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The method of killing tumor cells by focused bi-frequency ultrasound activated hematoporphyrin derivatives is presented and evaluated in this paper.

Photodynamic therapy (PDT) is an emerging non-invasive treatment based on a combination of photochemistry and photophysics. PDT has more advantages compared with traditional chemotherapy and surgical treatment, which is more targeted, less harmful to healthy tissue [1][2][3][4]. When the photosensitizer (PS) molecule is illuminated by a light of particular wavelength, it passes from the first excited singlet state to the first excited triplet state T1, which will initiate a photochemical reaction by generating reactive free radicals or transferring its energy to the ground state oxygen molecule (3O2) to produce singlet oxygen (1O2) that can oxidate the bio-molecules of diseased cells and apoptosis or necrosis was resulted [5,6]. Photodynamic therapy was discovered nearly 100 years ago but medically approved drugs and technologies are still limited [7,8].The first photosensitizer used in clinics was Hematoporphyrin Derivative (HPD) which was called Photofrin or porfimer sodium. It is a mixture of six hematoporphyrin derivatives with long retention in skin which resulted in that patient need to avoid the light for 4 weeks. Hemeporfin (HMME) is a mixture of two enantiomers which was first discovered by Xu [9]. HMME has better performance than porfimer sodium. It shows low toxicity to normal tissues with rapid metabolism property. For nearly a century, the design and synthesis of hematoporphyrin derivatives are still of concern to many scientists. Here the photophysical property, cytotoxicity of new hematoporphyrin derivative BL-1 in vitro and in vivo were investigated As Photosensitizer for Photodynamic Therapy (PDT). Results and Discussion Photophysical PropertiesCompound BL-1 was dissolved in DMSO. UV-vis spectrum and fluorescence emission spectrum of Compound BL-1were investigated. As shown in (Figure 1) BL -1 had the characteristic soret and Q band absorptions at 401nm (soret), 498nm, 532nm, 569nm and 622nm (Q band), respectively. Compound BL -1 displayed a fluorescence excitation band at approximately 400nm and emission band at 620nm. HMME was chosen as the control compound.