تحضير و تشخيص مركبات السيليكا النانوية بواسطة طريقة السول-جل ودراسة فعاليتها البايولوجيه

Synthesis , Characterization of Silica-Metal Nanoparticles Via Sol–Gel Method and Studying Their Biological Activity

Abstract
This study involved the use of rice husks to produce four metal-silica nanoparticles compounds (SiO2@Ni(II), SiO2@Ni(0), SiO2@Cu(II), and SiO2@Cu(0)) with high capacity to inhibit certain two types of bacteria Escherichia coli (E.Coli) and Staphylococcus aureus (S.aureus) that are harmful to human health.
In the first step, sodium silicate solution was prepared from rice husks, then silica was functionalized with nickel and copper ons by adding nickel nitrate hexahydrate to produce SiO2@Ni(II) and copper nitrate trihydrate to produce SiO2@Cu(II) via the sol-gel method. Then, the prepared compounds were reduced with a reducing agent, sodium borohydride, to prepare SiO2@Ni(0) and SiO2@Cu(0) nanoparticles. The prepared compounds were characterized using several techniques (FTIR, XRD, FESEM-EDX, XPS, AFM, TEM, and TGA/DTA). Samples of bacteria isolated using conventional methods were collected from Al-Husseini Teaching Hospital in Karbala and these strains were chemically characterized using the API staph system applied according to the manufacturer’s instructions. The nanocomposites prepared from rice husks SiO2@Ni(II), SiO2@Ni(0), SiO2@Cu(II), and SiO2@Cu(0)) were tested against bacteria (E.Coli and S.aureus) at dilute concentrations (20, 40, 60, 80, 100) mg/mL and compared with DMSO as a negative control. It was found that the inhibitory effect of the studied compounds increases with increasing concentration. It was also found that bacterial growth occurs at low concentrations of nanoparticles compared to the studied compounds at High concentrations. From the diameters of inhibition, it appears that inhibition of S. aureus is somewhat higher than inhibition of E. coli.