Oxygen-deficient tungsten oxide perovskite nanosheets-based photonic nanomedicine for cancer theranostics

Tungsten Oxide (WO3) is a typical perovskite semiconductor with layered structure. In this work, an advanced two-dimensional (2D) photonic drug-delivery platform based on PEGylated WO2.9 (a substoichiometric form of WO3) nanosheets (NSs) is explored. The developed platform have multiple merits such as: i) excellent photo thermal performance in near-infrared-II (NIR-II) biowindow, ii) high drug load efficiency, iii) controlled drug release activated via NIR-II light or weakly acidic pH, iv) efficient tumor accumulation, v) deep tumor penetration through both exogenous stimuli (i.e. NIR-II light) or endogenous stimuli (i.e. weakly acidic in tumor), vi) good fluorescence/ photoacoustic (PA)/computerized tomography (CT)/photothermal multimodal imaging capability, and vii) significant tumor growth inhibition without obvious side effects. These particular advantages can provide valuable experiences for addressing several limitations in the development of cancer nanomedicines. To the best of our knowledge, this is the first time to study 2D WO2.9 NSs-based photonic nanomedicine, which may make an exciting jumping-off point for the study of the application of WO2.9 NSs in cancer theranostics.