Engineering a Point-of-Care Paper-Microfluidic Electrochemical Device Applied to the Multiplexed Quantitative Detection of Biomarkers in Sputum.

Health initiatives worldwide demand affordable point-of-care devices to aid in the reduction of morbidity and mortality rates of high-incidence infectious and noncommunicable diseases. However, the production of robust and reliable easy-to-use diagnostic platforms showing the ability to quantitatively measure several biomarkers in physiological fluids and that could in turn be decentralized to reach any relevant environment remains a challenge. Here, we show the particular combination of paper-microfluidic technology, electrochemical transduction, and magnetic nanoparticle-based immunoassay approaches to produce a unique, compact, and easily deployable multiplex device to simultaneously measure interleukin-8, tumor necrosis factor-α, and myeloperoxidase biomarkers in sputum, developed with the aim of facilitating the timely detection of acute exacerbations of chronic obstructive pulmonary disease.

Detection of SARS-CoV-2 Virus by Triplex Enhanced Nucleic Acid Detection Assay (TENADA).

SARS-CoV-2, a positive-strand RNA virus has caused devastating effects. The standard method for COVID diagnosis is based on polymerase chain reaction (PCR). The method needs expensive reagents and equipment and well-trained personnel and takes a few hours to be completed.

Rapid Colorimetric Detection of Wound Infection with a Fluidic Paper Device.

Current procedures for the assessment of chronic wound infection are time-consuming and require complex instruments and trained personnel. The incidence of chronic wounds worldwide, and the associated economic burden, urge for simple and cheap point-of-care testing (PoCT) devices for fast on-site diagnosis to enable appropriate early treatment. The enzyme myeloperoxidase (MPO), whose activity in infected wounds is about ten times higher than in non-infected wounds, appears to be a suitable biomarker for wound infection diagnosis.

Array of individually addressable two-electrode electrochemical cells sharing a single counter/reference electrode for multiplexed enzyme activity measurements.

This work reports on the fabrication and performance of a new on-chip array of gold thin-film electrodes arranged into five individually addressable miniaturized electrochemical cells. Each cell shows a two-electrode configuration comprising a single working electrode and a counter/pseudo-reference electrode that is compartmentalized to be shared among all the cells of the array. Using this configuration, just six contact pads are required, which significantly reduces the chip overall surface area.

Compact analytical flow system for the simultaneous determination of L-lactic and L-malic in red wines.

During the malolactic fermentation of red wines, L-malic acid is mainly converted to L-lactic acid. Both acids should be precisely measured during the entire process to guarantee the quality of the final wine, thus making real-time monitoring approaches of great importance in the winemaking industry. Traditional analytical methods based on laboratory procedures are currently applied and cannot be deployed on-site.

Electrochemical Paper-Based Biosensor Devices for Rapid Detection of Biomarkers.

In healthcare, new diagnostic tools that help in the diagnosis, prognosis, and monitoring of diseases rapidly and accurately are in high demand. For in-situ measurement of disease or infection biomarkers, point-of-care devices provide a dramatic speed advantage over conventional techniques, thus aiding clinicians in decision-making. During the last decade, paper-based analytical devices, combining paper substrates and electrochemical detection components, have emerged as important point-of-need diagnostic tools.

A self-calibrating and multiplexed electrochemical lab-on-a-chip for cell culture analysis and high-resolution imaging.

In vitro analysis requires cell proliferation in conditions close to physiological ones. Lab-on-a-chip (LoC) devices simplify, miniaturize and automate traditional protocols, with the advantages of being less expensive and faster due to their shorter diffusion distances. The main limitation of current LoCs is still the control of the culture conditions.

Organoleptic Analysis of Drinking Water Using an Electronic Tongue Based on Electrochemical Microsensors.

The standards that establish water's quality criteria for human consumption include organoleptic analysis. These analyses are performed by taste panels that are not available to all water supply companies with the required frequency. In this work, we propose the use of an electronic tongue to perform organoleptic tests in drinking water.

Analysis of free and total sulfur dioxide in wine by using a gas-diffusion analytical system with pH detection.

The use of sulfur dioxide as preservative in winemaking industry has a direct impact on wine quality. The standard methods to analyze this parameter require several processes and are time consuming. In this paper a simple and rapid analytical method for free and total sulfur dioxide detection is proposed.

Robust l-malate bienzymatic biosensor to enable the on-site monitoring of malolactic fermentation of red wines.

Monitoring the malolactic fermentation process is strictly required to guarantee the sensorial quality and freshness of red wines. This could be achieved by in-field and real-time continuous measurements of l-malate concentration in the fermentation tanks. The potential of a miniaturized amperometric bienzymatic biosensor as an analytical tool to be applied in such scenario is described in this paper.

Portable Electronic Tongue Based on Microsensors for the Analysis of Cava Wines.

Cava is a quality sparkling wine produced in Spain. As a product with a designation of origin, Cava wine has to meet certain quality requirements throughout its production process; therefore, the analysis of several parameters is of great interest. In this work, a portable electronic tongue for the analysis of Cava wine is described.

Monitoring of malolactic fermentation in wine using an electrochemical bienzymatic biosensor for L-lactate with long term stability.

L-lactic acid is monitored during malolactic fermentation process of wine and its evolution is strongly related with the quality of the final product. The analysis of L-lactic acid is carried out off-line in a laboratory. Therefore, there is a clear demand for analytical tools that enabled real-time monitoring of this process in field and biosensors have positioned as a feasible alternative in this regard.

Electrochemical nanocomposite-derived sensor for the analysis of chemical oxygen demand in urban wastewaters.

This work reports on the fabrication and comparative analytical assessment of electrochemical sensors applied to the rapid analysis of chemical oxygen demand (COD) in urban waste waters. These devices incorporate a carbon nanotube-polystyrene composite, containing different inorganic electrocatalysts, namely, Ni, NiCu alloy, CoO, and CuO/AgO nanoparticles. The sensor responses were initially evaluated using glucose as standard analyte and then by analyzing a set of real samples from urban wastewater treatment plants.

Thin-film electrochemical sensor for diphenylamine detection using molecularly imprinted polymers.

This work reports on the development of a new voltammetric sensor for diphenylamine based on the use of a miniaturized gold electrode modified with a molecularly imprinted polymer recognition element. Molecularly imprinted particles were synthesized ex situ and further entrapped into a poly(3,4-ethylenedioxythiophene) polymer membrane, which was electropolymerized on the surface of the gold electrode. The thickness of the polymer layer was optimized in order to get an adequate diffusion of the target analyte and in turn to achieve an adequate charge transfer at the electrode surface.

Classification and characterization of different white grape juices by using a hybrid electronic tongue.

A multisensor system combined with multivariate analysis is applied for the characterization and classification of white grape juices. The proposed system, known as hybrid electronic tongue, consists of an array of electrochemical microsensors and a colorimetric optofluidic system. A total of 25 white grape juices representing the large variability of vines grown in the Northwest Iberian Peninsula were studied.

Beer classification by means of a potentiometric electronic tongue.

In this work, an electronic tongue (ET) system based on an array of potentiometric ion-selective electrodes (ISEs) for the discrimination of different commercial beer types is presented. The array was formed by 21 ISEs combining both cationic and anionic sensors with others with generic response. For this purpose beer samples were analyzed with the ET without any pretreatment rather than the smooth agitation of the samples with a magnetic stirrer in order to reduce the foaming of samples, which could interfere into the measurements.