14 research outputs found
The bio-oscillator: A circuit for cell-culture assays
A system for cell-culture real-time monitoring using an oscillation-based approach is proposed. The system transforms a cell culture under test into a suitable “biological” oscillator, without needing complex circuitry for excitation and measurement. The obtained oscillation parameters are directly related to biological test, owed to an empirically extracted cell–electrode electrical model. A discrete prototype is proposed and experimental results with living cell culture are presented, achieving the expected performances.Ministerio de Economía y Competitividad TEC2011-28302, TEC2013-46242-C3-1-
Remote Sensing of Cell-Culture Assays
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
Practical Characterization of Cell-Electrode Electrical Models in Bio-Impedance Assays
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.Ministerio de Economía y Competitividad TEC2013-46242-C3-1-
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-
Cell-Culture Measurements Using Voltage Oscillations
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
bio-electrical 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.Ministerio de Economía y Competitividad TEC2013-46242-C3-1-
A CMOS Tracking System Approach for Cell Motility Assays
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.Ministerio de Economía y Competitividad TEC2013-46242-C3-1-
Monitoring Muscle Stem Cell Cultures with Impedance Spectroscopy
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.Ministerio de Economía y Competitividad TEC2013-46242-C3-1-
A Tracking Algorithm For Cell Motility Assays in CMOS Systems
This work proposes a method for the study and
real-time monitoring 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 the 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.Ministerio de Economía y Competitividad TEC2013-46242-C3-1-
Characterization of Implanted Stents through Neointimal Tissue Bioimpedance Simulations
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®.Junta de Andalucía 2017/TIC-17
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