<p>Photocatalytic antibacterial application of zinc oxide nanoparticles and self-assembled networks under dual UV irradiation for enhanced disinfection</p>

Abstract

Background: Zinc oxide (ZnO) nanoparticles and their networks have been developed for use in various applications such as gas sensors and semiconductors. Aim: In this study, their antibacterial activity against Escherichia coli under dual ultraviolet (UV) irradiation for disinfection was investigated. Materials and methods: ZnO nanoparticles were synthesized and immobilized onto silicon (Si) wafers by self-assembly. The physicochemical properties and antibacterial activity of ZnO nanoparticles and their networks were evaluated. Gene ontology was analyzed and toxicity levels were also monitored. Results: Synthesized ZnO nanoparticles were spherical nanocrystals (,100 nm; Zn, 47%; O, 53%) that formed macro-mesoporous three-dimensional nanostructures on Si wafers in a concentration-dependent manner. ZnO nanoparticles and their networks on Si wafers had an excellent antibacterial activity against E. coli under dual UV irradiation (.3log CFU/mL). Specifically, arrayed ZnO nanoparticle networks showed superior activity compared with free synthesized ZnO nanoparticles. Oxidative stress-responsive proteins in E. coli were identified and categorized, which indicated antibacterial activity. Synthesized ZnO nanoparticles were less cytotoxic in HaCaT with an IC50 of 6.632 mg/mL, but phototoxic in Balb/c 3T3. Conclusion: The results suggested that ZnO nanoparticles and their networks can be promising photocatalytic antibiotics for use in next-generation disinfection systems. Their application could also be extended to industrial and clinical use as effective and safe photocatalytic antibiotics.

A Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic Investigation

“…The obtained highest ZOI on S. aureus bacteria was 21 mm. The synthesized spherical ZnO nanocrystals immobilized onto silicon wafers by self-assembly techniques were informed as antibacterial deactivating materials under dual UV irradiation [ 61 ]. Compared to dual UV irradiation without ZnO, the dual UV irradiation in the presence of ZnO NPs showed good E. coli bacterial deactivation within 30 s. Furthermore, the spherical ZnO nanocrystals immobilized onto silicon wafers showed enhanced bacterial deactivation within 10 s. The ROS generation was proposed to be the major disinfection mechanism against E. coli.…”

In Vitro Toxicity of TiO2:SiO2 Nanocomposites with Different Photocatalytic Properties

“…In particular, metal oxide nanoparticles (NPs), thanks to their several properties (antibacterial, photocatalytic, etc.) [1,2] are gaining great attention. Nevertheless, there is a growing concern about the safety of these NMs, due to the increasing release in the market and their consequent intentional and unintentional emission into the environment.…”

A Review of Microwave Synthesis of Zinc Oxide Nanomaterials: Reactants, Process Parameters and Morphologies

“…It has been proved that ZnO NPs applied in textiles effectively fight bacteria, e.g., Staphylococcus aureus or Klebsiella pneumoniae [ 182 ]. In medicine, research is in progress on the application of ZnO NMs as a potential contrast agent (imaging), drug carrier, iron delivery, gene carrier, biosensor, a potential anti-cancer agent, in a photodynamic therapy, for prophylactic and therapeutic vaccines, support for antifungal treatments, in photocatalytic antibiotics, inhibition of influenza virus infection, diagnostic-therapeutic functions, wound dressing and tissue engineering [ 70 , 166 , 168 , 183 , 184 , 185 , 186 , 187 , 188 , 189 , 190 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 202 , 203 , 204 , 205 , 206 , 207 , 208 , 209 , 210 , 211 , 212 , 213 ]. However, before implementing ZnO NMs in biomedical applications on a commercial scale, the toxicity of ZnO NMs must be carefully learnt and their toxicity mechanisms must be explained [ 121 , 162 , 171 , 174 , 178 , ...…”