DescriptionBio-particles transported in viscous flows have a large range of dynamic behaviour, including morphological transitions, orientation dynamics or deformations. The characterization of such complex dynamics under well controlled flows is essential to understand the mechanics of microscopic biological particles but also the rheology of their suspensions. While generating regions of simple shear flow in microfluidic devices is relatively straightforward, generating straining flows in which the strain rate is maintained constant long enough to observe the evolution of objects’ morphology remains a technical hurdle. Here, we coupled an innovative approach based on optimised design of microfluidic converging–diverging channels coupled with a microscope-based tracking method to characterise the dynamic behaviour of individual bio-particles under homogeneous straining flow. The tracking algorithm, combining a motorised stage and a microscopy imaging system controlled by external signals, allows the transport of individual bio-particles over long-distances with accurate resolution on the image to be monitored. This experimental implementation of the numerically optimised microchannels clearly shows the ability of this approach to provide linear velocity streamwise gradients along the centreline of the device, allowing for extended consecutive regions of homogeneous elongation and compression. We followed the transport of three different bioparticles (DNA, actin filaments and protein aggregates) in channels with this design to highlight the ability of our approach for investigating dynamics of objects with a wide range of sizes, characteristics and behaviours of relevance in the biological world.
|14 Apr 2021
|14th Annual European Rheology Conference, AERC 2021
|Degree of Recognition