Surface enhanced spectroscopy-active composite nanoparticles
Metal nanoparticles associated with a spectroscopy-active (e.g., Raman-active) analyte and surrounded by an encapsulant are useful as sensitive optical tags detectable by surface-enhanced spectroscopy (e.g., surface-enhanced Raman spectroscopy).
1 . A collection of distinguishable particles, each particle comprising: a surface-enhanced spectroscopy (SES)-active metal nanoparticle, a spectroscopy-active analyte associated with said SES-active metal nanoparticle, and an encapsulant surrounding said SES-active metal nanoparticle and said spectroscopy-active analyte, wherein said particles have distinguishable SES spectra.
2 . The collection of claim 1 , wherein a plurality of said particles comprises a metal nanoparticle comprising a metal selected from the group consisting of Au, Ag, Cu, Na, Al, and Cr.
3 . The collection of claim 2 , wherein a plurality of said particles comprises a metal nanoparticle comprising Au.
4 . The collection of claim 2 , wherein a plurality of said particles comprises a metal nanoparticle comprising Ag.
5 . The collection of claim 1 , wherein a plurality of said particles comprises a metal nanoparticle having a diameter less than about 200 nm.
6 . The collection of claim 5 , wherein a plurality of said particles comprises a metal nanoparticle having a diameter between about 20 nm and about 200 nm.
7 . The collection of claim 6 , wherein a plurality of said particles comprises a metal nanoparticle having a diameter between about 40 nm and about 100 nm.
8 . The collection of claim 1 , wherein a plurality of said particles comprises an encapsulant having a thickness less than about 1 micron.
9 . The collection of claim 8 , wherein a plurality of said particles comprises an encapsulant having a thickness between about 1 nm and about 40 nm.
10 . The collection of claim 9 , wherein a plurality of said particles comprises an encapsulant having a thickness between about 5 nm and about 15 nm.
11 . The collection of claim 1 , wherein a plurality of said particles comprises a metal nanoparticle comprising an alloy of metals selected from the group consisting of Au, Ag, Cu, Na, Al, and Cr.
12 . The collection of claim 1 , wherein a plurality of said particles comprises a submonolayer coating of said spectroscopy-active analyte formed on said metal nanoparticle.
13 . The collection of claim 1 , wherein a plurality of said particles comprises a monolayer coating of said spectroscopy-active analyte formed on said metal nanoparticle.
14 . The collection of claim 1 , wherein a plurality of said particles comprises a multilayer coating of said spectroscopy-active analyte formed on said metal nanoparticle.
15 . The collection of claim 1 , wherein a plurality of said particles comprises an encapsulant comprising a material selected from the group consisting of glass, polymers, metals, metal oxides, and metal sulfides.
16 . The collection of claim 1 , wherein a plurality of said particles comprise an encapsulant comprising a plurality of materials selected from the group consisting of glass, polymers, metals, metal oxides and metal sulfides.
17 . The collection of claim 1 , wherein a plurality of said particles comprises an encapsulant comprising glass oxide (SiO x ).
18 . The collection of claim 1 , wherein a plurality of said particles comprises an encapsulant comprising TiO x .
19 . The collection of claim 1 , wherein said distinguishable spectra are obtained by a method selected from the group consisting of SERS, SERRS, SEHRRS and SEIRA.
20 . The collection of claim 1 , wherein a plurality of said particles comprises an spectroscopy-active analyte that is an aromatic analyte.
21 . The collection of claim 1 , wherein said particles encode information that is recorded or stored.
22 . The collection of claim 21 , wherein said information is stored in a location selected from the group consisting of a database, a computer file and a paper record.
23 . The collection of claim 1 , wherein said collection comprises at least about 20 distinguishable particles.
24 . A dispersion comprising a solvent and a plurality of particles, said particles comprising: a surface-enhanced spectroscopy (SES)-active metal nanoparticle, a spectroscopy-active analyte associated with said SES-active metal nanoparticle, and an encapsulant surrounding said SES-active metal nanoparticle and said spectroscopy-active analyte, wherein said spectroscopy-active analyte has a measurable SES spectrum.