Biosensing and Delivery of Nucleic Acids Involving Selected Well-Known and Rising Star Functional Nanomaterials

In the last fifteen years, the nucleic acid biosensors and delivery area has seen a breakthrough due to the interrelation between the recognition of nucleic acid’s high specificity, the great sensitivity of electrochemical and optical transduction and the unprecedented opportunities imparted by nanotechnology. Advances in this area have demonstrated that the assembly of nanoscaled materials allows the performance enhancement, particularly in terms of sensitivity and response time, of functional nucleic acids’ biosensing and delivery to a level suitable for the construction of point-of-care diagnostic tools. Consequently, this has propelled detection methods using nanomaterials to the vanguard of the biosensing and delivery research fields. This review overviews the striking advancement in functional nanomaterials’ assisted biosensing and delivery of nucleic acids. We highlight the advantages demonstrated by selected well-known and rising star functional nanomaterials (metallic, magnetic and Janus nanomaterials) focusing on the literature produced in the past five years

Opportunities, Challenges, and Prospects in Electrochemical Biosensing of Circulating Tumor DNA and its Specific Features

Nowadays, analyzing circulating tumor DNA (ctDNA), a very small part of circulating free DNA (cfDNA) carried by blood, is considered to be an interesting alternative to conventional single-site tumor tissue biopsies, both to assess tumor burden and provide a more comprehensive snapshot of the time-related and spatial heterogeneity of cancer genetic/epigenetic scenery. The determination of ctDNA and/or mapping its characteristic features, including tumor-specific mutations, chromosomal aberrations, microsatellite alterations, and epigenetic changes, are minimally invasive, powerful and credible biomarkers for early diagnosis, follow-up, prediction of therapy response/resistance, relapse monitoring, and tracking the rise of new mutant subclones, leading to improved cancer outcomes This review provides an outline of advances published in the last five years in electrochemical biosensing of ctDNA and surrogate markers. It emphasizes those strategies that have been successfully applied to real clinical samples. It highlights the unique opportunities they offer to shift the focus of cancer patient management methods from actual decision making, based on clinic-pathological features, to biomarker-driven treatment strategies, based on genotypes and customized targeted therapies. Also highlighted are the unmet hurdles and future key points to guide these devices in the development of liquid biopsy cornerstone tools in routine clinical practice for the diagnosis, prognosis, and therapy response monitoring in cancer patients

Phage-Derived and Aberrant HaloTag Peptides Immobilized on Magnetic Microbeads for Amperometric Biosensing of Serum Autoantibodies and Alzheimer's Disease Diagnosis

An electrochemical biosensing platform for serum autoantibodies (AAbs) detection is reported in this work, exploiting for the first time six Alzheimer's disease (AD)-specific phage-derived and frameshift aberrant HaloTag peptides as receptors, immobilized on magnetic microbeads (MBs) surface and captured on disposable electrodes to perform amperometric detection. Operational analytical characteristics and clinical diagnostic ability of the bioplatform were probed in optimized key experimental conditions by analysing serum AAbs of AD patients and healthy subjects. The value of 100% obtained for AUC, sensitivity, and selectivity from the all peptides combined ROC curve, indicate full AD-diagnostic capability of the methodology, which was further implemented, as proof of concept, in a POC multiplexing platform to detect the signature in a single test over clinically actionable times (1 h 15 min), opening great promise for the type of diagnosis and AD patients’ monitoring follow-up currently pursued

Paving the Way for Reliable Alzheimer’s Disease Blood Diagnosis by Quadruple Electrochemical Immunosensing

Alzheimer’s disease (AD), the most common neurodegenerative disorder, demands new cost-effective and easy-to-use strategies for its reliable detection, mainly in the preclinical stages. Here, we report the first immunoplatform for the electrochemical multidetermination of four candidate protein biomarkers in blood, neurofilament light chain (NfL), Tau, phosphorylated Tau (p-Tau) and TAR DNA-Binding Protein 43 (TDP-43). It involves implementation of sandwich-type immunoassays and enzymatic labelling with horseradish peroxidase (HRP) on the surface of magnetic microbeads (MBs). Amperometric detection is performed after depositing the magnetic immunoconjugates on disposable quadruple transduction platforms by monitoring the enzymatic reduction of H2O2 mediated by hydroquinone (HQ). The immunoplatform achieved LOD values smaller than the content of target biomarkers in plasma of healthy subjects, with RSD values

Implementación de la metodología flipped classroom en los laboratorios de Química Analítica

Adaptar el sistema tradicional de aprendizaje a las necesidades actuales del alumnado empleando la metodología flipped classroom en el laboratorio de Química Analítica I, con el objetivo de fomentar el aprendizaje utilizando herramientas digitales.Depto. de Química AnalíticaFac. de Ciencias QuímicasFALSEsubmitte

Biosensores electroquímicos basados en nanomateriales y en materiales magnéticos para la determinación de analitos de interés bioquímico

