Active particles can self-propel by exploiting locally available energy resources. When powered by light, these resources can be distributed with high resolution allowing spatio-temporal modulation of motility. Here we show that the random walks of light-driven bacteria are rectified when they swim in a structured light field that is obtained by a simple geometric transformation of a previous system snapshot. The obtained currents achieve an optimal value that we establish by general theoretical arguments. This optical feedback is used to gather and confine bacteria in high-density and high-activity regions that can be dynamically relocated and reconfigured. Moving away from the boundaries of these optically confined states, the density decays to zero in a few tens of micrometers, exhibiting steep exponential tails that suppress cell escape and ensure long-term stability. Our method is general and scalable, providing a versatile tool to produce localized and tunable active baths for microengineering applications and systematic studies of non-equilibrium phenomena in active systems.

Rectification and confinement of photokinetic bacteria in an optical feedback loop / Massana-Cid, Helena; Maggi, Claudio; Frangipane, Giacomo; Di Leonardo, Roberto. - In: NATURE COMMUNICATIONS. - ISSN 2041-1723. - 13:1(2022), pp. 1-8. [10.1038/s41467-022-30201-1]

Rectification and confinement of photokinetic bacteria in an optical feedback loop

Massana-Cid, Helena;Maggi, Claudio;Frangipane, Giacomo;Di Leonardo, Roberto
2022

Abstract

Active particles can self-propel by exploiting locally available energy resources. When powered by light, these resources can be distributed with high resolution allowing spatio-temporal modulation of motility. Here we show that the random walks of light-driven bacteria are rectified when they swim in a structured light field that is obtained by a simple geometric transformation of a previous system snapshot. The obtained currents achieve an optimal value that we establish by general theoretical arguments. This optical feedback is used to gather and confine bacteria in high-density and high-activity regions that can be dynamically relocated and reconfigured. Moving away from the boundaries of these optically confined states, the density decays to zero in a few tens of micrometers, exhibiting steep exponential tails that suppress cell escape and ensure long-term stability. Our method is general and scalable, providing a versatile tool to produce localized and tunable active baths for microengineering applications and systematic studies of non-equilibrium phenomena in active systems.
2022
feedback; physical phenomena; swimming; bacteria; feedback sensory
01 Pubblicazione su rivista::01a Articolo in rivista
Rectification and confinement of photokinetic bacteria in an optical feedback loop / Massana-Cid, Helena; Maggi, Claudio; Frangipane, Giacomo; Di Leonardo, Roberto. - In: NATURE COMMUNICATIONS. - ISSN 2041-1723. - 13:1(2022), pp. 1-8. [10.1038/s41467-022-30201-1]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1651640
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