Mechanical Loading of Single Cells

Optically Responsive Material

Design of active cell encapsulating materials (top). Nanoactuators (gold particles) within the gels transfer defined stresses to the surrounding gel, and nearby cells. Significant gel strain (bottom) result from Near IR exposure.

A team at the Harvard MRSEC led by Mooney and Weitz has developed a mechanically active, composite material capable of applying defined loading to singly encapsulated mammalian cells. Optically-responsive hydrogels are created by encapsulating gold nanoactuators, coated with a temperature-sensitive polymer, into hydrogels. Near IR light causes heating of nanoactuators, resulting in shrinkage of the coating and transfer of stresses to surrounding hydrogel. This allows highly defined mechanical loading of individuals cells within the gels. This system is being used to probe and understand cellular-level mechano-transduction, and design new mechanically active materials to regulate biological processes in various contexts.