Particles for detecting intracellular targets
Methods describing the use of nanoparticles modified with binding moieties are provided.
1. A method of determining the intracellular concentration of a target polynucleotide comprising the step of contacting the target polynucleotide with a nanoparticle under conditions that allow association of the target polynucleotide with the nanoparticle, said nanoparticle comprising a binding moiety polynucleotide specific for said target polynucleotide, said binding moiety polynucleotide labeled with a marker, wherein the association of the target polynucleotide and the nanoparticle results in detectable change in the marker, wherein the change in the detectable marker is proportional to the intracellular concentration of said target polynucleotide, said binding moiety polynucleotide is covalently attached to said nanoparticle and said marker is a label attached to a polynucleotide hybridized to said binding moiety polynucleotide, wherein association of said binding moiety polynucleotide with said target polynucleotide releases said hybridized polynucleotide and said marker is detectable after release.
2. The method of claim 1 wherein the binding moiety polynucleotide is DNA.
3. The method of claim 1 wherein the binding moiety polynucleotide is RNA.
4. The method of claim 1 wherein said label attached to said polynucleotide is quenched when said polynucleotide with said label is hybridized to said binding moiety polynucleotide.
5. The method of claim 1 wherein said binding moiety polynucleotide comprises a marker which is a detectable label, wherein said marker is detectable only when said binding moiety polynucleotide is associated with the target polynucleotide.
6. The method of claim 5 wherein said marker is quenched when said binding moiety polynucleotide is not associated with said target polynucleotide.
7. The method of claim 1 wherein said nanoparticle comprises a multiplicity of binding moiety polynucleotides.
8. The method of claim 7 wherein the binding moiety polynucleotides specifically associate with one target polynucleotide.
9. The method of claim 7 wherein the binding moiety polynucleotides specifically associate with more than one target polynucleotide.