Coated water soluble nanoparticles

• US 20060029802A1
• Filed: 08/04/2004
• Published: 02/09/2006
• Est. Priority Date: 08/04/2004
• Status: Active Grant

• Current Assignee: Agency For Science Technology and Research
• Original Assignee: Agency For Science Technology and Research
• Inventors: Ying, Jackie Y., Tan, Timothy T., Selvan, Subramanian T.
• Granted Patent: US 7,405,002 B2
• Time in Patent Office: Days
• US Class Current: 428/403
• CPC Class Codes: C30B 29/60 characterised by shape
• CPC Class Codes: Y10S 977/773 Nanoparticle, i.e. structure having three dimensions of 100 nm or less
• CPC Class Codes: Y10S 977/777 Metallic powder or flake
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/2993 Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]
• CPC Class Codes: Y10T 428/2998 including synthetic resin or polymer

Abstract

Nanoparticles and methods of making nanoparticles are provided. The nanoparticles may include semiconductor nanocrystals. A shell may encapsulate a nanoparticle core, and the shell may include non-organic material and may be silica. The shell may also include additional species such as PEG. In some embodiments, a passivation layer is in contact with the core.

Claims

1. A coated nanoparticle comprising:

a core comprising a semiconductor material;

a non-semi-conductor passivation layer contacting at least a portion of the core; and

a non-organic shell encapsulating at least partially the core and the passivation layer.

2. The coated nanoparticle of claim 1, wherein the nanoparticle is water soluble.

3. The nanoparticle of claim 1 wherein the passivation portion comprises an amine.

4. The nanoparticle of claim 3 wherein the passivation portion comprises an amino silane.

5. The nanoparticle of claim 2 wherein the non-organic shell comprises silica.

6. The nanoparticle of claim 5 wherein the non-organic shell is not chemically bound to the core.

7. The nanoparticle of claim 1 wherein the non-organic shell comprises polyethylene glycol or a derivative thereof.

8. A method of making a water-soluble nanoparticle, the method comprising:

contacting an amine with a nanoparticle to modify the nanoparticle surface;

suspending the nanoparticle in an aqueous phase of an aqueous-in-nonaqueous emulsion;

introducing a silica precursor to the emulsion; and

polymerizing the silica precursor to form a silica shell that at least partially encapsulates the nanoparticle.

9. The method of claim 8 wherein the aqueous-in-nonaqueous emulsion comprises a non-ionic surfactant.

10. The method of claim 8 wherein the nanoparticle is capped with a surfactant.

11. The method of claim 10 further comprising exchanging the surfactant with a second surfactant in the emulsion.

12. The method of claim 8 wherein the amine is an amino silane.

13. The method of claim 12 wherein the amino silane is aminopropyl trimethoxysilane.

14. The method of claim 8 further comprising introducing a polyethylene glycol, or a derivative thereof, to the emulsion.

15. A semiconductor nanocrystal solution comprising:

an aqueous solution having a pH of less than about 8.0;

a plurality of semiconductor nanocrystals dissolved in the aqueous solution wherein at least 90% of the semiconductor nanocrystals, by weight, remain dissolved for greater than 6 hours.

16. The semiconductor nanocrystal solution of claim 15 wherein the aqueous solution is a biological fluid.

17. The semiconductor nanocrystal solution of claim 15 wherein the aqueous solution is mammalian blood.

18. The semiconductor nanocrystal solution of claim 15 wherein the aqueous solution has a pH of less than equal to 7.0.

19. The semiconductor nanocrystal solution of claim 15 wherein the semiconductor nanocrystals comprise polyethylene glycol.

20. A semiconductor nanocrystal wherein the nanocrystal is soluble in water at a pH of less than about 8.0.

21. The semiconductor nanocrystal of claim 20 wherein the nanocrystal comprises a shell comprising silica.

22. The semiconductor nanocrystal of claim 21 wherein the shell includes a polyethylene glycol.

23. The semiconductor nanocrystal of claim 22 wherein the polyethylene glycol has a molecular weight of about 5,000 to 10,000.

24. A nanoparticle comprising a silica shell encapsulating a core, the silica shell including polyethylene glycol, or a derivative thereof.

25. The nanoparticle of claim 24 wherein the polyethylene glycol has a molecular weight of about 5,000 to about 10,000.