Subdiffusive motion of phages through mucus*

In the mucus, a viscoelastic fluid that coats many organs, phages can dramatically increase their ability to infect bacteria. It is expected that understanding the mechanisms underlying the beneficiary role of mucus will provide insight into how phages interact with their bacterial hosts, infectious diseases and their cures in general. Possible mechanisms by which mucus could help phages find their hosts are: (1) by sticking to mucus, phages could increase the encounter rate with bacteria; (2) the motion of bacteria could influence the viscolestic properties of the mucus network and induce a mechanical response to attract phages. A key element is the observed sub-diffusive motion of the phages. This could be caused by fractional Brownian motion or a Continuous Time Random Walk. Numerically generated data sets are currently employed to investigate the number and length of data tracks needed to discern between origins of subdiffusion and set them apart from normal Fickian diffusion. Experiments performed using nanoparticles to mimic phages will be analyzed and compared with those previously published for phage diffusion through mucus*. Recommendations will be made for future measurements.
* Barr et al. Proc. Natl. Acad. Sci. 112,13675 (2015)