title: Avidin: a natural bridge for quantum dot-antibody conjugates.
abstract: 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.
authors.affiliation: 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
authors.forename: Ellen R
authors.initials: ER
authors.lastname: Goldman
authors.forename: Eric D
authors.initials: ED
authors.lastname: Balighian
authors.forename: Hedi
authors.initials: H
authors.lastname: Mattoussi
authors.forename: M Kenneth
authors.initials: MK
authors.lastname: Kuno
authors.forename: J Matthew
authors.initials: JM
authors.lastname: Mauro
authors.forename: Phan T
authors.initials: PT
authors.lastname: Tran
authors.forename: George P
authors.initials: GP
authors.lastname: Anderson
mesh_terms: 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
chemical_list: 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