Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, Xi'an Jiaotong University, Xi'an 710049, China.
School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Anal Chem. 2021 Sep 14;93(36):12296-12304. doi: 10.1021/acs.analchem.1c01918. Epub 2021 Aug 4.
Scanning ion conductance microscopy (SICM) is a type of in situ measurement technology for noncontact detection of samples in electrolytes with nanoscale resolution and has been used increasingly in biomedical and electrochemical fields in recent years. However, there is an inherent contradiction in the technique that makes SICM's sensitivity and accuracy difficult to balance. Higher sensitivity allows for faster probe speeds and higher scanning reliability but leads to lower accuracy, and vice versa. To resolve this problem, an adaptive sensitivity scanning method is proposed here that is designed to increase SICM's imaging efficiency without reducing its scanning reliability and accuracy. In the proposed scanning method, the sensitivity is automatically switched via the bias voltage based on the probe-sample distance. When the probe is located far away from the sample, the probe then predetects the sample position rapidly with high sensitivity. When the sample has been sensed in the high-sensitivity phase, the probe then detects the sample with low sensitivity. The basic theory and the feasibility of the alterable sensitivity detection strategy is also studied using the finite element method (FEM) and by performing experiments in this work. Finally, through testing of the standard silicon and polydimethylsiloxane (PDMS) samples, the proposed method is shown to increase SICM imaging efficiency significantly by up to 5 times relative to the conventional hopping mode without sacrificing the scanning accuracy and reliability.
扫描离子电导显微镜（SICM）是一种用于在纳米尺度分辨率下对电解质中的样品进行非接触检测的原位测量技术，近年来在生物医学和电化学领域得到了越来越多的应用。然而，该技术存在一个固有矛盾，使得 SICM 的灵敏度和准确性难以平衡。更高的灵敏度允许更快的探针速度和更高的扫描可靠性，但会导致更低的准确性，反之亦然。为了解决这个问题，本文提出了一种自适应灵敏度扫描方法，旨在提高 SICM 的成像效率，同时不降低其扫描可靠性和准确性。在提出的扫描方法中，通过偏置电压自动切换灵敏度。当探针远离样品时，探针以高灵敏度快速预检测样品位置。当在高灵敏度阶段检测到样品后，探针再以低灵敏度检测样品。本文还使用有限元法（FEM）进行了理论研究和实验验证，研究了可变灵敏度检测策略的基本原理和可行性。最后，通过对标准硅和聚二甲基硅氧烷（PDMS）样品的测试，与传统的跳跃模式相比，该方法可将 SICM 成像效率提高 5 倍以上，而不牺牲扫描的准确性和可靠性。
