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Research University who, naturally, have an interest in innova- cell; if you place it on a synthetic material with the
tive walking aids. "Other Technion students at the lab mechanical properties of bone, it will become a bone
are mechanically-inclined bioengineering students," cell. We still don't know why this happens, but we are
she adds. "An M.Sc. or a Ph.D. student from this fac- absolutely certain it does happen."
ulty can certainly do their research at our lab."
At first, the new discovery attracted mostly physi-
cists, who believed this pointed toward a new gener-
al principle. Then engineers began to show interest,
Cell Biomechanical Engineering
"Cells adapt to their
environment's mechanical
properties. These properties
are something we can control"
Associate Professor Shelly Tzlil studied physics,
chemistry, and computer science. Her Ph.D. is about
the statistical mechanics of biological systems. "I
was a theoretical researcher writing equations, most-
ly about how viruses organize and invade cells. At a
certain point, I grew tired of asking other researchers
to run experiments for me. I decided I wanted to run
experiments too."
It was this realization that led her to her post-doc
at California Institute of Technology. "The lab I worked
Associate Professor Shelly Tzlil: Assoc. Prof. Shelly Tzlil's lab team. "I was a theoretical
"Each separate heart cell beats researcher writing equations until one day I decided I wanted
to its own rhythm, but when they to run my own lab experiments"
sense each other's deformations,
they synchronize. We built a and several mechanical engineers got into the field.
device that mimics the mechanical "We tried to figure out not only how the cells were
forces of a heart cell and causes changing because of the environment's mechanical
cells to synchronize and remain properties, but also how they were acting on the en-
in sync even after a mechanical vironment to 'know' what it was. If these cells could
pacemaker has stopped working" detect environmental deformations, they were also
likely to detect deformations caused by neighboring
at made artificial protein matrices for cell cultures, cells. This effectively means the cells communicate
and at one point, the team started to notice that the with each other. A discovery like this has a lot of im-
mechanics of the environment affected biological plications."
cells. This was a hot research topic in 2006 and 2007.
Like what? Like wound closure, Tzlil explains.
"Dennis Discher's lab at UPenn discovered that if "There can be two different mechanisms for this: in
you take stem cells, which could potentially differen- one mechanism, each cell works independently until
tiate into any type of cell, their differentiation route eventually, the wound closes. But there is a second
is determined by the elasticity of their environment. possibility where the cells 'lock hands', creating a co-
If you place a stem cell on a material with similar ordinated molecular engine that closes the wound. If
elasticity to muscle tissue, it will become a muscle the cells all work together, there is no scar tissue. But
how do we make them work together? This is where
the mechanics-based communication method we
discovered comes in, and this is relevant to almost
all areas of medicine: cell development, cell differen-
tiation, cancer – in every area, the forces the cells ex-
ert and the cells' mechanical environment are critical
18 | MEgazine | Faculty of Mechanical Engineering
