Detection of Ochratoxin A Mycotoxin with Graphene Nanosheets Functionalized with Selective Peptides Using Molecular Dynamics

Abstract

Ochratoxin A (OTA) is a mycotoxin commonly found in improperly stored grains, posing significant risks to food safety. Accurate detection of this mycotoxin in food matrices is crucial for ensuring consumer protection. In this study, we used in silico methods to design new peptides with high affinity and selectivity for recognizing OTA, starting crystal structures of OTA-protein complexes, which served to identify short key peptides within the interaction regions. Through deliberate point mutations, the stability and affinity of these peptides towards OTA were enhanced. To assess their suitability as capture probes for OTA sensing, we investigated the interaction of the selected peptides with OTA in a saline aqueous solution to mimic wet-lab experiments. Molecular docking, molecular dynamics simulations were used to evaluate the affinity and stability of the peptide-OTA complexes. Various parameters, including conformational changes, Molecular Mechanics Poisson–Boltzmann Surface Area energetics, the number of contacts, and the number of hydrogen bonds were analyzed to identify the most promising candidates. Among them, the peptide CWC11 has the highest affinity to OTA. Next, CWC11 peptide was used to functionalize the surfaces of two different carbonaceous nanomaterials: reduced graphene oxide (rGO) and graphene oxide (GO). The performance of the peptide-functionalized surfaces in presence of OTA was evaluated, revealing that GO exhibited superior performance compared to rGO. This study provides valuable insights into the design OTA-binding peptides and their use for the functionalization of carbonaceous surfaces, emphasizing the importance of surface selection to tune the efficiency and sensitivity of the detection.