# ZnO/Ag Nanocomposites with Enhanced Antimicrobial Activity  
[PERSON]  
1 Department of Inorganic and Organic Chemistry, Universitat Jaume I, Avenida Vicent Sos Baynat, s/n, 12071 Castelloin de la Plana, Spain; saporcar@ujes (S.P. ); [EMAIL_ADDRESS] (D.F. ); [EMAIL_ADDRESS] (B.C.) [PERSON]  
2 Department of Biology, Biochemistry and Natural Sciences, Universitat Jaume I, Avenida Vicent Sos Baynat,  s/n, 12071 Castelloin de la Plana, Spain; [EMAIL_ADDRESS] (L.S. ); bviced@ujies. (B.V.)  
[PERSON]  
2 Department of Biology, Biochemistry and Natural Sciences, Universitat Jaume I, Avenida Vicent Sos Baynat,  s/n, 12071 Castelloin de la Plana, Spain; [EMAIL_ADDRESS] (L.S. ); bviced@ujies. (B.V.)  
[PERSON]  
3 Calatolena Institute for Energy Research (REC), Jardins de les Dones de Negre 1, 2\" pl., 08930 Sant Adria de Besos, Spain; [EMAIL_ADDRESS] (M.G. ); [EMAIL_ADDRESS] (V.I-R.)  
[PERSON]  
3 Calatolena Institute for Energy Research (REC), Jardins de les Dones de Negre 1, 2\" pl., 08930 Sant Adria de Besos, Spain; [EMAIL_ADDRESS] (M.G. ); [EMAIL_ADDRESS] (V.I-R.)  
[PERSON]  
1 Department of Inorganic and Organic Chemistry, Universitat Jaume I, Avenida Vicent Sos Baynat, s/n, 12071 Castelloin de la Plana, Spain; saporcar@ujes (S.P. ); [EMAIL_ADDRESS] (D.F. ); [EMAIL_ADDRESS] (B.C.) [PERSON]  
1 Department of Inorganic and Organic Chemistry, Universitat Jaume I, Avenida Vicent Sos Baynat, s/n, 12071 Castelloin de la Plana, Spain; saporcar@ujes (S.P. ); [EMAIL_ADDRESS] (D.F. ); [EMAIL_ADDRESS] (B.C.) Footnote 1: email: {cudra.j.c.ca, j.c.ca, j.  
Nano-hybrid crystals, especially metal oxides and rare earth oxides [7], have attracted special attention as they combine the properties of the constituent elements to produce a deeper and more synergistic effect, as in the case of the doping of structures using transition metals [8]. In recent years, zinc oxide (ZnO) has been recognized as a safe material by the U.S. Food and Drug Administration (21 CFR182.8991; FDA, 2011), and the antibacterial activity of ZnO NPs has received a significant amount of interest worldwide particularly due to the implementation of nanotechnology to synthesize particles in the nanometer region [9]. ZnO NPs show great photocatalytic activity as they are an n-type II-VI semiconductor with a relatively large bandgap of \(\sim\)3.3 eV and high excitation binding energy (\(\sim\)60 meV) at room temperature [10]. They also have good chemical stability as well as high temperature resistance (\(\sim\)1950 \({}^{\circ}\)C) in the hexagonal wurtzite structure [11]. ZnO maintains high optical absorption in the UVA (315-400 nm) and UVB (280-315 nm) regions, which is advantageous in antibacterial response because this feature significantly promotes the interaction of ZnO with bacteria [12; 13; 14; 15]. ZnO is a more efficient photocatalyst than titanium dioxide (TiO\({}_{2}\)) under visible light irradiation because it has greater quantum efficiency, lower cost of production, and higher biocompatibility than TiO\({}_{2}\)[16]. The photocatalytic activity can be modulated by allowing absorption in the visible range by introducing different types of dopants (metals or non-metals) [17; 18]. Doping ZnO with noble metals such as gold (Au) and silver (Ag) has been reported to increase the photocatalytic activity of ZnO [19] because of improved charge separation and reduction in electron-hole recombination in ZnO [20]. The optical vibration of surface plasmon in metal nanoparticles enables absorption in the visible range (380-750 nm) and improves the photocatalytic activity of these metal-semiconductor composites under visible light [21]. Ag nanoparticles have been investigated by many researchers owing to this important role in a wide array of pathogens, particularly multi-resistant pathogens that are difficult to treat with the antibiotics currently available [22]. The most commonly used bacteria to test the bactericidal effect of nanoparticles of different compositions are _S. aureus_ and _E. coli_[3; 23; 24]. _S.