Nanoparticles of magnesium oxyhydroxide and copper oxide: Synthesis and evaluation of their in vitro fungicidal activity on the fungus Omphalia sp.

Abstract

• MgO-Mg(OH) 2 and Cu oxide nanoparticles were synthesized in a controlled and reproducible manner. • Some basic aspects of the mechanism of formation of the MgO-Mg(OH) 2 and Cu oxide nanoparticles were indicated. • The effect of different concentrations of MgO-Mg(OH) 2 and Cu oxide nanoparticles on Omphalia sp. fungus was evaluated. • The results indicated that these treatments generated important morphological changes in the mycelial area and texture of the pathogen. • The information obtained allows us to consider the potential use of these nanoparticles to control the Omphalia sp. fungus. In this work, nanoparticles of magnesium oxyhydroxide and copper oxide were synthesized using the polyol method. The oxides of interest were obtained at 500 °C for the magnesium system and 400 °C for the copper system. A mechanism was proposed to explain the formation of the nanoparticles, taking account of the synthesis process. The synthesized powders were characterized using infrared spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The specific surface of the obtained powders was also determined using the BET technique, and the area and specific pore volume were determined via BJH analysis. The XRD results indicated that the solids contained MgO-Mg(OH) 2 and CuO-Cu 2 O. In addition, the average size of the crystallite was determined, obtaining values of ∼13.2 nm for magnesium oxyhydroxide and ∼25.9 nm for copper oxide, with a surface area of ∼17.98 m 2 /g and ∼7.18 m 2 /g respectively. SEM characterization showed that the particles of the synthesized ceramic powders had a spheroidal morphology, with a primary particle size of ∼61 nm, the particles showing appreciable agglomeration. On evaluating the effect of MgO-Mg(OH) 2 -NPs and Cu oxide nanoparticles on the Omphalia sp. fungus, there was no complete inhibition of fungal growth for the concentrations used. Despite this condition, the presence of NPs generated important morphological changes in the mycelial area and texture of the pathogen, causing the mycelia to acquire an abnormal structure, evidence of NPs-pathogen interaction.