Pilot Project from Network Plus

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).

Microparticle entrainment à la Taylor


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]

Dr. Matteo Contino

Matteo had a great Ph.D. viva yesterday, and is finally Dr. Contino! (Ok, he still has some minor corrections… but still). He will now move to Oxford to work for a spin-off of the University of Oxford.

Well done Matteo and good luck for the future!

Visit to U. Melbourne!

It’s always nice to start the week with some good news. Today I just heard from my good friend Douglas Brumley that the travel grant application we submitted was successful!! This will allow me & rest of the family to move to Melbourne for 6-8 weeks to work with Doug and an amazing array of other people at U. Melbourne. We still need to work out the details but I’m already very excited!!

Chlamydomonas Phototaxis: turn and what?

Phototaxis is one of the main categories of motility regulation by microorganisms. Arguably, it is particularly important for motile micro algae, due to their photosynthetic activity. One of the organisms where it has been studied the most is our beloved micro alga Chlamydomonas reinhardtii. Currently, we have a pretty good idea of the mechanism leading the cells to reorient towards/away from the light, but not much is known about what happens after they’ve reoriented…. In our recent paper we start looking into this, with surprising results.