Monovalent, reduced-size quantum dots for imaging receptors on living cells.
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.
Howarth
Mark
M
Department of Chemistry, 77 Massachusetts Avenue, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA.
Liu
Wenhao
W
Puthenveetil
Sujiet
S
Zheng
Yi
Y
Marshall
Lisa F
LF
Schmidt
Michael M
MM
Wittrup
K Dane
KD
Bawendi
Moungi G
MG
Ting
Alice Y
AY
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
D002272:Carcinoembryonic Antigen; D005456:Fluorescent Dyes; D008024:Ligands; D011956:Receptors, Cell Surface; D017470:Receptors, Glutamate; D011092:Polyethylene Glycols; D019809:Streptavidin