Cucurbit[7]uril-mediated aqueous self-assembly and supramolecular functionalisation of selenium nanoparticles

We report the first example of noncovalent binding interactions between cucurbit[7]uril (CB7, a synthetic molecular receptor) and a surface comprising a non-metallic elemental solid (selenium, Se). The interaction enabled the preparation of CB7-selenium nanocomposites with controllable morphologies via aqueous self-assembly. Colloidal Se nanomaterials have broad applications in human and animal health due to their excellent anti-oxidant, antimicrobial and chemotherapeutic properties. We demonstrate that chemical functionality can be readily introduced to the surface of selenium colloids functionalised with CB7, via host-guest complexation with guests of interest. In this instance, drug molecules were encapsulated within CB7 molecules at the selenium nanoparticle surface to produce functionalised CB7-Se NP nanoaggregates with enhanced antimicrobial and cytotoxic activity. Tuneable aggregation of non-metallic nanoparticles opens up new routes to functional hybrid nano-assemblies for safe and precise integration with biology. Meanwhile, our supramolecular approach is expected to facilitate rapid development of selenium-based nanomaterials and drug formulations via mix-and-match of guest molecules within the in-built molecular receptors.