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008			220328t20212021my a|||fram|| 00| 0 eng d
020			_aTHE0009247(Local)
040			_aUMP _beng _cUMP _erda
090			_aFTKKP .L56 2021 r Thesis
100	0		_aNorlin Pauzi, _eauthor.
245	1	0	_aMicrowave-assisted synthesis and characterization of agglomerated zinc oxide nanoparticles stabilized with gum arabic and studies of antibacterial properties / _cNorlin Pauzi
264		1	_aKuantan, Pahang : _bUMP ; _c2021
264		4	_a© 2021
300			_axix, 157 pages : _billustrations (some color) ; _c30 cm. + _e1 CD-ROM.
336			_atext _2rdacontent
337			_aunmediated _2rdamedia
338			_avolume _2rdacarrier
347			_atext file _bPDF _2rda
500			_aFaculty of Chemical and Process Engineering Technology
502			_aThesis (Doctor of Philosophy) -- Universiti Malaysia Pahang – 2021
504			_aIncludes bibliographical references
520	3		_aAntibacterial 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.
610	2	0	_aFaculty of Chemical and Process Engineering Technology _xDissertations
650		0	_aUniversities and colleges _xDissertations
650		0	_aTheses
942			_2lcc _cRESTRICT