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

New Designs for Phototherapeutic Transition Metal Complexes

“…[1,61] On the other hand, at longer wavelengths (> 900 nm) light absorption by water increases significantly (with l max at 960, 1440 and 1950 nm), thus limiting the range of wavelength available for PDT in the NIR-II. [62] Notably, some polypyridyl ruthenium complexes can achieve high red-light PDT efficiency due to their low-lying and long-lived emissive intra-ligand triplet excited states, despite their low absorption coefficients at this wavelength. [63] Attempts to achieve longerwavelength photoactivation include attachment to upconversion nanoparticles [64] and multiphoton photosensitization.…”

Evaluation of Perylene Bisimide‐Based RuII and IrIII Complexes as Photosensitizers for Photodynamic Therapy

“…In this range, light is less harmful for biological systems and yet able to penetrate more deeply in the tissues. [54,55] Intrigued by these characteristics, we investigated the potential application of 1 and 2 as PDT PSs. In this article, we describe the singlet oxygen production of the complexes and their ligands L1 and L2 upon irradiation at 420 and 575 nm.…”

Lightening up Ruthenium Complexes to Fight Cancer?

“…Red and near IR light penetrates human tissues deeper than light at shorter wavelength, allowing for better activation of the prodrug. [50] Furthermore, light in this part of the spectrum is less harmful for tissues. Nowadays, most of the reported metal-based PSs are activated with blue or green light.…”

“…As a cited with light at wavelengths above 600 nm, which allows for deep tissue penetration. [50,51] Furthermore, they are known for higher accumulation in cancer cells compared to healthy cells. Nonetheless, despite these 'ideal' characteristics, the discovery of novel PSs with even better properties is required.…”