Fluorescent ink compositions comprising functionalized fluorescent nanocrystals

• US 6,576,155 B1
• Filed: 01/05/2001
• Issued: 06/10/2003
• Est. Priority Date: 11/10/1998
• Status: Expired due to Term

• Current Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: BioCrystal, Ltd.
• Inventors: Barbera-Guillem, Emilio
• Primary Examiner(s): KOSLOW, CAROL M
• Application Number:
  US09/755,407
• Time in Patent Office: 886 Days
• Field of Search: 283/92, 428/690, 428/403, 106/31.15, 106/31.64, 252/301.36, 252/301.4 R, 252/301.4 S, 252/301.6 R, 252/301.6 S, 430/10
• US Class Current: 252/301.36
• CPC Class Codes: A61K 9/167 with an outer layer or coating comprising drug; with chemically bound drugs or non-active substances on their surface with further drug-free outer coating A61K9/5073
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: C09D 11/50 Sympathetic, colour changing or similar inks
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/0805 Chalcogenides
• CPC Class Codes: G07F 7/086 by passive credit-cards adapted therefor, e.g. constructive particularities to avoid counterfeiting, e.g. by inclusion of a physical or chemical security-layer for security documents G07D7/00; for the reading of record-carriers in general G06K7/00; for the design of coded credit-cards G06K19/10
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 428/253 Cellulosic [e.g., wood, paper, cork, rayon, etc.]

Abstract

A fluorescent ink composition comprising functionalized fluorescent nanocrystals, an aqueous-based ink carrier comprising water or a water-based solution, and a binder. Also provided are methods of providing an image or a security mark on a substrate for subsequent identification by applying a fluorescent ink composition onto the substrate

Claims

1. A fluorescent ink composition comprising functionalized fluorescent nanocrystals, an aqueous-based ink carrier comprising water or a water-based solution, a surfactant and a binder.

2. The fluorescent ink composition according to claim 1, further comprising an additional component selected from the group consisting of a biocide, a defoamer, a corrosion inhibitor, and a combination thereof.

3. The fluorescent ink composition according to claim 1, wherein the functionalized fluorescent nanocrystals comprise semiconductor nanocrystals.

4. The fluorescent ink composition according to claim 1, wherein the functionalized fluorescent nanocrystals comprise doped metal oxide nanocrystals.

5. The fluorescent ink composition according to claim 1, wherein the functionalized fluorescent nanocrystals are excitable by exposure to a wavelength spectrum in a spectral range of from about 300 nm to about 400 nm, and fluoresces at a peak emission wavelength in the spectral range of from about 410 nm to about 750 nm.

6. The fluorescent ink composition according to claim 1, wherein the functionalized fluorescent nanocrystals comprise fluorescent nanocrystals functionalized by a plurality of molecules comprising amino acid.

7. The fluorescent ink composition according to claim 1, wherein the functionalized fluorescent nanocrystals comprise a substantially uniform size in the range of about 2 nm to about 10 nm.

8. The fluorescent ink composition according to claim 1, wherein the functionalized fluorescent nanocrystals comprise an amount in the range of from about 0.0005% to about 5%, based on total weight of the fluorescent ink composition.

9. The fluorescent ink composition according to claim 1, wherein the aqueous-based ink carrier comprises water.

10. The fluorescent ink composition according to claim 1, wherein the aqueous-based ink carrier comprises a water-based solution comprising a mixture of water and at least one water-soluble organic solvent.

11. The fluorescent ink composition according to claim 1, wherein the aqueous-based ink carrier comprises an amount in the range of from about 75% to about 99.5%, based on total weight of the fluorescent ink composition.

12. The fluorescent ink composition according to claim 1, wherein the binder comprises an amount in the range of from about 1% to about 25%, based on total weight of the fluorescent ink composition.

13. The fluorescent ink composition according to claim 1, wherein the functionalized fluorescent nanocrystals are operably bound to the binder in forming a cross-linked fluorescent ink composition.

14. The fluorescent ink composition according to claim 1, wherein the functionalized fluorescent nanocrystals and the aqueous-based ink carrier and the binder comprise at least 90% by weight of the fluorescent ink composition.

15. The fluorescent ink composition according to claim 1, wherein the fluorescent ink composition further comprises a defoamer in the range of from about 0.5% to about 1.2% by weight of the fluorescent ink composition.

16. The fluorescent ink composition according to claim 1, wherein the surfactant comprises a range of from about 0.01% to about 1.5% by weight of the fluorescent ink composition.

17. The fluorescent ink composition according to claim 1, wherein the fluorescent ink composition further comprises a biocide in the range of from about 0.02% to about 0.5% by weight of the fluorescent ink composition.

18. The fluorescent ink composition according to claim 1, wherein the fluorescent ink composition further comprises a corrosion inhibitor in the range of from about 0.01% to about 0.5% by weight of the fluorescent ink composition.

19. A method of formulating the fluorescent ink composition according to claim 1, wherein the method comprises:

contacting the functionalized fluorescent nanocrystals with the aqueous-based ink carrier in forming a mixture; and

adding a binder to the mixture in forming the fluorescent ink composition.

20. A method of providing an image on a substrate for subsequent identification comprising applying onto the substrate a fluorescent ink composition comprising functionalized fluorescent nanocrystals, an aqueous-based ink carrier comprising water or a water-based solution, and a binder operably bound to the functionalized fluorescent nanocrystals in forming a cross-linked fluorescent ink composition.

21. The method according to claim 20, wherein the image comprises a security mark.

22. The method according to claim 20, wherein the fluorescent ink composition further comprises an additional component selected from the group consisting of a biocide, a surfactant, a defoamer, a corrosion inhibitor, and a combination thereof.

23. The method according to claim 20, further comprising applying onto the substrate a plurality of fluorescent ink compositions wherein each of the plurality of fluorescent ink compositions is capable of fluorescing a specific color in providing an image which is multicolor upon subsequent identification.

24. An image formed on a substrate by the method according to claim 20.

25. An image comprising a security mark formed on a substrate by the method according to claim 21.

26. An image formed on a substrate by the method according to claim 22.

27. An image formed on a substrate by the method according to claim 23.

28. A method for identifying an object comprising the steps of:

exposing a fluorescent ink composition comprising functionalized fluorescent nanocrystals, an aqueous-based ink carrier, and a binder to an excitation light source having a wavelength spectrum in a range of from about 300 nm to about 400 nm;

detecting a peak fluorescent emission in a spectral range of from about 410 nm to about 750 nm; and

identifying an object in response to the detecting.

29. The method according to claim 28, further comprising applying a security mark to the object using a plurality of fluorescent ink compositions, wherein each of the plurality of fluorescent ink compositions is capable of fluorescing a specific color in providing a security mark which fluoresces in multicolor when visualized;

and identifying the object based on the visualization of the security mark fluorescing in multicolor.

30. The method according to claim 28, wherein the fluorescent ink composition further comprises an additional component selected from the group consisting of a biocide, a surfactant, a defoamer, a corrosion inhibitor, and a combination thereof.

31. The method according to claim 28, wherein the functionalized fluorescent nanocrystals are operably bound to the binder in forming a cross-linked fluorescent ink composition.

32. A fluorescent ink composition comprising:

functionalized fluorescent doped metal oxide nanocrystals;

an aqueous-based ink carrier; and

a binder.