الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The aim of this study was to develop a system comprising trastuzumab surface modified polymeric (PLGA) and metallic (gold) nanoparticles. The proposed system was expected to combine the targeted anticancer drug delivery system properties with the photothermal potential of gold nanoparticles providing thus a safe and specific, though highly cytotoxic multifunctional therapy for breast cancer. The use of the natural plant extract, magnolol, with wide safety margin on normal cells and high cytotoxic activity on cancer cells is thought to enhance the safety of the system.
Methodology: Blank and magnolol loaded targeted PLGA nanoparticles were prepared by the nanoprecipitation method in chapter one. The effects of different formulation factors viz: organic solvent type, surfactant type and concentration as well as organic to aqueous phase volume ratio were investigated. Nanoparticles surface modification with the protein was attempted by two methods: adsorption and conjugation. In chapter two, magnolol and gold nanoparticles encapsulated in targeted PLGA nanoparticles were prepared by a modified nanoprecipitation method. The effect of gold nanoparticles concentration and placement were investigated. The prepared nanoparticles were characterized by ultraviolet spectroscopic analysis, FT-IR, 1H-NMR, surface morphology by TEM, size, PDI and zeta potential, %EE, stability in serum as well as in-vitro drug release study. Finally, the system was challenged on MCF-7 breast cancer cells in chapter three. Four studies were performed: cytotoxicity evaluation using MTT assay, the potential of photothermal effect, cell uptake and internalization by confocal laser scanning microscope and targeting efficiency.
Results and discussion: Results showed that acetone provided uniform nanoparticles with smaller size compared to acetonitrile. TPGS, when placed in the organic phase in low concentration (0.18% w/v), showed better nanoparticles stabilization compared to the conventional surfactant (PVA) placed in the aqueous phase. The change of aqueous to organic phase ratio was insignificant on the system. The optimum magnolol to PLGA ratio was 0.2:1 achieving %EE of 85.69% w/w. TZB coupling through covalent conjugation using carbodiimide chemistry with EDC and NHS provided higher protein binding of 73.4% w/w compared to adsorption method. A volume not exceeding 1.25% v/v of the organic phase of gold nanoparticles (10mM), placed in the organic phase provided the optimum nanoparticles characteristics. Coupling the prepared PLGA nanoparticles co-loaded with magnolol and gold with trastuzumab using covalent method provided uniform, spherical nanoparticles with PS: 136.1nm, PDI: 0.109, ζ: -8.15mV, magnolol %EE: 81.4% w/w and trastuzumab %CE: 66.8% w/w with more sustained release over 40 days compared to free (non-encapsulated) magnolol. Magnolol loaded nanoparticles exhibited lower IC50 compared to Mag alone. Mag-GNPs/PLGA NPs showed enhanced photothermal effect after irradiation with NIR. Both TZB modified and unmodified NPs show efficient cell uptake and internalization with faster uptake with the modified nanoparticles.
Conclusion: The developed system was found to boost the cytotoxic activity of magnolol on breast cancer cells. Mag-GNPs/PLGA-TZB NPs could be considered a safe breast cancer multifunctional therapy showing notable combined targeted anticancer drug delivery system with a photothermal potential.