Infuence of Swimming Strategies on Microorganisms Separation and Control

I. BERDAKIN; L. VENKEN; Y. JEYARAM; V. V. MOSHCHALKOV; A. V. SILHANEK; J. VANDERLEYDEN; V.I. MARCONI; C.A. CONDAT

Strasburgo

Encuentro; Cell Physics Days; 2011

Institut de Science et d'Ingénierie Supramoléculaires

It has been shown that a nanoliter chamber separated by amembrane of asymmetric obstacles can lead to inhomogeneousdistribution of self-propelled microorganisms. Although it is wellestablished that this rectification effect arises from the interactionbetween swimmers and the non-centrosymmetric pillars, here weshow that its efficiency is strongly dependent on the detaileddynamics of the individual microorganism. In particular, we showthat for run-and-tumble dynamics, the distribution of run lengthsand the partial preservation of run orientation memory through atumble are important factors when computing the efficiency. Thesetheoretical results are compared with measurements done in theextreme case of no-tumble swimmers, such as human spermatozoa.In addition, we optimized the geometrical dimensions of theasymmetric membrane, for a given swimmer, in order to maximizethe separation efficiency. We also show that the use of a series ofequivalent confining structures leads to exponentially increasingrectification.