Direct electrochemistry of Trametes versicolor Laccase (LAC) was found at a Sonogel-Carbon electrode. The bioamplification, performed by dual immobilization of this enzyme and Mushroom Tyrosinase (TYR), of the bio-electrocatalytic reduction of O(2) was investigated. The calculated alpha transfer coefficients were 0.64 and 0.67, and the heterogeneous electron-transfer rate constants were 6.19 and 8.52 s(-1), respectively, for the individual LAC and dual LAC-TYR-based Nafion/Sonogel-Carbon bio-electrodes. The responses of the dual enzymes electrode to polyphenols were stronger than those of the individual LAC or TYR biosensors. Hypotheses are offered about the mechanism of bioamplification. The surfaces of the biosensors were also characterized by AFM.
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http://dx.doi.org/10.1016/j.talanta.2008.01.055 | DOI Listing |
Chem Sci
December 2024
Department of Physical Chemistry, University of Málaga, Andalucia-Tech Campus de Teatinos s/n 29071 Málaga Spain
The synthesis, electrochemical, spectroelectrochemical, photophysical and light induced electron transfer reactions in two new anthanthrene quinodimethanes have been studied and analyzed in the context of dynamic electrochemistry. Their properties are dependent on the interconversion between folded and twisted forms, which are separated by a relatively small energy range, thus allowing to explore their interconversion by variable temperature measurements. The photophysics of these molecules is mediated by a diradical excited state with a twisted structure that habilitates rapid intersystem crossing.
View Article and Find Full Text PDFFood Chem
December 2024
Sensors and Biosensors Group, Analytical Chemistry and Electrochemistry Lab (LR99ES15), University of Tunis El Manar, Tunis El Manar, 2092 Tunis, Tunisia. Electronic address:
Improper use and harmful effects of nitrite ions pose a significant risk to human health. To address this concern, the use of carbon-based materials for electrochemical sensing is regarded as one of the most promising detection tools for ensuring the quality of drinking water and food products. In this context, we developed laser-ablated graphene electrodes (LAGEs) by direct laser scribing on a polyimide substrate, which were subsequently modified by electrochemical deposition of a redox-active melanin-like film (MeLF/LAGEs).
View Article and Find Full Text PDFAdv Mater
December 2024
Department of Mechanical & Industrial Engineering (MIE), University of Toronto, Toronto, Ontario, M5S 3G8, Canada.
MXene has garnered growing interest in the field of electrochemistry, thanks to its unique electrical and surface characteristics. Nonetheless, significant challenges persist in realizing its full potential in chemoresistive sensing applications. In this study, a novel unidirectional freeze-casting approach for fabricating a Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-facilitated vertically aligned MXene-based aerogel with enhanced chemoresistive sensing properties was introduced.
View Article and Find Full Text PDFSmall Methods
December 2024
Frumkin Institute of Physical Chemistry and Electrochemistry Russian Academy of Sciences, Leninsky pr., 31, building 4, Moscow, 119071, Russia.
A novel phthalocyanine-based hybrid nanofilm is for the first time successfully applied as an oxidative platform for surface enhanced Raman spectroscopy (SERS) sensing to fine-resolve Raman-inactive compounds. The hybrid is formed by self-assembly of zinc(II) 2,3,9,10,16,17,23,24-Octa[(3',5'-dicarboxy)-phenoxy]phthalocyaninate (ZnPc*) with the solid-supported monolayer of graphene oxide (GO) mediated by zinc acetate metal cluster. Atomic force microscopy, UV-vis and fluorescence spectroscopies confirm that this simple coordination motive in combination with molecular structure of ZnPc* prevents contact quenching of the light-excited triplet state through aromatic stacking with GO particles.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
College of Chemistry, Beijing Normal University, Beijing 100875, China.
The quantitative analysis of vesicular neurotransmitters in neurons in situ is paramount for investigating neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease (PD). Unfortunately, a direct approach for monitoring neurotransmitter chemistry in single vesicles in fresh brain tissue has remained inaccessible so far. Here, we introduce an innovative platform of single-vesicle electrochemistry (SVE) in fresh brain tissue, enabling the quantification of neurotransmitters at the single-vesicle level for both soma and varicosity.
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