Field-deployable pencil lead-based electrochemical cell for the determination of the emerging contaminant and antidepressant drug venlafaxine in wastewater.

Screening and quantification of emerging contaminants in water is of enormous relevance due to its scarcity and harmful effects on aquatic life and human health. We present a simple and cost-effective electrochemical cell for determination of the antidepressant venlafaxine, an emerging contaminant included in the EU Watch list 2022. The cell consists of pencil leads used as electrodes and a microcentrifuge tube.

ElectrochemCap: an integrated detection for loop-mediated isothermal amplification reactions.

Loop-mediated isothermal amplification (LAMP) of genetic materials has emerged as a powerful molecular biology technique with great potential to be a standard point-of-care (POC) technique. This method has found several applications, but it still presents challenges for its direct on-site application, particularly in terms of integrated reaction and detection systems and the risk of carryover contamination. In this work, we propose an innovative solution - an electrochemical microcentrifuge tube cap (ElectrochemCap) based on a screen-printed electrode, a 3D printed adapter and an adhesive layer - which integrates the amplification reaction and its subsequent electrochemical detection in a single device.

Palladium nanoclusters as a label to determine GFAP in human serum from donors with stroke by bimodal detection: inductively coupled plasma-mass spectrometry and linear sweep voltammetry.

Water-soluble, stable, and monodisperse palladium nanoclusters (PdNCs) were synthesized using NaBH as a reductant and lipoic acid as a ligand. PdNCs, measured by high-resolution transmission electron microscopy, showed a round shape and a diameter of 2.49 ± 0.

Measurement of GFAP in Nasal Exudate in the Differential Diagnosis between Ischemic Stroke and Intracerebral Hemorrhage.

Background: Differential diagnosis between ischemic stroke (IS) and intracerebral hemorrhage (ICH) is a great challenge. Recently, the discovery of cerebral lymphatic drainage toward the nostrils suggested nasal exudate (NE) as a new source for measuring biomarkers from neural damage.

Objectives: In this study, we sought to confirm whether glial fibrillary acidic protein (GFAP) levels in NE could identify ICH.

A do-it-yourself electrochemical cell based on pencil leads and transparency sheets: Application to the enzymatic determination of histamine.

The availability of more efficient analytical methods that answer the world's demands is a challenge and their development continues to be a difficult task. In this work the construction of an electrochemical cell, based on low-cost and accessible materials, that can be easily constructed and used for electroanalytical purposes, is described. Pencil leads were used as electrodes and a transparency sheet as the base.

Phenol red as electrochemical indicator for highly sensitive quantification of SARS-CoV-2 by loop-mediated isothermal amplification detection.

The current COVID-19 pandemic has made patent the need for rapid and cost-effective diagnostic tests, crucial for future infectious outbreaks. Loop-mediated isothermal amplification (LAMP) is a promising and decentralized alternative to qPCR. In this work we have developed a sensitive, fast, and simple innovative methodology for quantification of SARS-CoV-2 RNA copies, combining reverse-transcription LAMP with electrochemical detection.

Electrocatalytic Palladium Nanoclusters as Versatile Indicators of Bioassays: Rapid Electroanalytical Detection of SARS-CoV-2 by Reverse Transcription Loop-Mediated Isothermal Amplification.

Quantitative polymerase chain reaction (qPCR) is considered the gold standard for pathogen detection. However, improvement is still required, especially regarding the possibilities of decentralization. Apart from other reasons, infectious diseases demand on-site analysis to avoid pathogen spreading and increase treatment efficacy.

Electrochemical Detection for Isothermal Loop-Mediated Amplification of Pneumolysin Gene of Based on the Oxidation of Phenol Red Indicator.

A highly sensitive electrochemical methodology for end-point detection of loop-mediated isothermal nucleic acid amplification reactions was developed. It is based on the oxidation process of phenol red (PR), commonly used as a visual indicator. The dependence of its redox process on pH, which changes during amplification, allows performing quantitative measurements.

Paper-Based Enzymatic Electrochemical Sensors for Glucose Determination.

The general objective of Analytical Chemistry, nowadays, is to obtain best-quality information in the shortest time to contribute to the resolution of real problems. In this regard, electrochemical biosensors are interesting alternatives to conventional methods thanks to their great characteristics, both those intrinsically analytical (precision, sensitivity, selectivity, etc.) and those more related to productivity (simplicity, low costs, and fast response, among others).

Food allergen control: Tropomyosin analysis through electrochemical immunosensing.

Regulations of the EU obliges the indication of the presence of allergens on food labels. This work reports the development of an electrochemical immunosensor to determine tropomyosin (TPM) - a major shellfish allergen - prevailing in the muscles of crustacean species. Two linear ranges between the signal and TPM concentration were obtained: between 2.

Fully integrated sampler and dilutor in an electrochemical paper-based device for glucose sensing.

An electroanalytical platform capable to take and dilute the sample has been designed in order to fully integrate the different steps of the analytical process in only one device. The concept is based on the addition of glass-fiber pads for sampling and diluting to an electrochemical cell combining a paper-based working electrode with low-cost connector headers as counter and reference electrodes. In order to demonstrate the feasibility of this all-in-one platform for biosensing applications, an enzymatic sensor for glucose determination (requiring a potential as low as -0.

Paper-Based Screen-Printed Electrodes: A New Generation of Low-Cost Electroanalytical Platforms.

