In vitro evaluation of the intensifying photodynamic effect due to the presence of plasmonic hollow gold nanoshells loaded with methylene blue on breast and melanoma cancer cells.

Background: Hypoxia is one of the most important limiting factors in photodynamic therapy that can reduce the effectiveness of this treatment. By designing a nanocomplex of plasmonic nanoparticles and photosensitizers with similar optical properties, the rate of free oxygen radical production can be increased and the efficiency of photodynamic therapy can be improved. in this study, we tried to use the outstanding capacities of hollow gold nanoshells (HGNSs) as a plasmonic nanocarrier of methylene blue (MB) to improve the performance of photodynamic therapy.

Methods And Material: After synthesis and optimization of hollow gold nanoshells loaded with Methylene blue (HGNSs-PEG-MB), the characteristics of MB, HGNSs, HGNSs-PEG, HGNSs-PEG-MB, and their toxicity at different concentrations on the cell lines was determined. After determining of optimum concentration of nano agents, irradiation of cell was performed with non-coherent of light source with 670 nm wavelength and an intensity of 14.9 mW/cm. Twenty-four hours after irradiation, an MTT assay was used to determine cell survival percentage. To compare the results, we defined different indexes such as treatment efficiency (TE), synergism ratio (SYN), and the amount of exposure required for 50% cell death (ED50). All the tests were repeated at least four times on the DFW and MCF-7 cancer cell lines.

Results: For combination therapies with Lumacare irradiated HGNSs-PEG-MB, the UC index was less than one for all concentrations (P < 0.05). Also, the IC50 index for this nanostructure in non-irradiated conditions and less than 9 min irradiation time was lower than other treatment groups (P < 0.05). ED50 amounts for HGNSs-PEG-MB in all concentrations were greater than the other groups. TE Index was also reported to be greater than 1 in all irradiation conditions and concentrations.

Conclusion: In this study, HGNSs-PEG in the role of nanocarriers for methylene Blue was used. The results showed that irradiated HGNSs-PEG-MB by 670 nm light severely induced cell death and greatly improved the efficiency of photodynamic therapy in melanoma and breast cancer cells.