Supramolecular Click Chemistry for Surface Modification of Quantum Dots Mediated by Cucurbit[7]uril
Katie McGuire, Suhang He, J. Alastair Gracie, Charlotte Bryson, Dazhong Zheng, Alasdair W. Clark, Jesko Koehnke, David J. France, Werner M. Nau, Tung‐Chun Lee, William J. Peveler
Abstract
High Resolution Image Download MS PowerPoint Slide Cucurbiturils (CBs), barrel-shaped macrocyclic molecules, are capable of self-assembling at the surface of nanomaterials in their native state, via their carbonyl-ringed portals. However, the symmetrical two-portal structure typically leads to aggregated nanomaterials. We demonstrate that fluorescent quantum dot (QD) aggregates linked with CBs can be broken-up, retaining CBs adsorbed at their surface, via inclusion of guests in the CB cavity. Simultaneously, the QD surface is modified by a functional tail on the guest, thus the high affinity host–guest binding (log K a > 9) enables a non-covalent, click-like modification of the nanoparticles in aqueous solution. We achieved excellent modification efficiency in several functional QD conjugates as protein labels. Inclusion of weaker-binding guests (log K a = 4–6) enables subsequent displacement with stronger binders, realising modular switchable surface chemistries. Our general “hook-and-eye” approach to host–guest chemistry at nanomaterial interfaces will lead to divergent routes for nano-architectures with rich functionalities for theranostics and photonics in aqueous systems.