A method that models biological cell-to-cell
adhesion that could also have industrial applications has been developed by
This system, created in the laboratory of Jasna
Brujić, an assistant professor in NYU's Department of Physics and part of its
Center for Soft Matter Research, is an oil-in-water solution whose surface
properties reproduce those found on biological cells. Specifically, adhesion
between compressed oil droplets mimics the mechanical properties of tissues and
opens the path to numerous practical applications, ranging from biocompatible
cosmetics to artificial tissue engineering.
Their method is described in the journal the Proceedings
of the National Academy of Sciences
Previously, Brujić's laboratory has determined
how spheres pack and devised methods for manipulating the packing process. In
this PNAS study, Brujić and her research team sought to create a method that
would address the role of packing in tissues from the point of view of how
mechanical forces affect protein-protein adhesion between cells.
In biology, cell-to-cell adhesion is crucial to
the integrity of tissue structure—cells must come together and stick in order
to ensure tissue cohesion. However, the daunting complexity of biological
systems has long prevented their description using general theoretical concepts
taken from the physical sciences. For this reason, the research team designed
an original biomimetic solution, or emulsion, that reproduces the main features
of cell-to-cell adhesion in tissues.
Emulsions form the basis for a range of consumer
products, including butter, ice cream, and milk. In addition, the emulsion in
the PNAS study is tuned to match the attractive and repulsive interactions that
govern adhesion between cells. The experimental conditions reveal the
circumstances under which pushing forces are necessary to create adhesion.
By varying the amount of force by which the
droplets of oil were compressed by centrifugation and the amount of salt added
to this solution, the NYU team was able to isolate the optimal conditions for
cell-to-cell adhesion. Screening electrostatic charges by the addition of salt
and compressing the droplets by force enhances protein-protein interactions on
the droplet surfaces. This leads to adhesion between contacting droplets
covering all the interfaces, just as in the case of biological tissues.
Their results, which matched the researchers'
theoretical modeling of the process, offer a method for manipulating force and
pressure in order to bind emulsions. This serves as a starting point for
enriching a range of consumer products, by reconfiguring their molecular
make-up to enhance consistency and function, and for improving pharmaceuticals,
by bolstering the delivery of therapeutic molecules to the blood stream.