title: Monovalent, reduced-size quantum dots for imaging receptors on living cells.
abstract: We describe a method to generate monovalent quantum dots (QDs) using agarose gel electrophoresis. We passivated QDs with a carboxy-terminated polyethylene-glycol ligand, yielding particles with half the diameter of commercial QDs, which we conjugated to a single copy of a high-affinity targeting moiety (monovalent streptavidin or antibody to carcinoembryonic antigen) to label cell-surface proteins. The small size improved access of QD-labeled glutamate receptors to neuronal synapses, and monovalency prevented EphA3 tyrosine kinase activation.
authors.affiliation: Department of Chemistry, 77 Massachusetts Avenue, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Howarth
authors.forename: Wenhao
authors.initials: W
authors.lastname: Liu
authors.forename: Sujiet
authors.initials: S
authors.lastname: Puthenveetil
authors.forename: Yi
authors.initials: Y
authors.lastname: Zheng
authors.forename: Lisa F
authors.initials: LF
authors.lastname: Marshall
authors.forename: Michael M
authors.initials: MM
authors.lastname: Schmidt
authors.forename: K Dane
authors.initials: KD
authors.lastname: Wittrup
authors.forename: Moungi G
authors.initials: MG
authors.lastname: Bawendi
authors.forename: Alice Y
authors.initials: AY
authors.lastname: Ting
mesh_terms: D000818:Animals; D002272:Carcinoembryonic Antigen; D002470:Cell Survival; D002477:Cells / Q000166:cytology* / Q000378:metabolism*; D002478:Cells, Cultured; D004587:Electrophoresis, Agar Gel; D005456:Fluorescent Dyes; D007091:Image Processing, Computer-Assisted; D008024:Ligands; D036103:Nanotechnology / Q000379:methods; D011092:Polyethylene Glycols; D045663:Quantum Dots; D051381:Rats; D011956:Receptors, Cell Surface / Q000032:analysis*; D017470:Receptors, Glutamate / Q000378:metabolism; D013194:Staining and Labeling / Q000379:methods; D019809:Streptavidin; D013569:Synapses / Q000378:metabolism
chemical_list: D002272:Carcinoembryonic Antigen; D005456:Fluorescent Dyes; D008024:Ligands; D011956:Receptors, Cell Surface; D017470:Receptors, Glutamate; D011092:Polyethylene Glycols; D019809:Streptavidin