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DTSTART:20190331T030000
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DTSTART:20191027T020000
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DTSTAMP:20260405T192612Z
UID:5d764b5b80b6b000041280@ist.ac.at
DTSTART:20190917T100000
DTEND:20190917T110000
DESCRIPTION:Speaker: Andreas Zöttl\nhosted by Michael Sixt\nAbstract: Many
  cells in the human body have to move through dense complex fluids such as
  various cells in the extracellular matrix or bacteria in mucus. While the
  motion of swimming bacteria in simple Newtonian fluids can be well quanti
 fied using continuum low Reynolds number hydrodynamics\, the presence of s
 upramolecular elements such as biopolymers leads to a much more complex be
 havior. Although the presence of polymers generally lowers particle mobili
 ty\, surprisingly\, several experiments have shown that bacterial speeds i
 ncrease in polymeric fluids\, but there is no clear understanding why. We 
 perform extensive coarse-grained MPCD simulations of a bacterium swimming 
 in explicitly modeled solutions of supramolecular model polymers of differ
 ent lengths\, stiffness and densities [1]. We observe an increase of up to
  60% in swimming speed with polymer density and show that this is a conseq
 uence of a non-uniform distribution of polymers in the vicinity of the bac
 terium leading to an effective slip. However\, this alone cannot explain t
 he large speed-up\, but coupling to the chirality of the bacterial flagell
 um is essential. We also present results for swimming in crosslinked polym
 er networks where hydrodynamics is screened and the heterogeneous network 
 microstructure induce a diverse migration behavior. Our approach can be us
 ed to study other important transport processes in biological fluids\, suc
 h as sedimentation of differently shaped nano-and microparticles [2]\, whi
 ch are of relevance for drug delivery through mucus or motion of food part
 icles in the gut. Finally we suggest how our approach could be used to stu
 dy physical principles of the migration of deformable cells in fibrous net
 works such as the extracellular matrix.[1] A. Zttl and J. M. Yeomans\, Enh
 anced bacterial swimming speeds in macromolecular polymer solutions\, Natu
 re Physics 15\, 554 (2019).[2] A. Zttl and J. M. Yeomans\, Driven spheres\
 , ellipsoids and rods in explicitly modeled polymer solutions\, J. Phys.: 
 Condens. Matter 31\, 234001 (2019)
LOCATION:Mondi Seminar Room 2\, Central Building\, ISTA
ORGANIZER:astawick@ist.ac.at
SUMMARY:Andreas Zöttl: Hydrodynamic simulations of swimming cells in biolo
 gical fluids and networks
URL:https://talks-calendar.ista.ac.at/events/2149
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