Investigation of dynamics and hydrodynamic coupling of swimming bacteria

Swimming in fluidic environments is essential for life: microorganisms swim to carry out processes like searching for food or forming aggregates. Their movement takes place in the Low Reynolds number regime, in which long range hydrodynamic effects are relevant for coupling between swimmers. Since microswimmers are hardly ever isolated, the investigation of interactions due to hydrodynamic coupling is a pertinent point still to be addressed.

In this Master Thesis work we are going to explore the dynamical behavior of live bacteria due to interactions with the bounded environment (cell-surface), and with other swimming bacteria (cell-cell). Hence, bacteria will be placed in constrained scenarios, like mazes, to track and analyze their dynamical behavior when swimming. State-of-the-art photonic techniques will be used. Maze designs will be assembled using two-photon polymerization, a process based on the focusing of laser pulses into the desired volume of a photosensitive material, consequently inducing two-photon absorption and polymerization. The manipulation and location of bacteria and/or nutrients will be done with holographic optical tweezers (HOT), an exceptionally suitable tool to arrange the position of the micro-sized objects with high precision. To evaluate the results, we will use theory of nonlinear dynamical systems, as well as statistical methods.

This Master thesis is organized thematically into the ongoing research of the "optical tweezers" team of Nonlinear Photonics group. In such team, Bachelor, Master, PhD students and Post-docs discuss frequently about results, problems, scientific articles and new ideas in an enjoyable atmosphere.

We are looking for committed students interested in biophysical applications of Photonics and eager to work on actual research activities.

Contact person: Interested? Do not hesitate to contact Dr. Neus Oliver to know more about the topic, the labs, and the proposed thesis within the framework of optical micromanipulation.