Active motility and wetting cooperatively regulate liquid-liquid phase separation

Fuente: arXiv
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Autores principales: Yang, Dixi, Wang, Anheng, Wang, Chunming, Tanaka, Hajime, Yuan, Jiaxing
Formato: Preprint
Publicado: 2025
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author Yang, Dixi
Wang, Anheng
Wang, Chunming
Tanaka, Hajime
Yuan, Jiaxing
author_facet Yang, Dixi
Wang, Anheng
Wang, Chunming
Tanaka, Hajime
Yuan, Jiaxing
contents Liquid-liquid phase separation of aqueous two-phase system (ATPS) is fundamental across physical and biological sciences. While well understood for passive systems, how this process is regulated by active agents such as motile bacteria remains largely unexplored. By combining experiments on Pseudomonas aeruginosa in a prototypical dextran-polyethylene glycol ATPS with hydrodynamic simulations, we show that the interplay between bacterial activity and interfacial wetting gives rise to a robust sequence of nonequilibrium morphologies, including self-spinning droplets, elongated droplet chains, branched capillary-like clusters, and highly deformed droplets. We find that activity plays a dual role in coarsening kinetics: it suppresses coarsening through hydrodynamically driven, activity-induced droplet rotation, yet accelerates it when dextran is the minority phase, where wetting-mediated attraction governs bacterial aggregation. These findings reveal a generic physical mechanism through which motility and wetting cooperatively control phase-separation dynamics, offering new physical insight into activity-regulated LLPS and suggesting strategies for engineering ATPS morphology using active agents.
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id arxiv_https___arxiv_org_abs_2511_18077
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Active motility and wetting cooperatively regulate liquid-liquid phase separation
Yang, Dixi
Wang, Anheng
Wang, Chunming
Tanaka, Hajime
Yuan, Jiaxing
Soft Condensed Matter
Liquid-liquid phase separation of aqueous two-phase system (ATPS) is fundamental across physical and biological sciences. While well understood for passive systems, how this process is regulated by active agents such as motile bacteria remains largely unexplored. By combining experiments on Pseudomonas aeruginosa in a prototypical dextran-polyethylene glycol ATPS with hydrodynamic simulations, we show that the interplay between bacterial activity and interfacial wetting gives rise to a robust sequence of nonequilibrium morphologies, including self-spinning droplets, elongated droplet chains, branched capillary-like clusters, and highly deformed droplets. We find that activity plays a dual role in coarsening kinetics: it suppresses coarsening through hydrodynamically driven, activity-induced droplet rotation, yet accelerates it when dextran is the minority phase, where wetting-mediated attraction governs bacterial aggregation. These findings reveal a generic physical mechanism through which motility and wetting cooperatively control phase-separation dynamics, offering new physical insight into activity-regulated LLPS and suggesting strategies for engineering ATPS morphology using active agents.
title Active motility and wetting cooperatively regulate liquid-liquid phase separation
topic Soft Condensed Matter
url https://arxiv.org/abs/2511.18077