Surface area or diameter – which factor really determines the antibacterial activity of silver nanoparticles grown on TiO₂coatings?

Abstract

Titanium dioxide coatings were prepared on Si wafers using the sol-gel method. Four different types of coatings with silver nanoparticles (AgNPs) were synthesized. The diameter and surface density of AgNPs were conditioned by the concentration of Ag + ions in the initial solution, time and UV illumination source. The bactericidal activity of AgNPs on the titanium dioxide coatings against the S. aureus strain were calculated as the percentage of the inhibition of bacterial growth after 24 hour incubation of microorganisms at 37 1C on TiO 2 coatings with AgNPs. Control samples were coated with titanium dioxide without AgNPs. We concluded that the titanium dioxide coatings modified with silver nanoparticles had a high antibacterial activity. Moreover, we demonstrated strong dependence between surface areas of AgNPs and inhibition of bacterial growth. The obtained results evidence that the surface area of AgNPs grown on titanium dioxide coatings is a major factor determining their antimicrobial potential.

Preparation of monodispersed and cytotoxic silver nanoparticles using Launaea taraxacifolia leaf extract

“…As observed, the microstructure shows homogeneous spherical particles that are mostly devoid of agglomeration, and consequently, presents excellent distribution and large surface area. Particle topography, including size and distribution are known to be important for nanoparticles to exhibit antimicrobial and optical properties [28][29][30]. The shape of the AgNPs as observed in the SEM micrograph was spherical and uniform, thus supporting the UV-Vis result.…”

“…The high degree of potency could be due to the excellent surface topography containing homogeneous, spherical, monodisperse particles of average size 12 nm. Several in vitro studies [29][30][31][32][33][34][35][36][37][38][39][40] have provided evidence that particle size and shape uniformity are important in cytotoxicity, because they influence cellular membrane deformability, biodistribution and the kinetics of absorbability [30]. Furthermore, the monodisperse nature of the AgNPs promoted toxicity due to better penetration and destruction of the cell walls of the bacteria [41,42].…”

Impact of AgNPs on Seed Germination and Seedling Growth: A Focus Study on Its Antibacterial Potential againstClavibacter michiganensissubsp.michiganensisInfection inSolanum lycopersicum

“…When AgNPs interact with a bacterial cell, they bind to the proteins in the cell membrane and penetrate into the cell. The released Ag + interacts with cellular structures such as respiratory enzymes and releases reactive oxygen species (ROS) resulting in apoptosis like DNA damage and cell death [33,34].…”

Reaction Engineering for Continuous Production of Silver Nanoparticles

“…Beyond 10, there was little variation in the product concentration, suggesting that a near kinetic control was established for Bo > 10. Thus, very high Bo will be required to synthesize monodispersed Ag NPs, while Bo ∼ 10 can be suitable for applications like antibacterial technologies which may not need the best monodispersity . In order to quantify the role of Bo on conversion as well as on mean particle size and the extent of polydispersity, experiments were carried out in a helical coil, a continuous stirred‐tank reactor (CSTR) and CSTRs in series.…”