Methods of preparing multicolor quantum dot tagged beads and conjugates thereof

• US 20030148544A1
• Filed: 06/28/2002
• Published: 08/07/2003
• Est. Priority Date: 06/28/2001
• Status: Abandoned Application

• Current Assignee: Indiana University Research & Technology Corporation (Indiana University)
• Original Assignee: ADVANCED RESEARCH & TECHNOLOGY INSTITUTE
• Inventors: Nie, Shuming, Han, Mingyong, Gao, Xiaohu
• Application Number:
  US10/185,226
• Publication Number:
  US 20030148544A1
• Time in Patent Office: Days
• US Class Current: 436/524
• 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: G01N 33/54393 Improving reaction conditions or stability, e.g. by coating or irradiation of surface, by reduction of non-specific binding, by promotion of specific binding
• CPC Class Codes: G01N 33/544 the carrier being organic
• CPC Class Codes: G01N 33/588 with semiconductor nanocrystal label, e.g. quantum dots

Abstract

The present invention provides a method of preparing a multicolor quantum dot-tagged bead, a multicolor quantum dot-tagged bead, a conjugate thereof, and a composition comprising such a bead or conjugate. Additionally, the present invention provides a method of making a conjugate thereof and methods of using a conjugate for multiplexed analysis of target molecules.

Claims

1. A method of preparing a multicolor quantum dot-tagged bead, which method comprises:

(a) providing at least one porous polymer bead, wherein the pores of the bead are large enough to incorporate quantum dots;

(b) combining predetermined amounts of multicolor quantum dots with at least one bead; and

(c) isolating the multicolor quantum dot-tagged bead.

2. The method of claim 1, wherein the porous polymer bead is provided by emulsion polymerization, suspension polymerization, or seeded polymerization.

3. The method of claim 2, wherein the multicolor quantum dots are added sequentially.

4. The method of claim 2, wherein the multicolor quantum dots are added in parallel.

5. The method of claim 2, wherein the bead is sealed with a sealant compound.

6. The method of claim 5, wherein the sealant compound is selected from the group consisting of mercaptopropyltrimethoxysilane, aminopropyltrimethoxysilane, and trimethoxysilylpropylhydrazide.

7. The method of claim 2, wherein the bead is swelled in a solvent.

8. The method of claim 7, wherein the solvent comprises butanol.

9. The method of claim 2, wherein the bead is a cross-linked polymer.

10. The method of claim 9, wherein the cross-linked polymer comprises polystyrene, divinylbenzene, and acrylic acid.

11. A multicolor quantum dot-tagged bead prepared by the method of claim 2, which comprises at least one multicolor quantum dot and a bead, wherein the quantum dots are present in a precisely controlled ratio.

12. The multicolor quantum dot-tagged bead of claim 11, wherein the multicolor quantum dots are embedded in a bead.

13. The multicolor quantum dot-tagged bead of claim 11, wherein the bead is sealed with a sealant compound.

14. The multicolor quantum dot-tagged bead of claim 13, wherein the sealant compound is selected from the group consisting of mercaptopropyl-trimethoxysilane, aminopropyltrimethoxysilane, and trimethoxysilylpropylhydrazide.

15. The multicolor quantum dot-tagged bead of claim 11, wherein the bead comprises a cross-linked polymer.

16. The multicolor quantum dot-tagged bead of claim 15, wherein the crosslinked polymer comprises polystyrene, divinylbenzene, and acrylic acid.

22. A conjugate comprising a multicolor quantum dot-tagged bead prepared by the methods of claim 2, which comprises at least one multicolor quantum dot, a bead, and a probe, wherein the probe is attached to the bead.

23. The conjugate of claim 22, wherein the probe is a protein or a fragment thereof.

24. The conjugate of claim 23, wherein the protein or fragment thereof is an antibody or an antigenically reactive fragment thereof.

25. The conjugate of claim 22, wherein the probe is a nucleic acid.

26. The conjugate of claim 22, wherein the probe is attached to the bead via a linker.

27. A composition comprising the conjugate of claim 22 and a carrier.

28. A method of making a conjugate comprising a multicolor quantum dot tagged bead of claim 11 and a probe, which method comprises:

(a) contacting a multicolor quantum dot tagged bead of claim 11 with a probe, which can directly attach to the bead; and

(b) isolating the conjugate.

29. The method of claim 28, wherein (a) further comprises contacting the multicolor quantum dot-tagged bead and the probe with a cross-linker.

30. A method of making a conjugate comprising a multicolor quantum dot tagged bead of claim 11 and a probe, which method comprises:

(a) contacting a multicolor quantum dot-tagged bead of claim 11 with (i) a linker, an intermediate cross-linker or a bifunctional molecule, and (ii) a probe, which can indirectly attach to the linker, intermediate cross-linker, or bifunctional molecule; and

(b) isolating the conjugate.

31. A method of making a conjugate comprising a multicolor quantum dot tagged bead of claim 11 and a probe, which method comprises:

(a) contacting a probe with (i) a linker, an intermediate cross-linker or a bifunctional molecule, and (ii) a multicolor quantum dot tagged bead of claim 11;

and

(b) isolating the conjugate.

32. The method of claim 30, wherein the probe is a protein or a fragment thereof or a nucleic acid.

33. The method of claim 30, wherein the bead is a cross-linked polymer.

34. The method of claim 30, wherein the linker is streptavidin, neutravidin or biotin.

35. A method of detecting one or more targets in a sample, which method comprises:

(a) contacting the sample with a conjugate of claim 22, wherein the probe of the conjugate specifically binds to a target; and

(b) detecting luminescence, wherein the detection of luminescence indicates that the conjugate bound to the target in the sample.

