Frequency-dependent Chemolocation and Chemotactic Target Selection

TL;DR

This paper introduces a novel frequency-dependent chemotaxis model where cells use chemical signaling to select targets, akin to echolocation, enhancing flexibility in biological and physical systems.

Contribution

It proposes a new time-dependent chemotaxis mechanism involving chemical signaling and frequency-based target selection, extending traditional static models.

Findings

Target selection depends on probe chemical release frequency.

Frequency influences the cell's ability to distinguish and move toward targets.

Chemical pinging offers flexible regulation of target choice.

Abstract

Chemotaxis is typically modeled in the context of cellular motion towards a static, exogenous source of chemoattractant. Here, we propose a time-dependent mechanism of chemotaxis in which a self-propelled particle ({\it e.g.}, a cell) releases a chemical that diffuses to fixed particles (targets) and signals the production of a second chemical by these targets. The particle then moves up concentration gradients of this second chemical, analogous to diffusive echolocation. When one target is present, we describe probe release strategies that optimize travel of the cell to the target. In the presence of multiple targets, the one selected by the cell depends on the strength and, interestingly, on the frequency of probe chemical release. Although involving an additional chemical signaling step, our chemical ``pinging'' hypothesis allows for greater flexibility in regulating target selection, as seen in a number of physical or biological realizations.