Dynamic density shaping of light driven bacteria

TL;DR

This paper demonstrates a method to control and reconfigure bacterial density patterns using light, enabling complex shape formation and grayscale image reproduction through feedback control.

Contribution

It introduces a novel approach to manipulate bacterial populations with light, including modeling non-local effects and implementing feedback control for precise patterning.

Findings

Complex and reconfigurable bacterial density patterns achieved.

Effective mitigation of non-local effects in light response.

Successful reproduction of grayscale density images.

Abstract

Many motile microorganisms react to environmental light cues with a variety of motility responses guiding cells towards better conditions for survival and growth. The use of spatial light modulators could help to elucidate the mechanisms of photo-movements while, at the same time, providing an efficient strategy to achieve spatial and temporal control of cell concentration. Here we demonstrate that millions of bacteria, genetically modified to swim smoothly with a light controllable speed, can be arranged into complex and reconfigurable density patterns using a digital light projector. We show that a homogeneous sea of freely swimming bacteria can be made to morph between complex shapes. We model non-local effects arising from memory in light response and show how these can be mitigated by a feedback control strategy resulting in the detailed reproduction of grayscale density images.