma (N2A) cell differentiation: preliminary results

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.Junta de Andalucía P18-FR-2308Ministerio de Ciencia, Innovación y Universidades RTI2018-093512-B-C2

An Empirical-Mathematical Approach for Calibration and Fitting Cell-Electrode Electrical Models in Bioimpedance Tests

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

Remote Cell Growth Sensing Using Self-Sustained Bio-Oscillations

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

Electrical Modeling of the Growth and Differentiation of Skeletal Myoblasts Cell Cultures for Tissue Engineering

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.Spanish Government’s Ministerio de Ciencia, Innovación y Universidades, Plan Estatal 2017-2020 Retos- Proyectos I+D+I and FEDER RTI2018-093512-B-C2

Modeling and simulation of non-linear bioelectronic systems applied to cell culture assays

Monitoring the properties of biological samples (BS) is expensive in terms of time consumption and cost in resources and human effort. There are monitoring methods using different techniques, depending on the type of biological sample (cells, tissues, blood, etc.). In this thesis, we improve the accuracy of the ECIS (electrical cell-substrate impedance spectroscopy) technique of bioimpedance (BI) measurement of a monolayer cell-culture (CC), which measures the electrical response of a CC when an alternating current is applied to it at several frequencies. Specifically, this dissertation is focused on the modeling of the cell-electrode (CE) block, and the real-time monitoring and acquisition of the cell concentration in a CC assay experiment. In addition, using as a database the CE model obtained in the modeling stage, a toolbox has been built to perform efficient electrical real-time simulations with Ngspice, launching these simulations from Matlab. Herein, the BI measurement is applied indirectly. Instead of injecting a signal, the CE block is connected to an electronic oscillator, which fulfills the Barkhausen Stability Criterion (BSC) to ensure that self-maintained and self-sustained oscillations are generated. The technique is known as Oscillation Based Test (OBT) [1]. Instead of measuring the changes between the output and input signal, the oscillation frequency and amplitude are acquired and, using the BSC, the parameters of the CE model used can be obtained on the fly. As can be seen, this technique is much more powerful than injecting a signal, since instead of obtaining the BI for a given frequency, the whole CE electrical model of the CE block is obtained. The CE model used is based on previous work, but some improvements are introduced to increase its accuracy. The data base for this work are real measurements made by the research group in CC assays with three different cell lines using an OBT circuit. From these data, the parameters of the CE model block are successfully obtained. The modeling technique is tested on some variations of the CE model, reaching better results by increasing its complexity, making the model closer to reality or introducing Fractional Oden (FO) elements. Data from real experiments, and the best variants of the electrical model are used to build a simulator of a CC assay experiment. The simulator calculates model parameters and cell concentration in real-time (without taking into account future measurements) using the minimization of a cost function (CF). The minimization of an appropriate CF ensures that the oscillation requirements are satisfied and that the obtained CE model parameter values are consistent with the theoretical values. The acquired results are very satisfactory since the simulation of a real-time experiment demonstrates that the technique of minimizing a CF can be used to obtain the cell concentration in real-time. As a result, cell concentration data are attained whose trend and values present a relatively low error when compared to the cell concentration achieved by traditional optical cell counting methods. Electrical simulations of an electronic circuit are very useful during the design and testing process prior to the build of the circuit. The model parameters obtained during the simulation of a CC assay experiment, in addition to showing the feasibility of the technique, can be used in electrical simulations of the OBT circuit. For future improvements of the OBT measurement circuit, which are discussed at the end of this dissertation, electrical simulations must be performed with realistic data to ensure that the measurement circuit will work robustly. To perform such simulations, a toolbox has been built in Matlab, which performs electrical simulations using Ngspice (open-source Spice simulator) in an efficient way. This toolbox is applied to the oscillator circuit simulation successfully, being able to perform multiple simulations, varying the CE model automatically, in an efficient way. In addition, it can be applied to any electronic circuit to launch electrical simulations from Matlab

Predictive Cell Culture Time Evolution Based on Electric Models

Obtaining cell concentration measurements from a culture assay by using bioimpedance is a very useful method that can be used to translate impedances to cell concentration values. The purpose of this study was to find a method to obtain the cell concentration values of a given cell culture assay in real time by using an oscillator as the measurement circuit. From a basic cell–electrode model, enhanced models of a cell culture immersed in a saline solution (culture medium) were derived. These models were used as part of a fitting routine to estimate the cell concentration in a cell culture in real time by using the oscillation frequency and amplitude delivered by the measurement circuits proposed by previous authors. Using real experimental data (the frequency and amplitude of oscillations) that were obtained by connecting the cell culture to an oscillator as the load, the fitting routine was simulated, and real-time data of the cell concentration were obtained. These results were compared to concentration data that were obtained by using traditional optical methods for counting. In addition, the error that we obtained was divided and analyzed in two parts: the first part of the experiment (when the few cells were adapting to the culture medium) and the second part of the experiment (when the cells exponentially grew until they completely covered the well). Low error values were obtained during the growth phase of the cell culture (the relevant phase); therefore, the results obtained were considered promising and show that the fitting routine is valid and that the cell concentration can be measured in real time by using an oscillator.Ministerio de Ciencia e Innovación PID2021- 122529OB-I0