Patent ID: 7259252

Claim:
Nanoparticles having at least two types of oligonucleotides attached thereto, the oligonucleotides being present on a surface of the nanoparticles at a surface density of at least 10 picomoles/cm 2 , at least one type of oligonucleotides comprises recognition oligonucleotides, the recognition oligonucleotides comprising a spacer portion and a recognition portion, the recognition portion having a sequence complementary to at least one portion of the sequence of a nucleic acid or another oligonucleotide; and a second type of oligonucleotides comprises diluent oligonucleotides, wherein the spacer portion of the recognition oligonucleotides and diluent oligonucleotides have functional groups that are attached to the nanoparticles.