%0 Journal Article %J Angew Chem Int Ed Engl %D 2018 %T A Ligand System for the Flexible Functionalization of Quantum Dots via Click Chemistry %A Chen, Yue %A Cordero, Jose M %A Wang, Hua %A Franke, Daniel %A Achorn, Odin B %A Freyria, Francesca S %A Coropceanu, Igor %A Wei, He %A Chen, Ou %A Mooney, David J %A Bawendi, Moungi G %X We present a novel ligand, 5-norbornene-2-nonanoic acid, which can be directly added during established quantum dot (QD) syntheses in organic solvents to generate "clickable" QDs at a few hundred nmol scale. This ligand has a carboxyl group at one terminus to bind to the surface of QDs and a norbornene group at the opposite end that enables straightforward phase transfer of QDs into aqueous solutions via efficient norbornene/tetrazine click chemistry. Our ligand system removes the traditional ligand-exchange step and can produce water-soluble QDs with a high quantum yield and a small hydrodynamic diameter of approximately 12 nm at an order of magnitude higher scale than previous methods. We demonstrate the effectiveness of our approach by incubating azido-functionalized CdSe/CdS QDs with 4T1 cancer cells that are metabolically labeled with a dibenzocyclooctyne-bearing unnatural sugar. The QDs exhibit high targeting efficiency and minimal nonspecific binding. %B Angew Chem Int Ed Engl %V 57 %P 4652-4656 %8 2018 Apr 16 %G eng %N 17 %1 http://www.ncbi.nlm.nih.gov/pubmed/29479792?dopt=Abstract %R 10.1002/anie.201801113