Green one-step reduction approach to prepare rGO@AgNPs coupled with molecularly imprinted polymer for selective electrochemical detection of lactic acid as a cancer biomarker

Abstract

Herein, for the first time, we report a novel one-step green reduction approach of reduced graphene oxide decorated with silver nanoparticles (rGO-AgNPs) that is both cost-effective and ecologically friendly using Allium sativum extract. The rGO-AgNPs were then coupled with a molecularly imprinted polymer to create a highly sensitive selective electrochemical sensor to detect lactic acid, a key agent in cancer cell screening. The scanning electron microscope, X-ray diffraction, and Fourier-transform infrared spectroscopy were used to study the morphology and surface characteristics of the synthesized nanomaterials. In contrast, cyclic voltammetry was used to characterize the modified electrodes in the presence of [Fe(CN)6]3-/4-. The electrochemical detection of LA was indirectly performed using AuE/rGO-AgNPs/MIP and based on the signal generated from [Fe(CN)6]3-/4- redox peaks which were steadily decreased with the increase of LA concentration due to the interruption of electron transfer paths suggesting high sensitivity towards the target molecule. The current variation ΔI(I BLANK - I LA) was directly proportional to LA concentration between 10 and 250 μM with a very low detection limit of 0.726 μM (S/N = 3). The developed LA sensor revealed an excellent selectivity with strong stability. Furthermore, the LA sensor robustness was tested against different pH mediums, and good results were obtained; the practical use of the developed sensor was validated in human serum samples revealing the strong potential use in cancer screening and monitoring.