Fast Specimen Boundary Tracking and Local Imaging with Scanning Probe Microscopy

The target region focused imaging method for scanning ion conductance microscopy

Scanning ion conductance microscopy (SICM) has developed rapidly and has wide applications in biomedicine, single-cell science and other fields. SICM scanning speed is limited by the conventional raster-type scanning method, which spends most of time on imaging the substrate and does not focus enough on the target area. In order to solve this problem, a target region focused (TRF) method is proposed, which can effectively avoid the scanning of unnecessary substrate areas and enables SICM to image the target area only to achieve high-speed and effective local scanning. TRF method and conventional hopping mode scanning method are compared in the experiments using breast cancer cells and rat basophilic leukemia cells as experimental materials. It was demonstrated that our method can reduce the scanning time for a single sample image significantly without losing scanning information or compromising the quality of imaging. The TRF method developed in this paper can provide an efficient and fast scanning strategy for improving the imaging performance of SICM systems, which can be applied to the dynamic features of cell samples in the fields of biology and pharmacology analysis.

Particle and Particle Agglomerate Size Monitoring by Scanning Probe Microscope

In the present study, the use of a scanning probe microscope is described for monitoring the sizes of nanoparticles. Monitoring is the process of acquiring and analysing the set of overlapping images. The main analysis steps are image segmentation, determination of nanoparticles allocation and their sizes, determination of the overlap of images with one another, and exclusion of repeating measurements for the formation of the correct particle-size sampling. The thorough examination of commercial scanning probe microscopes, software, and image processing libraries showed that their capabilities are limited for image segmentation and determination of sizes in complex structured images. A method based on the surface curvature computation is proposed for the image segmentation (allocation of particles) and determination of particle sizes. The curvature is estimated using the surface area approximation with respect to the circumference. It is proposed to use sample displacement sensors as an aid for image stitching.

Scanning Ion Conductance Microscopy

Scanning ion conductance microscopy (SICM) has emerged as a versatile tool for studies of interfaces in biology and materials science with notable utility in biophysical and electrochemical measurements. The heart of the SICM is a nanometer-scale electrolyte filled glass pipette that serves as a scanning probe. In the initial conception, manipulations of ion currents through the tip of the pipette and appropriate positioning hardware provided a route to recording micro- and nanoscopic mapping of the topography of surfaces. Subsequent advances in instrumentation, probe design, and methods significantly increased opportunities for SICM beyond recording topography. Hybridization of SICM with coincident characterization techniques such as optical microscopy and faradaic electrodes have brought SICM to the forefront as a tool for nanoscale chemical measurement for a wide range of applications. Modern approaches to SICM realize an important tool in analytical, bioanalytical, biophysical, and materials measurements, where significant opportunities remain for further exploration. In this review, we chronicle the development of SICM from the perspective of both the development of instrumentation and methods and the breadth of measurements performed.