Metallic nanoparticles and methods for their preparation and use
View Patent ↗Provided herein are Raman active particles and methods for their preparation and use. The particles can include a SERS-active material that is at least partially encased within a spherical porous hollow casing. In some embodiments, this can be especially advantageous when employed for water analysis and/or being employed in combination with silica particles.
1. A method of preparing a Raman active particle, the method comprising:
providing a spherical polystyrene particle;
adsorbing a SERS-active material onto the surface of the spherical polystyrene particle by electrostatic adsorption to form a SERS-active nanoparticle;
coating the SERS-active nanoparticle with a dissolvable material to form a coated SERS-active nanoparticle;
processing the coated SERS-active nanoparticle with a silanizing component to form a mesoporous SiO 2 containing shell structure over at least a portion of the SERS-active nanoparticle; and
adding a solvent to dissolve and remove the dissolvable material to obtain a SERS-active nanoparticle within a porous SiO 2 hollow shell, thereby preparing a Raman active particle.
2. The method of claim 1 , wherein the dissolvable material comprises polypyrrolidone and the solvent comprises ethanol.
3. The method of claim 1 , wherein the SERS-active nanoparticle is at least partially encased within the porous SiO 2 hollow shell.
4. The method of claim 1 , wherein the SERS-active nanoparticle comprises at least one metal other than gold.
5. The method of claim 1 , wherein the Raman active particle further comprises water.
6. The method of claim 1 , wherein the Raman active particle further comprises at least one organic compound.
7. The method of claim 1 , wherein the Raman active particle is about 500 nm to about 1000 nm in diameter.
8. The method of claim 1 , wherein the SERS-active nanoparticle is about 10 nm to about 50 nm in diameter.
9. The method of claim 1 , wherein the SERS-active nanoparticle is fully encased within the porous SiO 2 hollow shell.
10. The method of claim 1 , wherein adding a solvent to dissolve and remove the dissolvable material includes adding a solvent capable of dissolving the spherical polystyrene particle.
11. A method of preparing a Raman active particle, the method comprising:
providing a hollow spherical SiO 2 particle;
combining the hollow spherical SiO 2 particle with a SERS-active seed particle such that the SERS-active seed particle passes into the hollow spherical SiO 2 particle and associates with an interior surface of the SiO 2 particle; and
growing SERS-active nanoparticles on the interior surface, thereby preparing a Raman active particle.
12. The method of claim 11 , further comprising performing an in situ catalytic reduction technique.
13. The method of claim 11 , wherein the SERS-active nanoparticles are at least partially encased within the hollow spherical SiO 2 particle.
14. The method of claim 11 , wherein the SERS-active nanoparticle comprises at least one metal other than gold.
15. The method of claim 11 , wherein the Raman active particle further comprises water.
16. The method of claim 11 , wherein the Raman active particle further comprises at least one organic compound.
17. The method of claim 11 , wherein the Raman active particle is about 500 nm to about 1000 nm in diameter.
18. The method of claim 11 , wherein the SERS-active nanoparticle is about 10 nm to about 50 nm in diameter.
19. The method of claim 11 , wherein the SERS-active nanoparticle is fully encased within the hollow spherical SiO 2 particle.