Activating MoO3 nanobelts via aqueous intercalation as a near‐infrared type I photosensitizer for photodynamic periodontitis treatment

Abstract Although molybdenum trioxide nanomaterials have been widely explored as nanoagents for biomedical applications against bacteria through photothermal therapy, chemodynamic therapy, and catalytic therapy, their utilization as photosensitizers for photodynamic therapy (PDT) have been rarely reported so far. Herein, we report the activation of MoO 3 nanobelts via aqueous co‐intercalation of Na + and H 2 O into their van der Waals gaps as a near‐infrared Type I photosensitizer for photodynamic periodontitis treatment. The Na + /H 2 O intercalation of MoO 3 nanobelts can shorten its length, generate rich oxygen vacancies, and enlarge its interlayer gaps. Such structural changes thus can induce the color change from white to dark blue with a strong near‐infrared (NIR) absorption. When used as a photosensitizer, the I‐MoO 3− x nanobelts exhibit much higher activities for the generation of superoxide radical (·O 2 − ) under an 808 nm laser irradiation than that of the pristine MoO 3 nanobelts. Therefore, the prepared I‐MoO 3− x nanobelts show a spectral antibacterial activity against Escherichia coli and Saccharomyces aureus , thus yielding a good clinical therapeutic effect on periodontitis. Our study proves that aqueous intercalation can be a simple but powerful strategy to activate layered MoO 3 nanomaterials for high‐performance PDT.