Method of forming coated water-soluble nanoparticles by inverse emulsion

• US 7,824,731 B2
• Filed: 06/23/2008
• Issued: 11/02/2010
• Est. Priority Date: 08/04/2004
• Status: Expired due to Fees

• 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.
• Primary Examiner(s): LE, HOA T
• Application Number:
  US12/144,070
• Publication Number:
  US 20080258115A1
• Time in Patent Office: 862 Days
• Field of Search: 428/403, 427/212, 427/215, 427/220
• US Class Current: 427/212
• 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 method of making a water-soluble modified nanoparticle, the method comprising:

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

suspending the nanoparticle or the modified 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 modified nanoparticle.

2. The method of claim 1 wherein the aqueous-in-nonaqueous emulsion comprises a non-ionic surfactant.

3. The method of claim 1 wherein the nanoparticle is capped with a surfactant.

4. The method of claim 3 further comprising exchanging the surfactant with a second surfactant in the emulsion.

5. The method of claim 4, wherein the second surfactant comprises IGEPAL.

6. The method of claim 3, wherein the surfactant comprises trioctyl phosphine oxide (TOPO).

7. The method of claim 1 wherein the amine is an amino silane.

8. The method of claim 7 wherein the amino silane is aminopropyl trimethoxysilane.

9. The method of claim 1 further comprising introducing a polyethylene glycol, or a derivative thereof, having a molecular weight of about 1,000 to 20,000, to the emulsion.

10. The method of claim 9, wherein the polyethylene glycol, or the derivative thereof, has a molecular weight of about 5,000 to 10,000.

11. The method of claim 1, wherein the nanoparticle comprises a semiconductor nanocrystal.

12. The method of claim 11, wherein the semiconductor nanocrystal comprises cadmium chalcogenide.

13. The method of claim 1, wherein the silica precursor comprises a sol-gel precursor.

14. The method of claim 13, wherein the sol-gel precursor comprises tetraethylorthosilicate (TEOS).

15. The method of claim 1, wherein the nanoparticle is soluble in water at a pH of less than about 8.0.

16. The method of claim 1, wherein the silica shell completely encapsulates the nanoparticle.

17. The method of claim 1, wherein the aqueous-in-nonaqueous emulsion comprise an ionic surfactant.