Electrochemical antioxidant screening and evaluation based on guanine and chitosan immobilized MoS2 nanosheet modified glassy carbon electrode (guanine/CS/MoS2/GCE)

Ping Tang,Xiaosheng Tang,Yixi Xie,Shiyong Mei,Licheng Ren,Liangliang Liu

doi:10.1515/chem-2020-0003

Abstract

AbstractIn this study, an electrochemical biosensor based on guanine and chitosan immobilized MoS2 nanosheet modified glassy carbon electrode (guanine/CS/MoS2/GCE) was developed and employed for antioxidant screening and antioxidant capacity evaluation. The oxidation peak current of guanine was improved and nearly tripled after modifications of chitosan and MoS2 nanosheet. The immobilized guanine could be damaged by hydroxyl radicals generated in Fenton solution. However, in the presence of antioxidants, the guanine was protected and the oxidation peak current of guanine increased. This process mimics the mechanism of antioxidant protection in human body. The factors affecting preparation of sensor and detection of antioxidant capacity were optimized. At the optimum conditions, the guanine/CS/MoS2/GCE showed wide linear range, low detection limit, satisfactory reproducibility and stability for detection. Ascorbic acid was used as a model antioxidant to evaluate the antioxidant capacity. A good linearity was observed with a correlation coefficient of 0.9959 in the concentrations between 0.5 and 4.0 mg L-1. The antioxidant capacities of three flavonoids were also tested and the rank of antioxidant capacities was ascorbic acid (51.84%), quercetin (45.82%), fisetin (34.39%) and catechin (16.99%). Due to the rapid measurement and low cost, this sensor could provide an available sensing platform for antioxidant screening and evaluation.

Highlights

There is a growing attention paid to the damage of living cells caused by oxidative stress, which is generally associated with the generation of reactive oxygen species (ROS)
The exogenous antioxidant system can be provided by chemical antioxidants such as ascorbic acid, phenolic compounds and flavonoids, which exist in fruit, vegetables and beverages
The scanning electron microscopy (SEM) characterization confirmed that MoS2 nanosheet was successfully prepared from MoS2 powders

Summary

Introduction

There is a growing attention paid to the damage of living cells caused by oxidative stress, which is generally associated with the generation of reactive oxygen species (ROS). When the level of ROS increases dramatically to cause oxidative stress, it could lead to cellular damage to DNA, proteins and lipids, as well as being linked with various human diseases such as rheumatoid arthritis, cardiovascular disorders, cancer and diabetes, etc. The exogenous antioxidant system can be provided by chemical antioxidants such as ascorbic acid, phenolic compounds and flavonoids, which exist in fruit, vegetables and beverages. These antioxidants are important for the protection of human health [4]. Finding antioxidants and the following evaluation of antioxidant capacity for antioxidants has significant meaning in related research, and there is a

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Conclusion