Figure 1.

Principle of ruthenium-based photoactivated chemotherapy (PACT). Top: light-induced bond cleavage reaction in the prodrug. Either the photoreleased ligand (L) or the metal fragment (Ru), or both, interact(s) with biomolecules, leading to cell death. Bottom: PACT treatment of a patient with a lung tumor (in purple). The prodrug (orange) is injected intravenously, distributes in the body, and reaches the tumor in its non-toxic form. After the drug-to-light interval (DLI), light is shone onto the tumor, activating the prodrug and destroying the tumor. Finally, the body excretes the excess drug. Image courtesy Bianka Siewert.