Design of a Boron-Doped Diamond Microcell Grafted with HRP for the Sensitive and Selective Detection of Ochratoxin A

Abstract

Ochratoxin A (OTA) is considered the most toxic member of the ochratoxin group. Herein, a novel label-free electrochemical sensor based on the horseradish peroxidase (HRP) enzyme is developed for OTA detection. The HRP enzyme was covalently immobilized on the working electrode of a planar boron-doped diamond (BDD) electrochemical microcell previously covered with diazonium film and grafted with single-walled carbon nanotubes (SWCNTs). Each surface modification step was evaluated by cyclic voltammetry and scanning electron microscopy. Square wave voltammetry was used for the detection of OTA. The linear working range of the biosensors ranged between 10−14 and 0.1 M, with a limit of detection (LOD) of 10 fM, an RSD equal to 5%, and a sensitivity of 0.8 µA per decade. In addition, the sensor showed good selectivity in the presence of OTA analogs; it was validated in samples such as corn, feed, and wheat. The metrological performance of the present sensor makes it a good alternative for OTA detection.

RF Sensor with Graphene Film for HRP Concentration Detection

“…Horseradish peroxidase has been widely used as an enzyme for the detection of a number of markers [34,[36][37][38][39]. Horseradish peroxidase is not susceptible to ambient conditions when it is adequately stored.…”

A Nanograss Boron and Nitrogen Co-Doped Diamond Sensor Produced via High-Temperature Annealing for the Detection of Cadmium Ions

“…Among modified nanomaterials, doped diamond materials (with their eminent chemical stability [16][17][18][19][20], high conductivity, wide electrochemical potential window [21], chemical inertness [22], biocompatibility [23], low-noise characteristic, and high corrosion resistance [24]) have been proven to be excellent sensors. Additionally, the electrocatalytic activity of doped diamond can be further strengthened through doping/co-doping heteroatoms such as boron, nitrogen, and sulfur to increase electrochemical performance.…”