College of Chemistry and Chemical Engneering, Linyi University, Linyi 276000, P.R. China.
Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE; Shandong Key Laboratory of Biochemical Analysis; Qingdao University of Science and Technology, Qingdao 266042, P.R. China.
ACS Sens. 2022 Oct 28;7(10):3153-3160. doi: 10.1021/acssensors.2c01636. Epub 2022 Oct 11.
A novel label-free photoelectrochemical (PEC) biosensor is presented in this work. As a barrier, the DNA hydrogel could block the coupling between g-CN and CdS quantum dots (QDs). Therefore, extremely low photocurrent signals were obtained. The presence of target microRNA-21 can initiate the rolling circle amplification (RCA) reaction, which in turn produces many repeated sequences to activate the CRISPR/Cas12a system. The trans-cleavage activity of the CRISPR/Cas12a system led to the degradation of DNA hydrogels efficiently. As a result, the g-CN/CdS QDs heterojunction was formed through "click" chemistry. Through the amplification of the RCA and CRISPR/Cas12a system, the sensitivity of the PEC biosensor was improved significantly with the detection limit of 3.2 aM. The proposed sensor also showed excellent selectivity and could be used to detect actual samples. In addition, the modular design could facilitate the detection of different objects. Thus, the proposed CRISPR/Cas12a system responsive DNA hydrogel provides a simple, sensitive, and flexible way for label-free PEC analysis.
本工作提出了一种新颖的无标记光电化学（PEC）生物传感器。DNA 水凝胶可以作为一种屏障，阻止 g-CN 和 CdS 量子点（QDs）之间的耦合。因此，得到了极低的光电流信号。目标 microRNA-21 的存在可以引发滚环扩增（RCA）反应，进而产生许多重复序列来激活 CRISPR/Cas12a 系统。CRISPR/Cas12a 系统的转录切割活性有效地降解了 DNA 水凝胶。结果，通过“点击”化学形成了 g-CN/CdS QDs 异质结。通过 RCA 和 CRISPR/Cas12a 系统的放大，PEC 生物传感器的灵敏度显著提高，检测限达到 3.2 aM。该传感器还表现出优异的选择性，可用于检测实际样品。此外，模块化设计可以方便地检测不同的目标物。因此，所提出的 CRISPR/Cas12a 系统响应性 DNA 水凝胶为无标记 PEC 分析提供了一种简单、灵敏、灵活的方法。
