Photoresponsive glyco-nanostructures integrated from supramolecular metallocarbohydrates for the reversible capture and release of lectins

Abstract

The development of smart and controllable multivalent systems, which enable us to control interactions at the biological system–artificial material interface, is of great scientific and technological interest. In this work, we reported the construction of well-defined and photoreversible supramolecular glyco-nanostructures with switchable multivalent affinity, achieving the selective capture and release of proteins in response to light. Firstly, a new family of photoreversible supramolecular metallocarbohydrates containing precise metallacycles as cores was successfully prepared through the orthogonality of coordination-driven self-assembly and host–guest interactions between cucurbit[8]uril (CB[8]) and azobenzene. These metallocarbohydrates were found to further hierarchically self-assemble into well-defined glyco-vesicles or glyco-rods, depending on the molecular architectures of metallocarbohydrates. Interestingly, the resultant glyco-nanostructures exhibited photoresponsive behaviors under light irradiation at different wavelengths. Moreover, the high density of carbohydrate ligands on the glyco-nanostructures’ surface leads to high-affinity binding to lectins by virtue of the specific ligand–receptor interaction between carbohydrates and lectins. In the case of the galactose system investigated, the selective capture of peanut agglutinin (PNA) was demonstrated. More importantly, the glyco-assemblies were able to photoinduce fully reversible transition from high affinity to low affinity due to the inherent reversibility of host–guest interactions. The reversible transformation can effectively result in the light-controlled capture and release of proteins, which can be repeated for multiple cycles without obvious decay. Thus, these findings not only enrich the library of supramolecular metallocarbohydrates, but also provide a new avenue for the fabrication of smart supramolecular glyco-nanostructures, which have promising applications for the targeted and controllable delivery of therapeutic peptides and proteins.