CO$_2$-driven diffusiophoresis for removal of bacteria

TL;DR

This study explores how CO₂-driven diffusiophoresis can move bacteria in a controlled manner, providing insights into its potential for cleaning and anti-biofouling applications.

Contribution

It combines experiments and modeling to understand the scales of CO₂-driven diffusiophoresis and demonstrates its effectiveness across different bacterial types and shapes.

Findings

Bacteria can be directed by CO₂ diffusiophoresis regardless of shape or Gram stain.

The characteristic length and time scales depend on system dimensions and CO₂ diffusivity.

Potential applications include cleaning systems and anti-biofouling surfaces.

Abstract

We investigate CO$_2$-driven diffusiophoresis of colloidal particles and bacterial cells in a Hele-Shaw geometry. Combining experiments and a model, we understand the characteristic length and time scales of CO$_2$-driven diffusiophoresis in relation to system dimensions and CO$_2$ diffusivity. Directional migration of wild-type V. cholerae and a mutant lacking flagella, as well as S. aureus and P. aeruginosa, near a dissolving CO$_2$ source shows that diffusiophoresis of bacteria is achieved independent of cell shape and Gram stain. Long-time experiments suggest possible applications for bacterial diffusiophoresis to cleaning systems or anti-biofouling surfaces.