The Interest of Folic Acid in Targeted Photodynamic Therapy.

Photodynamic therapy is an alternative to chemotherapy and radiotherapy for cancer treatment. PDT is clinically applied to treat age-related macular degeneration and several types of cancer. Most of the time, the selectivity of the treatment is brought about by the application of light. Another strategy to improve selectivity is to design and synthesize targeted photosensitizers or nanoparticles, which can identify and selectively accumulate within tumor tissues. This review presents our inventory of all the data concerning the use of folic acid as a promising targeting unit to improve the selectivity of photosensitizers to folic acid receptors. We will discuss the strategies that are developed to couple folic acid to photosensitizers or nanoparticles as well as the influence of the presence of folic acid on the objects' photophysical properties and their effects on selectivity and phototoxicity in vitro and in vivo.