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Stochastic optical active rheology


Lee H. , Shin Y. , Kim S.T. , Reinherz E.L. , Lang M.J. . Applied Physics Letters. 2012 ; 101(3). 031902


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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 10−1–103 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 cellreceptors and an antigenic peptide due to force-induced cell activation.