Photodynamic Action (PDA) by using appropriate wavelength of irradiation conjugated with porphyrin derivatives is a powerful mechanism of tumor destruction. Hematoporphyrin derivative has been shown to selectively localize in neoplastic cells and then cause destruction of them by generation of singlet oxygen when activated by low power He-Ne laser. Light which used in this study has been emitting from this laser has a wavelength equal to 632.8 nm (red light). Doses of laser had been varied from 3.6 J/cm2 to 14.4 J/cm2 . The beam of laser adjusted with a modified tissue culture plate. Cell lines had exposed to Hematoporphyrin D (HpD) for 24 hours before Laser exposure, their concentrations were varied from 5 µg/ml to 80 µg/ml. Results clearly proved a Photodynamic Action of laser conjugated with photosensitizer. No significant difference in cell viability was detected using neither the laser doses alone nor the photosensitizer (HpD) alone. Therefore, we believe that the low power He-Ne laser conjugated with hematoporphyrin derivatives’ as a photosensitizer will open the door wide for photodynamic therapy of tumors.
