Antimicrobial Effect of Titanium Dioxide Nanoparticles

Abstract

The widespread use of antibiotics has led to the emergence of multidrugresistant bacterial strains, and therefore a current concern for food safety and human health. The interest for new antimicrobial substances has been focused toward metal oxide nanoparticles. Specifically, titanium dioxide (TiO 2) has been considered as an attractive antimicrobial compound due to its photocatalytic nature and because it is a chemically stable, non-toxic, inexpensive, and Generally Recognized as Safe (GRAS) substance. Several studies have revealed this metal oxide demonstrates excellent antifungal and antibacterial properties against a broad range of both Gram-positive and Gram-negative bacteria. These properties were significantly improved by titanium dioxide nanoparticles (TiO 2 NPs) synthesis. In this chapter, latest developments on routes of synthesis of TiO 2 NPs and antimicrobial activity of these nanostructures are presented. Furthermore, TiO 2 NPs favor the inactivation of microorganisms due to their strong oxidizing power by free radical generation, such as hydroxyl and superoxide anion radicals, showing reductions growth against several microorganisms, such as Escherichia coli and Staphylococcus aureus. Understanding the main mechanisms of antimicrobial action of these nanoparticles was the second main purpose of this chapter.

Antibacterial Activity of TiO2 Nanoparticles Prepared by One-Step Laser Ablation in Liquid

“…The crystalline structure and the shape of TiO2 NPs are both considered as the most important conditions that affect its physicochemical factors and therefore its antimicrobial activity [38]. The anatase crystalline structure of TiO2 presents its highest photocatalytic The crystalline structure and the shape of TiO 2 NPs are both considered as the most important conditions that affect its physicochemical factors and therefore its antimicrobial activity [38]. The anatase crystalline structure of TiO 2 presents its highest photocatalytic and antimicrobial activities among other crystalline structures.…”

Nanoparticulate Antibiotic Systems as Antibacterial Agents and Antibiotic Delivery Platforms to Fight Infections

“…Gelover et al have shown the greater efficacy of photocatalysis with sol-gel-immobilized TiO 2 films over glass cylinders in inactivating both the total and faecal coliforms naturally present in spring water compared to solar disinfection (SODIS) [136]. As already reported for the other nanosized structures, the antibacterial activity of TiO 2 is closely related to nanoparticle properties such as size, morphology, and crystal nature, and also above all, because TiO 2 photocatalytic efficiency depends on them [141]. In this regard, TiO 2 nanotubes, thanks to their hollowed shape, gain a large surface area through which ROS can be generated; therefore, they possess a high antimicrobial activity [139].…”

Inorganic Nanoparticles and Composite Films for Antimicrobial Therapies

“…Similar to ZnO NPs, TiO 2 NPs have a wide band gap of 3.2 eV that can trigger the production of high-energy electron–hole pairs when exposed to UV light with wavelengths of 385 nm or lower [ 114 , 115 ]. Consequently, UV light irradiation leads to ROS production with high oxidative potential in the presence of oxygen [ 115 , 116 ]. As a result, ROS will cause DNA synthesis alteration, DNA and protein damage, and metabolic enzyme inactivation [ 114 , 117 , 118 ].…”

“…The main factors influencing the antimicrobial properties of TiO 2 NPs are related to their morphology, size, crystal structure, and surface charge and chemistry, as well as their concentration and exposure time [ 114 , 115 , 117 , 119 ]. Additionally, the difference in the composition of the cell wall in Gram-positive and Gram-negative bacteria might also affect their antimicrobial bioactivity [ 118 ].…”