Elaboration of integrated microelectrodes for the detection of antioxidant species

Abstract

International audience(Pt-€“Pt-Ag/AgCl) and (Au-€“Pt-€“Ag/AgCl) electrochemical microcells (ElecCell) were developed for the detection of redox species by cyclic voltammetry. A special emphasis was placed on the SU-8 waferlevel passivation process in order to optimize the electrochemical properties of the different “thin film” metallic layers, i.e. gold or platinum for the working electrode, platinum for the counter electrode and silver/silver chloride for the reference electrode. (Au–Pt–Ag/AgCl) microcells were applied for the detection of antioxidant species such as ascorbic and uric acids in phosphate buffer solution, evidencing high sensitivity but low selectivity. Works were extended to skin analysis, demonstrating that a good electrical contact with the skin hydrolipidic film allowed the effective evaluation of the skin global antioxidant capacity

Phenolic Compounds as Potential Antioxidant

“…Due to importance of this class of compounds, assessment of antioxidant or radical-scavenging capacity has attracted increasing attention in a number of areas, which demands the availability of simple, convenient, rapid and reliable in vitro analytical methodologies. Many different methods are used to screen matrixes or to find specific antioxidants (6). …”

On-Line Monitoring the Growth of E. coli or HeLa Cells Using an Annular Microelectrode Piezoelectric Biosensor

“…The electric field spatial distributions of microelectrodes with different finger or gap widths in the medium were separately simulated under static conditions in three-dimensional (3D) space using COMSOL Multiphysics coupling analysis software [17]. The terminal voltage was set at 1 V. Voltage distribution was calculated using the following Poisson equation: $-\nabla ·\left({\mathsf{\epsilon }}_{\mathrm{r}}{\mathsf{\epsilon }}_0\nabla \mathrm{normalV}\right)=0$ where ε0 is the dielectric constant in vacuum (8.86 × 10 −12 F/m), and εr is the relative dielectric constant of the electrolyte solution.…”

Silicon-based electrochemical microdevices for silicate detection in seawater

“…The electrochemical microdevices were fabricated according to the ElecCell (Electrochemical microCell) silicon-based technological platform previously developed in LAAS [42]. Starting from an oxidized silicon wafer (oxide thickness: ∼1 m) in order to ensure electrical insulation between the different metallic layers, the different thin metallic layers were deposited by evaporation in conventional Physical Vapour Deposition (PVD) equipment, and patterned using a bilayer lift-off process in order to improve fabrication reproducibility.…”

“…Organic passivation layers such as polymers are generally deposited by spin coating processing and were used for medical applications [41,42]. However, organic passivation layers suffer from water adsorption and are not suitable for liquid media such as seawater.…”