## 1 Introduction  
There has been grown interest in the use of nanomaterials as antibacterial agents against different bacterial species with the aim of treating and preventing bacterial infections [1, 2]. The unique chemical and physical characteristics of nonmetals can overcome antibiotic resistance by initiating a leakage in the bacterial membrane cells [2, 3]. Metals, metal oxide NPs, and metallic NPS/graphene- or graphene oxide (GO)-based nanomaterials have been widely tested against Gram-positive and Gram-negative bacteria due to their synergetic effects [4, 5, 6, 7]. Carbon-based nanomaterials have been used in many applications, such as renewable energy alternatives, energy storage, environmental sensors, pollution preventative material, and as antimicrobial agents [8, 9, 10, 11, 12]. Graphene is a single layer of graphite, sp\({}^{2}\)-bonded carbon, and a 2-dimensional material that can be molded into various structures with unique physical, chemical, and mechanical properties [13, 14, 15, 16]. In fact, graphene can be chemically modified, and its physical and chemical properties can change [13, 14]. Moreover, graphene, graphene oxide, and reduced graphene oxide have all shown some antibacterial resistance [4, 17, 18]. The antibacterial properties of graphene are improved even further by oxidation, which results in graphene oxide, a product that includes significant oxygen functional groups in its structure. These functional groups include carbonyl, carboxyl, and hydroxyl, which make graphene oxide hydrophilic and negatively charged. The fact that GO is able to form stable solutions in water results in GO solutions for versatile applications [19]. GO is also easily processed, low-cost, and mass-produced. Recently, graphene oxide has shown strong antibacterial properties [20; 21]. In fact, the presence of oxygen functional groups in its structure makes GO excellent for antibacterial applications, drug delivery, and decontamination. The cytotoxicity and good antibacterial properties of graphene and GO can be attributed to different mechanisms, including oxidative stress generated by charge transfer and reactive oxygen species (ROS), membrane stress caused by the direct contact between the graphene (or GO) sharp edge and the bacterial membrane, wrapping or trapping the bacteria cell membrane (by GO sheets), basal plane destruction (defects in graphene), and photothermal effects [4]. Graphene and graphene oxide can also chemically react with bacteria via oxidative stress and charge transfer mechanisms [18]. Oxidative stress is the most important factor in determining the antibacterial activity or toxicity of graphene and GO [22; 23]. In fact, the ROS of GO can damage the DNA and cause mitochondrial dysfunction, hence leading to the inhibition of bacteria [24; 25; 26]. The production of ROS leads to severe oxidative stress that can disrupt the cell by causing RNA/DNA damage, disruption of protein production, and inhibition of enzymes [27; 28; 29]. There have also been reports attributing the strong antibacterial activity of GO to membrane stresses caused by the sharp, thin edges of the GO nanosheets [7; 30]. The destruction of _E-coli_ cells by direct contact with GO has already been reported in the literature [26]. Moreover, various metals and metal oxides such as Ag, Cu, TiO, CuO, and ZnO have been reported to inhibit bacteria [27; 31; 32; 33; 34]. Zinc and Zn-based nanomaterials have been commonly used for commercial applications such as cosmetics, sunscreen, semiconductors, and food preservation [35; 36; 37]. The cytotoxicity and good antibacterial properties of metals and metal oxides are attributed to the fact that they can inactivate proteins and enzymes in bacteria via the binding of metal ions\({}^{+}\) on the cell surface, forming reactive oxygen species (ROS) and/or interfering with nutrient absorption and the cell structure [5; 38]. In fact, the interaction between metallic ions and bacterial cell membranes can spoil the metabolic activity of the bacterium by inactivating its cell [33; 39].