Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200030, People's Republic of China.
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, People's Republic of China.
ACS Sens. 2022 Jul 22;7(7):2069-2074. doi: 10.1021/acssensors.2c00929. Epub 2022 Jun 16.
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.
单分子传感器相对于传统的集合技术的一个主要优势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特异性检测目标分子的特征指纹。这种策略为开发具有 fM 级检测限的超灵敏生物传感器提供了一种独特的方法，比传统检测方法低三个数量级。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，我们提出了基于流体动力学模型的传感性能理论研究。我们定量地表明，在探针设计方面存在一个两难的选择。高亲和力的探针提供更高的特异性，但需要极其长的检测时间，而低亲和力的探针可以缩短检测时间，但容易受到不需要的分子的干扰。这项研究还表明，解决这一两难困境的一种可能方法是通过向系统施加外部干扰，正如我们最近的实验所证明的那样。我们期望这项工作能够启发单分子传感器的合理设计，以进一步提高灵敏度、特异性和多重检测能力。
