Elasticity of Single Biopolymers
Heev L. Ayade
A cell constitutes different types of biopolymers that
form a complex network. These constituent
biopolymers provide mechanical support in
maintaining the cell’s shape and facilitate molecular
transport within the intracellular environment. Each
type of biopolymer in a cell plays an important role
in biological functions due to its unique elastic
properties. The interplay of these intracellular
biopolymers contributes to the cellular dynamics that
affect biological function. Therefore, understanding
the physics behind the adaptive elasticity of a
biopolymer is crucial in gaining biological insights
on emergent cellular behavior. The elastic properties
of biopolymers have been investigated by stretching
the biopolymers using different experimental
techniques such as hydrodynamic drag [1], glass
needles [2], magnetic tweezers [3], atomic force
microscopy [4], magneto-optical tweezers [5], and
optical tweezers [6]. The wormlike chain and freely
jointed chain models [7] are the common elasticity
models used in curve fitting through the experimental
force-extension data. The two models use the
persistence length, which is employed to describe the
elasticity of the biopolymer, and is extracted from the
two models after curve fitting. However, the two
models set a certain limitation; they cannot fit a
broader range of forces in the force-extension data
[8]. Therefore, a newly derived elasticity model is
used
in investigating the elastic properties of
biopolymers under tensile stress. The novel elastic
model was shown to predict the behavior of stretched
biopolymers in a broader range of forces, in contrast
to the wormlike chain and freely jointed chain
models. Our approach is generically applicable to
biopolymers and is applicable to other polymer types
of similar properties.
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Figure: The stretching of a biopolymer. One end of a biopolymer could be clamped using a micropipette.
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