Rational design of activatable photosensitizers for controlled generation of singlet oxygen remains a challenge for precise photodynamic therapy (PDT). Herein, we present an aptamer-based nanodevice for adenosine 5′-triphosphate (ATP)-activatable bioimaging and PDT. The nanodevice is constructed by modifying ATP-responsive duplex DNA units and polyethylene glycol on the surface of a gold nanoparticle (AuNP) through the thiolate-Au chemistry. The DNA units were designed by the hybridization of the ATP aptamer strand with a methylene blue (MB)-modified complementary DNA (cDNA). The close proximity of MB to the surface of AuNP results in the low photodynamic activity of MB (OFF state). Once internalized into cancer cells, the ATP-binding induced conformation switch of aptamer strand leads to the release of the MB-bearing DNA strand from AuNPs, resulting in the activatable generation of singlet oxygen under light irradiation (ON state). We demonstrate that the DNA nanodevice represents a promising platform for ATP-responsive bioimaging and specific PDT in vitro and in vivo. This work highlights a potential way for specific tumor diagnosis and therapy.

合理设计可激活的光敏剂以控制单线态氧的产生仍然是精确光动力疗法（PDT）的挑战。在这里，我们提出了基于适体的纳米装置，可用于5'-三磷酸腺苷（ATP）激活的生物成像和PDT。通过硫醇盐-Au化学修饰金纳米颗粒（AuNP）表面上的ATP响应双链DNA单元和聚乙二醇来构造纳米器件。通过将ATP适体链与亚甲基蓝（MB）修饰的互补DNA（cDNA）杂交来设计DNA单元。MB与AuNP的表面非常接近，导致MB的光动力学活性低（关闭状态）。一旦内化到癌细胞中，ATP结合诱导的适体链构象转换会导致含金的DNA链从AuNPs中释放出来，导致在光照射（ON状态）下可激活的单线态氧的产生。我们证明了DNA纳米设备代表了ATP响应生物成像和特定PDT的有前途的平台体外和体内。这项工作突出了特定肿瘤诊断和治疗的潜在途径。