Professor Igor Sokolov Uses Atomic Force Microscopy to Study Human
Igor Sokolov, in collaboration with his M.S. student Tamara Berdyyeva
and Professor Craig Woodworth (of Clarkson's Biology Department),
discovered a change of elasticity of human epithelial (HKC) cells
with ageing. This result was found by using an atomic force microscopy
(AFM) technique in-vitro. The method used a silica sphere (5 Ám
in diameter) glued to an AFM cantilever. This modified AFM probe
provided stable and repeatable results over the entire area of an
individual cell, which was a problem while using a standard AFM
probe. See Figure 5.
measurements, three different areas of rigidity were identified
on the cell surface: the area of the nucleus, the cytoplasmic area,
and the cell edge area.
(10 to 20 population doublings) were found to be consistently softer
than the old cells (40 to 60 doublings), so-called senescent cells.
Specifically, the nuclear regions of the old cells have 2 times
higher Young modulus than the Young modulus of the young cells.
Also the cytoplasm and edge regions of senescent cells have a 3-5
times higher Young's modulus than young ones.
have been proved statistically. The change of cell rigidity was
proved based on measurements of tens of different cell samples.
Also each cell was measured in hundreds of points.
rigidity change might be attributed to a difference in the organization
of cell cytoskeleton. At present, Professor Sokolov and his collaborators
have developed a new method for visualizing the cellular cytoskeleton
by using atomic force microscopy. Figure 6 presents an AFM scan
showing a few cells and their cytoskeletons. Professor Sokolov's
group is also investigating directional enzyme alteration of the
cytoskeleton and its influence on the rigidity of young and old
cells. Change of elasticity of human epithelial tissues with ageing
has been known for a long time and is an important factor in the
development of various diseases. Therefore rigidity change of the
epithelial cells found in Professor Sokolov's work may be useful
in the area of skin disease treatments. His reported results may
have applications in the pharmaceutical industry as a preliminary
screening tool of anti-ageing drugs, which would help to maintain
the "young" cellular elasticity. In addition, this research may
even bring attention to a new direction in rejuvenating human skin.
5. A 5 Ám silica sphere, glued to a standard AFM cantilever,
was used to obtain stable and repeatable results over the
area of the whole individual cell.
6. Visualizing the cell
cytoskeleton is possible by the AFM technique using a new
method developed by Professor Sokolov and his colleagues.
more information about Professor Sokolov and his research, please
call him at 315-268-2375 or send email to email@example.com.