Screen-printed technology has helped considerably to the development of portable electrochemical sensors since it provides miniaturized but robust and user-friendly electrodes. Moreover, this technology allows to obtain very versatile transducers, not only regarding their design, but also their ease of modification. Therefore, in the last decades, the use of screen-printed electrodes (SPEs) has exponentially increased, with ceramic as the main substrate.

Electrochemical micropipette-tip for low-cost environmental applications: Determination of anionic surfactants through their interaction with methylene blue.

Miniaturization is one of the main requirements in the design of portable devices that allow in-field analysis. This is especially interesting in environmental monitoring, where the time of the sample-to-result process could be decreased considerably by approaching the analytical platforms to the sampling point. We employed traditional mass-produced and low-cost elements (micropipette tips and pins) in an out-of-box application to generate an innovative and cost-effective platform for analytical purposes.

Molecularly imprinted polymer-based electrochemical sensors for environmental analysis.

The ever-increasing presence of contaminants in environmental waters is an alarming issue, not only because of their harmful effects in the environment but also because of their risk to human health. Pharmaceuticals and pesticides, among other compounds of daily use, such as personal care products or plasticisers, are being released into water bodies. This release mainly occurs through wastewater since the treatments applied in many wastewater treatment plants are not able to completely remove these substances.

Screen-Printed Electrode-Based Sensors for Food Spoilage Control: Bacteria and Biogenic Amines Detection.

Food spoilage is caused by the development of microorganisms, biogenic amines, and other harmful substances, which, when consumed, can lead to different health problems. Foodborne diseases can be avoided by assessing the safety and freshness of food along the production and supply chains. The routine methods for food analysis usually involve long analysis times and complex instrumentation and are performed in centralized laboratories.

Competitive electrochemical immunosensor for the detection of unfolded p53 protein in blood as biomarker for Alzheimer's disease.

Alzheimer's disease is one of the most common causes of dementia nowadays, and its prevalence increases over time. Because of this and the difficulty of its diagnosis, accurate methods for the analysis of specific biomarkers for an early diagnosis of this disease are much needed. Recently, the levels of unfolded isoform of the multifunctional protein p53 in plasma have been proved to increase selectively in Alzheimer's Disease patients in comparison with healthy subjects, thus entering the list of biomarkers that can be used for the diagnosis of this illness.

Preconcentration and sensitive determination of the anti-inflammatory drug diclofenac on a paper-based electroanalytical platform.

This work describes the development of a paper-based platform for highly sensitive detection of diclofenac. The quantification of this anti-inflammatory drug is of importance in clinical (e.g.

Disposable electrochemical immunosensor for analysis of cystatin C, a CKD biomarker.

Specific monitoring of cystatin C (CysC) levels in biological fluids is critical for diagnosis, treatment and mechanistic understanding of a spectrum of diseases, particularly chronic kidney disease (CKD). Despite evidences that CysC correlates with the high risk and/or progression of CKD, its use in clinical practice is still scarce. In this context, we report the development of a simple and sensitive immunosensor for the detection of CysC.

Disposable Sensors in Diagnostics, Food, and Environmental Monitoring.

Disposable sensors are low-cost and easy-to-use sensing devices intended for short-term or rapid single-point measurements. The growing demand for fast, accessible, and reliable information in a vastly connected world makes disposable sensors increasingly important. The areas of application for such devices are numerous, ranging from pharmaceutical, agricultural, environmental, forensic, and food sciences to wearables and clinical diagnostics, especially in resource-limited settings.

Sampling and multiplexing in lab-on-paper bioelectroanalytical devices for glucose determination.

In this work, we present a multiplexed (eight simultaneous measurements) paper-based electrochemical device developed in a very simple way and using low-cost materials, such as paper, carbon ink and multifunctional connector headers. Meanwhile, we have also combined the paper-based electrochemical platform with a glass-fiber strip in order to integrate easily a sampling step. Both approaches, simultaneous measuring and sampling, have been applied to the determination of glucose using bienzymatic biosensors.

Paper-based maskless enzymatic sensor for glucose determination combining ink and wire electrodes.

In this work we have developed an amperometric enzymatic biosensor in a paper-based platform with a mixed electrode configuration: carbon ink for the working electrode (WE) and metal wires (from a low-cost standard electronic connection) for reference (RE) and auxiliary electrodes (AE). A hydrophobic wax-defined paper area was impregnated with diluted carbon ink. Three gold-plated pins of the standard connection are employed, one for connecting the WE and the other two acting as RE and AE.

Comparative study of different alcohol sensors based on Screen-Printed Carbon Electrodes.

Different very simple single-use alcohol enzyme sensors were developed using alcohol oxidase (AOX) from three different yeast, Hansenula sp., Pichia pastoris and Candida boidinii, and employing three different commercial mediator-based Screen-Printed Carbon Electrodes as transducers. The mediators tested, Prussian Blue, Ferrocyanide and Co-phthalocyanine were included into the ink of the working electrode.

Amperometric fructose sensor based on ferrocyanide modified screen-printed carbon electrode.

The first fructose sensor using a commercial screen-printed ferrocyanide/carbon electrodes (SPFCE) is reported here. The ferrocyanide is included in the carbon ink of the commercial screen-printed carbon electrode. The immobilization of enzyme d-fructose dehydrogenase (FDH) was carried out in an easy way.