Cerium-based nanoparticles for cancer photodynamic therapy

Metal-and metal-oxide-based nanoparticles have been widely exploited in cancer photodynamic therapy(PDT).Among these materials,cerium-based nanoparticles have drawn extensive attention due to their superior biosafety and distinctive physicochemical properties,especially the reversible transition between the valence states of Ce(Ⅲ)and Ce(Ⅳ).In this review,the recent advances in the use of cerium-based nanoparticles as novel photosensitizers for cancer PDT are discussed,and the activation mechanisms for electron transfer to generate singlet oxygen are presented.In addition,the types of cerium-based nanoparticles used for PDT of cancer are summarized.Finally,the challenges and prospects of clinical translations of cerium-based nanoparticles are briefly addressed.

Orthogonal Aza-BODIPY–BODIPY dyad as heavy-atom free photosensitizer for photo-initiated antibacterial therapy

Photodynamic antibacterial therapy shows great potential in bacterial infection and the reactive oxygen species(ROS)production of the photosensitizers is crucial for the therapeutic e®ect.Introducing heavy atoms is a common strategy to enhance photodynamic performance,while dark toxicity can be induced to impede further clinical application.Herein,a novel halogen-free photosensitizer Aza-BODIPY-BODIPY dyad NDB with an orthogonal molecular conguration was synthesized for photodynamic antibacterial therapy.The absorption and emission peaks of NDB photosensitizer in toluene were observed at 703 nm and 744 nm,respectively.The°uorescence(FL)lifetime was measured to be 2.8 ns in toluene.Under 730 nm laser illumination,the ROS generation capability of NDB was 3-fold higher than that of the commercial ICG.After nanoprecipitation,NDB NPs presented the advantages of high photothermal conversion e±ciency(39.1%),good photostability,and excellent biocompatibility.More importantly,in vitro antibacterial assay conrmed that the ROS and the heat generated by NDB NPs could extirpate methicillin-resistant S.aureus e®ectively upon exposure to 730 nm laser,suggesting the potential application of NDB NPs in photo-initiated antibacterial therapy.