Great paper: a droplet #microfluidics assay to encapsulate single micron-sized algae to study long-term #behaviour.
https://elifesciences.org/articles/76519#fig4
by Bentley et al. gielenlab.com and @micromotility
A thread.
#Chlamydomonas (2 #cilia) and #Pyramimonas (8 cilia) #algae were encapsulated into droplets by #microfluidics and imaged at high speed to characterise gait switching dynamics and the effect of light.
The locomotion of single-cells is characterised by a trio of motility macrostates (run, stop, tumble) with distinct transition probabilities that could be quantified by long-term imaging.
The motility is light-switchable, which was known, but the long-term imaging of single cells in light and dark revealed a cellular #memory: the light-altered behavioural state persisted after light off.
The authors also developed and tested a novel droplet-fusion assay to expose single cells in a controlled manner to chemicals. This could be a very elegant way to e.g., dissect #signalling mechanisms in the cells by #pharmacology.
@jekely This is so cool- so many possibiities for screening. I am now super-envious of your micro-organisms Gaspar & @micromotility! Congrats beautiful work Kirsty & co!
@StearnsLab @Mill_lab @jekely
Thanks Tim! Great question! Yes there will always be some boundary effects, depending on whether it's a water-air interface or a solid boundary. In fact we show in the paper that the solid boundary is what tends to align the cell with the wall and makes it swim in circles in our set-up.
But in the end it depends on the question you're trying to answer... if you use a big enough droplet/trap then there's a good chance that behaviour will be largely unaffected. Secondly, consistency is key - so if you're looking at the effect on behaviour of some orthogonal parameter say light or chemicals, then as long as you keep the physical environment the same, it's a valid comparison!
@micromotility Cool science. Look forward to broader applications in other single-cell entities. 👍
@MingqingCai thanks very much for your interest! yes we hope this technology is useful for many different specimens!
@micromotility @Mill_lab @jekely Nice work! I’ve always worried about edge effects with microbes under the scope (next to bubbles, for example). @micromotility, do you see effects of the interface of the droplet with the surrounding medium being different re: behavior?