AbstractThe authors describe a highly sensitive method for the aptamer (Apt) based impedimetric determination of cocaine. The surface of a screen-printed electrode (SPE) was modified with a nanocomposite of dendrimer and silver nanoparticles (AgNPs). The cocaine-binding Apt was attached to a dendrimer/AgNP/SPE surface, forming a sensitive layer for the determination of cocaine. The incubation with the analyte resulted in the formation of a cocaine/Apt complex on the electrode surface. As a consequence, folding and conformational change in the aptamer structure was induced, this resulting in a change in the impedimetric signal. The aptaassay exhibits highly efficient sensing characteristics with a good linearity of 1 fmol L−1 to 100 nmol L−1 (with two linear ranges) and a limit of detection (LOD) of 333 amol L−1. Its excellent specificity and high sensitivity suggest that this kind of aptamer-based assay may be applied to detect other targets in this field. Graphical AbstractDesigning of an aptaassay via immobilization of a functionalized aptamer with silver nanoparticle (AgNPs-Apt) on the modified screen-printed electrode (SPE) with dendrimer/silver nanoparticle nanocomposite (Den-AgNPs) for impedimetric detection of cocaine.

中文翻译：

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通过使用附着在用树枝状聚合物/银纳米颗粒纳米复合材料修饰的丝网印刷电极上的适体对可卡因进行阻抗检测

摘要作者描述了一种基于适体 (Apt) 的可卡因阻抗测定法的高灵敏度方法。丝网印刷电极 (SPE) 的表面用树枝状聚合物和银纳米粒子 (AgNPs) 的纳米复合材料改性。可卡因结合 Apt 附着在树枝状聚合物/AgNP/SPE 表面，形成用于测定可卡因的敏感层。与分析物一起孵育导致在电极表面形成可卡因/Apt 复合物。结果，诱导了适配体结构的折叠和构象变化，这导致了阻抗信号的变化。aptaassay 具有高效的传感特性，具有 1 fmol L-1 至 100 nmol L-1（具有两个线性范围）的良好线性和 333 amol L-1 的检测限 (LOD)。其优异的特异性和高灵敏度表明这种基于适体的检测可用于检测该领域的其他目标。图形摘要通过将带有银纳米颗粒 (AgNPs-Apt) 的官能化适体固定在带有树枝状聚合物/银纳米颗粒纳米复合材料 (Den-AgNPs) 的改良丝网印刷电极 (SPE) 上设计用于可卡因阻抗检测的适体分析。