Carbon nanotubes for electrochemical (bio)sensing

Descripció del recurs: el 28 de Gener de 2010El progreso de la nanociencia y la nanotecnología está haciendo posible generar nuevos materiales basados en estructuras de carbono con propiedades únicas y con numerosas aplicaciones tecnológicas. Entre estas aplicaciones se encuentra la mejora de los biosensores, dispositivos capaces de realizar análisis químicos con gran rapidez. Las propiedades mecánicas y eléctricas extraordinarias de los nanotubos de carbono han estimulado extensamente su investigación a lo largo de todo el mundo desde su descubrimiento por Sumio Iijima en 1991. En esta tesis, el estudio del comportamiento electrocatalítico de nanotubos de carbono y al mismo tiempo el diseño de nuevos (bio)sensores electroquímicos han sido el principal objetivo, haciendo uso de diferentes alternativas de integración dentro de los sistemas de (bio)detección, basadas en modificaciones de las superficies del electrodo con nanotubos de carbono, o en el uso de nanotubos de carbono basados en (bio)compositos

Nanomaterials based biosensors for food analysis applications

The development of novel sensors and biosensors with interest for food industry is one of the key fields for the nowadays nanobiotechnology and nanomaterial science. The functionalized nanomaterials are used as catalytic tools, immobilization platforms or as optical or electroactive labels to improve the bio-sensing performance exhibiting higher sensitivity, stability, and selectivity. Nanomaterials, such as carbon nanotubes, metal nanoparticles, nanowires, nanocomposite and nanostructurated materials are playing an increasing role in the design of sensing and biosensing systems with interest for applications in food analysis. Furthermore, these nanobiosystems are also bringing advantages in terms of the design of novel food detection strategies. © 2011 Elsevier Ltd.Peer Reviewe

Nanoparticles for the development of improved (bio) sensing systems

14 páginas, 8 figuras.Nanoparticles serve as fundamental building blocks for nanobiotechnology, especially in several applications in the development of novel (bio)sensing systems. Nanoparticles can be used for modification of the surfaces of (bio)sensing transducers or as optical or electroactive labels to improve different aspects of performance, for example sensitivity, detection limit, multidetection capability, and response stability. Nanoparticles can be integrated into the transducer materials on an individual basis or inside other matrices to ensure the immobilization of recognition biomolecules and/or receptors which are the principal components of the (bio)sensing systems. Incorporation of nanoparticles into optical and electrochemical (bio)sensing systems, including their use in microfluidic based systems has the advantages of enabling the design of robust, easy to use, portable, and cost-effective devices.We acknowledge funding from the MEC (Madrid) for projects MAT2008-03079/NAN, CSD2006-00012 “Nanobiomed” (Consolider-Ingenio 2010) and the Torres Quevedo scholarship (B. Pérez López).Peer reviewe

Nanoparticles for the development of improved (bio) sensing systems

14 páginas, 8 figuras.Nanoparticles serve as fundamental building blocks for nanobiotechnology, especially in several applications in the development of novel (bio)sensing systems. Nanoparticles can be used for modification of the surfaces of (bio)sensing transducers or as optical or electroactive labels to improve different aspects of performance, for example sensitivity, detection limit, multidetection capability, and response stability. Nanoparticles can be integrated into the transducer materials on an individual basis or inside other matrices to ensure the immobilization of recognition biomolecules and/or receptors which are the principal components of the (bio)sensing systems. Incorporation of nanoparticles into optical and electrochemical (bio)sensing systems, including their use in microfluidic based systems has the advantages of enabling the design of robust, easy to use, portable, and cost-effective devices.We acknowledge funding from the MEC (Madrid) for projects MAT2008-03079/NAN, CSD2006-00012 “Nanobiomed” (Consolider-Ingenio 2010) and the Torres Quevedo scholarship (B. Pérez López).Peer reviewe

Electrochemical detection of Salmonella using gold nanoparticles

A disposable immunosensor for Salmonella enterica subsp. enterica serovar Typhimurium LT2 (S) detection using a magneto-immunoassay and gold nanoparticles (AuNPs) as label for electrochemical detection is developed. The immunosensor is based on the use of a screen-printed carbon electrode (SPCE) that incorporates a permanent magnet underneath. Salmonella containing samples (i.e. skimmed milk) have been tested by using anti-Salmonella magnetic beads (MBs-pSAb) as capture phase and sandwiching afterwards with AuNPs modified antibodies (sSAb-AuNPs) detected using differential pulse voltammetry (DPV). A detection limit of 143 cellsmL -1 and a linear range from 10 3 to 10 6 cellsmL -1 of Salmonella was obtained, with a coefficient of variation of about 2.4%. Recoveries of the sensor by spiking skimmed milk with different quantities of Salmonella of about 83% and 94% for 1.5×10 3 and 1.5×10 5 cellsmL -1 were obtained, respectively. This AuNPs detection technology combined with magnetic field application reports a limit of detection lower than the conventional commercial method carried out for comparison purposes in skimmed milk samples. © 2012 Elsevier B.V.We acknowledge MICINN (Madrid) for the projects PIB2010JP- 00278 and IT2009-0092, and the NATO Science for Peace and Security Programme's support under the project SfP 983807 and to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brasil for the scholarship given to André Santiago Afonso, grant number 200826/2011-5 and also Torres Quevedo scholarship given to Briza Pérez-López.Peer Reviewe

Simple Forster resonance energy transfer evidence for the ultrahigh quantum dot quenching efficiency by graphene oxide compared to other carbon structures

Förster resonance energy transfer (FRET) entails the transfer of energy from a photoexcited energy donor to a close energy acceptor. In this regard, quantum dots (QDs), as donors, are quenched when they are next to an acceptor material. Graphite, carbon nanotubes (CNTs), carbon nanofibers (CNFs) and graphene oxide (GO) were explored as energy acceptors of QD FRET donors in the solid phase. In our setup, the higher estimated values of quenching efficiency for each material are as follows: graphite, 66 ± 17%; CNTs, 71 ± 1%; CNFs, 74 ± 07% and GO, 97 ± 1%. Among these materials, GO is the best acceptor of QD FRET donors in the solid phase. Such an ultrahigh quenching efficiency by GO and the proposed simple mechanism may open the way to several interesting applications in the field of biosensing.Peer ReviewedPostprint (published version

Permeability Improvement of Electropolymerized Polypyrrole Films in Water Using Magnetic Hydrophilic Microbeads

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Electrocatalytic tuning of biosensing response through electrostatic or hydrophobic enzyme-graphene oxide interactions

The effect of graphene oxidative grades upon the conductivity and hydrophobicity and consequently the influence on an enzymatic biosensing response is presented. The electrochemical responses of reduced graphene oxide (rGO) have been compared with the responses obtained from the oxide form (oGO) and their performances have been accordingly discussed with various evidences obtained by optical techniques. We used tyrosinase enzyme as a proof of concept receptor with interest for phenolic compounds detection through its direct adsorption onto a screen-printed carbon electrode previously modified with oGO or rGO with a carbon-oxygen ratio of 1.07 or 1.53 respectively. Different levels of oGO directly affect the (bio)conjugation properties of the biosensor due to changes at enzyme/graphene oxide interface coming from the various electrostatic or hydrophobic interactions with biomolecules. The developed biosensor was capable of reaching a limit of detection of 0.01. nM catechol. This tuning capability of the biosensor response can be of interest for building several other biosensors, including immunosensors and DNA sensors for various applications. © 2014 Elsevier B.V.MEC (Spain) for MAT2011-25870 grant is acknowledged.Peer Reviewe