Javiera Leemhuis, 3rd year undergraduate in Physics at Warwick, was awarded a £1000 URSS bursary for a 10-weeks URSS project this summer in collaboration with me and Kela Lushi, looking at the behaviour of microswimmers in complex confinement. Well done Javiera!
We’re delighted to share the news that we have received travel funds from the EPSRC Network Plus Emergence and Physics Far From Equilibrium to kickstart a collaboration with the groups of Dr. Giorgio Volpe (UCL, UK), Dr. Nuno Araújo (U. Lisbon, Portugal) and Dr. Idan Tuval (IMEDEA-UIB, Spain). The project, which will start later this year, focusses on understanding and controlling transport properties of binary suspensions where microscopic active particles interact with passive ones (cargoes).
Close contact between microorganisms underpins fundamental interactions including infection, microbial grazing and fertilisation, but whether or not these interactions actually happen depends critically on the duration of contact. For swimming microorganisms, prolonged contact with an object should manifest as entrainment, and its extend hinge on the physics of escape from the entrained state. At present, neither the existence of entrainment nor the physical mechanisms determining its duration are well established. In our new paper, published in Physical Review Fluids, we combine experiments and theory to show that particle entrainment is indeed a generic feature of swimming microorganisms, and that its duration depends on an interplay between advection and diffusion. A Taylor-dispersion-type theory rationalises the dependence of the distribution of contact times on swimmers’ parameters, and predicts an optimal size for entrainment (~1μm), which we confirm experimentally. [ArXiv Preprint]