Living cell study at the single-molecule and single-cell levels by atomic force microscopy

Nanomedicine ◽  
2012 ◽  
Vol 7 (10) ◽  
pp. 1625-1637 ◽  
Author(s):  
Xiaoli Shi ◽  
Xuejie Zhang ◽  
Tie Xia ◽  
Xiaohong Fang
2021 ◽  
Author(s):  
Yuan Qiu ◽  
Chen-Chi Chien ◽  
Basilis Maroulis ◽  
Angelo Gaitas ◽  
Bin Gong

Abstract In this article, a review of the application of atomic force microscopy (AFM) for the analyses of extracellular vesicles is presented. This information is then extended to include fluidic Atomic Force Microscopy (fluidic AFM) applications. Fluidic AFM is an offshoot of AFM that combines a microfluidic cantilever with AFM and has enabled the research community to conduct biological, pathological, and pharmacological studies on cells at the single-cell level in a liquid environment. AFM applications involving single cell and extracellular vesicle studies, colloidal force spectroscopy, and single cell adhesion measurements are discussed. In this review, new results are offered, using fluidic AFM, to illustrate (1) the speed with which sequential measurements of adhesion using coated colloid beads can be done, (2) the ability to assess lateral binding forces (LBFs) of endothelial or epithelial cells in a confluent cell monolayer in appropriate physiological environment, and (3) the ease of measurement of vertical binding force (VBFs) of intercellular adhesion between heterogeneous cells. Finally, key applications are discussed that include extracellular vesicle absorption, manipulation of a single living cell by intracellular injection, sampling of cellular fluid from a single living cell, patch clamping, and mass measurements of a single living cell.


2013 ◽  
pp. 102-112
Author(s):  
Memed Duman ◽  
Andreas Ebner ◽  
Christian Rankl ◽  
Jilin Tang ◽  
Lilia A. Chtcheglova ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 687
Author(s):  
Amna Abdalla Mohammed Khalid ◽  
Pietro Parisse ◽  
Barbara Medagli ◽  
Silvia Onesti ◽  
Loredana Casalis

The MCM (minichromosome maintenance) protein complex forms an hexameric ring and has a key role in the replication machinery of Eukaryotes and Archaea, where it functions as the replicative helicase opening up the DNA double helix ahead of the polymerases. Here, we present a study of the interaction between DNA and the archaeal MCM complex from Methanothermobacter thermautotrophicus by means of atomic force microscopy (AFM) single molecule imaging. We first optimized the protocol (surface treatment and buffer conditions) to obtain AFM images of surface-equilibrated DNA molecules before and after the interaction with the protein complex. We discriminated between two modes of interaction, one in which the protein induces a sharp bend in the DNA, and one where there is no bending. We found that the presence of the MCM complex also affects the DNA contour length. A possible interpretation of the observed behavior is that in one case the hexameric ring encircles the dsDNA, while in the other the nucleic acid wraps on the outside of the ring, undergoing a change of direction. We confirmed this topographical assignment by testing two mutants, one affecting the N-terminal β-hairpins projecting towards the central channel, and thus preventing DNA loading, the other lacking an external subdomain and thus preventing wrapping. The statistical analysis of the distribution of the protein complexes between the two modes, together with the dissection of the changes of DNA contour length and binding angle upon interaction, for the wild type and the two mutants, is consistent with the hypothesis. We discuss the results in view of the various modes of nucleic acid interactions that have been proposed for both archaeal and eukaryotic MCM complexes.


Biochemistry ◽  
2007 ◽  
Vol 46 (10) ◽  
pp. 2797-2804 ◽  
Author(s):  
Theeraporn Puntheeranurak ◽  
Barbara Wimmer ◽  
Francisco Castaneda ◽  
Hermann J. Gruber ◽  
Peter Hinterdorfer ◽  
...  

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