An amperometric aptasensor for ultrasensitive detection of sulfadimethoxine based on exonuclease-assisted target recycling and new signal tracer for amplification
An amperometric aptasensor for ultrasensitive detection of sulfadimethoxine based on exonuclease-assisted target recycling and new signal tracer for amplification
复制标题
基于核酸外切酶辅助靶标回收和新型放大信号示踪剂的超灵敏检测磺胺二甲氧嘧啶的安培适配体传感器
DOI：
10.1016/j.bios.2018.06.011
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发表时间：
2018-10-15
影响因子：
12.6
通讯作者：
Mu, Zhaode
中科院分区：
文献类型：
--
作者：
You, Huan;Bai, Lijuan;Mu, Zhaode
动物性食品中兽药残留所带来的风险是公众十分关注的问题。因此，本工作报道了一种用于磺胺二甲氧嘧啶（SDM）高灵敏检测的电流型适体传感器。设计并制备了功能化富勒烯（C-60）掺杂石墨烯（C-60-rGO）纳米杂化材料，通过π-π堆积负载电活性甲苯胺蓝（Tb），形成C-60-rGO-Tb纳米复合材料。此外，所制备的纳米复合物修饰有金纳米颗粒，并用于固定信号探针，形成一种新的信号示踪剂，这是耦合核酸外切酶催化的目标循环扩增。为了构建适体传感器，适体-捕获探针复合物的硫醇化双链DNA（dsDNA）通过强Au-S键固定在金电极表面。在SDM存在下，适体优先形成适体-SDM复合物，这导致dsDNA解离。核酸外切酶RecJ（f）选择性地消化核酸适体，释放出的SDM分子参与下一个反应循环，实现信号放大。然后，从循环过程中释放的捕获探针与信号示踪剂杂交，这可以进一步增强电化学信号响应。基于级联信号放大策略，构建的适体传感器对SDM的线性范围为10 fg/mL ~ 10 ng/mL，具有灵敏度高、选择性好、稳定性好等特点。
The risks caused by veterinary drug residues in animal foodstuffs are of great concern to the public. Accordingly, this work reported an amperometric aptasensor for highly sensitive detection of sulfadimethoxine (SDM). Functionalised fullerene (C-60)-doped graphene (C-60-rGO) nanohybrid was designed and prepared to load electroactive toluidine blue (Tb) through the pi-pi stacking, forming a C-60-rGO-Tb nanocomposite. Furthermore, the as-prepared nanocomposite was decorated with gold nanoparticles and used for the immobilization of signal probes to form a new signal tracer, which was coupled with exonuclease-catalyzed target recycling for amplification. To construct the aptasensor, a thiolated double-stranded DNA (dsDNA) of aptamer-capture probe complex was immobilised on a gold electrode surface through strong Au-S bond. In the presence of SDM, the aptamer preferred to form an aptamer-SDM complex, which led to the dissociation of dsDNA. Then aptamer could be selectively digested by RecJ(f) exonuclease, resulting in liberated SDM molecules to participate in the next reaction cycling and achieve signal amplification. Then, capture probes released from the cyclic processes were hybridized with the signal tracer, which could further enhance electrochemical signal responses. On the basis of cascade signal amplification strategies, the proposed aptasensor exhibited a wide linear range from 10 fg/mL to 10 ng/mL for SDM with high sensitivity, good selectivity and satisfactory stability.