# Geometric control of bacterial surface accumulation

## TL;DR

This study investigates how complex surface geometries influence bacterial accumulation, demonstrating that concave boundary designs can significantly reduce bacterial surface concentration through experiments and simulations.

## Contribution

It provides new insights into the role of boundary curvature in bacterial accumulation, combining experimental and numerical approaches to inform surface design.

## Key findings

- Concave geometries reduce bacterial accumulation by over 50%.
- Boundary curvature significantly influences bacterial scattering and attachment.
- Experiments and simulations agree on the impact of surface shape.

## Abstract

Controlling and suppressing bacterial accumulation at solid surfaces is essential for preventing biofilm formation and biofouling. Whereas various chemical surface treatments are known to reduce cell accumulation and attachment, the role of complex surface geometries remains less well understood. Here, we report experiments and simulations that explore the effects of locally varying boundary curvature on the scattering and accumulation dynamics of swimming Escherichia coli bacteria in quasi-two-dimensional microfluidic channels. Our experimental and numerical results show that a concave periodic boundary geometry can decrease the average cell concentration at the boundary by more than 50% relative to a flat surface.