Shifting the Light Activation of Metallodrugs to the Red and Near-Infrared Region in Anticancer Phototherapy

Abstract

The light activation of inorganic prodrugs is a unique opportunity for inorganic chemistry. Major breakthroughs in the last decade showed that photoreactions could transform a kinetically inert and biologically non-active inorganic compounds into a highly toxic form of the molecule. When performed in vitro or in vivo, such photochemical transformations offer promises, notably in anticancer phototherapy, as a generalization of photodynamic therapy, a clinically approved technique combining light, a photosensitizer, and molecular oxygen to selectively kill cancer cells. However, many inorganic complexes absorb light in the low-wavelength region of the visible spectrum, or even in the UV range, which is sub-optimal in medicine because short wavelengths poorly penetrate human tissues and can be rather toxic to cells. The review addresses these issues, discusses the definition of the photodynamic window, and sums up the different strategies that allow for obtaining photoactivation of inorganic prodrugs with high-wavelength, long-penetrating photons.

GRAPHICAL ABSTRACT

• molecular design
• photobiology
• photodynamic
• photoreactions
• phototherapy
• prodrugs
• upconversion

ACKNOWLEDGMENTS

The COST network CM1105 “Functional metal complexes that bind to biomolecules” and its working group 5 “Prodrugs with novel activation strategies” is acknowledged for scientific discussion.