For ionic current rectification (ICR) based sensing, nanopore functionalizations are mostly designed for directly binding target molecules to generate detectable signals from surface charge variation. However, this strategy is highly dependent on the charge difference between the captured molecules and surface functionalization layers, which will increase the nanopore design difficulty and subsequently limit the nanopore applicability. Another key challenge for ICR based sensing is the nanopore regenerability that is critical if online monitoring or repeated determination needs to be performed with one sensor. Though some types of nanopore regeneration have been realized on some specific targets or with harsh conditions, it is still highly favored to develop a regenerability using mild conditions for various targets. To address these two challenges, we developed a novel and universal sensing strategy for aptamer-functionalized nanopore that can be easily regenerated after each usage without any harsh conditions and independent of target molecule charge or size for ICR based nanopore sensing. Ochratoxin A (OTA) was used as a model analyte and its corresponding aptamer partially hybridized with the pre-immobilized complementary DNA (cDNA) onto the nanopore inner surface. We demonstrated that the recognition and conjugation of OTA with its aptamer resulted in rectified ionic current variations due to the dissociation between the OTA aptamer and its partially paired cDNA. The performance of this nanopore sensor including sensitivity, selectivity, regenerability, and applicability was characterized using rectified ionic current. This nanopore sensing strategy will provide a promising platform for extensive targets and online sensing applications.

中文翻译：

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基于靶标诱导的适体解离的超灵敏可再生纳米孔传感。

对于基于离子电流整流（ICR）的传感，纳米孔官能化主要用于直接结合靶分子，以根据表面电荷变化生成可检测的信号。然而，该策略高度依赖于捕获的分子与表面功能化层之间的电荷差，这将增加纳米孔的设计难度并随后限制纳米孔的适用性。基于ICR的传感的另一个关键挑战是纳米孔的可再生性，如果需要使用一个传感器进行在线监测或重复测定，则纳米孔的再生能力至关重要。尽管已经在某些特定的目标上或在苛刻的条件下实现了某些类型的纳米孔再生，但是仍然强烈希望使用温和的条件对各种目标开发可再生性。为了解决这两个挑战，我们为适体功能化的纳米孔开发了一种新颖而通用的传感策略，该策略可在每次使用后轻松再生，而无需任何苛刻的条件，并且与基于ICR的纳米孔传感的目标分子电荷或大小无关。ch曲霉毒素A（OTA）被用作模型分析物，其相应的适体与预先固定的互补DNA（cDNA）部分杂交到纳米孔内表面上。我们证明，由于OTA适体与其部分配对的cDNA之间的解离，OTA及其适体的识别和缀合导致整流的离子电流变化。使用整流离子电流表征了该纳米孔传感器的性能，包括灵敏度，选择性，可再生性和适用性。