Patent ID: 7208587

Claim:
A nanoparticle conjugate for detecting an analyte comprising: (i) nanoparticles having oligonucleotides bound thereto, wherein the oligonucleotides are attached to the nanoparticles in an aging process comprising contacting the oligonudeotides with the nanoparticles in aqueous solution for a period of time suffiecient to allow some of the first oligonucleotides to bind to the nanoparticles; and contacting the first oligonucleotides and nanoparticles in an aqueous salt solution for an additional period of time sufficient to enable additional first oligonucleotides to bind to the nanoparticles; and (ii) oligonucleotide having bound thereto a specific binding complement of an analyte, the oligonucleotides having the specific binding complement bound thereto have a sequence that is complementary to at least a portion of the oligonucleotides bound to the nanoparticles and are bound, as a result of hybridization, to at least a portion of the oligonucleotides bound to the nanoparticles.