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Cytotoxic Efficacy of Photodynamic Therapy in Osteosarcoma Cells In Vitro
Published on: March 18, 2014
Dicyanomethylene Substituted Benzothiazole Squaraines: The Efficiency of Photodynamic Therapy In Vitro and In Vivo
Yongbiao Wei1, Xiaoxiao Hu2, Luyao Shen3
1Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; Department of Pharmaceutical Chemistry, School of Pharmaceutical Sciences, Guangxi Medical University, No. 22, Shuangyong Road, Nanning 530021, Guangxi, PR China.
Abstract:
The lack of ideal photosensitizers limits the clinicalapplication of photodynamic therapy (PDT). Here we report the PDT efficiency of dicyanomethylene substituted benzothiazole squaraine derivatives. This class of squaraine derivatives possess strong absorption and long excitation and emission wavelengths (ex/em, 685/720nm). They show negligible dark toxicity, but can generate singlet oxygen under irradiation resulting in the apoptosis and necrosis of cells (phototoxicity). Changing the side chains of these compounds greatly influences their albumin-binding rate, cellular uptake and their phototoxicity. One of the squaraine derivatives with two methyl butyrate side chains shows high PDT efficiency in a mouse subcutaneous xenograft model under the irradiation of a 690nm laser. These results show the great potential of dicyanomethylene substituted benzothiazole squaraines to be the leading compound of near-infrared photosensitizers in PDT.

