04035nam a2200349 i 4500 0 0 lcc 0 1 1 REF 10000 10000 REF 2022-01-12 0 FTKKP .L56 2021 r Thesis T000001636 2022-05-12 00:00:00 1 2022-01-12 RESTRICT 0 0 lcc 0 1 6 REF 10000 10000 2022-03-28 0 CD 12984 T000001637 2022-08-25 00:00:00 1 2022-03-28 RESTRICT 96262 96268 MY-KuUP 20251125105943.0 a||||fr|||| 001 0 ta 220328t20212021my a|||fram|| 00| 0 eng d THE0009247(Local) UMP eng UMP rda FTKKP .L56 2021 r Thesis Norlin Pauzi, author. Microwave-assisted synthesis and characterization of agglomerated zinc oxide nanoparticles stabilized with gum arabic and studies of antibacterial properties / Norlin Pauzi Kuantan, Pahang : UMP ; 2021 © 2021 xix, 157 pages : illustrations (some color) ; 30 cm. + 1 CD-ROM. text rdacontent unmediated rdamedia volume rdacarrier text file PDF rda Faculty of Chemical and Process Engineering Technology Thesis (Doctor of Philosophy) -- Universiti Malaysia Pahang – 2021 Includes bibliographical references Antibacterial activity of safe and sustainable zinc oxide (ZnO) nanoparticles has huge potential in tackling antibiotic-resistant bacterial infections, especially for nano-green biomedical purposes. Various chemical methods in ZnO nanoparticles synthesis required sophisticated equipment and produce toxic as by product. It is very important to eliminate the biological risks to ensure it safe and not display unexpected side effect. The goal of this study is to investigate the effect of gum arabic on the size, optical properties, and stability of agglomerated ZnO nanoparticles and to evaluate its antibacterial properties. In this study, agglomerated ZnO nanoparticles were synthesized using a precipitating technique with the aid of a microwave heating method. Zinc nitrate had been used as salt, sodium hydroxide (NaOH) as a reducing and precipitating agent, and gum arabic as a stabilizing agent. Moreover, the effect of pH ranging from 5 to 12 on the agglomerated ZnO nanoparticle size was as well investigated. All the parameters in synthesizing agglomerated ZnO nanoparticles which include zinc salt concentration, NaOH concentration, microwave power, and microwave irradiation time were statistically optimized to achieve the smaller size of agglomerated ZnO nanoparticles; the optimization was analysed using Response Surface Methodology (RSM). The optimum agglomerated ZnO nanoparticle of 66.87 nm was achieved using gum arabic of 1.01%, 0.05 M zinc nitrate, 1.46 M NaOH, 8 min of microwave irradiation time, and 275 W of microwave heating. These agglomerated ZnO nanoparticles were relatively stabilized for a minimum of 6 months. Dynamic Light Scattering (DLS) analysis demonstrated that the hydrodynamic size was around 200 to 350 nm compared to the unstabilized agglomerated ZnO nanoparticles which were around 1020 nm. The pH value equivalent to 10 was required to attain a pure phase of ZnO nanoparticles. Additionally, stabilized agglomerated ZnO nanoparticles have better antibacterial properties on Staphylococcus aureus and Escherichia coli compared to unstabilized agglomerated ZnO nanoparticles. At a higher concentration above 500 μg/mL, the percentage of toxicity to biofilm was observed to be above 50% for both S. aureus and E. coli. Besides, agglomerated ZnO nanoparticles demonstrated antibacterial and antibiofilm activities under dark condition. However, the more effective antibacterial effect was seen in agglomerated ZnO nanoparticles under normal light. These results show that agglomerated ZnO nanoparticles can affect S. aureus and E. coli viability and biofilm formation. Therefore, agglomerated ZnO nanoparticles stabilized through gum arabic are proposed as a new naturally generated antibacterial agent. Faculty of Chemical and Process Engineering Technology Dissertations Universities and colleges Dissertations Theses lcc RESTRICT