Patent ID: 8198099

Claim:
A method for detection of at least presence or quantity of an analyte, said method comprising: (a) contacting (i) at least one luminescent nanoparticle having a surface and comprising an essentially spherical, semiconductor nanocrystal, (ii) one or more quencher-ligand molecules which may be noncovalently associated on said surface, thereby modulating a luminescent signal of said nanoparticle, or may be removed from said surface, thereby modulating a luminescent signal of said nanoparticle, wherein said molecule(s) are comprised of quencher and ligand moieties, (iii) one or more receptors which may bind at least one quencher-ligand molecule, and (iv) a solution which might contain an analyte, wherein binding of receptor and ligand removes quencher molecule(s) from said luminescent nanoparticle's surface; (b) measuring whether or not there is a detectable change in luminescent signal; and (c) correlating the change in luminescent signal with detection of at least presence or quantity of the analyte.