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Cell membranes control mass, energy, and information flow to and from the cell. In the cell membrane a lipid bilayer serves as the barrier layer, with highly efficient molecular machines, membrane proteins, serving as the transport elements. In this way, highly specialized transport properties are achieved by these composite materials by segregating the matrix function from the transport function using different components. For example, cell membranes containing aquaporin proteins can transport ∼4 billion water molecules per second per aquaporin while rejecting all other molecules including salts, a feat unmatched by any synthetic system, while the impermeable lipid bilayer provides the barrier and matrix properties. True separation of functions between the matrix and the transport elements has been difficult to achieve in conventional solute separation synthetic membranes. In this study, we created membranes with distinct matrix and transport elements through designed coassembly of solvent-stable artificial (peptide-appended pillar[5]arene, PAP5) or natural (gramicidin A) model channels with block copolymers into lamellar multilayered membranes. Self-assembly of a lamellar structure from cross-linkable triblock copolymers was used as a scalable replacement for lipid bilayers, offering better stability and mechanical properties. By coassembly of channel molecules with block copolymers, we were able to synthesize nanofiltration membranes with sharp selectivity profiles as well as uncharged ion exchange membranes exhibiting ion selectivity. The developed method can be used for incorporation of different artificial and biological ion and water channels into synthetic polymer membranes. The strategy reported here could promote the construction of a range of channel-based membranes and sensors with desired properties, such as ion separations, stimuli responsiveness, and high sensitivity.

Supramolecular construction of multistimuli platform for drug delivery is a challenging task. In this work, a pH and GSH (glutathione) dual-responsive bola-type supramolecular amphiphile was successfully fabricated by the complexation between a water-soluble pillar[5]arene (WP5) and a bolaform naphthalimide guest (G) in water. The resulting bola-type amphiphile further self-assembled into supramolecular binary vesicles, which could be disassembled by low pH, a high-GSH-concentration environment, or both. Furthermore, the results of drug loading and releasing tests showed that doxorubicin (DOX), the hydrophobic anticancer drug, could be successfully encapsulated into the Stern region of the obtained supramolecular vesicles and generated the DOX-loaded vesicles with good drug-loading efficiency. Moreover, the obtained DOX-loaded vesicles displayed efficient and rapid DOX release at a simulated tumor microenvironment with low-pH or excess-GSH conditions or both. Significantly, cytotoxicity experiments revealed that the DOX-loaded supramolecular vesicles could obviously improve the anticancer efficiency of free DOX for tumor cells while remarkably reducing its side effects for normal cells. In vitro cellular uptake and subcellular localization assays further proved that these smart drug nanovehicles, entering cancer cells mainly via endocytosis, could cause excellent drug accumulation in cancer cells. The present study provides a successful example with which to rational design an effective bola-type stimuli-responsive supramolecular nanocarrier, which might have wide potential applications in the construction of various controlled drug-delivery systems.

The swelling-shrinking transition of hydrogels is crucial for their wide applications such as actuators and drug delivery. We hereby fabricated a smart hydrogel with ferrocene groups on pendant of polymer networks. While it was immersed in the water-soluble pillar[6]arene (WP6) aqueous solution, the hydrogel was dramatically swollen, which was an approximately 11-fold promotion in weight compared with that in pure water, due to the formation of the inclusion complexes between WP6 and ferrocene groups in the hydrogel. In particular, the well-swollen hydrogel exhibited good responsiveness to multistimuli including temperature, pH, redox, and competitive guests by tuning the dissociation/formation of WP6-ferrocene inclusion complexes or the strength of their charges. Meanwhile, potential application of such a smart hydrogel in pH-responsive drug release was demonstrated as well.