Self-quenching synthesis of coordination polymer pre-drug nanoparticles for selective photodynamic therapy.

The design and preparation of a photoactive coordination polymer nanoplatform with tumor-related stimuli-activatability and biodegradability is highly desirable for achieving highly precise photodynamic therapy (PDT). Herein, novel "pre-photodynamic" nanoparticles (Fe-IBDP NPs) with a tumor microenvironment (TME)-activatable PDT and good biodegradability were synthesized by carrying out facile coordination assembly of an IBDP photosensitizer with an Fe3+ quenching agent. After being taken up by cancer cells, our "inactive" Fe-IBDP NPs were activated by the TME and as a result decomposed and released the photoactive carboxyl-functionalized diiodo-substituted BODIPY (IBDP) photosensitizer, which generated cytotoxic singlet oxygen (1O2) under light irradiation. By contrast, these NPs showed relatively low cytotoxicity in normal cells. This work also provided a feasible method for preparing the next generation of photoactive nanomedicines for use in precise phototherapy.