Synthesis and characterization of a squaraine dye-folate complex for photodynamic therapy

Cancer is the second leading cause of death in the USA and cancer kills more than half a million people die annually in the United States alone. Photodynamic therapy (PDT) has emerged as a revolutionary medical technology to more safely fight solid tumors. The core of this technique is to administer a photosensitizing drug that can be activated by a specific wavelength of light in the presence of oxygen. PDT efficacy can be enhanced by improved photosensitizing dyes and increasing its selectivity for tumors. This goal can be achieved by synthesizing dye-folic acid complexes. Attempts have been made to covalently connect squaraine dyes to folic acid as a selectivity director. Squaraines are a class of dyes possessing sharp intense absorption bands above 600 nm in the visible red to near infrared region with the molar absorption coefficients in the neighborhood of 150,000-300,000 M-1cm -1.;The synthesis of a squaraine dye-folate complex, the characterization of its chemical, biophysical and spectroscopic properties, the investigation of its dark photostability, its cellular uptake and its photoaction in two different cancerous cell lines will be discussed.