Person: Reviejo García, Ángel Julio
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First Name
Ángel Julio
Last Name
Reviejo García
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Analítica
Area
Química Analítica
Identifiers
4 results
Search Results
Now showing 1 - 4 of 4
Item Comparison of Different Strategies for the Development of Highly Sensitive Electrochemical Nucleic Acid Biosensors Using Neither Nanomaterials nor Nucleic Acid Amplification(ACS Sensors, 2017) Ruiz Valdepeñas Montiel, Víctor; Povedano Muñumel, Eloy; Vargas, Eva; Torrente Rodríguez, Rebeca Magnolia; Pedrero Muñoz, María; Reviejo García, Ángel Julio; Campuzano Ruiz, Susana; Pingarrón Carrazón, José ManuelCurrently, electrochemical nucleic acid-based biosensing methodologies involving hybridization assays, specific recognition of RNA/DNA and RNA/RNAduplexes, and amplification systems provide an attractive alternative to conventional quantification strategies for the routine determination of relevant nucleic acids at different settings. A particularly relevant objective in the development of such nucleic acid biosensors is the design of as many as possible affordable, quick, and simple methods while keeping the required sensitivity. With this aim in mind, this work reports, for the first time, a thorough comparison between 11 methodologies that involve different assay formats and labeling strategies for targeting the same DNA. The assayed approaches use conventional sandwich and competitive hybridization assays, direct hybridization coupled to bioreceptors with affinity for RNA/DNA duplexes, multienzyme labeling bioreagents, and DNA concatamers. All of them have been implemented on the surface of magnetic beads (MBs) and involve amperometrictransduction at screen-printed carbon electrodes (SPCEs). The influence of the formed duplex length and of the labeling strategy have also been evaluated. Results demonstrate that these strategies can provide very sensitive methods without the need for using nanomaterials or polymerase chain reaction (PCR). In addition, the sensitivity can be tailored within several orders of magnitude simply by varying the bioassay format, hybrid length or labeling strategy. This comparative study allowed us to conclude that the use of strategies involving longer hybrids, the use of antibodies with specificity for RNA/DNA heteroduplexes and labeling with bacterial antibody binding proteins conjugated with multiple enzyme molecules, provides the best sensitivity.Item Electrochemical detection of peanuts at trace levels in foods using a magnetoimmunosensor for the allergenic protein Ara h 2(Sensors and Actuators B: Chemical, 2016) Ruiz Valdepeñas Montiel, Víctor; Pellicanò, Alessandro; Campuzano Ruiz, Susana; Torrente Rodríguez, Rebeca Magnolia; Reviejo García, Ángel Julio; Cosio, Maria Stella; Pingarrón Carrazón, José ManuelA highly sensitive disposable amperometric magnetoimmunosensor for the rapid determination of Ara h 2 protein, one of the major peanut allergens, is reported. The approach uses a sandwich configuration involving selective capture and detector antibodies and carboxylic acid-modified magnetic beads (HOOC-MBs). Detector antibodies are labeled with HRP-conjugated secondary antibodies and the MBs bearing the immunoconjugates are magnetically captured on surface of a disposable screen-printed carbon electrode (SPCE). The affinity reactions are monitored amperometrically at −0.20 V (vs a Ag pseudo-reference electrode) in the presence of hydroquinone (HQ) as electron transfer mediator and upon addition of hydrogen peroxide as the enzyme substrate. The developed magnetoimmunosensor exhibits a wide range of linearity between 87 and 10,000 pg/mL Ara h 2 with a detection limit of 26 pg/mL as well as a great selectivity against other non-target proteins. The magnetoimmunosensing platform was successfully applied for the detection of Ara h 2 in different food extracts. After an appropriate sample dilution no matrix effects were observable. The developed methodology was able to detect trace amounts of the peanut allergen (0.0005% or 5.0 mg/kg) in wheat flour spiked samples. The results correlated properly with those provided by a commercial ELISA kit.Item Electrochemical magnetoimmunosensing platform for determination of the milk allergen β-lactoglobulin(Talanta, 2015) Ruiz Valdepeñas Montiel, Víctor; Campuzano Ruiz, Susana; Conzuelo, Felipe; Torrente Rodríguez, Rebeca Magnolia; Gamella Carballo, María; Reviejo García, Ángel Julio; Pingarrón Carrazón, José ManuelA very sensitive magnetoimmunosensor for the determination of β-lactoglobulin (β-LG) is reported in this work. A sandwich configuration involving covalent immobilization of the capture antibody (antiβ-LG) onto activated carboxylic-modified magnetic beads (HOOC-MBs) and incubation of the modified MBs with a horseradish peroxidase labeled antibody (HRP-antiβ-LG), is used. The resulting modified MBs are captured by a magnet placed under the surface of a disposable carbon screen-printed electrode (SPCE) and the amperometric responses are measured at −0.20 V (vs. Ag pseudo-reference electrode), upon addition of hydroquinone (HQ) as electron transfer mediator and hydrogen peroxide as the enzyme substrate. The β-LG magnetoimmunosensor exhibited a wide range of linearity (2.8–100 ng/mL) and a low detection limit of 0.8 ng/mL (20 pg in 25 μL sample). The magnetoimmunosensing platform was successfully applied for the detection of β-LG in different types of milk without any matrix effect after just a sample dilution. The results correlated properly with those provided by a commercial ELISA method offering a truthful analytical screening tool. These features make the developed methodology a promising alternative in the development of user-friendly devices for on-site determination of β-LG in dairy products.Item Electrochemical magnetic beads-based immunosensing platform for the determination of α-lactalbumin in milk(Food Chemistry, 2016) Ruiz Valdepeñas Montiel, Víctor; Campuzano Ruiz, Susana; Torrente Rodríguez, Rebeca Magnolia; Reviejo García, Ángel Julio; Pingarrón Carrazón, José ManuelAlpha-lactalbumin (α-LA) is one of the whey proteins in cows’ milk that has been identified as allergenic. In this work, we present, for the first time, a very sensitive magnetic beads (MBs)-based immunosensor for the determination of α-LA. A sandwich configuration involving selective capture and horseradish peroxidase-labeled detector antibodies was implemented on carboxylic acid-modified magnetic beads, captured magnetically under the surface of a disposable screen-printed carbon electrode for amperometric detection using the hydroquinone (HQ)/hydrogen peroxide system. The α-LA immunosensor exhibited a wide linear range (37.0–5000 pg/ml), a low limit of detection (LOD, 11.0 pg/ml) and noteworthy selectivity against other non-target proteins. The MBs-based immunosensing platform was applied successfully for the determination of α-LA in several varieties of milk (raw and UHT cows’ milk as well as human milk) and infant formulations. The results were corroborated with those obtained using a commercial ELISA method, thereby substantiating the analytical merits of this unique method.