A microscopy technique based on bio-impedance sensors

It is proposed a microscopy for cell culture applications based on impedance sensors. The imagined signals are measured with the Electrical Cell-Substrate Spectroscopy (ECIS) technique, by identifying the cell area. The proposed microscopy allows real-time monitoring inside the incubator, reducing the contamination risk by human manipulation. It requires specific circuits for impedance measurements, a two-dimensional sensor array (pixels), and employing electrical models to decode efficiently the measured signals. Analogue Hardware Description Language (AHDL) circuits for cell-microelectrode enables the use of geometrical and technological data into the system design flow. A study case with 8x8 sensor array is reported, illustrating the evolution and power of the proposed image acquisition.Junta de Andalucía P0-TIC-538

Using microelectrode models for real time cell-culture monitoring

This paper proposes a cell-microelectrode model for cell biometry applications, based on the area overlap as main parameter. The model can be applied to cell size identification, cell count, and their extension to cell growth and dosimetry protocols. Experiments performed with comercial electrodes are presented, illustrating a procedure to obtain cell number in both growth and dosimetry processes. Results obtained for the AA8 cell line are promising.Junta de Andalucía P0-TIC-538

Bioimpedance real-time charazterization of neointimal tissue inside stents

It is hereby presented a new approach to monitor restenosis in arteries fitted with a stent during an angioplasty. The growth of neointimal tissue is followed up by measuring its bioimpedance with Electrical Impedance Spectroscopy (EIS). Besides, a mathematical model is derived to analytically describe the neointima’s histological composition from its bioimpedance. The model is validated by finite-element analysis (FEA) with COMSOL Multiphysics®. Satisfactory correlation between the analytical model and the FEA simulation is achieved for most of the characterization range, detecting some deviations introduced by the thin "double layer" that separates the neointima and the blood. It is shown how to apply conformal transformations to obtain bioimpedance models for stack-layered tissues over coplanar electrodes. Particularly, this is applied to characterize the neointima in real-time. This technique is either suitable as a main mechanism of restenosis follow-up or it can be combined with proposed blood-pressure-measuring intelligent stents to auto-calibrate the sensibility loss caused by the adherence of the tissue on the micro-electro-mechanical sensors (MEMS).Ministerio de Economía, Industria y Competitividad (Spain): projects TEC2013-46242-C3-1-PMinisterio de Economía, Industria y Competitividad (Spain): projects TEC2013-46242-C3-2-

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

A Microelectrode-Cell Sensor Model for Real Time Monitoring

In this paper the application of a cellmicroelectrode model to cell biometry experiments is proposed, using the cell-electrode area overlap as main parameter. The model can be applied to cell size identification, cell count, and their extension to cell growth and dosimetry protocols. Experimental results using AA8 cell line are presented, obtaining promising results.Ministerio de Ciencia e Innovación de España y FEDER (Unión Europea) P0-TIC-5386Departamento de Biología Celular, Facultad de Biología, Universidad de Sevilla

Cell-culture real time monitoring based on bio-impedance measurements

This paper proposes the application of a cell-microelectrode model in cell biometry experiments, using the cell-electrode area overlap as its main parameter. The model can be applied to cell size identification and cell count, and further extended to study cell growth and dosimetry protocols. Experiments have been conducted in AA8 cell line, obtaining promising results.Junta de Andalucía P0-TIC-538

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-

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

Cell Biometrics Based on Bio-Impedance Measurements

Open Access.This work is in part supported by the funded Project: Auto-calibración y auto-test en circuitos analógicos, mixtos y de radio frecuencia: Andalusian Government project P0-TIC- 5386, co-financed with the FEDER program.Peer Reviewe

Vitrificación mediante microcapilares. Ultrasonidos y medidas de bioimpedancia

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