Photodynamic therapy (pdt) has been developed as a novel method for cancer therapy. pdt involves the combined use of a photosensitizer with light to produce cytotoxic singlet oxygen. improvements in designing photosensitizers have been made which would enhance the efficiency of pdt treatment. the predominantly used photosensitizers are porphyrins and their analogs.
Methods
Gnps were functionalized with 6-mercapto-1-hexanol to attach the ppix (protoporphyrin ix) to the gold surface. to determine the in vitro efficiency of these conjugated nanoparticles for pdt, multiple parameters including varying conjugated nanoparticle concentrations (2.5-20 g/ml) and different periods of irradiation of hela cells (1, 5 and 10 min) using a 630 nm light source were needed. cell viability for each parameter using the colorimetric mtt reagent was determined.
Results
Ed50 (as exposure time required for reducing cell survival to 50%) for ppix and conjugated nanoparticles at the concentration of 2.5 µg/ml are 6.7 and 5.1 min, respectively. increasing the concentration of ppix and conjugated nanoparticles with 5 min light irradiation decreases cell viability significantly up to 10 µg/ml. but, increasing the concentration of these compounds from 10 µg/ml to 20 µg/ml with 5 min light irradiation did not affect on the loss of the cell viability significantly. the required concentration of photosensitizer to reduce cell survival to 50% (ic50) for ppix and conjugated nanoparticles is predicted as 3.7 and 2.02 µg/ml, respectively.
Conclusion
In this study, we have described a highly efficient drug vector for photosensitizer delivery into the cells via synthesizing ppix-gnp conjugates. these nanoparticles were uptaken by hela cells in vitro. the designed conjugated gold nanoparticle has greatly provided a highly efficient agent for pdt in cancer indications.
Keywords
Protoporphyrin ix; gold nanoparticles; photodynamic therapy; hela cells
