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

Rapid diagnostic tools based on the use of bioelectroanalytical platforms applicable to low-resource settings

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Químicas, leída el 14-04-2023Los grandes avances en ciencia y tecnología han sido claves para identificar, entender e incluso curar numerosas enfermedades que fueron devastadoras en épocas anteriores y a las que era difícil anticiparse. Hoy en día, disponemos de pruebas diagnósticas que tienen como objetivo detectar las enfermedades en fases tempranas y permiten aplicar en el momento oportuno tratamientos eficientes, con las consecuencias que esto tiene tanto en la supervivencia y calidad de vida de los pacientes como en la reducción de la carga económica que soportan los sistemas nacionales de salud. Sin embargo, el elevado coste de las técnicas, su aplicación centralizada, la dificultad en el análisis de muestras complejas y su naturaleza invasiva limitan la evolución del diagnóstico clínico hacia una medicina personalizada, descentralizada y accesible para todos. La sociedad cada vez exige una atención más rápida, de mayor calidad y que se adapte a las necesidades de cada paciente. De hecho, hoy en día, y en gran parte potenciado por la reciente pandemia, una de las mayores demandas clínicas reside en la posibilidad de realizar un diagnóstico precoz, rápido y mínimamente invasivo de enfermedades de elevada prevalencia y mortalidad mediante pruebas médicas masivas fuera del entorno de un laboratorio y gestionadas por personal no especializado, lo que se conoce como pruebas en el lugar de asistencia o punto de atención (Point-Of-Care, POC). La descentralización del sistema sanitario a laboratorios clínicos, centros de atención primaria, ambulatorios o incluso el hogar del paciente resulta imprescindible, tanto para minimizar las consecuencias de futuras posibles pandemias por el retraso en el diagnóstico derivado del colapso sanitario, como para seguir avanzando en el ámbito de la medicina personalizada, permitiendo aumentar la probabilidad de curación del paciente y reducir los costes asociados a su tratamiento. Por todo ello, resulta esencial disponer de herramientas sensibles, cuantitativas, precisas, asequibles, fáciles de usar y mínimamente invasivas que contribuyan al diagnóstico fiable y descentralizado incluso en entornos de pocos o bajos recursos, desafíos que la tecnología de biosensores electroquímicos parece afrontar con éxito...Breakthroughs in science and technology have helped to identify, understand, and even cure many diseases that in earlier times were devastating and unpredictable. Today, available diagnostic tests make it possible to detect diseases at an early stage and to apply timely and effective treatments, with beneficial consequences in terms of patient survival and quality of life, as well as reducing the financial burden on national health systems. However, the high cost of the techniques, their centralized application, the difficulty of analysing complex samples, and their invasive nature hinder the evolution of clinical diagnostics towards personalized medicine accessible to all.Society increasingly demands faster and higher quality care, tailored to the needs of each patient. In fact, and largely driven by the recent pandemic, one of the biggest clinical demands lies in the possibility of early, rapid, and minimally invasive diagnosis of high prevalence and high mortality diseases through mass medical testing outside a laboratory setting and managed by non-specialised staff, known as Point-Of-Care (POC) testing. Decentralization of the healthcare system to clinical laboratories, primary care centres, outpatient clinics or even the patient's home is essential, both to minimise the consequences of future pandemics due to diagnostic delays resulting from the collapse of healthcare, and to further advance in the field of personalized medicine, increasing the probability of curing patients and reducing the costs associated with their treatment. Sensitive, quantitative, accurate, fast, affordable, easy-to-use, and minimally invasive tools that contribute to reliable and decentralised diagnostics are therefore essential challenges that electrochemical biosensor technology seems to successfully address...Fac. de Ciencias QuímicasTRUEunpu

A combined analytical-chemometric approach for the in vitro determination of polyphenol bioaccessibility by simulated gastrointestinal digestion

CRUE-CSIC (Acuerdos Transformativos 2022)In this study, an integrated characterisation through polyphenol and cafeine content and antioxidant activity was combined with chemometric analysis to assess the efects of simulated in vitro gastrointestinal digestion on the bioaccessibility of these bioactive compounds from nine diferent tea infusions. Tea infusions were characterised based on total favonoids, total polyphenols and antioxidant activity, together with the determination of individual polyphenol content. Fourteen phenolic compounds, including phenolic acids, stilbenes and favonoids, were selected based on their reported bioactivity and high accessibility, attributed to their low molecular weight. Both polyphenols and cafeine were initially monitored in raw tea infusions and through the diferent digestion stages (salivary, gastric and duodenal) by capillary high performance liquid chromatography coupled to diode array detection (cHPLC-DAD) and/or HPLC coupled to a triple quadrupole mass analyser (HPLC–MS/MS). Multivariate analysis of the studied bioactives, using principal component analysis and cluster analysis, revealed that the decafeination process seems to increase the stability and concentration of the compounds evaluated during digestion. The greatest transformations occurred mainly in the gastric and duodenal stages, where low bioactivity indices (IVBA) were shown for resveratrol and cafeic acid (IVBA=0%). In contrast, the polyphenols gallic acid, chlorogenic acid and quercetin gave rise to their availability in white, green and oolong infusion teas (IVBA>90%). Furthermore, highly fermented black and pu-erh varieties could be designated as less bioaccessible environments in the duodenum with respect to the tested compounds.Ministerio de Ciencia e Innovación (MICINN)Comunidad de Madrid/FEDERUniversidad Complutense de MadridDepto. de Química AnalíticaFac. de Ciencias QuímicasTRUEpu

