الفهرس 
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Abstract
Development of drug resistant strains such as multi drug resistant TB (MDR-TB) and extensive drug resistant TB (EXDR-TB) threatens the progress made in TB controls and prompt the need to alternative strategies. The aim of this work was to investigate the anti-mycobacterial activity of two noble metal nanoparticles either in non-conjugated form or conjugated with rifampicin. Gold (spheres and rods) and silver (spheres) nanoparticles were synthesized and characterized using TEM and UV–vis spectroscopy. The anti-mycobacterial activity of silver nanospheres (AgNSs) was studied using the malachite green decolorisation assay (MGDA) and cultivation on Lowenstein Jensen media, and the results indicate that AgNSs have a strong anti-mycobacterial effect with 80 µg/ml MIC. To test the cytotoxic effect of gold and silver nanospheres on RAW264.7 cell line as a macrophage cell model, which is the host of TB, we did a comparative study using XTT assay and microscopic examination. Results indicated that silver nanospheres were severely toxic while the gold nanospheres were safer to murine macrophage RAW264.7 cell. Therefore, silver nanospheres were excluded from this work as its toxicity to host cells. Gold nanoparticles (spheres and rods) were conjugated with rifampicin and the successful conjugation was confirmed with UV–vis spectroscopy. Then, the anti-mycobacterial activity of conjugated and non-conjugated AuNPs with rifampicin against extracellular TB were assayed using the malachite green decolorisation assay (MGDA) and cultivation on Lowenstein Jensen media and Middlebrook agar, the results revealed that the shapes of gold nanoparticles played an important role in the anti-mycobacterial activity, as the rods have a strong anti-mycobacterial activity while the spheres have no anti-mycobacterial effect. The impact of the cell types (RAW264.7 macrophage cell line, HSC-3 human oral squamous cell carcinoma and MCF7 human breast adenocarcinoma cells) on the gold nanoparticle uptake was studied using the dark field scattering microscopy. Results showed that the macrophages have the highest uptake while the other two cancer cell lines showed less uptake. Studying the cell death variation on RAW264.7 murine macrophages and two human cancer cell lines (MCF-7 and HSC-3), after the incubation with functionalized AuNRs with rifampicin (AuNRs@RF), assayed by the cell viability and apoptosis /necrosis assay. The decrease of viability of RAW can be attributed to the phagocytic power of macrophage which is not possessed by other cancerous cell lines. Apoptosis/ necrosis study using the AuNRs either conjugated or not with RF on RAW and two cancer cell lines, showed that AuNRs and AuNR@RF caused apoptotic way of cell death with high apoptotic cells in RAW cell compared with the other two cell lines. The intramacrophage activities of conjugated and nonconjugated AuNPs against intracellular mycobacteria were assayed by the CFU assay. The AuNRs in size 25 length x 5 width represent a promising drug delivery candidate for anti-tuberculosis drug in addition of their anti-mycobacterial activity. However AuNSs and AuNSs @RF had no anti-mycobacterial effect against the extracellular TB, they resulted in significant reduction of the intracellular mycobacterial CFU. Plasmonic photothermal study was conducted on M. tuberculosis, and its host cell (RAW264.7 murine macrophage cell line).The AuNRs (0.5 OD) is promising in killing the TB bacteria by plasmonic photothermal without harming the host cell. We characterized the unique Raman band of RAW cell using the Raman spectroscopy technique. In the future work we are planning to study the Raman vibrational change and it is relation to the cell death. This powerful technique might help in explaining the molecular mechanism of cell death. We concluded that AuNPs especially the conjugated form with rifampicin efficiently internalized and accumulated inside the macrophages. And the AuNRs might be a promising antimycobacterial agent, and or a smart delivery vehicle for anti-tuberculosis drug (Rifampicin), while the AuNSs have no anti-mycobacterial activity, they might be a successful delivery system for anti-tuberculosis drugs able to target safely the M. tuberculosis infected macrophage, the conjugated AuNPs with rifampicin were superior than the free rifampicin in combating the intracellular M. tuberculosis. So the AuNPs as antimycobacterial drug delivery system might be recommended for application in tuberculosis therapy.