State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
Institute of Inspection and Testing for Industrial Products of Jiangxi General Institute of Testing, Nanchang 330052, China.
Biosensors (Basel). 2022 Jun 16;12(6):423. doi: 10.3390/bios12060423.
G-quadruplexes have received significant attention in aptasensing due to their structural polymorphisms and unique binding properties. In this work, we exploited the fluorescence-quenching properties of G-quadruplex to develop a simple, fast, and sensitive platform for fluorescence detection of ochratoxin A (OTA) and potassium ions (K) with a label-free fluorophore and quencher strategy. The quenching ability of G-quadruplex was confirmed during the recognition process after the formation of the G-quadruplex structure and the quenching of the labeled fluorescein fluorophore (FAM). The fluorescence-quenching mechanism was studied by introducing specific ligands of G-quadruplex to enhance the quenching effect, to show that this phenomenon is due to photo-induced electron transfer. The proposed fluorescence sensor based on G-quadruplex quenching showed excellent selectivity with a low detection limit of 0.19 nM and 0.24 µM for OTA and K, respectively. Moreover, we demonstrated that our detection method enables accurate concentration determination of real samples with the prospect of practical application. Therefore, G-quadruplexes can be excellent candidates as quenchers, and the strategy implemented in the study can be extended to an aptasensor with G-quadruplex.
四链体因其结构多态性和独特的结合特性而在适体传感中受到了广泛关注。在这项工作中，我们利用四链体的荧光猝灭特性，开发了一种简单、快速、灵敏的荧光检测平台，用于无标记荧光团和猝灭剂策略检测赭曲霉毒素 A（OTA）和钾离子（K）。在形成四链体结构后，通过识别过程确认了四链体的猝灭能力，并猝灭了标记的荧光素荧光团（FAM）。通过引入四链体的特定配体来增强猝灭效应，研究了荧光猝灭机制，表明这种现象是由于光诱导电子转移。基于四链体猝灭的荧光传感器表现出优异的选择性，对 OTA 和 K 的检测限分别低至 0.19 nM 和 0.24 µM。此外，我们证明我们的检测方法能够准确测定实际样品的浓度，具有实际应用的前景。因此，四链体可以作为优秀的猝灭剂，本研究中实施的策略可以扩展到基于四链体的适体传感器。
