Photodynamic Therapy (PDT) is one of the emerging modalities for the treatment of cancer. Limitations associated with the current FDA approved photosensitizer (Photofrin) for cancer treatment includes prolonged cutaneous phototoxicity, complex mixture of compounds, and relatively low absorption in therapeutic window. In addition, Photofrin/R shows no selectivity for intracavity tumors such as disseminated ovarian cancers. During this project, Lynntech develops a new receptor-targeted photosensitizer based on a rational design. In this design, a far-red absorbing photosensitizer is covalently attached to a receptor-targeting moiety via a linker. The selected targeting moiety binds receptors that are overexpressed on the cancer cells with high selectivity and affinity. As a proof of the concept, during the Phase I, Lynntech will demonstrate the feasibility of this technology by synthesizing two new photosensitizer conjugates. These conjugates will be tested for in vitro cellular uptake and phototoxicity in a human ovarian cancer cell line. The proposed project could lead to the development of a clinically useful agent for the treatment of various human cancers. This will have a significant impact on the survival of cancer patients and the technology developed during this SBIR project could potentially be used for treating several thousands of cancer patients each year.