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Atomic force microscopy: A tool for high resolution imaging and force spectroscopy in biology

Friday, September 16, 2016 — Poster Session IV

12:00 p.m. – 1:30 p.m.
FAES Terrace
NIBIB
BIOENG-9

Author

  • EK Dimitriadis

Abstract

Atomic force microscopy (AFM) is a non-optical microscopy that employs a physically sharp probe (tip) to trace topographical features at sub-nm resolution. The tip can also be used to apply and/or measure forces with sensitivity of a few pN. A major advantage, compared to other high resolution imaging (e.g., EM), of AFM is that with minimal sample preparation and without the need for special staining, biological samples can be examined in ambient and under physiological buffer conditions. Furthermore, force spectroscopy can be used to map material properties at the nanoscale, to observe antigen-antibody binding events and to study protein folding and unfolding under the forces applied by the tip. AFM can also be combined with optical techniques, such as fluorescence (e.g. TIRFM and confocal) or Raman spectroscopy, for co-localized observations. We present a few typical applications of the technology including high resolution imaging of protein-DNA complexes (e.g. HU and sRNA with DNA, nucleosome arrays), co-localized AFM with fluorescence (e.g. fibrin fibers in a blood clot), and force spectroscopy to map elastic properties at high resolution (e.g. cartilage) and to measure the elasticity of nuclei in the presence of hypothesized chromatin decompacting agents (e.g. HMGN5). The facility operates four instruments each designed with certain applications in mind. Two are equipped with micro-incubators for live cell/tissue experiments and with fluorescence capabilities (epi-, TIRF, confocal) that allow simultaneous registration of AFM and fluorescence images. The AFM facility is open to a wide range of collaborative projects.

Category: Biomedical Engineering and Biophysics