# Active Transport of Macrocycles into Micelles Using Molecular Pumps

## TL;DR

Scientists created artificial molecular pumps that move charged rings into micelles, mimicking natural transporters and enabling non-equilibrium storage of hydrophilic molecules.

## Contribution

Demonstration of active transport of macrocycles into micelles using artificial molecular pumps in aqueous conditions.

## Key findings

- Artificial molecular pumps can drive charged macrocycles into micelles against concentration gradients.
- Micelles remain stable after pumping, storing macrocycles at non-equilibrium concentrations.
- Pumping efficiency is only modestly reduced in micellar systems compared to nonmicellar ones.

## Abstract

During the past decade, researchers have designed and synthesised a variety of artificial molecular pumps capable of the active transport of macrocycles (rings) from free solution into mechanically interlocked states. In their ability to drive non‐equilibrium transport, these artificial molecular pumps imitate natural transmembrane transporters, which are widespread in living organisms. Despite this resemblance, ring‐threading molecular pumps have not previously been operated in aqueous supramolecular assemblies in imitation of their natural counterparts. Here, we demonstrate the active transport of charged macrocycles from aqueous solution into micellar assemblies of polymer chains, which remain stable after pumping has occurred. While micelles are used routinely to encapsulate and solubilise hydrophobic small molecules in aqueous solution, this report, by contrast, shows that artificial molecular pumps can harness external energy to drive hydrophilic molecules into micelles where they are stored at concentrations far from equilibrium.

Artificial molecular pumps attached to polymeric micelles were found capable of transporting charged macrocycles into the micelles. The pumps operate with only modestly reduced pumping efficiency as compared to nonmicellar counterparts, indicating that ring‐threading molecular pumps can transport charged solutes into supramolecular assemblies, akin to nature's transmembrane transporters which actively transport solutes into and out of cells.