Jaime Punter-Villagrasa

Combined Dielectrophoresis and Impedance Systems for Bacteria Analysis in Microfluidic On-Chip Platforms

Bacteria concentration and detection is time-consuming in regular microbiology procedures aimed to facilitate the detection and analysis of these cells at very low concentrations. Traditional methods are effective but often require several days to complete. This scenario results in low bioanalytical and diagnostic methodologies with associated increased costs and complexity. In recent years, the exploitation of the intrinsic electrical properties of cells has emerged as an appealing alternative approach for concentrating and detecting bacteria. The combination of dielectrophoresis (DEP) and impedance analysis (IA) in microfluidic on-chip platforms could be key to develop rapid, accurate, portable, simple-to-use and cost-effective microfluidic devices with a promising impact in medicine, public health, agricultural, food control and environmental areas. The present document reviews recent DEP and IA combined approaches and the latest relevant improvements focusing on bacteria concentration and detection, including selectivity, sensitivity, detection time, and conductivity variation enhancements. Furthermore, this review analyses future trends and challenges which need to be addressed in order to successfully commercialize these platforms resulting in an adequate social return of public-funded investments.

An Instantaneous Low-Cost Point-of-Care Anemia Detection Device

We present a small, compact and portable device for point-of-care instantaneous early detection of anemia. The method used is based on direct hematocrit measurement from whole blood samples by means of impedance analysis. This device consists of a custom electronic instrumentation and a plug-and-play disposable sensor. The designed electronics rely on straightforward standards for low power consumption, resulting in a robust and low consumption device making it completely mobile with a long battery life. Another approach could be powering the system based on other solutions like indoor solar cells, or applying energy-harvesting solutions in order to remove the batteries. The sensing system is based on a disposable low-cost label-free three gold electrode commercial sensor for 50 μL blood samples. The device capability for anemia detection has been validated through 24 blood samples, obtained from four hospitalized patients at Hospital Clínic. As a result, the response, effectiveness and robustness of the portable point-of-care device to detect anemia has been proved with an accuracy error of 2.83% and a mean coefficient of variation of 2.57% without any particular case above 5%.

Toward an Anemia Early Detection Device Based on 50-μL Whole Blood Sample

A first approach to a portable and compact device for point-of-care (PoC) early instantaneous detection of anemia is described. This device works directly with whole blood samples relying on hematocrit analysis by means of impedance analysis. This device consists of a custom electronic instrumentation, postprocessing software and plug-and-play disposable sensor. The designed electronics are connected to a remote computer, which allows control of the instrumentation and results displaying with a user friendly software panel. The disposable sensor is based on a low-cost label-free three gold electrode commercial sensor for 50-μL volume samples. Forty-eight whole blood samples, randomly collected from hospitalized patients in Hospital Clínic, were used to validate the device capability for anemia detection. Whole blood samples were distributed in two groups: 10 samples for system calibration, and 38 samples for system validation. To calibrate the device, a complete EIS experiment has been performed to get a full impedance spectrum analysis, defining an accurate frequency working range for hematocrit detection. Afterward, we developed a protocol for instant impedance detection to determine the system detection accuracy, sensitivity, and coefficient of variation. As a result, impedance variations between different samples have been detected with less than 2% accuracy error for both impedance magnitude and phase. A hematocrit detection algorithm, relying on impedance analysis, has been developed based on the previous studies. The response, effectiveness, and robustness of the portable PoC device to detect anemia have been proved with an accuracy error of 1.75% and a coefficient of variation of less than 5%.

