Topological Doping of Charged Bottlebrush Polymers for Efficient Artificial Ion Channels

Despite the promise of bottlebrush polymers as tunable platforms for artificial ion channels, their development using densely charged variants is limited by a tendency to disrupt or repel lipid bilayers. Here, we introduce a doping strategy to construct efficient artificial ion channels from charged bottlebrush polymers. By incorporating neutral hydrophobic segments, we suppress the membrane-disruptive behavior of positively charged bottlebrush polymers and activate transport through nanopore formation. For negatively charged bottlebrush polymers, doping increases ion transport activity by enhancing hydrophobicity and membrane insertion. Interestingly, the channel efficiency of the doped negatively charged bottlebrush channels is strongly governed by the doping topology. The ion transport activity of radially doped architectures significantly outperforms that of axially doped counterparts. Radial doping spatially isolates functional groups to prevent activity-diminishing intramolecular hydrogen bonding, establishing shorter, more direct pathways that facilitate synergistic co-transport. This topological doping approach establishes a powerful paradigm for designing highly efficient channels from charged bottlebrush polymers with customized transport functionalities.