Tunable design of carbon nanotube porins

Biological aquaporins, being too unstable and costly for practical applications, have inspired the design of various artificial water channels. These channels leverage similar nonconfined, narrow nanopores to separate substances in industrial processes. Their insertion into biological membranes can also aid drug transport. Exhibiting high permeability and selectivity, carbon nanotube porins (CNTPs) have shown exceptional promise as artificial water channels, but the effects of their early fabrication stages on filtration parameters remain poorly understood.

CNTP fabrication involves coating carbon nanotubes (CNTs) with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), which produces short DOPC-coated CNTs that are then inserted into DOPC-based lipid membranes, forming functional CNTPs.

Most simulation studies, however, treat CNTs as bare while studying insertion. By conducting molecular dynamics simulations on the self-assembly of DOPC-coated CNTs, Li et al. sought to uncover the molecular-scale “black box” of CNTP fabrication.

“We expect this will help shift CNTP development from largely empirical trial-and-error toward a more predictive, mechanism-driven strategy,” said author Chongqin Zhu.

Following the simulations, free energy calculations on the self-assembly of DOPC-coated CNTs revealed two stable energy modes — partially wrapped and fully wrapped states — corresponding to the extent of DOPC coating on the CNT surface. Their relative stability is tunable by DOPC cluster size and CNT dimensions, enabling predictions on assembly outcomes.

The authors next aim to connect these thermodynamic end-states to the membrane insertion stage, thereby completing the understanding of CNTP design.

“Beyond CNTPs, our conceptual framework may also inform broader studies of self-assembly kinetics at bio-nano interfaces, where soft matter components organize on nanostructured surfaces,” said Zhu. “Ultimately, we hope these insights will accelerate progress toward scalable, tunable biomimetic channels for both separation and delivery applications.”

Source: “Cluster-mediated assembly of lipid-coated carbon nanotubes for biomimetic water channels,” by Chenruyuan Li, Qi Bai, Xiaojiao Li, Shixuan Wang, Shihan Luan, Muyang Jiang, Zixuan Wang, and Chongqin Zhu, Journal of Chemical Physics (2026). The article can be accessed at https://doi.org/10.1063/5.0313955 .