Extending applications of AFM to fluidic AFM in single living cell studies

Abstract

In this article, a review of a series of applications of atomic force microscopy (AFM) and fluidic Atomic Force Microscopy (fluidic AFM, hereafter fluidFM) in single-cell studies is presented. AFM applications involving single-cell and extracellular vesicle (EV) studies, colloidal force spectroscopy, and single-cell adhesion measurements are discussed. FluidFM 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. In this review, capacities of fluidFM are discussed 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 of endothelial or epithelial cells in a confluent cell monolayer in an appropriate physiological environment, and(3) the ease of measurement of vertical binding forces of intercellular adhesion between heterogeneous cells. Furthermore, key applications of fluidFM are reviewed regarding to EV 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.

Identification of common sequence motifs shared exclusively among selectively packed exosomal pathogenic microRNAs during rickettsial infections

“…(B) Representative immunofluorescence stainingof VE-cadherin in recipient PMECs after exposure to ECExos, R -ECExos, and R -ECExos that were treated with 20 μg/mL ribonuclease (RNase) in the presence or absence of 0.1% saponin as we reported for ECExos from BMECs( 61 ). (C) The lateral binding forces (LBFs) were assessed by Fluid AFM-measured detachment works in recipient PMECs after exposure to ECExos, R -ECExos, and R -ECExos that were treated with 20 μg/mL ribonuclease (RNase) in the presence or absence of 0.1% saponin as reported( 76, 85 ).…”

“…2B ). Furthermore, measuring the lateral binding forces (LBFs) between PMECs, the biomechanical nature of the endothelial barrier( 76, 85 ), suggested that PMEC paracellular barrier dysfunction occurs after treatment with R -ECExos ( Fig. 2C ).…”

Exosomally Targeting microRNA23a Ameliorates Microvascular Endothelial Barrier Dysfunction Following Rickettsial Infection

“…Therefore, measuring the lateral binding forces (LBFs) between homogenous cells in response to different stimuli is crucial to understanding the precise biomechanical mechanism underlying intercellular barrier dysfunctions, which is a major outcome of host responses to infections and inflammation. A new biomechanical strategy using AFM-based fluidic force micropipette technology (fluidic AFM) can directly measure live EC-to-EC LBFs in EC monolayers ( Supplementary Figure 4 ) ( 58 , 59 ). We found that the LBFs between living BMECs were reduced after treatment with R -ECExos ( Figure 5D ), providing direct evidence of the biomechanical nature of the endothelial barrier dysfunction during rickettsial infections.…”

Circulating exosomes from Alzheimer’s disease suppress VE-cadherin expression and induce barrier dysfunction in recipient brain microvascular endothelial cell

“…Therefore, the measurement of lateral binding forces (LBFs) between BMECs is crucial in evaluating the precise biomechanical features underlying BBB dysfunctions. To directly measure the LBFs between live BMECs Employing, a new biomechanical strategy using fluidic force microscopy (fluidic AFM) 97,100,101 was employed (. The results revealed that the LBFs between live BMECs were reduced in a dose-dependent manner after 72-hr treatment with AD-Exos (Fig.…”