Biological Applications
Atomic Force Microscopy for Tumor Research at Cell and Molecule Levels by Y Qin, W Yang, H Chu, Y Li, S Cai, H Yu, and L Liu, Microsc Microanal |
https://doi.org/10.1017/S1431927622000290. Tumors pose a serious
threat to human life and health.
Researchers can determine if cells are cancerous, whether the cancer cells are invasive or have metastasized, and the effects of drugs on cancer cells by physical properties such as hardness, adhesion, and Young’s modulus. Atomic force microscopy (AFM) has emerged as an important tool for biomechanics research on tumor cells due to its ability to image and collect force spectroscopy information of biological samples with its nano-level spatial resolution under near- physiological conditions. Tis article reviews results from studies of cancer cells with AFM. Te main focus is on the operating principles of AFM and research advances in mechanical property measurement, ultra-microtopography, and molecular recognition of tumor cells. Studies are presented in a systematic way with a summary and discussion of future directions.
Schematic illustration of how an AFM works. A laser diode emits a beam onto the back of the cantilever at the tip. The magnitude of the beam deflection changes in response to the interactive force between the tip and the sample. The AFM system senses these changes in position and maps surface topography or monitors the interactive force between the tip and the sample.
Materials Applications
Focused Ion Beam Preparation of Low Melting Point Metals: Lessons Learned From Indium by JR Michael, DL Perry, DP Cummings, JA Walraven, and MB Jordan, Microsc Microanal |
https://doi.org/10.1017/S1431927622000496. Low melting point metals (like indium and lead) are commonly
used to make interconnections in electronic devices. Indium is a low melting point metal that is used in producing modern hybridized circuits. Te metallurgy of the indium impacts the reliability of these interconnects. Focused ion beam (FIB), using Ga+
or Xe+ , has been
used to prepare cross sections of these interconnects with limited success due to voiding artifacts that occur in the indium. In this work, it is shown that the artifacts observed are related to the temperature rise caused by the exposure of the indium to the energetic ion beam. Te use of modified milling strategies to minimize the increased local sample temperature are shown to produce cross sections that are representative of the indium microstructure in some, but not all, sample configurations. Furthermore, cooling of the sample to cryogenic temperatures is shown to reliably eliminate artifacts in FIB- prepared cross sections of indium allowing the true microstructure to be observed (Figure).
Electroplated indium bump cross sections prepared with Xe+
FIB. The
cross section prepared at room temperature (top) shows the typical void artifact, while the sample cross sectioned at cryogenic temperatures (bottom) is free of the artifact.
52 doi:10.1017/S1551929522000797
www.microscopy-today.com • 2022 July
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