Abstract

Bacterial infections are considered the second main cause of death worldwide and the third main cause of death in the developed countries and as a result, many antibacterial coatings have been prepared in order to fight the different strains of bacteria and decrease the mortality rates. Natural antibacterial products become of great interest nowadays and their use is preferred over the synthetic products in order to overcome the resistance to the synthetic antibiotics. A wide variety of antibacterial coatings have been developed ranging from polymeric to polymer Nano-composites (PNCs) materials. Using nanomaterials as fillers within polymer matrices have been reported to enhance the antibacterial properties significantly. The polymeric nanoparticles (NPs) are promising for natural antibacterial drug delivery. In this study, two types of Garlic oil nano-composites (GO-NCs) have been developed by using two polymers which are poly lactic-co-glycolic (PLGA) and poly lactic-co-glycolic/poly ethylene glycol (PLGA/PEG) mixed with garlic oil (GO). The two polymer Nano-composites were named PLGA-GO-NCs and PLGA-PEG-GO-NCs respectively. Single emulsion/solvent evaporation (SE/SE) technique was involved in the preparation of the different nanocomposite formulations. The polymers conjugated with GO were prepared at three different homogenization time intervals (5, 10 and 15 min.) at the same homogenization speed of 11,000 rpm. All the preparation parameters, such as the concentration of polymers, concentration of GO, amounts of surfactant used (polaxmer 407) and the homogenization speed, were kept constant to identify the effect of the homogenization time on the physicochemical properties and the antibacterial activities of the PNCs. In addition, the effect of other factors such as the effect of solution settling, the use of Buchner funnel in solution filtration, the use of biological filters in solution filtration and the effect of mechanical shaking the solutions by using vortex stirring on the different formulations were carefully examined. The particle sizes, zeta potential and poly dipsersity index (PDI) and GO% in each formulation have been measured. The morphological examination of the prepared nanocomposite formulations was carried out by using Scanning Electron Microscope (SEM), and the chemical structural characteristics were examined by using Fourier Transform-Infra-red spectroscopy (FT-IR) and Ultraviolet-Visible spectrophotometry (UV-vis). In addition, antibacterial assessment has been carried out against Eichercia Coli (E. coli) (ATCC 8739) as a Gram-negative bacterium, and Staphylococcus aureus (S. aureus) (ATCC 6538) as a Gram-positive bacterium using Colony Counting Method (CCM). The results revealed four important factors that need to be considered during the preparation of GO NPs which are (i) settling of the solutions, (ii) filtration through biological filters, (iii) Buchner filtration and (iv) vortex stirring of solutions. These factors play a crucial role in controlling the size and stability of PNCs. Furthermore, we have observed that the addition of PEG to the PLGA-GO formulations has a significant effect on decreasing the particle sizes and increasing the GO% in the formulations. These results could be promising in producing polymeric drug/extract NPs of small particle sizes, high stability and of pronounced antibacterial activity which is stronger than the original dtug/extract.

Department

Chemistry Department

Degree Name

MS in Chemistry

Graduation Date

6-1-2015

Submission Date

May 2015

First Advisor

Mamdouh, Wael

Committee Member 1

El-Meshad, Aliaa

Committee Member 2

El-Sayed, Mayyada

Extent

119 p.

Document Type

Master's Thesis

Library of Congress Subject Heading 1

Nanochemistry.

Library of Congress Subject Heading 2

Antibacterial agents.

Rights

The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy.

Institutional Review Board (IRB) Approval

Not necessary for this item

Comments

First and foremost, I would like to thank God for helping me in this project and giving me the strength and patience needed to achieve it. I would like to thank and acknowledge the efforts of my supervisor Dr. Wael Mamdouh, who has supervised my project and gave me his time, support, advice and encouragement that helped me in finishing this project in a reasonable time and for being a bigger brother who cares for each one in his research group. Also, I want to thank Dr. Adham Ramadan and Dr. Tamer Shoeib for their continuous support and encouragement and for helping me to face any obstacle during my research period. I would sincerely like to thank all the academic and technical staff in the AUC for their efforts during the MSc course especially Mr. Mahmoud AbdelMoez, Ahmed Omaia, Samir Nabhan and Emad Rafaat for staying with me in the research labs till late afternoons. I would like to thank my dear parents, brother and his wife who have always been encouraging and motivating me to perform better. Also, I want to thank my dearest friend Ahmed Samy who was always motivating me. Also, I want to thank the STRC center and the AUC student Grant support.

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