College of Chemistry and Chemical Engineering, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China.
Biosens Bioelectron. 2010 Jun 15;25(10):2232-7. doi: 10.1016/j.bios.2010.02.030. Epub 2010 Mar 4.
Simple, fast and direct analysis or monitoring of significant molecules in complex biological samples is important for many biological study, clinical diagnosis and forensic investigations. Herein we highlight a general method to tailor aptamer sequence into functional subunits to design target-induced light-switching excimer sensors for rapid, sensitive and selective detection of important molecules in complex biological fluids. Our approach is to split one single strand aptamer into two pieces and each terminally labeled with a pyrene molecule while maintaining their binding affinity to target molecules. In the presence of target molecules, two aptamer fragments are induced to self-assemble to form aptamer-target complex and bring two pyrene molecules into a close proximity to form an excimer, resulting in fluorescent switching from approximately 400 nm to 485 nm. With an anti-cocaine sensor, as low as 1 microM of cocaine can be detected using steady-state fluorescence assays and more importantly low picomole level of target can be directly visualized with naked eyes. Because the excimer has a long fluorescence lifetime, time-resolved measurements were used to directly detect as low as 5 microM cocaine in urine samples quantitatively without any sample pretreatment.
简单、快速、直接地分析或监测复杂生物样本中的重要分子，对于许多生物学研究、临床诊断和法医学调查都很重要。在此，我们强调了一种通用的方法，即将适体序列剪裁成功能亚基，设计用于目标诱导的光开关激基复合物传感器，用于快速、灵敏和选择性地检测复杂生物流体中的重要分子。我们的方法是将一条单链适体分成两段，并在每个末端标记一个芘分子，同时保持它们与靶分子的结合亲和力。在靶分子存在的情况下，两个适体片段被诱导自组装形成适体-靶复合物，并将两个芘分子拉近形成激基复合物，从而导致荧光从大约 400nm 切换到 485nm。对于可卡因传感器，使用稳态荧光分析可以检测到低至 1µM 的可卡因，更重要的是，可以直接用肉眼观察到低皮摩尔级别的靶标。由于激基复合物具有较长的荧光寿命，因此可以使用时间分辨测量法直接定量检测尿液样品中的低至 5µM 的可卡因，而无需任何样品预处理。
