Surface enhanced spectroscopy-active composite nanoparticles comprising Raman-active reporter molecules

1. A Surface Enhanced Spectroscopy-Active Composite Nanoparticle (SACH), comprising a nanoparticle core, a Raman-active reporter molecule associated with the nanoparticle core, and an SiO 2 encapsulant which encapsulates the nanoparticle core and the reporter molecule;

wherein the encapsulant comprises a reactive group chosen from —SH, —NH 2 , or —COO − .

2. The SACN of claim 1 , wherein the nanoparticle core has a spheroid, rod, disk, pyramid, cube, cylinder, nanohelix, nanospring, nanoring, arrow, teardrop, tetrapod, or prism shape.

3. The SACN of claim 2 , wherein the nanoparticle core is rod-shaped, and has a diameter of about 250 nm and a length of about 250 nm.

4. The SACN of claim 1 , wherein the nanoparticle core has internal surface area.

5. The SACN of claim 4 , wherein the nanoparticle core is porous.

6. The SACN of claim 1 , wherein the Raman-active reporter molecule comprises pyridine, triazine, pyrimidine, pyrrole, oxazole, imidazole, furan, cyanide, cyanamide, or acetylene, or a derivative thereof; or comprises a molecule having at least one reactive croup chosen from nitro, nitroso, —CCl 2 , —CCl 3 , isothiocyanate, or isocyanide.

7. The SACN of claim 1 , wherein the Raman-active reporter molecule comprises a molecule having a reactive group chosen from cyanide, SCN − , ClO 3 − , or HCO 2 − .

8. The SACN of claim 1 , wherein the Raman-active reporter molecule comprises a transition metal.

9. A Surface Enhanced Spectroscopy-Active Composite Nanoparticle (SACN) comprising:

a) a core/shell nanoparticle comprising a nanoparticle core covered with a shell, wherein the core and the shell may comprise the same or different materials;

b) at least one Raman-active reporter molecule associated with said core/shell nanoparticle; and

c) an SiO 2 encapsulant which encapsulates the core/shell nanoparticle and the at least one Raman-active reporter molecule.

10. The SACN of claim 9 , wherein said core/shell nanoparticle comprises an Au 2 S core/Au shell nanoparticle, an Ag core/Au shell nanoparticle, a silica core/Au shell nanoparticle, a silica core/Ag shell nanoparticle, an alumina core/Au shell nanoparticle, an alumina core/Ag shell nanoparticle, a TiO 2 core/Au shell nanoparticle, or a TiO 2 core/Ag shell nanoparticle.

11. A Surface Enhanced Spectroscopy-Active Composite Nanoparticle (SACN) comprising:

a core/shell nanoparticle comprising a nanoparticle core covered with a shell, wherein the core and the shell may comprise the same or different materials,

a Raman-active reporter molecule associated with the core/shell nanoparticle, and

an SiO 2 encapsulant which encapsulates the core/shell nanoparticle and the Raman-active reporter molecule, wherein the encapsulant comprises a reactive group chosen from —SH, —NH 2 , or —COO − .

12. The SACN of claim 11 , wherein said core/shell nanoparticle comprises an Au 2 S core/Au shell nanoparticle, an Ag core/Au shell nanoparticle, a silica core/Au shell nanoparticle, a silica core/Ag shell nanoparticle, an alumina core/Au shell nanoparticle, an alumina core/Ag shell nanoparticle, a TiO 2 core/Au shell nanoparticle, or a TiO 2 core/Ag shell nanoparticle.

13. The SACN of claim 11 , wherein the Raman-active reporter molecule comprises pyridine, triazine, pyrimidine, pyrrole, oxazole, imidazole, furan, cyanide, cyanamide, or acetylene, or a derivative thereof; or comprises a molecule having at least one reactive group chosen from nitro, nitroso, —CCl 2 , —CCl 3 , isothiocyanate, or isocyanide.

14. The SACN of claim 11 , wherein the Raman-active reporter molecule comprises a molecule having a functional group chosen from cyanide, SCN − , ClO 3 − , or HCO 2 − .

15. The SACN of claim 11 , wherein the Raman-active reporter molecule comprises a transition metal.