Figure 1.

(A) Scheme illustrating automated and modular synthesis of AS1411/hemin-PA ApDC as a molecular domino reactor and its application for cascading amplified photodynamic therapy. Inside the tumor microenvironment, AS1411/hemin-PA, as a photodynamic domino reactor, can catalyze two consecutive reactions, i.e., decomposition of inherent H₂O₂ to produce O₂ and utilization of produced O₂ to generate ¹O₂ for cascading amplified PDT. (B) Synthetic route of phosphoramidite PA as a module for DNA solid-phase synthesis. Pyrochlorophyll-A (PA), a photosensitizer, was linked with solid-phase synthesis functionalities to form modular phosphoramidite-PA for automated solid-phase synthesis of AS1411-PA ApDC. Subsequently, hemin, an iron-containing porphyrin, was inserted into the G-rich region of AS1411 to form AS1411/hemin-PA with G-quadruplex/hemin DNAzyme structure.