College of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210046, China.
Nanjing Hospital of Chinese Medicine Afliated to Nanjing University of Chinese Medicine, Nanjing, 210012, China.
Anal Chim Acta. 2021 Feb 8;1145:124-131. doi: 10.1016/j.aca.2020.11.010. Epub 2020 Nov 11.
Serotonin is one of the important neurotransmitters in human nervous system and associated with central nervous system diseases. Herein, we have prepared a novel electrochemical aptasensor for rapid and sensitive detection of serotonin by using the pre-designed and prepared DNA aptamers. In the absence of serotonin, the electron transfer rate on the aptasensor was faster than that in the presence of serotonin due to the hairpin structure of the aptamer was loose and MB could be closer to the electrode surface. While in the presence of serotonin, the hairpin structure of the aptamer was extended and MB was far away from the electrode surface. The effect of MB labeled sites on analytical performances of the proposed aptasensors was discussed by comparing sensitivity of the aptasensors that MB labeled in the intermediate of the aptamer with that MB labeled at the 3' end of the aptamer. It was found that sensitivity of the intermediate-labeled aptasensor was much higher than the terminal-labeled aptasensor due to the specific conformational changes before and after aptamer binding to serotonin. The developed aptasensors exhibits a rapid electrochemical response and high sensitivity for the determination of serotonin. Under the optimal experimental conditions, the linear range for serotonin concentrations by the intermediate-labeled aptasensor was 1 pM-10 nM with a detection limit of 0.017 fM (S/N = 3). Moreover, the proposed aptasensor is reusable and shows good reproducibility and selectivity for the detection of serotonin in 100-fold diluted rat cerebrospinal fluid, suggesting a good application prospect in the detection of serotonin in real samples.
血清素是人类神经系统中的一种重要神经递质，与中枢神经系统疾病有关。在此，我们通过使用预先设计和制备的 DNA 适体，制备了一种用于快速灵敏检测血清素的新型电化学适体传感器。在没有血清素的情况下，由于适体的发夹结构较松散，因此适体传感器上的电子转移速率比存在血清素时更快，并且 MB 可以更接近电极表面。而在存在血清素的情况下，适体的发夹结构被延伸，MB 远离电极表面。通过比较 MB 标记在适体中间与标记在适体 3' 端的适体传感器的灵敏度，讨论了 MB 标记位置对所提出的适体传感器分析性能的影响。结果发现，由于适体与血清素结合前后的特异性构象变化，中间标记适体传感器的灵敏度远高于末端标记适体传感器。开发的适体传感器具有快速的电化学响应和对血清素的高灵敏度检测。在最佳实验条件下，中间标记适体传感器对血清素浓度的线性范围为 1 pM-10 nM，检测限为 0.017 fM（S/N = 3）。此外，该适体传感器可重复使用，并在 100 倍稀释的大鼠脑脊液中对血清素的检测表现出良好的重现性和选择性，表明其在实际样品中检测血清素具有良好的应用前景。
