3D-nanostructured Au electrodes for the event-specific detection of MON810 transgenic maize

In the present work, the development of a genosensor for the event-specific detection of MON810 transgenic maize is proposed. Taking advantage of nanostructuration, a cost-effective three dimensional electrode was fabricated and a ternary monolayer containing a dithiol, a monothiol and the thiolated capture probe was optimized to minimize the unspecific signals. A sandwich format assay was selected as a way of precluding inefficient hybridization associated with stable secondary target structures. A comparison between the analytical performance of the Au nanostructured electrodes and commercially available screen-printed electrodes highlighted the superior performance of the nanostructured ones. Finally, the genosensor was effectively applied to detect the transgenic sequence in real samples, showing its potential for future quantitative analysis

DNA-based biosensor for the electrocatalytic determination of antioxidant capacity in beverages

Reactive oxygen species (ROS) are produced as a consequence of normal aerobic metabolism and are able to induce DNA oxidative damage. At the cellular level, the evaluation of the protective effect of antioxidants can be achieved by examining the integrity of the DNA nucleobases using electrochemical techniques. Herein, the use of an adenine-rich oligonucleotide (dA21) adsorbed on carbon paste electrodes for the assessment of the antioxidant capacity is proposed. The method was based on the partial damage of a DNA layer adsorbed on the electrode surface by OH• radicals generated by Fenton reaction and the subsequent electrochemical oxidation of the intact adenine bases to generate an oxidation product that was able to catalyze the oxidation of NADH. The presence of antioxidant compounds scavenged hydroxyl radicals leaving more adenines unoxidized, and thus, increasing the electrocatalytic current of NADHmeasured by differential pulse voltammetry (DPV). Using ascorbic acid (AA) as a model antioxidant species, the detection of as low as 50nMof AA in aqueous solution was possible. The protection efficiency was evaluated for several antioxidant compounds. The biosensor was applied to the determination of the total antioxidant capacity (TAC) in beverages

Detección de alérgenos de cacahuete mediante un sensor de ADN

In the present work an electrochemical genosensor for detecting a DNA segment encoding part of the allergenic protein peanut Ara h 2 is proposed. Genosensors is based on a sandwich assay format, the analyte hybridized with two base sequences, one immobilized onto a screen printed gold electrode, forming a self-assembled monolayer. The optimization of the device was performed using Response Surface Methodology. The maximum response was found to be 1 µM of capture probe concentration and 2,5 mM of blocking agent concentration.En el presente trabajo se propone un genosensor electroquímico para la detección de un segmento de ADN que codifica parte de la proteína alergénica Ara h 2 del cacahuete. El genosensor se basa en un ensayo tipo sándwich, el analito hibrida con dos secuencias de bases, una de ellas inmovilizada sobre un electrodo de oro serigrafiado, formando una monocapa autoensamblada. La optimización del dispositivo se realizó utilizando la metodología de Superficies de Respuesta. La máxima respuesta se encontró para concentraciones de sonda de captura y agente bloqueante, 1 μM y 2,5 mM respectivamente

Nanomotor-based biocatalytic patterning of helical metal microstructures

A new nanomotor-based surface-patterning technique based on the movement of a magnetically powered enzyme-functionalized flexible nanowire swimmer offers the ability to create complex helical metal microstructures