MAPPING MEMBRANE PROTEINS ON LIVING CELLS USING THE ATOMIC FORCE MICROSCOPE - Life at the Nanoscale: Atomic Force Microscopy of Live Cells - page 273

12.8 CONCLUSIONS
The use of AFM-based technology to map speciic proteins on live cells
together with other types of physical and chemical mapping will clearly be
useful and important in future cell biology research. For this purpose, the
initial barrier of the technology for a beginner to overcome must be lowered
in terms of cost and training. AFM is still a relatively expensive instrument,
and it takes a while to acquire the basic knowledge for its operation compared
with most other instruments used in biological laboratories. In a sense, it is
inevitable because the AFM is one of few instruments that enable us to touch
single atoms and molecules with a virtual hand. Maybe it is true that nothing
of this sort comes cheap and easy, but it is still vital to make the technology
more accessible to many.
Future prospects of membrane protein mapping using AFM include
combining the method with the mapping of other local properties on the cell
surface, such as elasticity mapping, surface charge mapping, etc. Through
such combinations, broader application ields will be opened. A good example
is the use of AFM in elasticity mapping of the cross section of hair to detect
the effect of hair caring materials such as taurin on damaged hair. 76 If such
measurement is done in parallel with protein/polysaccharide mapping, the
result would considerably improve the interpretation of hair care treatment.
Combination of protein mapping with charge distribution mapping
determined by Kelvin probe force microscopy is another interesting
possibility because non-uniform protein distribution on a cell membrane
should affect the charge distribution as well. 77,78 The resulting non-uniform
charge distribution would be an important factor in cell-cell interactions
and 2D/3D construction of tissues and organs. Recent advancement of the
resolution and reliability of scanning ion conductance microscopy seems to
hold promise to map protein distribution together with topography of the
cell surface. 79 Force measurement has been shown to be possible using this
technology. 80 The least invasive nature of the method is an attractive feature
for biological applications.
Acknowledgements
This work was supported by Grants-in-Aid for Exploratory Research for RA
(19651058) and for Scientiic Research (S) (No. 15101004) and Creative
Scientiic Research (19GS0418) to AI from the Japan Society for the Promotion
of Science (JSPS).