A Visible‐ and NIR‐Light Responsive Photothermal Therapy Agent by Chirality‐Dependent MoO3−x Nanoparticles

Chirality‐based semiconducting nanocrystals, as an emerging area, are envisioned to have great potential in chiral sensing, biomedicine, and chiroptical devices. Herein, chiral substoichiometric molybdenum oxide (l/d‐Cys‐MoO3−x) nanoparticles are synthesized via step‐by‐step reduction treatment with chiral cysteine molecules. The obtained nanoparticles are used as visible‐ and near‐infrared‐light dual responsive photothermal therapy agent for tumor cell ablation. Notably, the chiral nanoparticles show chiral selectivity for incident light, i.e., when irradiated by left‐circularly polarized light, l‐Cys‐MoO3−x is the most sensitive agent giving the highest mortality for HeLa cell ablation in vitro, and vice versa for right‐circularly polarized light with d‐Cys‐MoO3−x. In comparison to traditional photothermal therapy with near‐field light source, the investigations with chiral visible light at 532 nm indicate the possibility of chiral Cys‐MoO3−x nanoparticles for visible light‐based phototherapy via metal–ligand charge transfer chirality, which provides insights for new methods in nanotechnology supported photothermal treatments. Visible‐ and near‐infrared (NIR)‐light responsive chiral substoichiometric MoO3−x nanocrystals are investigated and applied as an ultrasensitive photothermal therapy agent for tumor cell ablation. Compared to traditional photothermal therapy, such chiral MoO3−x nanocrystal‐based systems show chiral selectivity for incident circular polarized light, resulting in enhanced photothermal therapy performance with both visible and NIR polarized light sources.