Highly Sensitive Impedimetric Biosensor Based on Thermolysin Immobilized on a GCE Modified with AuNP‐decorated Graphene for the Detection of Ochratoxin A

• Published in: Electroanalysis (New York, N.Y.) Vol. 33; no. 1; pp. 136 - 145
• Main Authors: Zinoubi, Khaoula, Chrouda, Amani, Soltane, Raya, Al‐Ghamdi, Youssef O., Garallah Almalki, Sami, Osman, Gamal, Barhoumi, Houcine, Jaffrezic Renault, Nicole
• Format: Journal Article
• Language: English
• Published: 01-01-2021
• Subjects: Biosensor; Electrochemical impedance spectroscopy; Ochratoxin A; Thermolysin
• ISSN: 1040-0397; 1521-4109
• DOI: 10.1002/elan.202060247

The fabrication of a thermolysin‐based biosensor capable of detecting ochratoxin A (OTA) from food samples is described. The electrochemical deposition of calcium cross‐linked cellulose film (CCLC) and gold nanoparticles (AuNPs) on graphene (GR) for modification of a glassy carbon electrode (GCE) is the first step. Then the thermolysin (TLN) enzyme in a polyvinyl alcohol (PVA)/polyethylenimine (PEI) matrix is immobilized. The impedimetric biosensor response is linear from 0.2 nM to 100 nM with a detection limit of 0.2 nM. The obtained stable and reproducible biosensor is then applied for the detection of OTA in spiked extracts from coffee beans.