LABEL-FREE MONITORING OF CELL SIGNALLING PROCESSES THROUGH AFM-BASED FORCE MEASUREMENTS - Life at the Nanoscale: Atomic Force Microscopy of Live Cells - page 349

AFM was shown to be particularly suitable to cell mechanical studies as
demonstrated in the monitoring of single cardiomyocytes pulsatile activity 15
as well as monitoring mechanical properties of various cell types. 19-21
The technique was also applied to the monitoring of metabolically driven
cell membrane luctuation in

Saccharomyces cerevisiae 16,17 and to the
monitoring of cell pulsation in different human cell phenotypes. 18,22 Cell
membrane receptor activation involves spatiotemporal events, starting with
ligand-receptor recognition, receptor activation, proteins recruitment and
associated production of second messengers, internalization, cytoskeletal
remodelling, adhesion contact remodelling as well as genes expression.
Each of these events is susceptible to produce a speciic signature in
the AFM force signal, mainly in terms of amplitude, kinetics and duration.
In Fig. 17.1 , we combined the AFM with an inverted phase contrast and

(a)

(b)

Figure 17.1. Monitoring of cell activity using an AFM-based force measurement
instrument mounted over an inverted luorescence microscope. (a) In a typical
experiment, an AFM cantilever is allowed to contact the apical region of an individual
cell. (b) The stimulation of receptors present at the cell surface or in the cytosol
by selective agonist induces morphological or mechanical activity, which can be
monitored in real time with the AFM.