Objective
Due to its simplicity of application, the economy of its sample size and its non invasive nature, microrheology proves an ideal tool for probing mechanical properties of complex environments. Conventionally, microrheology is based on translating the diffusive motion of colloidal particles into the elastic properties of the diffusing medium by means of linear response and the fluctuation-dissipation theorem. However, non linear processes such as stress transduction in cellular environments and strong shear in complex fluids are not accessible by this method. It has recently been suggested that by using active microrheology, where the tracer particles are driven, the non-linear nature of stress transmission in complex fluids can be measured. However, the interpretation of these experiments is not straightforward since the fluctuation-dissipation theorem no longer holds. We propose to systematically develop active microrheology as a tool for probing stress transmission in complex fluids with the far goal of applying it to study mechanotransduction in living cells. We will start by studying complex fluids such as dense colloidal suspensions and biological gels in which the nonlinear rheological properties in bulk are known. We will then proceed to study artificial biomimetic model systems and finally apply our method to live cells.
To this end we will use a system of holographic optical tweezers to drive colloidal particles in complex fluids in combination with confocal imaging of fluorescent tracer particles to visualize the response of the fluid.
Fields of science
Keywords
Call for proposal
FP7-PEOPLE-IRG-2008
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Funding Scheme
MC-IRG - International Re-integration Grants (IRG)Coordinator
69978 Tel Aviv
Israel