36. The method of claim 35, wherein the target comprises a protein.

37. The method of claim 35, wherein the target comprises a nucleic acid.

38. The method of claim 35, wherein the target is labeled with a tag that fluoresces.

39. The method of claim 35, wherein the probe of the conjugate is a protein or a fragment thereof.

40. The method of claim 39, wherein the probe of the conjugate is an antibody or an antigenically reactive fragment thereof, and the protein in the sample is an antigen or an epitope thereof that is bound by the antibody or the antigenically reactive fragment thereof.

41. The method of claim 40, wherein the antigen or the epitope thereof is viral or bacterial.

42. The method of claim 35, wherein the probe of the conjugate is an antigen or an epitope thereof, and the protein in the sample is an antibody or an antigenically reactive fragment thereof that binds to the antigen or epitope thereof.

43. The method of claim 42, wherein the antibody or the antigenically reactive fragment thereof is specific for a virus, a bacterium, a part of a virus, or a part of a bacterium.

44. The method of claim 35, wherein the probe is a nucleic acid.

45. The method of claim 44, wherein the nucleic acid is labeled with a tag that fluoresces.

46. A method of simultaneously detecting (i) two or more different molecules and/or (ii) two or more regions of a given molecule in a sample, which method comprises:

(a) contacting the sample with two or more conjugates of claim 22, wherein each of the two or more conjugates comprises multicolor quantum dots of different predetermined ratios and a probe that specifically binds to a different molecule or a different region of a given molecule in the sample; and

(b) detecting luminescence, wherein the detection of luminescence of a given spectral code is indicative of a conjugate binding to a molecule in the sample.

47. The method of claim 46, wherein the sample comprises two or more different proteins or fragments thereof.

48. The method of claim 46, wherein the sample comprises two or more different nucleic acids.

49. The method of claim 46, wherein the sample comprises at least one nucleic acid and at least one protein or fragment thereof.

50. The method of claim 35, wherein wavelength-resolved spectroscopy combined with a microchannel is used to detect fluorescence emission.

51. A diagnostic library comprising one or more conjugates of claim 22 that flow through a microchannel or are spread on a substrate surface for multiplexed analysis of one or more targets.

52. The diagnostic library of claim 51, wherein the probe is attached to the bead via a linker.

53. The diagnostic library of claim 52, wherein the linker is a primary amine.

54. The diagnostic library of claim 52, wherein the linker is strepavidin, neutravidin or biotin.

55. The diagnostic library of claim 51, wherein the probe is a protein or a fragment thereof or a nucleic acid.

56. The diagnostic library of claim 51, wherein wavelength-resolved spectroscopy combined with a microchannel is used to detect fluorescence emission.

57. The conjugate of claim 22, wherein the probe is a single-stranded oligonucleotide comprising a stem and loop structure, wherein one end of the single-stranded oligonucleotide is attached to a fluorophore and a quenching moiety is attached to the other end of the single-stranded oligonucleotide, wherein the bead is attached to the fluorophore or the quenching moiety indirectly by a linker, and wherein the quenching moiety quenches the luminescence of the fluorophore.

58. A method of detecting a nucleic acid in a sample, which method comprises:

(a) contacting the sample with a conjugate of claim 57, wherein the loop comprises a probe sequence that binds to a target sequence in the nucleic acid, whereupon the conjugate undergoes a conformational change that forces the stem to open, thereby separating the fluorophore and the quenching moiety; and

(b) detecting luminescence, wherein the detection of luminescence of the fluorophore indicates that the conjugate is bound to the nucleic acid in the sample.

59. The method of claim 58, wherein the target sequence of the nucleic acid is not fluorescently labeled.

17. A multicolor quantum dot-tagged bead, which comprises at least one quantum dot and a porous polymer bead, wherein the bead has pores large enough to incorporate the quantum dot, and wherein the quantum dots are present in a precisely controlled ratio.

18. The multicolor quantum dot-tagged bead of claim 17, wherein the bead is sealed with a sealant compound.

19. The multicolor quantum dot-tagged bead of claim 17, wherein the quantum dots are modified with a silane compound before incorporation into the bead.

20. The multicolor quantum dot-tagged bead of claim 19, wherein the silane compound is polymerized after the quantum dots are incorporated in the bead.

21. A composition comprising the multicolor quantum dot-tagged bead of claim 17 and a carrier.

60. A conjugate comprising at least one quantum dot and a porous polymer bead, and a probe, wherein the bead has pores large enough to incorporate the quantum dot, wherein the quantum dots are present in a precisely controlled ratio, wherein the conjugate hybridizes to a target sequence, wherein the probe is attached to the bead, and wherein the target is labeled with a quantum dot.

61. A method of preparing a multicolor quantum dot-tagged bead, which method comprises:

(a) providing at least one porous bead by solvent-system polymerization that includes about 0.3-5% by volume of a cross-linking agent, wherein the pores of the bead have an average diameter of at least about 1 nm;

(b) combining predetermined amounts of multicolor quantum dots with at least one bead; and

(c) isolating the multicolor quantum dot-tagged bead.

62. The method according to claim 61, wherein about 1% by volume of the cross-linking agent is added.

63. The method according to claim 61, wherein the cross-linking agent is selected from the group consisting of divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, trimethylolpropane trimethacrylate, and N,N′

methylene-bis-acrylamide.

64. The method according to claim 61, wherein the solvent-system polymerization includes styrene monomer and a functionalizing monomer with a terminal COOH, OH, NH₂, or SH group.

65. The method according to claim 61, wherein the solvent-system polymerization is precipitation polymerization.