Evaluation of the catalytic activity of graphene oxide and zinc oxide nanoparticles on the electrochemical sensing of T1R2-Rebaudioside A complex supported by in silico methods

Herein, we report on the performance of graphene oxide (GOx) and zinc oxide nanoparticles (ZnONPs) on a platinum (Pt) electrode, immobilized with the human T1R2 sweet taste receptor subunit for the detection of rebaudioside A (Reb-A). The characterization studies performed in this work confirmed the thinlayered structure of GOx and the polydispersed nature of ZnONPs. The elucidation of the mass loss observed by TGA demonstrates the stability of GOx. The cyclic voltammetry results for Pt/GOx revealed good catalytic activity over Pt/ZnONPs for adsorption of the T1R2-Reb-A complex. In addition, a series of computational modelling studies were carried out to better understand the surface adsorption phenomena of GOx and ZnONPs to mimic the layer-by-layer electrode modification strategies independently. The strongest interaction energy observed (-573 kcal mol(-1)) for the direct interaction of ZnONPs onto the Pt electrode surface, demonstrates a stronger adsorption in contrast to the GOx modified Pt electrode (-23 kcal mol-1). However, the overall results for the layered-nanocomposite revealed that the GOx (-256 kcal mol(-1)) were more strongly adsorbed in contrast to ZnONPs (-231 kcal mol(-1)) for the detection of the T1R2-ReB-A complex, demonstrating the reliability of our GOx electrode functionalization strategy. The results of this study can potentially be used to improve the design of rapid Reb-A sensors for the food and beverage industry.