title: Interactions between redox complexes and semiconductor quantum dots coupled via a peptide bridge.
abstract: Colloidal quantum dots (QDs) have a large fraction of their atoms arrayed on their surfaces and are capped with bifunctional ligands, which make their photoluminescence highly sensitive to potential charge transfer to or from the surrounding environment. In this report, we used peptides as bridges between CdSe-ZnS QDs and metal complexes to promote charge transfer between the metal complexes and QDs. We found that quenching of the QD emission is highly dependent on the relative position of the oxidation levels of QDs and metal complex used; it also traces the number of metal complexes brought in close proximity of the nanocrystal surface. In addition, partial bleaching of the absorption was measured for the QD-metal complex assemblies. These proximity driven interactions were further used to construct sensing assemblies to detect proteolytic enzyme activity.
authors.affiliation: Center for Bio/Molecular Science and Engineering and Division of Optical Sciences, U.S. Naval Research Laboratory, Washington, DC 20375, USA.
authors.forename: Igor L
authors.initials: IL
authors.lastname: Medintz
authors.forename: Thomas
authors.initials: T
authors.lastname: Pons
authors.forename: Scott A
authors.initials: SA
authors.lastname: Trammell
authors.forename: Amy F
authors.initials: AF
authors.lastname: Grimes
authors.forename: Doug S
authors.initials: DS
authors.lastname: English
authors.forename: Juan B
authors.initials: JB
authors.lastname: Blanco-Canosa
authors.forename: Philip E
authors.initials: PE
authors.lastname: Dawson
authors.forename: Hedi
authors.initials: H
authors.lastname: Mattoussi
mesh_terms: D000042:Absorption; D019187:Cadmium Compounds / Q000737:chemistry; D004563:Electrochemistry; D004579:Electron Transport; D031541:Fluorescence Resonance Energy Transfer; D006639:Histidine; D008024:Ligands; D049449:Luminescence; D009942:Organometallic Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry; D012666:Semiconductors; D012697:Serine Endopeptidases / Q000378:metabolism; D013440:Sulfides / Q000737:chemistry; D013499:Surface Properties; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D008024:Ligands; D009942:Organometallic Compounds; D010455:Peptides; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; D006639:Histidine; C058667:cadmium selenide; D012697:Serine Endopeptidases; C031238:zinc sulfide