Tension Sensing Nanoparticles for Mechano-Imaging
at the Living/Nonliving Interface
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Abstract
Studying
chemomechanical coupling at interfaces is important for
fields ranging from lubrication and tribology to microfluidics and
cell biology. Several polymeric macro- and microscopic systems and
cantilevers have been developed to image forces at interfaces, but
few materials are amenable for molecular tension sensing. To address
this issue, we have developed a gold nanoparticle sensor for molecular
tension-based fluorescence microscopy. As a proof of concept,
we imaged the tension exerted by integrin receptors at the interface
between living cells and a substrate with high spatial (<1 μm)
resolution, at 100 ms acquisition times and with molecular specificity.
We report integrin tension values ranging from 1 to 15 pN and a mean
of ∼1 pN within focal adhesions. Through the use of a conventional
fluorescence microscope, this method demonstrates a force sensitivity
that is 3 orders of magnitude greater than is achievable by traction
force microscopy or polydimethylsiloxane micropost arrays, which are the standard in cellular biomechanics