Researchers led by Aloke Kumar at the Oak Ridge National Laboratory, USA, and Thomas Thundat at the University of Alberta, Canada, used a porous microfluidic device to study biofilm streamer development in porous media.
The microfluidic method allowed close observation and measurement of streamers developing between microposts embedded in a microchannel. The formation of streamers in the device forming a web connecting different microposts was strongly influenced by the hydrodynamics.
Higher flow rates resulted in thicker structures and higher numbers of streamers as they grew much faster. At very high flow rate, their formation was only transient as they were destabilized after forming. The fluid flow seems to be the cause of both the formation and destabilization of the streamers. Interestingly, streamers formed parallel to the flow direction in regions of high flow rate and transverse to it in regions of low flow rate. In contrast with a previous report, they observe streamers distributed throughout the height of the device, attributed to secondary flow in the corners of the device. Carrying out numerical simulations, Kumar and Thundat et al. showed that secondary flows in the z-direction do not have a large role to play.
Development of streamers is complex and a great deal of detail remains to be elucidated, however, this Lab on a Chip article indicates that streamer formation might lead to mature microbial structures under the right conditions.
This HOT article is free to access* on our site for the next four weeks, so why not download the paper here:
A web of streamers: biofilm formation in a porous microfluidic device
Amin Valiei , Aloke Kumar , Partha P. Mukherjee , Yang Liu and Thomas Thundat
DOI: 10.1039/C2LC40815E
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