59 research outputs found
Nuevas aplicaciones de sustratos indoxílicos en biosensores y en análisis clínicos
No full textEL USO DE SUSTRATOS INDOXÍLICOS ESTÁ GENERALMENTE RELACIONADO CON LA REALIZACIÓN DE ENSAYOS CUALITATIVOS O SEMICUANTITATIVOS SONDE UN PRODUCTO INSOLUBLE Y COLOREADO ES DEPOSITADO SOBRE UN SUSTRATO SÓLIDO. EN ESTA TESIS DOCTORAL SE EMPLEAN SUSTRATOS ENZIMÁTICOS INDOXÍLICOS EN ENSAYOS CUANTITATIVOS HACIENDO USO DE TÉCNCIAS ELECTROQUÍMICAS Y OPTICO.ESPECTROSCÓPICAS. SE MUESTRAS LA POTENCIALIDAD DE UTILZIAR EL SUSTRATO 3-INDOXIL FOSFATO COMO SUSTRATO DE LA PEROXIDASA UNIDO A LA POSTERIOR CUANTIFICACIÓN DEL AZUL DE ÍNDIGO PREVIA SULFONACIÓN CON ÁCIDO SULFURICO CONCENTRADO. LA DETERMINACIÓN DEL DERIVADO SOLUBLE, INDIGO CARMÍN, SE REALIZA POR TÉCNICAS VOLTAMPEROMÉTRICAS SOBRE ELECTRODOS SERIGRAFIADOS DE CARBONO Y SE DEMUESTRA LA POSIBLIDAD DE UTILIZAR ESTA METODOLOGÍA EN INMUNOENSAYOS TIPO ELISA PARA LA DETERMINACIÓN DE NEUMOLISINA. SE PRESENTA TAMBIÉN LA POSIBILIDAD DE SOLUBILIZAR EL AZUL DE INDIGO EN PRESENCIA DE UN AGENTE REDUCTOR EN UN MEDIO BÁSICO, PROCEDIENDO A CUANTIFICAR FINALEMNTE EL LEUCOÍNDIGO GENERADO POR TÉCNICAS ELECTROQUÍMICAS SOBRE ELECTRODOS DE PASTA DE CARBONO O HACIENDO USO DE TECNICAS COMO LA FLUORESCENCIA MOLECULAR O LA ESPECTROFOTOMETRÍA DE ABSORCIÓN MOLECULAR. SE PLANTEA TAMBIÉN EL USO DE SUSTRATOS INDOXÍLICOS EN COMBINACIÓN DE IONES PLATA COMO UN NUEVO SUSTRATO DE LA FOSFATASA ALCALINA. A TRAVÉS DE ESTA REACCIÓN SE GENERA UN COPRECIPITADO DE PLATA METÁLICA Y DE AZUL DE INDIGO, AUNQUE LA MEDIDA DE LA PLATA METÁLICA POR REDISOLUCIÓN ANODICA PERMITE LA REALIZACIÓN DE GENOSENSORES ELECTROQUÍMICOS DE ALTA SENSIBILIDAD
Bioresponsive, Electroactive, and Inkjet‐Printable Graphene‐Based Inks
Get PDFWith the advent of flexible electronics, the old fashioned and conventional solid-state technology will be replaced by conductive inks combined with low-cost printing techniques. Graphene is an ideal candidate to produce conductive inks, due to its excellent conductivity and zero bandgap. The possibility to chemically modify graphene with active molecules opens up the field of responsive conductive inks. Herein, a bioresponsive, electroactive, and inkjet-printable graphene ink is presented. The ink is based on graphene chemically modified with selected enzymes and an electrochemical mediator, to transduce the products of the enzymatic reaction into an electron flow, proportional to the analyte concentration. A water-based formulation is engineered to be respectful with the enzymatic activity while matching the stringent requirements of inkjet printing. The efficient electrochemical performance of the ink, as well as a proof-of-concept application in biosensing, is demonstrated. The versatility of the system is demonstrated by modifying graphene with various oxidoreductases, obtaining inks with selectivity toward glucose, lactate, methanol, and ethanol
Selective Ion Sensing in Artificial Sweat Using Low-Cost Reduced Graphene Oxide Liquid-Gated Plastic Transistors
Get PDFHealth monitoring is experiencing a radical shift from clinic-based to point-of-care and wearable technologies, and a variety of nanomaterials and transducers have been employed for this purpose. 2D materials (2DMs) hold enormous potential for novel electronics, yet they struggle to meet the requirements of wearable technologies. Here, aiming to foster the development of 2DM-based wearable technologies, reduced graphene oxide (rGO)-based liquid-gated transistors (LGTs) for cation sensing in artificial sweat endowed with distinguished performance and great potential for scalable manufacturing is reported. Laser micromachining is employed to produce flexible transistor test patterns employing rGO as the electronic transducer. Analyte selectivity is achieved by functionalizing the transistor channel with ion-selective membranes (ISMs) via a simple casting method. Real-time monitoring of K+ and Na+ in artificial sweat is carried out employing a gate voltage pulsed stimulus to take advantage of the fast responsivity of rGO. The sensors show excellent selectivity toward the target analyte, low working voltages (<0.5 V), fast (5-15 s), linear response at a wide range of concentrations (10 μm to 100 mm), and sensitivities of 1 μA/decade. The reported strategy is an important step forward toward the development of wearable sensors based on 2DMs for future health monitoring technologies
Molecular electrochemistry. An overview of a cross-field: Electrochemistry/spectroscopic/theoretical integrated approach
Get PDFThis work summarizes state-of-the-art results achieved by combining, in a synergetic approach, the outcome obtained by electrochemical, spectroscopic and theoretical methods. A number of selected case-studies are reported, where such a synergetic approach enables to draw a complete picture of complex experimental systems. Finally, the relevance of the combined experimental and theoretical approach in solid-state electrochemistry, a territory amidst novel concepts in solidstate electronics, is recapped
Detection of hydrogen peroxide by flow injection analysis based on electrochemiluminescence resonance energy transfer donor–acceptor strategy
No full textDetection of leucoindigo in alkaline phosphatase and peroxidase based assays using 3-indoxyl phosphate as substrate
No full textVoltammetric Determination of Leucoindigo Adsorbed on Pretreated Carbon Paste Electrodes: Its Application in a Flow System
No full textManufacture and evaluation of cup-stacked carbon nanofiber-modified screen printed electrodes as electrochemical tools
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