Green synthesis of silver@graphene oxide nanocomposite for antibacterial, cytotoxicity assessment, and hydrogen peroxide electro-sensing

Abstract

The nanocomposite of graphene oxide and silver nanoparticles has attracted great interest from scientists. In this work, silver@graphene oxide (Ag@GO) nanocomposite was synthesized via a biological reduction route using Andrographis paniculata extract as the reducing agent. The factors affecting the material preparation, comprising AgNO₃ volume, temperature, reaction time, and the amount of GO used, were investigated to select the appropriate conditions. As a result, silver nanoparticles were indicated to successfully form spherical-shaped particles with an average size of 31.93 ± 3.42 nm at 0.8 mL of the AgNO₃, pH 10, and 90 °C for 30 min of the reaction time with a ratio of AgNO₃ : GO = 1 : 1, corresponding to the Ag@GO-1.6 sample. Moreover, Ag@GO-1.6 showed high antibacterial activity against both Gram-negative and Gram-positive bacteria. The composite also induced notable cytotoxicity against the cancerous KB cells while barely affecting the normal HEK-293 ones. Besides, Ag@GO-1.6 showed great sensing ability for H₂O₂ with a relatively low limit of detection (2.65 μL) along with a wide detection range of 0–15 μM. Therefore, those results confirmed the potential applications of bio-synthesized Ag@GO in the medical and environmental fields.