title: Tracking single proteins in live cells using single-chain antibody fragment-fluorescent quantum dot affinity pair.
abstract: Quantum dots (QDs) are extremely bright fluorescent imaging probes that are particularly useful for tracking individual molecules in living cells. Here, we show how a two-component system composed of a high-affinity single-chain fragment antibody and its cognate hapten (fluorescein) can be utilized for tracking individual proteins in various cell types. The single-chain fragment antibody against fluorescein is genetically appended to the protein of interest, while the hapten fluorescein is attached to the end of the peptide that is used to coat the QDs. We describe (i) the method used to functionalize QDs with fluorescein peptides; (ii) the method used to control the stoichiometry of the hapten on the surface of the QD; and (iii) the technical details necessary to observe single molecules in living cells.
authors.affiliation: Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, California, USA.
authors.forename: Gopal
authors.initials: G
authors.lastname: Iyer
authors.forename: Xavier
authors.initials: X
authors.lastname: Michalet
authors.forename: Yun-Pei
authors.initials: YP
authors.lastname: Chang
authors.forename: Shimon
authors.initials: S
authors.lastname: Weiss
mesh_terms: D000818:Animals; D002477:Cells / Q000648:ultrastructure*; D019793:Fluorescein / Q000737:chemistry*; D006801:Humans; D011506:Proteins / Q000648:ultrastructure*; D045663:Quantum Dots; D057127:Single-Chain Antibodies; D013194:Staining and Labeling
chemical_list: D011506:Proteins; D057127:Single-Chain Antibodies; D019793:Fluorescein