Active colloidal particles in emulsion droplets: A model system for the cytoplasm

Type of Work

Article

Date

3-2019

Journal Title

The European Physical Journal Special Topics

Journal ISSN

1951-6355

Journal Volume

227

Journal Issue

17

First Page

2413

Last Page

2424

DOI

10.1140/epjst/e2019-800026-y

Abstract

In living cells, molecular motors create activity that enhances the diffusion of particles throughout the cytoplasm, and not just ones attached to the motors. We demonstrate initial steps toward creating artificial cells that mimic this phenomenon. Our system consists of active, Pt-coated Janus particles and passive tracers confined to emulsion droplets. We track the motion of both the active particles and passive tracers in a hydrogen peroxide solution, which serves as the fuel to drive the motion. We first show that correcting for bulk translational and rotational motion of the droplets induced by bubble formation is necessary to accurately track the particles. After drift correction, we find that the active particles show enhanced diffusion in the interior of the droplets and are not captured by the droplet interface. At the particle and hydrogen peroxide concentrations we use, we observe little coupling between the active and passive particles. We discuss the possible reasons for lack of coupling and describe ways to improve the system to more effectively mimic cytoplasmic activity.

Hamilton Areas of Study

Physics

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