En esta Tesis Doctoral, se han desarrollado diferentes biosensores e inmunosensores electroquímicos basados en superficies electródicas modificadas con materiales de última generación para la determinación de analitos de interés bioquímico. Se han preparado biosensores amperométricos basados en el empleo de un material compósito de nanotubos de carbono y nanopartículas de oro para la determinación de glucosinolatos y creatinina, así como electrodos serigrafiados de carbono modificados con nanopartículas de oro y poli 3,4 etilendioxitiofeno PEDOT electrodepositado en medio líquido iónico, para la determinación de etanol. Además, se diseñan y aplican diferentes inmunosensores electroquímicos para la determinación de prolactina PRL , hormona del crecimiento hGH y factor de crecimiento insulínico1 IGF 1 , basados en el empleo de diferentes de diferentes materiales y superficies electródicas: electrodos serigrafiados de carbono modificados con nanotubos de carbono y nanopartículas de oro y PEDOT. Esta estrategia de modificación fue aplicada con éxito a un electrodo serigrafiado de carbono en configuración dual para la determinación simultánea de hGH y PRL. Se han empleado también micropartículas magnéticas y electrodos de carbono vitrificado modificados con nanotubos de carbono y ácido poli pirrolpropiónico . En todos los casos, se estudió la influencia de las variables involucradas en la preparación y el funcionamiento de cada configuración. Las superficies electródicas se caracterizaron mediante técnicas de microscopía electrónica y por voltamperometría cíclica. Se obtuvieron los calibrados, estableciéndose sus características analíticas, considerando la sensibilidad, límite de detección, selectividad, reproducibilidad y tiempo de vida, entre otras. Por último, la utilidad de los sensores desarrollados se demostró por aplicación al análisis de estos analitos en muestras reales de diferente naturaleza, suero humano, orina, saliva, coles de Bruselas y cerveza Debe destacarse la originalidad de los dispositivos desarrollados, siendo en su mayor parte las primeras configuraciones de sensores electroquímicos descritos en la bibliografía para los analitos de interés, así como mejorando notablemente las características analíticas de los ya descritos anteriormente

Cutting-Edge Advances in Electrochemical Affinity Biosensing at Different Molecular Level of Emerging Food Allergens and Adulterants

The presence of allergens and adulterants in food, which represents a real threat to sensitized people and a loss of consumer confidence, is one of the main current problems facing society. The detection of allergens and adulterants in food, mainly at the genetic level (characteristic fragments of genes that encode their expression) or at functional level (protein biomarkers) is a complex task due to the natural interference of the matrix and the low concentration at which they are present. Methods for the analysis of allergens are mainly divided into immunological and deoxyribonucleic acid (DNA)-based assays. In recent years, electrochemical affinity biosensors, including immunosensors and biosensors based on synthetic sequences of DNA or ribonucleic acid (RNA), linear, aptameric, peptide or switch-based probes, are gaining special importance in this field because they have proved to be competitive with the methods commonly used in terms of simplicity, test time and applicability in different environments. These unique features make them highly promising analytical tools for routine determination of allergens and food adulterations at the point of care. This review article discusses the most significant trends and developments in electrochemical affinity biosensing in this field over the past two years as well as the challenges and future prospects for this technology

Beyond Sensitive and Selective Electrochemical Biosensors: Towards Continuous, Real-Time, Antibiofouling and Calibration-Free Devices

Nowadays, electrochemical biosensors are reliable analytical tools to determine a broad range of molecular analytes because of their simplicity, affordable cost, and compatibility with multiplexed and point-of-care strategies. There is an increasing demand to improve their sensitivity and selectivity, but also to provide electrochemical biosensors with important attributes such as near real-time and continuous monitoring in complex or denaturing media, or in vivo with minimal intervention to make them even more attractive and suitable for getting into the real world. Modification of biosensors surfaces with antibiofouling reagents, smart coupling with nanomaterials, and the advances experienced by folded-based biosensors have endowed bioelectroanalytical platforms with one or more of such attributes. With this background in mind, this review aims to give an updated and general overview of these technologies as well as to discuss the remarkable achievements arising from the development of electrochemical biosensors free of reagents, washing, or calibration steps, and/or with antifouling properties and the ability to perform continuous, real-time, and even in vivo operation in nearly autonomous way. The challenges to be faced and the next features that these devices may offer to continue impacting in fields closely related with essential aspects of people’s safety and health are also commented upon

Magnetic Janus Particles for Static and Dynamic (Bio)Sensing

Magnetic Janus particles bring together the ability of Janus particles to perform two different functions at the same time in a single particle with magnetic properties enabling their remote manipulation, which allows headed movement and orientation. This article reviews the preparation procedures and applications in the (bio)sensing field of static and self-propelled magnetic Janus particles. The main progress in the fabrication procedures and the applicability of these particles are critically discussed, also giving some clues on challenges to be dealt with and future prospects. The promising characteristics of magnetic Janus particles in the (bio)sensing field, providing increased kinetics and sensitivity and decreased times of analysis derived from the use of external magnetic fields in their manipulation, allows foreseeing their great and exciting potential in the medical and environmental remediation fields

Electrochemical immunosensor for receptor tyrosine kinase AXL using poly(pyrrolepropionic acid)-modified disposable electrodes

A sensitive and rapid method for the determination of the clinically relevant biomarker receptor tyrosine kinase AXL in serum involving amperometric disposable immunosensors is reported. The target protein was sandwiched between a specific capture antibody covalently immobilized on screen-printed carbon electrodes modified with electropolymerized poly(pyrrolepropionic acid) and a biotinylated detector antibody labeled with a streptavidin-horseradish peroxidase conjugate. The amperometric responses were measured at −0.20 V vs the Ag pseudo-reference electrode of the SPCE upon the addition of H2O2 in the presence of hydroquinone (HQ) as mediator. This integrated immunosensing platform showed a low limit of detection (337 pg mL−1), a good selectivity against other non-target serum proteins, and provided results statistically in agreement with those obtained by using a commercial ELISA kit. These attractive features together with the simplicity and easy automation and miniaturization of the required instrumentation make the developed methodology a promising alternative in the development of devices for on-site clinical analysis.Ministry of Economy and CompetitivityFEDERSpanish Ministry of Economy and Competitivity Research ProjectsComunidad de MadridDepto. de Química AnalíticaFac. de Ciencias QuímicasTRUEpu