Use of an NIR-light-responsive CO nanodonor to improve the EPR effect in photothermal cancer treatment.

The carbon monoxide (CO)-carrying palladium nanosheet (PdNS-CO) was exploited as a photothermally triggered donor of CO. Irradiating material containing PdNS-CO with 808 nm-wavelength light caused a rapid heating of the material, triggering a release of CO. The enhanced permeability and retention (EPR) effect was found to be improved by such released CO and resulted in an increase in the accumulation of PdNS-CO at tumors and hence promoted its use in photothermal therapy (PTT) using a low laser power density.