Rehab K. Alhajjar
King Saud University, Saudi Arabia
2012/2013: M. Sc. Microbiology in King Saud University, Riyadh, Saudi Arabia, Excellence with first class honor and ranked first in class. 2013-2015: Lecturer in University of Princess Noura bint Abdul Rahman. 2013-2015: Visiting Lecturer for King Abdullah Institute for Nanotechnology for Training Course for University of Princess Noura bint Abdul Rahman.Teach Lecture and Practical [lab] in Biology College also in College of Pharmacy, College of Nursing and Preparatory Year for College of Medicine. Scholarships and Awards from King Abdullah Scholarship Program (2015). Author of several articles in the magazine “World of Food”. Issue 162 - November 2011 etc….
The current study investigated the antibacterial properties 0.25%, 0.50% and 1% of two different types of nano-TiO2 against a selection of pathogenic bacteria (Escherchia coli) isolated from a sample of wastewater from Riyadh, for the purposes of further application to time and cost effective water purification in Saudi Arabia. A commercial sample of nanoparticles metal oxide containing 98% titanium dioxide (TiO2) that was brown in colour – hereinafter (T2B). Another commercial sample of nanoparticles metal oxide was obtained containing 99% titanium dioxide (TiO2) that was white in colour – hereinafter (T2W). Pathogenic bacteria were cultured in liquid nutrient medium to evaluate the antibacterial effects of 0.25%, 0.50% and 1% of both types of nano-TiO2 . Electron microscopy was also used to observe the effect of both nanoparticles on the pathogenic bacterial cells in the liquid media specimens. For both nano-specimens significant results were seen for 0.25%0.50% and 1% concentration. The bacterial number substantially decreased with 0.25%, 0.50% and 1% of both nanoparticles. However, better results were obtained with 0.50% and 1% of (T2B), where bacterial inhibition was greater in both media. With (T2B), bacterial clearance was observed in nearly half the time needed (T2W). This has been observed in both media. In the liquid medium, complete cell death was seen with 1% (T2B) after 4 hours compared with 6 hours with 1% (T2W). Electron microscopy showed bacterial samples completely destroyed with 1% (T2B). E. coli appeared to be sensitive bacteria to the presence of both (T2W) and (T2B) nanoparticles, as they experienced significant bacteria disruption and damage