Near‐Infrared Light‐Activated Circular Oligonucleotides for Spatiotemporal Control of Gene Silencing in Mice

Abstract Oligonucleotide therapeutics hold great promise for gene regulation but face challenges in achieving spatiotemporal control of their functions in vivo. In this study we developed a novel design of near‐infrared (NIR) light‐activatable circular oligonucleotide platform that incorporates a cyanine‐scaffolded NIR photocleavable linker. These engineered circular DNAs, including DNAzymes and antisense oligonucleotides (ASOs) remain functionally inactive until NIR light irradiation triggers the linker cleavage and activates their functions, thereby enabling spatiotemporal control of gene silencing in cells and in vivo. Live cell studies demonstrated that circular DNAzymes and ASOs maintained minimal basal activity but could be efficiently activated by NIR light to achieve robust gene silencing of both exogenous and endogenous mRNAs. In vivo studies showed that lipid nanoparticle‐delivered circular DNAzymes targeting the early growth response protein 1 (EGR1) mRNA achieved localized tumor suppression upon NIR irradiation, while exhibiting minimal gene silencing activity in normal organs. Our work establishes a versatile and effective platform for the spatiotemporal control of oligonucleotide functions in vivo, providing a powerful tool for the basic study of gene function and highlighting their potential in the development of safe and on‐demand gene therapeutics.