Avidin: a natural bridge for quantum dot-antibody conjugates.
We describe the preparation and characterization of bioinorganic conjugates in which luminescent semiconductor CdSe-ZnS core-shell nanocrystal quantum dots (QDs) were coupled to antibodies through the use of an avidin bridge adsorbed to the nanocrystal surface via electrostatic self-assembly. Avidin, a highly positively charged protein, was found to adsorb tightly to QDs modified with dihydrolipoic acid, which gives their surface a homogeneous negative charge. QD conjugation to biotinylated antibodies subsequently is readily achieved. Fluoroimmunoassays utilizing these antibody conjugated QDs were successful in the detection of protein toxins (staphylococcal enterotoxin B, cholera toxin). QD-antibody conjugates formed in such a facile manner permit their use as a common immuno reagent, and in the development of multianalyte detection.
Goldman
Ellen R
ER
U.S. Naval Research Laboratory, Center for Bio/Molecular Science and Engineering and Division of Optical Sciences, Washington, D.C. 20375, USA. erg@cbmse.nrl.navv.mil
Balighian
Eric D
ED
Mattoussi
Hedi
H
Kuno
M Kenneth
MK
Mauro
J Matthew
JM
Tran
Phan T
PT
Anderson
George P
GP
D000906:Antibodies / Q000737:chemistry*; D000942:Antigens, Bacterial / Q000032:analysis; D001360:Avidin / Q000737:chemistry*; D001710:Biotin / Q000737:chemistry; D002104:Cadmium / Q000737:chemistry; D002352:Carrier Proteins / Q000737:chemistry; D002772:Cholera Toxin / Q000032:analysis; D004768:Enterotoxins / Q000032:analysis; D005470:Fluorometry / Q000379:methods; D007118:Immunoassay / Q000379:methods; D018796:Immunoconjugates / Q000737:chemistry*; D016350:Leucine Zippers; D058619:Maltose-Binding Proteins; D017434:Protein Structure, Tertiary; D012666:Semiconductors; D013440:Sulfides / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry
D000906:Antibodies; D000942:Antigens, Bacterial; D002352:Carrier Proteins; D004768:Enterotoxins; D018796:Immunoconjugates; D058619:Maltose-Binding Proteins; D013440:Sulfides; D017967:Zinc Compounds; D002104:Cadmium; D001360:Avidin; C031818:enterotoxin B, staphylococcal; D001710:Biotin; D002772:Cholera Toxin; C031238:zinc sulfide