Inorganic Nanomaterials with Intrinsic Singlet Oxygen Generation for Photodynamic Therapy

Abstract

Inorganic nanomaterials with intrinsic singlet oxygen ( ¹O ₂) generation capacity, are emerged yet dynamically developing materials as nano‐photosensitizers (NPSs) for photodynamic therapy (PDT). Compared to previously reported nanomaterials that have been used as either carriers to load organic PSs or energy donors to excite the attached organic PSs through a Foster resonance energy transfer process, these NPSs possess intrinsic ¹O ₂ generation capacity with extremely high ¹O ₂ quantum yield (e.g., 1.56, 1.3, 1.26, and 1.09) than any classical organic PS reported to date, and thus are facilitating to make a revolution in PDT. In this review, the recent advances in the development of various inorganic nanomaterials as NPSs, including metal‐based (gold, silver, and tungsten), metal oxide‐based (titanium dioxide, tungsten oxide, and bismuth oxyhalide), metal sulfide‐based (copper and molybdenum sulfide), carbon‐based (graphene, fullerene, and graphitic carbon nitride), phosphorus‐based, and others (hybrids and MXenes‐based NPSs) are summarized, with an emphasis on the design principle and ¹O ₂ generation mechanism, and the photodynamic therapeutic performance against different types of cancers. Finally, the current challenges and an outlook of future research are also discussed. This review may provide a comprehensive account capable of explaining recent progress as well as future research of this emerging paradigm.

Abstract

Inorganic nano‐photosensitizers possess higher extinction coefficient, resistance to photobleaching, larger absorption cross‐section, and high singlet oxygen quantum yield than their organic counterparts. These fascinating physiochemical features endow them with promising potential for reactive oxygen species‐mediated photodynamic tumor cell killing, antibacterial therapy, thermal ablation‐induced antitumor photothermal therapy, and simultaneous tumor diagnosis and treatment for multimodal cancer theranostics.