Towards a portable point-of-use blood analysis with EIS technique device

In this paper first approach to a compact system for point-of-use primarily blood characteristics analysis by means of an EIS (Electrochemical Impedance Spectroscopy) experience is described. This is based on a custom electronic instrumentation, post processing software and a commercial three electrodes gold sensor. The designed electronic is based on a potentiostat instrumentation supported by a real time platform connected to a remote computer, which allows the instrumentation control, real time monitoring data and its posterior resultant analysis. Moreover, the whole system has been characterized and validated using different sensors and biocompatible materials. The study consists on a complete EIS experience in order to get a full spectrum analysis of impedance behavior in terms of magnitude and phase. As a result, we were able to detect impedance with an average error of less than 3% and a SNR rejection of -40 dB in a frequency working range of 10 Hz to 100 kHz. This integrated approach pushes forward the development of truly autonomous point-of-care devices relying on impedance spectrometry detection.

A portable point-of-care device for multi-parametric diabetes mellitus analysis

We present a small, compact and portable envisaged lab-on-a-chip (LoC) device for point-of-care (PoC) detection of different key parameters on diabetes mellitus analysis; glucose, cholesterol, triglycerides and hematocrit. These four parameters, present in blood samples, are important in the standardized analysis affecting different patients with different medical conditions. The quantification of glucose, cholesterol, triglycerides and hematocrit it is performed with a single disposable device using a single blood drop, enhancing disposition decision time and improving patient satisfaction when compared with actual analytical methodology, and it is an easy to use device and no skilled personnel is needed to use it, avoiding the use of more complicated processes like phlebotomy. The presented device consists of a custom sensing system, low power electronic instrumentation and an easy user interpretation readout display, powered by a single battery.

Bioimpedance Technique for Point-of-Care Devices Relying on Disposable Label-Free Sensors – An Anemia Detection Case

In this chapter, the development of a point-of-care device for bio-medical applications has been discussed. Our main objective is to research new electronic solutions for the detection, quantification, and monitoring of important biological agents in medical environments. The proposed systems and technologies rely on label-free disposable sensors, with portable electronics for user-friendly, low-cost solutions for medical disease diagnosis, monitoring, and treatment. In this chapter, we will focus on a specific point-of-care device for cellular analysis, applied to the case of anemia detection and monitoring. The methodology used for anemia monitoring is based on hematocrit measurement directly from whole blood samples by means of impedance analysis. The designed device is based on straightforward electronic standards for low power consumption and low-cost disposable sensor for low volume samples, resulting in a robust and low power consumption device for portable monitoring purposes of anemia. The device has been validated through different whole blood samples to prove the response, effectiveness, and robustness to detect anemia.

A portable point-of-use EIS device for in-vivo biomédical applications

In this paper, a compact system for point-of-use EIS (Electrochemical Impedance Spectroscopy) experiences is described. This is based on a custom electronic instrumentation, post processing software and low-cost disposable three-electrodes sensor. The designed electronic is based on a signal generator, a potentiostat and a digital lock-in amplifier supported by a real time platform, which allows the instrumentation control and real time data processing. Moreover the device is connected to a remote computer for a user-friendly device management and easy data display. The studies presented consist on complete EIS experiences in order to get a full system characterization in terms of magnitude and phase using passive components and ferrocyanide/ferricyanide solution, a commonly used substance on sensor and equipment characterization. As a result, we were able to detect impedance with an average error of less than 3% and a SNR rejection of-40 dB in a frequency working range of 10 Hz to 100 kHz.

Introduction to Electronics. Study, Design and Validation Tests

This chapter presents in detail the design and validation of specific instrumentation electronics regarding ac and dc electrochemical applications. The development of such electronics will be defined through a design architecture that will build up for an easy and understandable way for its design and validation for different applications.

Electrochemical DC Techniques. Glucose Monitoring and Multi-parametric Detection

This chapter focuses on the conception and design of an autonomous and disposable multi-parametric analyzer for the early diagnosis of diabetes mellitus and its different associated risk factors.

Impedance Analysis AC Techniques. Cellular Quantification

This chapter describes the AC techniques for detection, quantification and monitoring of diluted cells suspensions. Electrochemical Impedance Spectroscopy (EIS) and Impedance Analysis (IA) are the techniques presented on this chapter as means to develop a compact, portable and user-friendly solution for accurate, reliable, and cost-effective cellular quantification.