Monovalent, reduced-size quantum dots for imaging receptors on living cells

Nat Methods. 2008 May;5(5):397-9. doi: 10.1038/nmeth.1206. Epub 2008 Apr 20.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Carcinoembryonic Antigen
  • Cell Survival
  • Cells / cytology*
  • Cells / metabolism*
  • Cells, Cultured
  • Electrophoresis, Agar Gel
  • Fluorescent Dyes
  • Image Processing, Computer-Assisted
  • Ligands
  • Nanotechnology / methods
  • Polyethylene Glycols
  • Quantum Dots*
  • Rats
  • Receptors, Cell Surface / analysis*
  • Receptors, Glutamate / metabolism
  • Staining and Labeling / methods
  • Streptavidin
  • Synapses / metabolism


  • Carcinoembryonic Antigen
  • Fluorescent Dyes
  • Ligands
  • Receptors, Cell Surface
  • Receptors, Glutamate
  • Polyethylene Glycols
  • Streptavidin