Synergistic Antibacterial Activity of Silver-Loaded Graphene Oxide towards Staphylococcus Aureus and Escherichia Coli

• Published in: Nanomaterials (Basel, Switzerland) Vol. 10; no. 2; p. 366
• Main Authors: Truong, V I Thi Tuong, Kumar, Selvaraj Rajesh, Pang, Jong-Hwei Su, Liu, Yu-Kuo, Chen, Dave W, Lue, Shingjiang Jessie
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 20-02-2020; MDPI AG
• Subjects: antibacterial activity; graphene oxide; reactive oxygen species; silver; synergistic; antibacterial activity; graphene oxide; silver; synergistic; reactive oxygen species
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano10020366

In this study, the physicochemical and surface properties of the GO-Ag composite promote a synergistic antibacterial effect towards both Gram-negative
(
) and Gram-positive
(
) bacteria. GO-Ag NPs have a better bactericidal effect on
(73%) and
(98.5%) than pristine samples (pure Ag or GO). Transmission electron microscopy (TEM) confirms that the GO layers folded entire bacteria by attaching to the membrane through functional groups, while the Ag NPs penetrated the inner cell, thus damaging the cell membrane and leading to cell death. Cyclic voltammetry (CV) tests showed significant redox activity in GO-Ag NPs, enabling good catalytic performance towards H
O
reduction. Strong reactive oxygen species (ROS) in GO-Ag NPs suggests that ROS might be associated with bactericidal activity. Therefore, the synergy between the physicochemical effect and ROS production of this material is proposed as the mechanism of its antibacterial activity.