الفهرس 
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Abstract
Cancer remains a major healthcare problem across the world; chemotherapy is one of the current methods for cancer treatments. A major problem of the conventional cancer drugs relates to their toxicity which causes the death of healthy cells as well as cancerous cells and acquirement of multidrug resistance. Therefore there is a need to find out drug delivery system which can efficiently kill cancer cells without harming normal healthy cells. Recently, the emergence of nanotechnology has made a significant impact on clinical therapeutics. Nanoscale drug carriers such as metallic and polymeric nanoparticles have enabled more efficient drug delivery. Tumor architecture causes nanoparticles to preferentially accumulate at the tumor site, thus improving cancer therapy and reducing the harmful nonspecific side effects of chemotherapeutics. In this thesis gold and chitosan nanoparticles are used as drug carrier moreover gold nanoparticles (AuNPs) are used as effective photothermal agent for efficient photothermal chemotherapy combined treatment in breast cancer (MCF7) cell line. This thesis divided in to two main parts: Part 1: The AuNPs were obtained by one step eco friendly method using chitosan as reducing and capping agent then loading anticancer 6-mercaptopurine (6MP) for the first time on chitosan reduced AuNPs forming 6MP-AuNPs nanocomposite. Our results showed that the prepared AuNPs and 6MP–AuNPs nanocomposite have small size 18±4 and 25±5 nm and exhibit high stability with Zeta potential 55.9±6.3 and 57±4 mV respectively and loading efficiency was 52٪. Cytotoxicity of the 6MP-AuNPs nanocomposite on MCF7cell line was significantly increased compared to free 6MP with IC50 1.11µM. Moreover Photothermal chemotherapy combined treatment produces improvement in therapeutic efficacy compared with chemotherapy or photothermal therapy alone. When 6MP-AuNPs nanocomposite irradiated with (Diod Pumped Solid State) DPSS laser a maximum inhibition in cell viability 63٪ at 1.25µM was achieved. Part2: Anticancer 6MP was encapsulated in chitosan nanoparticles (CNPs) to form the complexes 6MP-CNPs followed by loading on AuNPs generating a new ternary 6MP-CNPs-AuNPs nanocomposite. CNPs, 6MP-CNPs and 6MP-CNPs-AuNPs exhibit small size 130±10, 200±20 and 25±5 nm and high stability with zeta potential 36.9±4.11, 37 and 44.4 mV respectively. The encapsulation efficiency of 6MP -CNPs was found to be 57٪. Cytotoxicity of 6MP-CNPs and 6MP-CNPs-AuNPs was significantly increased compared to free 6MP reaching IC50 9.3 and 8.7µM respectively on MCF7 cell line. When 6MP-CNPs and 6MPCNPs-AuNPs nanocomposite irradiated with DPSS laser in photo thermal chemotherapy combined treatment more inhibition in cell viability with IC50 reached 5 and 4.4 µM respectively.