Human sulfite oxidase electrochemistry on gold nanoparticles modified electrode
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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ABSTRACT: The functions of metal structures of micro- or nano-dimensions in the sensing mechanisms of amperometric enzyme-based biosensors are considered in the light of the principles of detection of the latter. The applications of metal mono- or bimetallic nanoparticles-modified materials as catalytic electrodes in the fabrication of first-generation and the role which metal nanoparticles play in promoting or enhancing the electron transfer rates in third-generation electrochemical biosensors are reviewed. Some examples of gold NPs functionalised with enzymes via gold–thiol chemistry as a strategy for enzyme immobilisation and spatial orientation when developing amperometric biosensors are also discussed.Chemical Papers 01/2015; 69(1):17-26. DOI:10.1515/chempap-2015-0011 · 1.19 Impact Factor
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ABSTRACT: The ability to recognize and quantify the molecular chirality of enantiomers at the nanolevel in biological systems constitutes the basis of many critical areas for specific targeting in drug development and metabolite probing. Plasmonic nanoparticle dimers exhibit circular dichroism effects at visible wavelengths, amplifying the chiral signal of chiral molecules. We demonstrate the self-assembly of plasmonic chiroptical dimers through multibody attractive forces mediated by cysteine, which amplified the plasmonic chirality of enantiomers using enantiomeric cysteines (L and D), and achieved chiral recognition and a quantitative chiroptical sensing platform, with a detection limit of 20 pM level for L-cysteine. The versatility of nanoparticle dimers with customized chiroptical response opens up the avenue for adaptation of the plasmonic chiroptical platform for the drug development and proteomic profiling of metabolites.08/2013; 1(35). DOI:10.1039/C3TB20692K
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ABSTRACT: A direct electron transfer (DET) based sulphite/oxygen biofuel cell is reported that utilises human sulphite oxidase (hSOx) and Myrothecium verrucaria bilirubin oxidase (MvBOx) and nanostructured gold electrodes. For bioanode construction, the nanostructured gold microelectrodes were further modified with 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester) to which polyethylene imine was covalently attached. hSOx was adsorbed onto this chemically modified nanostructured electrode with high surface loading of electroactive enzyme and in presence of sulphite high anodic bioelectrocatalytic currents were generated with an onset potential of 0.05 V vs. NHE. The biocathode contained MyBOx directly adsorbed to the deposited gold nanoparticles for cathodic oxygen reduction starting at 0.71 V vs. NHE. Both enzyme electrodes were integrated to a DET-type biofuel cell. Power densities of 8 and 1 mu W cm(-2) were achieved at 0.15 V and 0.45 V of cell voltages, respectively, with the membrane based biodevices under aerobic conditions.Biosensors & Bioelectronics 04/2015; 66. DOI:10.1016/j.bios.2014.10.080 · 6.45 Impact Factor