Highly permeable artificial water channels that can self-assemble into two-dimensional arrays

Bioinspired artificial water channels aim to combine the high permeability and selectivity of biological aquaporin (AQP) water channels with chemical stability. Here, we carefully characterized a class of artificial water channels, peptide-appended pillar[5]arenes (PAPs). The average single-channel osmotic water permeability for PAPs is 1.0(+/- 0.3) x 10(-14) cm(3)/s or 3.5(+/- 1.0) x 10(8) water molecules per s, which is in the range of AQPs (3.4 similar to 40.3 x 10(8) water molecules per s) and their current synthetic analogs, carbon nanotubes (CNTs, 9.0 x 10(8) water molecules per s). This permeability is an order of magnitude higher than first-generation artificial water channels (20 to similar to 10(7) water molecules per s). Furthermore, within lipid bilayers, PAP channels can self-assemble into 2D arrays. Relevant to permeable membrane design, the pore density of PAP channel arrays (similar to 2.6 x 10(5) pores per mu m(2)) is two orders of magnitude higher than that of CNT membranes (0.1 similar to 2.5 x 10(3) pores per mu m(2)). PAP channels thus combine the advantages of biological channels and CNTs and improve upon them through their relatively simple synthesis, chemical stability, and propensity to form arrays.