摘要 |
A nanoparticle having a detectable feature and whose diameter is less than 200 nm, and which is coated with multiple specific binding reactants such that the affinity constant of the nanoparticle towards an analyte exceeds that of free binding reactant towards the analyte and/or the association rate constant between the nanoparticle and the analyte exceeds the association rate constant between the free binding reactant and the analyte. Also disclosed is a homogenous assay based on a first group labeled with a luminescent energy donor nanoparticle and a second group labeled with an energy acceptor compound, where the donor has a long excited state lifetime, and the increase or decrease, respectively, in the energy transfer from the donor to the acceptor resulting from shortening or lengthening, respectively, of the distance between these groups, is measured.
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