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Electrochemical Enzymatic Biosensing of Neotame Supported by Computational Methods

2020; Wiley; Volume: 32; Issue: 12 Linguagem: Inglês

10.1002/elan.202060208

1521-4109

Matshidiso Lephalala, Suvardhan Kanchi, Myalowenkosi I. Sabela, Krishna Bisetty,

Advanced biosensing and bioanalysis techniques

Abstract Herein a highly sensitive electrochemical enzymatic biosensor for the detection of neotame in soft drinks was developed based on multiwalled carbon nanotubes (MWCNTs) decorated with aloe vera‐derived gold nanoparticles (AuNPs) and carboxyl esterase (CaE) enzyme to support the wave strengthening strategy. The electrochemical biosensor revealed high sensitivity with a limit of detection (LOD) and limit of quantification (LOQ) of 27 μg L −1 and 83 μg L −1 respectively. The calibration curve showed a linear dependence of the cathodic peak current on the neotame concentration profile with a correlation factor of 0.9829, signifying an improved electrocatalytic property of the electrode. The good feasibility of the proposed strategy was confirmed by assessing the interactions between the analyte and the enzyme using computational tools. The density functional theory (DFT) calculations of neotame reveal a HOMO‐LUMO energy gap of −0.46618 eV, suggesting a great tendency to act as an electron donor. Furthermore, adsorption and analyte‐enzyme docking studies were carried out to better understand the redox mechanisms. These results revealed that neotame form hydrogen bonds with LEU 249 and GLU251 and other amino acids of the hydrophobic channel of the binding sites, thereby facilitating the redox reaction for the detection of neotame. These outcomes confirm that the aloe vera‐derived AuNPs are good platforms for immobilizing CaE because of its high surface area, promoting the electron transfer from neotame to form an enzyme‐substrate complex, contributing to an enhanced biosensing signal. Furthermore, the enhanced catalytic activity of this enzymatic biosensor for the detection of neotame in soft drinks has huge potential in the food and beverage industry.