Non-Dependency of In Vitro Fungicidal Efficiency of Copper Nanoparticles against Fusarium oxysporum upon Particle Size

Abstract

Although many papers have consented that the smaller the size of nanoparticles, the higher their efficiency, this paper sheds light on one potential exception of this rule. The paper shows that the in vitro antifungal efficiency of copper nanoparticles against the fusarium wilt pathogen, Fusarium oxysporum, isolated from the infected date palm, Phoenix dactylifera L., is not size-dependent; instead, as it was found that larger copper nanoparticles have better in vitro antifungal efficiency against the fungal pathogen than smaller ones. Copper nanoparticles were synthesized via chemical reduction method at two different pH values, 6.5 and 10.5. Dynamic light scattering was used to measure their particle sizes, which were 345.1 nm and 278.1 nm, respectively. Transmission Electron Microscopy was used to figure out the shapes of nanoparticles, which were polygonal and spherical, respectively. Poison food essay was used to test their in vitro inhibition efficiencies against the fusarium wilt pathogen, F. oxysporum, isolated from the infected date palm, Phoenix dactylifera L., which were 46% and 19%, respectively; at the same concentration. Ultimately, the paper has proposed and discussed a potential reason beyond these unexpected findings, which relies upon the larger surface area to volume ratio of the polygonal copper nanoparticles compared to the spherical copper nanoparticles. The paper concluded that, despite their larger size, polygonal copper nanoparticles have better in vitro antifungal efficiency than spherical copper nanoparticles against F. oxysporum isolated from the infected date palm, Phoenix dactylifera L. at the same concentration.