Orthogonal control over systems represents an advantage over mono-functional switches as both the nature and order of distinctly different stimuli manifest themselves in a wide array of outcomes. Host-guest complexes with multiple, simultaneously bound guests offer unique opportunities to address a set of 'on' and 'off' states accessible on demand. Here we report cucurbit[8]uril-mediated host-guest heteroternary complexes constructed with both redoxand light-responsive guests in a single, supramolecular entity. The complex responds to orthogonal stimuli in a controlled, reversible manner generating a multifunctional switch between a 'closed' heteroternary complex, a redox-driven 'closed' homoternary complex and a photo-driven 'open' uncomplexed state. We exploit both photochemical and electrochemical control over the supramolecular coding system and its surface wettability to demonstrate the system's complexity, which could be readily visualized on a macroscopic level, thus offering new opportunities in the construction of memory devices.

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The synthesis of a supramolecular double hydrophilic block copolymer (DHBC) held together by cucurbit[8]uril (CB[8]) ternary complexation and its subsequent self-assembly into micelles is described. This system is responsive to multiple external triggers including temperature, pH and the addition of a competitive guest. The supramolecular block copolymer assembly consists of poly(N-isopropylacrylamide) (PNIPAAm) as a thermoresponsive block and poly(dimethylaminoethylmethacrylate) (PDMAEMA) as a pH-responsive block. Moreover, encapsulation and controlled drug release was demonstrated with this system using the chemotherapeutic drug doxorubicin (DOX). This triple stimuli-responsive DHBC micelle system represents an evolution over conventional double stimuli-responsive covalent diblock copolymer systems and displayed a significant reduction in the viability of HeLa cells upon triggered release of DOX from the supramolecular micellar nanocontainers.

We demonstrate a supramolecular peptide separation approach by the selective immobilization of peptides bearing an N-terminal tryptophan onto a CB[8]-modified gold substrate, followed by electrochemical release. The CB[8]-stabilized heteroternary complexes were characterized by (1)H NMR, ESI-MS, UV/vis, and fluorescence spectroscopy and cyclic voltammetry. Micropatterned CB[8]-modified gold substrates were found to trap only the recognizable N-tryptophan-containing peptides from a peptide mixture that could be visualized as green peptide arrays under fluorescence microscopy. Subsequently, the bound peptides were released from the modified substrates by the controlled single-electron reduction of viologen. The fully reversible trap-and-release process was repeated for 13 cycles, and the cumulative release profile of the dye-peptide conjugate was monitored by fluorescence spectroscopy, indicating that no degradation occurred.