We demonstrate a stochastic based method for performing active rheology using optical tweezers. By monitoring the displacement of an embedded particle in response to stochastic optical forces, a rapid estimate of the frequency dependent shear moduli of a sample is achieved in the range of 10 -1-10 3 Hz. We utilize the method to probe linear viscoelastic properties of hydrogels at varied cross-linker concentrations. Combined with fluorescence imaging, our method demonstrates non-linear changes of bond strength between T cell receptors and an antigenic peptide due to force-induced cell activation.
Bibliographical noteFunding Information:
This work was supported by the NIH R21CA133576, Yonsei University Research Fund of 2012, NIGMS (GM076689), NIH AI19807, NSF Career Award (0643745), the Samsung Scholarship from the Samsung Foundation of Culture, and the Singapore-MIT Alliance for Research and Technology.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)