retour à l'accueil

Laboratoire d'Electrochimie Moleculaire, LEM, Paris

UMR CNRS - Université Paris Diderot - Paris France

   
 
Master Frontiers in Chemistry | UFR de Chimie - Université Paris Diderot - Paris 7 CNRS - Institut de chimie Université de Paris Master Chimie Sorbonne Paris Cité UFR de Chimie - Université Paris Diderot - Paris 7 CNRS - Institut de chimie
 |   Ecole Doctorale 388  |    Master Frontiers in Chemistry   |   C'Nano IdF   |   Respore  |
Université Paris Diderot
Université de Paris CNRS, Centre National de la Recherche Scientifique
 
 


Le LEM - Publications: Abstracts

Publication 612

Anal. Chem. , 79, 187 - 184, 2007.
DOI: 10.1021/ac061367a
 

Electrode surface confinement of self-assembled enzyme aggregates using magnetic nanoparticles and its application in bioelectrocatalysis

François Mavré, Mélanie Bontemps, Souad Ammar-Merah, Damien Marchal and Benoît Limoges

Laboratoire d' Electrochimie Moléculaire, UMR CNRS 7591, and Interfaces, Traitement, Organisation et Dynamiques des Systèmes (ITODYS), UMR CNRS 7086, Université de Paris 7, Denis Diderot, 2 place Jussieu, 75251 Paris Cedex 05, France

 


Self-assembled enzyme aggregates, prepared from magnetic iron oxide nanoparticles, avidin, and a biotinylated redox enzyme, were shown particularly useful for the simple, fast, and efficient construction of highly enzyme-loaded electrodes with the help of a magnet. The approach was illustrated in the case of the bioelectrocatalytic oxidation of NADH by a diaphorase oxidoreductase in the presence of a ferrocene mediator. Two different self-assembling procedures were tested, taking advantage of the spontaneous aggregation of the nanoparticles in the presence of avidin and also of the multivalency binding of biotinylated diaphorase toward avidin. Activities of the bound and unbound diaphorase were systematically controlled allowing determination of the number of active biotinylated diaphorase per nanoparticle incorporated within each magnetic enzyme aggregate. An active enzyme loading capacity of up to 2.35 nmol mg-1 was found for the best nanostructured enzyme assembly, which is 200 times better than for commercialized magnetic micrometer-sized beads coated with streptavidin and saturated with diaphorase. With the help of a permanent magnet, the magnetic enzyme aggregates were finally magnetically collected as a film on the surface of a small screen-printed carbon electrode and the catalytic currents recorded by cyclic voltammetry. From the analysis of the steady-state catalytic current responses and the kinetic rate constants of biotinylated diaphorase, it was possible to determine the enzyme concentration within the magnetic films. Owing to the high enzyme loading in the aggregates of nanoparticles (i.e., 130 M), the catalytic current responses were definitely higher than the ones measured at an electrode coated with a closed-packed monolayer of diaphorase or at an electrode covered with a film of magnetic micrometer-sized streptavidin beads saturated with diaphorase.
 
   
 
© 2005 LEM CréditsContactVenir au LEM