|
|
|
|
| LEADER |
07188nam a2200361 a 4500 |
| 001 |
ELB85618 |
| 003 |
FlNmELB |
| 006 |
m o d | |
| 007 |
cr cn||||||||| |
| 008 |
201208r2011 ag |||||s|||||||||||spa d |
| 035 |
|
|
|a (MiAaPQ)EBC3200540
|
| 035 |
|
|
|a (Au-PeEL)EBL3200540
|
| 035 |
|
|
|a (CaPaEBR)ebr10577111
|
| 035 |
|
|
|a (OCoLC)929368213
|
| 040 |
|
|
|a FlNmELB
|b spa
|c FlNmELB
|
| 050 |
|
4 |
|a QD553
|b S421 2011
|
| 080 |
|
|
|a 541.13
|
| 082 |
0 |
4 |
|a 541.37
|2 22
|
| 100 |
1 |
|
|a Scodeller, Pablo David.
|
| 245 |
1 |
0 |
|a Aplicaciones de electrodos enzim�aticos y multicapas enzim�aticas en biosensores y bioceldas de combustible
|h [recurso electronico] =
|b Applications of enzymatic electrodes and enzymatic multilayers in biosensors and biofuel cells /
|c Pablo David Scodeller ; director: Ernesto J. Calvo.
|
| 246 |
3 |
2 |
|a Applications of enzymatic electrodes and enzymatic multilayers in biosensors and biofuel cells
|
| 260 |
|
|
|a Buenos Aires, Argentina :
|b Universidad de Buenos Aires,
|c 2011.
|
| 502 |
|
|
|a Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales.
|
| 520 |
|
|
|a El presente trabajo de tesis se basa en el estudio de multicapas enzim�aticas y electrodos enzim�aticos destinados a la fabricaci�on de biosensores y bioc�atodos para celdas de combustible. Las multicapas, de espesores nanom�etricos, se fabricaron utilizando el m�etodo de autoensamblado capa por capa, empleando enzimas y el polielectrolito electroactivo PAH-Os. El primer objetivo es extender el sistema de reconocimiento molecular de glucosa integrado por una enzima redox (GOx) mediada por su cable molecular (PAH-Os) (que ha sido estudiado previamente en este laboratorio) al dise�no de un nuevo biosensor que brinde posibilidades de sensado �unicas y permita sensar diferentes analitos. A este respecto se construy�o el primer nanobiosensor �optico autoensamblando capa por capa esos dos componentes sobre la superficie de nanopart�iculas de Oro para dar una transducci�on �optica que adem�as aprovecha las propiedades plasmonicas de las nanopart�iculas de Oro. El segundo objetivo es extender ese mismo sistema (GOx/PAH-Os) a un sistema que emplee una enzima redox diferente, y que tambi�en posea inter�es industrial. En esta direcci�on, se estudi�o el sistema Lacasa/PAH-Os como bioc�atodo para celdas de combustible (la Lacasa es una enzima redox que cataliza la oxidaci�on de bifenoles reduciendo O2 a H20). Se encontr�o que durante la electroreducci�on de ox�igeno, catalizada por Lacasa y mediada por PAH-Os, la enzima produce peque�nas cantidades de per�oxido de hidr�ogeno (que adem�as la inhiben), demostr�andose que el mecanismo de Solomon, que predice la reducci�on de ox�igeno por 4 electrones sin producci�on de H2O2 es incompleto, al no tener en cuenta el camino de la desorci�on del H2O2 observado en el presente estudio. Este bioc�atodo, en condiciones de convecci�on forzada, posee una actividad espec�ifica considerable de 0.3mA.cm-2 a un potencial de 0.3V lo cual lo convierte en un posible candidato para su implementaci�on en celdas de biocombustible. Se compar�o adem�as este bioc�atodo con el sistema que emplea transferencia electr�onica directa de la enzima con una superficie de carbono grafitico, mostr�andose adem�as por primera vez las curvas de calibraci�on de de un sistema de este tipo. Se compararon ambos bioc�atodos entre s�i y a �estos con un c�atodo de Platino, concluyendo que el bioc�atodo no mediado no es apto para la producci�on de potencia el�ectrica debido a una baj�isima actividad espec�ifica. En base a las evidencias previas a esta tesis, sobre el marcado efecto de la naturaleza y carga de la ultima capa de multicapas electroactivas en el fen�omeno de transporte electr�onico, se estudi�o este mismo fen�omeno en los dos electrodos enzim�aticos (PAH- Os/Lac, PAH-Os/GOx), observ�andose que el proceso biocatal�itico es seriamente impedido por la adsorci�on de un poliani�on, reflejado a trav�es de la abrupta ca�ida en el coeficiente de difusi�on del electr�on.
|
| 520 |
|
|
|a The present thesis work is based on the study of enzymatic multilayers and enzymatic electrodes designed for biosensors and biofuel cell cathodes. These multilayers, of nanometric thicknesses, were built using layer by layer (lbl) self assembly of enzymes and an electroactive polyelectrolyte PAH-Os. The first goal is to extend the glucose molecular recognition system, comprised of a redox enzyme (GOx) and its molecular wire (PAH-Os) (which has been studied previously in this laboratory), to the design of a new biosensor which would allow unique sensing possibilities and sensing of different analytes. In this regard, the first optical nanobiosensor based on a wired enzyme inside the shell of 20nm gold nanoparticles was built using the lbl method to give optical transduction, and on top of that, taking advantage of the plasmonic properties of the gold particles. The second objective is to extend this same system (GOx/PAH-Os) to one which would make use of a different redox enzyme, also with industrial relevance. In this direction, the system Laccase/PAH-Os was studied as a biocathode for biofuel cells (Laccase is a redox enzyme which catalyzes the oxidation of biphenols reducing O2 to H2O). It was found that during the electroreduction of oxygen, small amounts of hydrogen peroxide are produced by the enzyme (it was also found that this H2O2 also inhibits it), thus showing that Solomon's mechanism which predicts the reduction of O2 by 4 electrons without production of H2O2 is incomplete, since it does not take into account the desorption path of H2O2 observed in this study. This biocathode under forced convection has a considerable specific activity of 0.3mA.cm-2 and a potential of 0.3V which make it a possible candidate for biofuel cells. This biocathode was also compared to the non mediated enzymatic system which makes use of the direct electron transfer of Laccase with graphitic carbon surfaces, showing for the first time the calibration curves for such a system. Both these biocathodes were compared with each other and with a Platinum cathode, showing that the non mediated biocathode is not fit for biofuel cells given its extremely low specific activity. Based on previous evidence regarding the clear effect of the nature and charge of the last layer in electroactive multilayers on the electron transport, this same phenomenon was studied in both enzymatic electrodes (PAH-Os/Lac and PAH-Os/GOx) showing that the catalytic process is severely hindered by the absorption of a polyanion, as reflected by the dramatic fall in the electron diffusion coefficient.
|
| 533 |
|
|
|a Recurso electr�onico. Santa Fe, Arg.: e-libro, 2015. Disponible v�ia World Wide Web. El acceso puede estar limitado para las bibliotecas afiliadas a e-libro.
|
| 650 |
|
4 |
|a Electroqu�imica.
|
| 650 |
|
4 |
|a Electrochemistry.
|
| 655 |
|
4 |
|a Libros electr�onicos.
|
| 700 |
1 |
|
|a Calvo, Ernesto J,
|e dir.
|
| 710 |
2 |
|
|a e-libro, Corp.
|
| 856 |
4 |
0 |
|u https://elibro.net/ereader/ufasta/85618
|
| 999 |
|
|
|c 180208
|d 180208
|