2 research outputs found
Gradient Mechanical Properties Facilitate <i>Arabidopsis</i> Trichome as Mechanosensor
It has been reported that <i>Arabidopsis thaliana</i> leaf trichome can act as a mechanosensory
switch, transducing mechanical stimuli into physiological signals,
mainly through a buckling instability to focus external force (e.g.,
exerted by insects) on the base of trichome. The material and structural
properties of trichomes remain largely unknown in this buckling instability.
In this report, we mainly focused on material standpoint to explore
the possible mechanism facilitating the buckling instability. We observed
that the Young’s modulus of trichome cell wall decreased gradually
from branch to the base region of trichome. Interestingly, we also
found a corresponding decline of calcium concentration on the trichome
cell wall. Results of finite element method (FEM) simulation suggested
that such a gradient distribution of Young’s modulus significantly
promotes force focusing and buckling instability on the base of trichome.
It is indicated that <i>Arabidopsis</i> trichome has developed
into an active mechanosensor benefiting from gradient cell wall mechanical
properties
Patterning Cellular Alignment through Stretching Hydrogels with Programmable Strain Gradients
The graded mechanical properties
(e.g., stiffness and stress/strain)
of excellular matrix play an important role in guiding cellular alignment,
as vital in tissue <i>reconstruction with proper functions</i>. Though various methods have been developed to engineer a graded
mechanical environment to study its effect on cellular behaviors,
most of them failed to distinguish stiffness effect from stress/strain
effect during mechanical loading. Here, we construct a mechanical
environment with programmable strain gradients by using a hydrogel
of a linear elastic property. When seeding cells on such hydrogels,
we demonstrate that the pattern of cellular alignment can be rather
precisely tailored by substrate strains. The experiment is in consistency
with a theoritical prediction when assuming that focal adhesions (FAs)
would drive a cell to reorient to the directions where they are most
stable. A fundamental theory has also been developed and is excellent
in agreement with the complete temporal alignment of cells. This work
not only provides important insights into the cellular response to
the local mechanical microenvironment but can also be utilized to
engineer patterned cellular alignment that can be critical in tissue
remodeling and regenerative medicine applications