Seminar über aktuelle Fragen zur Dynamik komplexer Fluide: Chemotaxis of cargo-carrying self-propelled particles
Seminar über aktuelle Fragen zur Dynamik komplexer Fluide
- Date: Dec 18, 2020
- Time: 10:15 AM - 11:15 AM (Local Time Germany)
- Speaker: Hidde Vuijk
- Leibniz-Institut für Polymerforschung, Dresden
- Location: Max-Planck-Institut für Dynamik und Selbstorganisation (MPIDS)
- Room: Video conference at www.zoom.us, Meeting ID: 980 3913 9623, Passcode: 050762
- Host: MPIDS/DCF
- Contact: knut.heidemann@ds.mpg.de
Active particles with their characteristic feature of self-propulsion are regarded as the simplest models for motility in living systems. The accumulation of active particles in low activity regions has led to the general belief that chemotaxis cannot arise from a direct coupling between fuel concentration and faster motion and requires additional features such as a minimal ability to process information and to control motion.
We show that self-propelled particles display chemotaxis and move into regions of higher activity, if the particles perform work on passive objects, or cargo, to which they are bound. The origin of this cooperative chemotaxis is the exploration of the activity gradient by the active particle when bound to a load, resulting in an average excess force on the load in the direction of higher activity. Using a new theoretical model, we capture the most relevant features of these active-passive dimers, and in particular we predict the crossover between anti-chemotactic and chemotactic behavior. Moreover we show that merely connecting active particles to chains is sufficient to obtain the crossover from anti-chemotaxis to chemotaxis with increasing chain length. Such an active complex is capable of moving up a gradient of activity such as provided by a gradient of fuel and to accumulate where the fuel concentration is at its maximum. The observed transition is of significance to proto-forms of life enabling them to locate a source of nutrients even in the absence of any supporting sensomotoric apparatus.
We show that self-propelled particles display chemotaxis and move into regions of higher activity, if the particles perform work on passive objects, or cargo, to which they are bound. The origin of this cooperative chemotaxis is the exploration of the activity gradient by the active particle when bound to a load, resulting in an average excess force on the load in the direction of higher activity. Using a new theoretical model, we capture the most relevant features of these active-passive dimers, and in particular we predict the crossover between anti-chemotactic and chemotactic behavior. Moreover we show that merely connecting active particles to chains is sufficient to obtain the crossover from anti-chemotaxis to chemotaxis with increasing chain length. Such an active complex is capable of moving up a gradient of activity such as provided by a gradient of fuel and to accumulate where the fuel concentration is at its maximum. The observed transition is of significance to proto-forms of life enabling them to locate a source of nutrients even in the absence of any supporting sensomotoric apparatus.