title: Multilabeling biomolecules at a single site. 1. Synthesis and characterization of a dendritic label for electrochemiluminescence assays.
abstract: Ultrasensitive bioanalytical assays are of great value for early detection of human diseases and pathogens. The sensitivities of immunoassays and DNA probing can be enhanced by multilabeling the biorecognition partner used for affinity-based assays. However, the bioreactivity of biomolecules is affected by a high degree of multilabeling at multiple functional sites. It is proposed that dendritic scaffoldings be used to link multiple signal-generating units to a single site with potentially minimum impact on the bioaffinity. A prototype label, a zeroth-generation dendron, bearing three [Ru(bpy)(3)](2+) units for electrochemiluminescence (ECL) assays was synthesized and characterized preliminarily by spectroscopic, electrochemical, and ECL methods. No evidence of interaction between the neighboring [Ru(bpy)(3)](2+) units in the label molecule was found from these characterizations. Both the photoluminescence and ECL of the prototype label have features very similar to those of mononuclear [Ru(bpy)(3)](2+) compounds. Labeling a model protein with a triad of [Ru(bpy)(3)](2+) at one NH(2) position was demonstrated. The results reported here provide support to applying the proposed multilabeling strategy to affinity-based bioanalytical assays.
authors.affiliation: Institute for National Measurement Standards, National Research Council of Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6, Canada. ming.zhou@nrc-cnrc.gc.ca
authors.forename: Ming
authors.initials: M
authors.lastname: Zhou
authors.forename: Jacques
authors.initials: J
authors.lastname: Roovers
authors.forename: Gilles P
authors.initials: GP
authors.lastname: Robertson
authors.forename: Chander P
authors.initials: CP
authors.lastname: Grover
mesh_terms: D000818:Animals; D002417:Cattle; D004563:Electrochemistry; D007553:Isotope Labeling / Q000379:methods*; D008163:Luminescent Measurements; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000032:analysis / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D009942:Organometallic Compounds; C415768:tris(2,2'-bipyridyl)ruthenium(II); D012710:Serum Albumin, Bovine