Polymeric Encapsulation of a Ru(II)-based Photosensitizer for Folate Targeted Photodynamic Therapy of Drug Resistant Cancers

The currently used photodynamic therapy (PDT) photosensitizers (PSs) are generally associated with a poor cancer cell selectivity, which is responsible for some undesirable side effects. To overcome these problems, the use of selective drug delivery systems is currently envisioned. In this article, the encapsulation of a promising Ru(II) polypyridine complex-based PDT PS in a polymer with terminal folate groups to form nanoparticles is presented. While showing a high selectivity for cancerous cells over non-cancerous cells, the nanoparticles were found to be highly phototoxic in 2D monolayer cells as well as 3D multicellular tumor spheroids upon 480 nm or 595 nm irradiation. Promisingly, the nanoparticles were also active in drug resistant cancer cells lines, indicating that they are able to overcome drug resistances.