Generation of biocompatible functional material by microfluidic manipulation of multiphase flows

The transport of complex fluids and multiphase flows such as colloidal suspensions, polymers or emulsions is a common feature of natural as well as industrial processes at all length scales. By exploiting laminar flow conditions typical of microfluidics, it is possible to achieve precise control over a range of flow characteristics. Moreover, by embedding electrodes and micro-heaters [Vigolo et al., Soft Matter, 6, 2010] into small lab-on-a-chip devices it is possible to induce external forces to manipulate single components, or to create gradients of concentration. For instance, biocompatible materials with mechanical properties gradients are of high importance in the study of tissue engineering and wound healing.

One of the expected outputs of this PhD project will be the generation of a new class of concentration gradient material, based on polymers and/or hydrogels, using complex fluids constrained in microfluidic geometries. We will create and maintain a steady-state in which a concentration gradient in a solution of monomers is balanced by the presence of a temperature gradient exploiting a phenomenon called thermophoresis [Vigolo et al., Langmuir, 26 (11): 7792–7801, 2010; Piazza et al., J. Phys. Condens. Matter, 20, 2008; Piazza, Soft Matter, 4, 2008]. A polymerization will then “freeze” the final configuration. By carefully choosing and controlling the components and the conditions under which the material is realized, we will manipulate its final properties. It will then be possible to grow cells (e.g. neurons, fibroblasts, cancer cells, etc.) on the functionalized material and study their response to a change in mechanical properties of the substrate.
It will also be required to perform a fundamental study on the thermophoretic behaviour of a suspension of functionalized anisotropic particles. Finally, we will study and model the fluid dynamic of the multiphase flow inside the microfluidic device.

Eligibility requirements: The project is intrinsically multi-disciplinary and thus it will require the PhD candidate to be highly motivated and interested in learning a wide range of scientifically challenging topics including microfluidics, physical chemistry, soft matter and biotechnology.