Transport of molecules via polymerization in chemical gradients

TL;DR

This paper introduces a novel method for directed molecular transport using active carriers and polymerization driven by chemical gradients, with analytical solutions for steady states and transit times.

Contribution

It develops an effective Fokker-Planck model for active-passive hybrid polymers and explores how active unit arrangements influence transport efficiency.

Findings

Derived steady-state distribution of polymer center of mass.

Calculated mean first passage times for target reaching.

Showed how active unit placement affects accumulation and motility.

Abstract

The transport of molecules for chemical reactions is critically important in various cellular biological processes. Despite thermal diffusion being prevalent in many biochemical processes, it is unreliable for any sort of directed transport or preferential accumulation of molecules. In this paper we propose a strategy for directed motion in which the molecules are transported by active carriers via polymerization. This transport is facilitated by chemical/activity gradients which generate an effective drift of the polymers. By marginalizing out the active degrees of freedom of the system, we obtain an effective Fokker-Planck equation for the Rouse modes of such active-passive hybrid polymers. In particular, we solve for the steady state distribution of the center of mass and its mean first passage time to reach an intended destination. We focus on how the arrangement of active units within the polymer affect its steady-state and dynamic behaviour and how they can be optimized to achieve high accumulation or rapid motility.