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

Vitrificación mediante microcapilares. Ultrasonidos y medidas de bioimpedancia

Tesis descargada en Tese

Use of CALPUFF to predict airborne Mn levels at schools in an urban area impacted by a nearby manganese alloy plant

Children are susceptible to the health effects derived from elevated manganese (Mn) environmental exposure; residents living in urban areas where ferromanganese alloy plants are located are usually exposed to high Mn levels. In this work, a dispersion model developed by the USEPA, CALPUFF, has been used to estimate the airborne Mn levels near educational centers located in Santander bay, Northern Spain, an urban area where high Mn levels have been measured in the last decade. The CALPUFF model was validated in a previous work from a multi-site one-year observation dataset. Air manganese levels in 96 primary, secondary and high schools located in Santander bay were estimated using the CALPUFF model for two months corresponding to warm and cold periods using real meteorological data and Mn emission rates corresponding to different emission scenarios. Results show that when the emission scenario that best represented the observations dataset is used, the air Mn levels exceed the WHO guideline (i.e. 150?ng?Mn/m3) in 24% and 11% of the studied schools in the cold and warm periods respectively. These exceedances depend on the distance from the FeMn alloy plant and the direction of the prevailing winds. Additional emission scenarios based on the implementation of preventive and corrective measures are simulated and analysed in terms of the number of exceedances of the WHO guideline. The age range of children has been also considered in the analysis.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the CTM2013-43904R Project. This funding source was not involved in the study design; data collection, analysis, or interpretation; the writing of the article; or the decision to submit for publication

Data-Analytics Modeling of Electrical Impedance Measurements for Cell Culture Monitoring

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 applicationsEspaña, Ministerio de Ciencia e Innovación y Universidades project RTI2018-093512-B-C2

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-

Microcontroller-Based Sinusoidal Voltage Generation for Electrical Bio-Impedance Spectroscopy Applications

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 Arduino™ 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.Spanish founded Project: TEC 2013- 46242-C3-1-P: Integrated Microsystem for Cell Culture AssaysFEDE

Integration of multimedia contents in the teaching of electronics : A practical test case in the teaching of digital circuits at the University of Seville

In this paper we present the integration of multimedia contents in the teaching of Digital Electronic Circuits and Computer Structure, of the first course of Computer Engineering at the University of Seville. Different tools for screenshot and video recording have been used for the preparation of audiovisual material, integrated in the learning platform currently used at the University of Seville. Feedback on the prepared material was collected in a survey, showing the interest and utility found by students in the preparation of theoretical and experimental classes with the videos. Successful results have been obtained in the evaluation of students. Suggestions of improvement and further work to be carried out are also described in the paper

Characterization and Monitoring of Titanium Bone Implants with Impedance Spectroscopy

Porous titanium is a metallic biomaterial with good properties for the clinical repair of cortical bone tissue, although the presence of pores can compromise its mechanical behavior and clinical use. It is therefore necessary to characterize the implant pore size and distribution in a suitable way. In this work, we explore the new use of electrical impedance spectroscopy for the characterization and monitoring of titanium bone implants. Electrical impedance spectroscopy has been used as a non-invasive route to characterize the volumetric porosity percentage (30%, 40%, 50% and 60%) and the range of pore size (100–200 and 355–500 mm) of porous titanium samples obtained with the space-holder technique. Impedance spectroscopy is proved to be an appropriate technique to characterize the level of porosity of the titanium samples and pore size, in an affordable and non-invasive way. The technique could also be used in smart implants to detect changes in the service life of the material, such as the appearance of fractures, the adhesion of osteoblasts and bacteria, or the formation of bone tissue

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

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-