Article

Human sulfite oxidase electrochemistry on gold nanoparticles modified electrode.

Institut für Biochemie und Biologie, Universität Potsdam, Golm, Germany.
Bioelectrochemistry (Amsterdam, Netherlands) (impact factor: 2.65). 12/2011; 87:33-41. DOI:10.1016/j.bioelechem.2011.11.012 pp.33-41
Source: PubMed

ABSTRACT The present study reports a facile approach for sulfite biosensing, based on enhanced direct electron transfer of a human sulfite oxidase (hSO) immobilized on a gold nanoparticles modified electrode. The spherical core shell AuNPs were prepared via a new method by reduction of HAuCl(4) with branched poly(ethyleneimine) in an ionic liquids resulting particles with a diameter less than 10nm. These nanoparticles were covalently attached to a mercaptoundecanoic acid modified Au-electrode where then hSO was adsorbed and an enhanced interfacial electron transfer and electrocatalysis was achieved. UV/Vis and resonance Raman spectroscopy, in combination with direct protein voltammetry, are employed for the characterization of the system and reveal no perturbation of the structural integrity of the redox protein. The proposed biosensor exhibited a quick steady-state current response, within 2 s, a linear detection range between 0.5 and 5.4 μM with a high sensitivity (1.85 nA μM(-1)). The investigated system provides remarkable advantages in the possibility to work at low applied potential and at very high ionic strength. Therefore these properties could make the proposed system useful in the development of bioelectronic devices and its application in real samples.

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  • Article: Bioelectrocatalysis at mesoporous antimony doped tin oxide electrodes - electrochemical characterization and direct enzyme communication
    Stefano Frasca, Anabel Molero Milan, Amandine Guiet, Caren Goebel, Fernando Pérez-Caballero, Konstanze Stiba, Silke Leimkühler, Anna Fischer, Ulla Wollenberger
    [show abstract] [hide abstract]
    ABSTRACT: In this paper we report immobilization and bioelectrocatalysis of human sulfite oxidase (hSO) on nanostructured antimony doped tin oxide (ATO) thin film electrodes. Two types of ATO thin film electrodes were prepared via evaporation induced self-assembly of ATO nanoparticle sols. The use of a porogen results in different porosity and film thickness. Nevertheless both electrode types reveal similar quasi reversible electrochemical behavior for positive and negatively charged small mediators. Facile and durable immobilization of catalytically active enzyme in a direct electron transfer configuration was achieved without further chemical modification of the ATO surfaces. Interestingly, the binding of hSO onto the ATO surface seem to be not only of electrostatic nature, but also originates from a strong interaction between the histidine-tag of the enzyme and the supporting material. This is suggested from stable sulfite dependent bioelectrocatalytic signals at high ionic strength and imidazole desorption experiments. As such, ATO appears as a promising conductive platform for the immobilization of complex enzymes and their application in bioelectrocatalysis.
    Electrochimica Acta 01/2013; · 3.83 Impact Factor
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Keywords

bioelectronic devices
 
direct electron transfer
 
direct protein voltammetry
 
enhanced interfacial electron transfer
 
facile approach
 
gold nanoparticles
 
hSO
 
human sulfite oxidase
 
investigated system
 
ionic liquids
 
mercaptoundecanoic acid
 
present study reports
 
proposed system useful
 
quick steady-state current response
 
real samples
 
remarkable advantages
 
resonance Raman spectroscopy
 
spherical core shell AuNPs
 
structural integrity
 
sulfite biosensing