Direct Synthesis of Water-Soluble Aptamer-Ag2S Quantum Dots at Ambient Temperature for Specific Imaging and Photothermal Therapy of Cancer

• Published in: Advanced healthcare materials 2016-09, Vol.5 (18), p.2437-2449
• Main Authors: Gao, Jingwen, Wu, Chuanli, Deng, Dan, Wu, Ping, Cai, Chenxin
• Format: Article
• Language: English
• Subjects: Ag2S quantum dots; aptamer; cancer diagnosis; fluorescence imaging; photothermal therapy
• ISSN: 2192-2640; 2192-2659
• DOI: 10.1002/adhm.201600545

Water‐soluble Ag2S near‐infrared (NIR) fluorescent quantum dots (QDs) are directly synthesized at ambient temperature for specific cancer imaging and photothermal therapy (PTT) using a designed aptamer (Apt43) as template, which consists of the following two fragments: an aptamer S2.2 sequence for specifically recognizing the cancer cells and an 18‐cytosine (18‐C) extending spacer for growing Ag2S QDs. The synthesized Ag2S QDs (Apt43‐Ag2S QDs), which exhibit strong absorption and fluorescence emission in the NIR region and high photothermal conversion capabilities, can specifically recognize MCF‐7 cells (human breast cancer cells) and are usable as a highly intensified imaging agent for cancer diagnosis. Moreover, they can be applied as photothermal agents for the in vitro killing of MCF‐7 cells and the in vivo ablation of tumors, which were constructed on the bodies of nude mice. MCF‐7 cells almost quantitatively die after they are incubated with the QDs (at 100 μg mL–1) for 2 h and irradiated under an 808 nm laser at a power density of 1.0 W cm–2 for 10 min. The tumors on the nude mice can also be effectively ablated without regrowth during the period of observation (at least 20 d) after PTT. Water‐soluble Ag2S NIR fluorescent quantum dots are directly synthesized at ambient temperature by utilization of a designed aptamer template. They can be applied as a high intensified imaging agent for MCF‐7 cancer cell diagnosis and as photothermal agents for in vitro killing of MCF‐7 cells and in vivo ablation of tumors, which were constructed on the body of nude mice.