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چکیده
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Cancer is one of the most complex diseases which still has no definitive treatments while combination radiotherapy of surgery and chemotherapy are applied. Considering that metal nanoparticles, especially gold, have an advantage of high light-to-heat conversion efficiency, in the present study, gold nanospheres (GN) were prepared and coated bovine serum albumin (BSA) protein to be used on MBA-MB231 cells when treated with leaser. GN were synthesized using Turkevich method and coated with BSA then characterized using UV-vis spectroscopy, dynamic light scattering (DLS), zeta potential measurement, and FTIR-ATR analysis. Using 400 and 800 μg/ml of GN, the MDA-MB231 cancerous cells were exposed to leaser for 5 minutes and incubated for 24 hours. Subsequently, cell viability, nucleus and cytoplasm morphology, and DNA damage were investigated. Furthermore, oxidative stress induced by photothermal therapy based on malondialdehyde production, changes in total antioxidant capacity and the activity of catalase and superoxide dismutase were estimated. Then the mechanism of cell death was examined using DNA ladder and flow cytometry analysis. The synthesized nanoparticles were spherical and 77.35±9.56 nm in size. Their IC50 was determined to be approximately 800 μg/ml and statistical analysis of the data showed that laser irradiation of the BSA coated gold nanospheres (BSA-BN) significantly induced oxidative stress in MDA-MB231 cells compared to the group treated with nanoparticles without laser irradiation. Additionally, the morphology of the treated cells revealed chromatin condensation, nuclear size reduction, and cytoplasmic shrinkage, where agarose gel electrophoresis showed that treatment of MDA-MB231 cells with BSA-GN and laser irradiation led to DNA fragmentation, forming a ladder pattern. Flow cytometry confirmed that the treatment caused apoptosis in the cells. Although in vivo studies are essential, the results showed coating GN with BSA effectively induce oxidative stress and apoptosis in MDA-MB-231 cells after laser irradiation.
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