Simultaneous amperometric immunosensing of the metastasis-related biomarkers IL-13Rα2 and CDH-17 by using grafted screen-printed electrodes and a composite prepared from quantum dots and carbon nanotubes for signal amplification

This paper describes a dual electrochemical immunoassay for the simultaneous determination of IL-13Rα2 and CDH-17, two biomarkers of emerging relevance in metastatic processes. The sandwich assay uses a screen-printed dual carbon electrode that was electrochemically grafted with p-aminobenzoic acid to allow the covalent immobilization of capture antibodies. A hybrid composed of graphene quantum dots (GQDs) and multiwalled carbon nanotubes (MWCNTs) act as nanocarriers for the detection antibodies and horseradish peroxidase. The use of this hybrid material considerably improves the assay (in comparison to the use of MWCNTs) due to the peroxidase mimicking activity of the GQDs. The method works at a low working potential (0.20 V vs. Ag pseudo-reference electrode) and thus is not readily interfered by unknown electroactive species. The dual immunoassay allows for the selective determination of both biomarkers with LOD values of 1.4 (IL-13sRα2) and 0.03 ng mL-1 (CDH-17). The simultaneous determination of IL-13Rα2 and CDH-17 was accomplished in lysates from breast and colorectal cancer cells with different metastatic potential, and in paraffin-embedded tumor tissues extracts from patients diagnosed with colorectal cancer at different stages. The applicability to discriminate the metastatic potential even in intact cells through the detection of both extracellular receptors has been demonstrated also. The assay can be performed within 3 h, requires small sample amounts (0.5 μg), and has a simple protocol. Graphical abstract Dual amperometric immunosensing of the metastasis-related biomarkers IL-13Rα2 and CDH-17 in human colorectal cancer cells and tissues by using grafted screen-printed electrodes and composites of quantum dots and carbon nanotubes as nanocarriers.Spanish Ministerio de Economía y CompetitividadComunidad de MadridAES-ISCIII programConsejería de Educación, Juventud y Deporte de la Comunidad de MadridFondo Social EuropeoDepto. de Química AnalíticaFac. de Ciencias QuímicasTRUEpu

Binary MoS2 nanostructures as nanocarriers for amplification in multiplexed electrochemical immunosensing: simultaneous determination of B cell activation factor and proliferation-induced signal immunity-related cytokines

A dual immunosensor is reported for the simultaneous determination of two important immunity-related cytokines: BAFF (B cell activation factor) and APRIL (a proliferation-induced signal). Sandwich-type immunoassays with specifc antibodies (cAbs) and a strategy for signal amplifcation based on labelling the detection antibodies (dAbs) with binary MoS2/ MWCNTs nanostructures and using horseradish peroxidase (HRP) were implemented. Amperometric detection was carried out at screen-printed dual carbon electrodes (SPdCEs) through the hydroquinone HQ/H2O2 system. The developed dual immunosensor provided limit of detection (LOD) of 0.08 and 0.06 ng mL−1 for BAFF and APRIL, respectively, and proved to be useful for the determination of both cytokines in cancer cell lysates and serum samples from patients diagnosed with autoimmune diseases and cancer. The obtained results agreed with those found using ELISA methodologies

Contribuyendo a la internacionalización de la docencia práctica inclusiva y sostenible en Química Analítica

Depto. de Química AnalíticaFac. de Ciencias QuímicasFALSEsubmitte

Ruralidad y campesinado

¿Existe aún el campo? ¿Desapareció el campesinado? ¿Triunfó la expansión del modo de vida urbano y de los urbanistas? ¿Subsiste aún un modo de vida rural? ¿Existe aún una cultura campesina? ¿Cuáles son las tensiones y principales amenazas que recorren el mundo rural latinoamericano? ¿Cuáles son las formas de resistencia desde la identidad campesina e indígena a la marea globalizante? ¿Qué experiencias promisorias y/ o exitosas se están desplegando en el mundo rural? ¿Cómo se ha transformado la ruralidad en las últimas décadas? ¿Cómo se enlaza la producción agraria con la emergencia de territorios intermedios? son algunas de las muchas preguntas que abordamos en este número de Polis