Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo, 315211, China.
Faculty of Marine Science, Ningbo University, Ningbo, 315211, China.
Anal Chim Acta. 2018 Aug 22;1020:1-8. doi: 10.1016/j.aca.2018.02.058. Epub 2018 Mar 3.
In the study, a novel two dimensional metal-organic framework (Cu-TCPP nanosheets) based fluorescence resonance energy transfer (FRET) aptasensing platform was developed for detecting antibiotics. Cu-TCPP nanosheets were employed for quenching the background fluorescence and circular strand-replacement DNA polymerization (CSRP) for signal amplification. To fulfill the purpose, we designed an aptamer hairpin probe (HP) whose stem can be opened while specifically binding to target. Then the opened HP would bind with the primer. Under the action of polymerase, extension reaction was induced to generate double-stranded DNA (dsDNA), and then the target was released for the next cycle. Finally, SYBR Green I (SG) can bind with dsDNA to produce strong fluorescence response for quantification of target. It's worth mentioning that the fluorescence of HP/SG complex and free SG could be completely quenched by Cu-TCPP nanosheets while that of dsDNA/SG complex wouldn't be affected. Thus, the sensor produced negligible background signals. It can produce 7.5-fold improved S/N compared to a graphene oxide (GO)-based FRET aptasensor. Chloramphenicol (CAP) was chosen as the model analyte to demonstrate the feasibility of the sensor system. The detection range is broad from 0.001 to 10 ng mL with a detection limit down to 0.3 pg mL. The proposed assay was label free and can be used in homogenous detection which greatly simplifies the complexity of operations. The strategy opens a new way to develop sensitive, in-situ and simple assay for antibiotics in foods.
在这项研究中，开发了一种基于新型二维金属有机骨架（Cu-TCPP 纳米片）的荧光共振能量转移（FRET）适体传感平台，用于检测抗生素。Cu-TCPP 纳米片用于猝灭背景荧光，而圆形链置换 DNA 聚合（CSRP）则用于信号放大。为了实现这一目的，我们设计了一种适体发夹探针（HP），其茎在与靶标特异性结合时可以打开。然后，打开的 HP 将与引物结合。在聚合酶的作用下，诱导延伸反应生成双链 DNA（dsDNA），然后释放靶标以进行下一个循环。最后，SYBR Green I（SG）可以与 dsDNA 结合产生强烈的荧光响应，用于定量靶标。值得一提的是，HP/SG 复合物和游离 SG 的荧光可以被 Cu-TCPP 纳米片完全猝灭，而 dsDNA/SG 复合物的荧光则不受影响。因此，传感器产生的背景信号可以忽略不计。与基于氧化石墨烯（GO）的 FRET 适体传感器相比，该传感器产生了 7.5 倍的信噪比提高。氯霉素（CAP）被选为模型分析物，以证明传感器系统的可行性。检测范围从 0.001 到 10 ng mL 宽，检测限低至 0.3 pg mL。该方法是无标记的，可以用于均相检测，大大简化了操作的复杂性。该策略为开发食品中抗生素的敏感、原位和简单检测方法开辟了新途径。
