PhD on Modeling of magnetically actuated microstructures in soft materials

We are looking for a PhD student for a four-year research project on the topic of numerical modeling of magnetically actuated microstructures as

sensors for characterizing local (bio)mechanical properties of soft (biological) materials. In this project you will develop a computational framework, using the finite element method, to characterize and predict complex material parameters from the time-dependent deformation of magnetic microstructures with external actuation, based on experimental data.

Job description
Local rheological properties are important in many biomechanical processes, such as extracellular matrix (ECM) remodeling during cancer metastasis, where the material is heterogeneous at the micrometer scale. However, measurements at this scale are not possible with traditional rheometers since these measure an integrated response of an entire millimeter scale sample. In this project, we will develop a numerical framework for using magnetic microstructures as local rheometers for soft materials. The microstructures are, for example, spherical or rod-shaped particles, or artificial cilia that are actuated with an external magnetic field to locally 'probe' the (bio)material. The first step is the development of an accurate physical model of the magnetic forces that act on the magnetic microstructure, coupled to the hydrodynamic problem, assuming non-Newtonian material behavior. State of the art FEM modeling will be used to generate high-fidelity data for a given magnetic actuation field and constitutive properties of the material to be probed. Model validation will be done using experiments on well-characterized model materials, e.g., hydrogels. The high-fidelity data will subsequently be used in a reduced order model, which is capable of quickly predicting the response of the magnetic microstructures as a function of the applied magnetic field. The reduced order model will then be used in an inverse problem, where we will obtain local rheological information about the material, given observations of the motion of the magnetic microstructures, and create a real-time, in-situ, 3D mapping of the rheological properties of the material. Finally, we will use the developed methodology to analyze experiments on challenging biomaterials such as mucus and extracellular matrix materials. The PhD position is in the Polymer Technology group, in collaboration with the Microsystems group.