Irradiation-free photodynamic therapy in vivo induced by enhanced deep red afterglow within NIR-I bio-window

In situ precise anti-cancer therapeutics, such as imaging-guided photodynamic therapy (PDT), is one of the major efforts in reducing the mortality caused by tumor proliferation. Up to now, PDT can only be executed in hospital because of the restriction of relevant facilities and PDT specialists, e.g. lasers whose power density needs to be adjusted to a patient tolerable level on time. Therefore, an irradiation-free and long-term PDT is highly desirable in precision medicine, which may help for the realization of PDT at home for cancer patients. Herein, based on the facilitated tunneling process induced by Bi substitution in Cr doped zinc gallogermanate (ZGGO:Cr,Bi) deep red persistent luminescent nanoparticles (DRPLNPs) within NIR-I bio-window (650–950 nm), an irradiation-free PDT nanoplatform was constructed by loading zinc phthalocyanine (ZnPc) molecules into mesoporous silica coated on the surface of ZGGO:Cr,Bi DRPLNPS (ZGGO:Cr,Bi@mSiO₂-ZnPc). It was demonstrated in vitro and in vivo that Bi substitution can effectively improve the afterglow intensity to such that the production of ¹O₂ is sufficient to have an apparent irradiation-free PDT. The inhibition factor of cancer growth two weeks after the injection of the nanocomposites was as high as ~80%. This work exhibits the interesting potential of the new generation of afterglow nanomaterials in precision medicine.