One of the key advantages of single-molecule sensors over conventional ensemble technologies is their capability of revealing the heterogeneity among molecular events. In dynamic single-molecule sensing, heterogeneity in molecular interaction kinetics is quantified as the fingerprint to specifically detect target molecules. This strategy offers a unique approach to develop ultrasensitive biosensors with a limit of detection at the fM level, which is three orders of magnitude lower than that of conventional assays. However, due to the lack of a comprehensive theoretical model, the rational design of dynamic single-molecule sensors is challenging. Herein, we present the theoretical study of sensing performance with a hydrodynamic model. We quantitatively show that there is a dilemma regarding the probe design. High-affinity probes offer higher specificity but require extremely long assay time, while low-affinity probes could shorten the assay time but are prone to the interference from unwanted molecules. This study also suggests that one possible solution to solve this dilemma is by applying external disturbance to the system, as we have recently demonstrated by experiments. We anticipate that this work could inspire the rational design of single-molecule sensors to further improve the sensitivity, specificity, and multiplexing capability.

中文翻译：

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动态单分子传感器：理论研究

与传统集成技术相比，单分子传感器的主要优势之一是它们能够揭示分子事件之间的异质性。在动态单分子传感中，分子相互作用动力学的异质性被量化为指纹以特异性检测目标分子。该策略提供了一种独特的方法来开发超灵敏生物传感器，其检测限在 fM 水平，比传统检测低三个数量级。然而，由于缺乏全面的理论模型，动态单分子传感器的合理设计具有挑战性。在此，我们提出了利用流体动力学模型对传感性能进行的理论研究。我们定量地表明，探针设计存在两难境地。高亲和力探针提供更高的特异性，但需要极长的检测时间，而低亲和力探针可以缩短检测时间，但容易受到不需要分子的干扰。这项研究还表明，解决这一困境的一种可能解决方案是对系统施加外部干扰，正如我们最近通过实验证明的那样。我们预计这项工作可以激发单分子传感器的合理设计，以进一步提高灵敏度、特异性和多路复用能力。正如我们最近通过实验证明的那样。我们预计这项工作可以激发单分子传感器的合理设计，以进一步提高灵敏度、特异性和多路复用能力。正如我们最近通过实验证明的那样。我们预计这项工作可以激发单分子传感器的合理设计，以进一步提高灵敏度、特异性和多路复用能力。