Carbocyanine Dyes

About

Introduction: Photodynamic therapy (PDT) is a type of phototherapy that utilizes light and photosensitizing chemical substances (drugs) to destroy harmful cells after light activation. It minimizes damage to the surrounding healthy tissues and is believed to have no severe side effects. PDT can treat a number of medical conditions, including various cancers. However, current clinically approved PDT agents, compatible with light sources at 689 nm or lower, can be absorbed by melanin and other chromophores on the body. This absorption prevents these PDT agents from being efficiently activated by the light. Previous studies have found minimal absorption of light in the range of near-infrared wavelength windows. Therefore, improved PDT agents that can be activated by near-infrared light could potentially improve the clinical outcomes of PDT. Technology: Georgia State researchers have synthesized structurally novel cyanine dyes that possess near-infrared absorption maxima extending from 700 nm to 900 nm. Studies show that low absorption of light in this range by the chromophores in the body results in enhanced penetration of the incident irradiation and highly efficient photo-activation of the cyanine dyes. It has been shown that these carbocyanine dyes generate effective oxidative damage to targeted DNA, when irradiated at 623 nm or 700 nm, in the DNA photocleavage assay. Using the synthesized cyanine dyes in combination with infrared light may substantially improve the clinical outcomes in PDT.