Amperometric hydrogen peroxide sensor based on a sol-gel-derived ceramic carbon composite electrode with toluidine blue covalently immobilized using 3-aminopropyltrimethoxysilane

Application of pyrite and chalcopyrite as sensor electrode for amperometric detection and measurement of hydrogen peroxide

The sensing performance of solid-state amperometric sensors based on natural sulfide minerals, i.e., pyrite and chalcopyrite, has been characterized for the detection and measurement of hydrogen peroxide (H₂O₂) in aqueous medium.

Horseradish peroxidase-immobilized magnetic mesoporous silica nanoparticles as a potential candidate to eliminate intracellular reactive oxygen species

Horseradish peroxidase-immobilized magnetic mesoporous silica nanoparticles (MMSNs-HRP) have been synthesized by a NHS/EDC coupling between the amino groups of horseradish peroxidase (HRP) and the carboxyl groups on the MMSNs surface. It is found that the immobilized HRP on MMSNs still retain high activity and the MMSNs-HRP can eliminate the reactive oxygen species (ROS) in Chinese hamster ovary (CHO) cells induced by the addition of H2O2 aqueous solution. Further, the fluorescent MMSN-HRP-CD nanoparticles have been prepared by attaching biocompatible, fluorescent carbon dots (CDs) to MMSNs-HRP. We have also investigated the effect of an applied magnetic field on cellular uptake of MMSNs-HRP-CDs and found that the internalization of MMSNs-HRP-CDs by CHO cells could be enhanced within 2 hours under the magnetic field. This work provides us with a novel and efficient method to eliminate ROS in living cells by using HRP-immobilized nanoparticles.

Preparation and electrochemical characterization of a carbon ceramic electrode modified with ferrocenecarboxylic acid

The present paper describes the characterization of a carbon ceramic electrode modified with ferrocenecarboxylic acid (designated as CCE/Fc) by electrochemical techniques and its detection ability for dopamine. From cyclic voltammetric experiments, it was observed that the CCE/Fc presented a redox pair at E_pa = 405 mV and E_pc = 335 mV (ΔE = 70 mV), related to the ferrocene/ferrocenium process. Studies showed a considerably increase in the redox currents at the same oxidation potential of ferrocene (E_pa = 414 mV vs. Ag/AgCl) in the presence of dopamine (DA), differently from those observed when using only the unmodified CCE, in which the anodic peak increase was considerably lower. From SWV experiments, it was observed that the AA (ascorbic acid) oxidation at CCE/Fc occurred in a different potential than the DA oxidation (with a peak separation of approximately 200 mV). Moreover, CCE/Fc did not respond to different AA concentrations, indicating that it is possible to determine DA without the AA interference with this electrode.