طراحي و ساخت نانو ذرات مغناطيسي بارگذاري شده با داروي ضد سرطاني دوكسوروبيسين و اصلاح شده با افيبادي ضد HER2 به منظور دارورساني هدفمند

Breast cancer has been recognized as the leading cause of cancer-related deaths and the second leading cause of death in women since 2020. A specific type of breast cancer, in which tumors exhibit a high expression of the human epidermal growth factor receptor 2 (HER2-enriched breast cancer), accounts for 15 to 30% of all breast cancers. This type of breast cancer is malignant, and in 75% of patients, the lack of effective treatments leads to death. Therefore, the development of novel therapeutic approaches for this type of cancer is significant. In this study, the drug Doxorubicin was loaded onto magnetic iron oxide nanoparticles coated with the polymer Chitosan. To enhance the specificity of the designed nanocarrier for targeted drug delivery to cells overexpressing HER2, the nanoparticles were modified using the ZHER2:342 affibody. For this purpose, the ZHER2 affibody was expressed in the E.coli BL21 expression strain. Magnetic iron oxide nanoparticles (Fe3O4) were synthesized using the co-precipitation method and then coated with the chitosan polymer. The optimal concentration of Doxorubicin loaded onto the magnetic nanoparticles was calculated by determining the drug loading efficiency and capacity at different concentrations. Afterward, the ZHER2 affibody was conjugated to the magnetic iron oxide nanoparticles using the EDC/NHS linkers. Drug release was studied at three different pH levels: 4.5, 6.5, and 7.4. The uptake mechanism of free and nanoparticle-loaded Doxorubicin was visualized through the fluorescent property of Doxorubicin using a fluorescence microscope. Finally, the cytotoxicity and efficacy of the designed nanosystems were eva‎luated on two cell lines, MCF-7 (representative of cells with low HER2 expression) and SK-BR-3 (representative of cells with high HER2 expression). Doxorubicin was loaded onto the chitosan-coated magnetic iron oxide nanoparticles with a maximum loading efficiency of 96% and a loading capacity of 80%. The drug-loaded nanoparticles were then modified with ZHER2 affibody, with a conjugation efficiency of 50%. Drug release studies showed that drug release from the Doxorubicin-loaded iron oxide nanoparticles modified with ZHER2 affibody was pH-dependent and controlled, with a significant increase (88%) in drug release observed at lower pH levels. MTT assay demonstrated that the viability of SK-BR-3 cells treated with the synthesized nanoparticles (ZHER2-DOX-Ch@MNPs) was significantly lower (P<0.05) compared to MCF-7 cells. In conclusion, the results of this study indicated that Doxorubicin and the ZHER2 affibody have a synergistic effect, and the active endocytosis of the synthesized nanoparticles into cancer cells through the interaction of ZHER2 with HER2 leads to enhanced drug specificity for the target cells.

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