Systems and methods for manufacturing quantum dot-doped polymer microbeads

• US 8,597,729 B2
• Filed: 06/23/2008
• Issued: 12/03/2013
• Est. Priority Date: 06/22/2007
• Status: Expired due to Fees

• Current Assignee: Fio Corporation
• Original Assignee: Fio Corporation
• Inventors: Fournier-Bidoz, Sebastien, Chan, Warren Che Wor
• Primary Examiner(s): Le, Hoa (Holly)
• Application Number:
  US12/666,112
• Publication Number:
  US 20120156490A1
• Time in Patent Office: 1,989 Days
• Field of Search: 427/212, 427/426, 427/427.4, 427/444, 239/10, 239/196, 239/246, 239/380, 239/398
• US Class Current: 427/212
• CPC Class Codes: B01J 2219/005 Beads
• CPC Class Codes: B01J 2219/00551 3-dimensional
• CPC Class Codes: B01J 2219/00576 fluorophore
• CPC Class Codes: C08L 25/14 with unsaturated esters
• CPC Class Codes: C08L 35/06 Copolymers with vinyl aromatic monomers
• CPC Class Codes: C40B 20/04 Identifying library members by means of a tag, label, or other readable or detectable entity associated with the library members, e.g. decoding processes
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

In a method and system for forming microbeads, a polymer solution includes particles and a polymer dissolved in a solvent. A stream of the polymer solution flows into a chamber. A focusing fluid contacts and focuses the polymer stream in the chamber. The focusing fluid and the focused polymer stream flow, as a single flow stream, out from the chamber. Pendant droplets detach from a leading end of the single flow stream to form the microbeads. The focusing fluid reacts with the polymer solution to form functional groups at a surface of the microbeads for binding with biorecognition molecules. In the system, a flow focusing apparatus includes a flow focusing body shaped to define the chamber. Microbeads formed according to the methods and systems are also disclosed.

Claims

1. A method of forming microbeads comprising the steps of:

(a) flowing a polymer stream of a polymer solution into an interior chamber of a flow focusing body, with the polymer solution comprising particles and a polymer dissolved in a solvent;

(b) flowing a focusing fluid into the chamber, with the focusing fluid capable of reacting with the polymer solution to form functional groups adapted to bind with biorecognition molecules;

(c) directing the focusing fluid into contact with the polymer stream in the chamber, so as to focus the polymer stream;

(d) flowing the focusing fluid and the polymer stream focused thereby, as a single flow stream, out from the chamber; and

(e) allowing detachment of pendant droplets from a leading end portion of the single flow stream so as to form the microbeads;

wherein each of the microbeads binds an identifiable set of the particles; and

wherein the focusing fluid reacts with the polymer solution to form one or more of the functional groups at a surface of each of the microbeads, such that the microbeads are adapted to bind with the biorecognition molecules.

2. The method according to claim 1, wherein in step (d) the focusing fluid substantially surrounds the polymer stream in the single flow stream.

3. The method according to claim 1, further comprising step (f), after step (e), wherein the microbeads are collected in a receptacle containing a fluid bath.

4. The method according to claim 3, wherein in step (f), the fluid bath is stirred and the microbeads are allowed to solidify.

5. The method according to claim 3, further comprising step (g), after step (e), wherein the microbeads allowed to solidify and are recovered from the fluid bath.

6. The method according to claim 5, wherein in step (g), the microbeads are recovered by centrifugation.

7. The method according to claim 3, wherein the fluid bath contains the focusing fluid.

8. The method according to claim 1, further comprising a preliminary step, before step (a), of forming the polymer solution by dissolving the particles and the polymer in the solvent.

9. The method according to claim 1, further comprising a preliminary step, before step (a), of forming the polymer solution by first dissolving the particles in the solvent, and then dissolving the polymer therein.

10. The method according to claim 1, wherein in step (a), the solvent comprises an organic solvent.

11. The method according to claim 1, wherein in step (a), the polymer is substantially hydrophobic.

12. The method according to claim 1, wherein in step (a), the polymer comprises a polystyrene powder or a derivative thereof.

13. The method according to claim 1, wherein in step (a), the polymer comprises a polystyrene-acid anhydride copolymer.

14. The method according to claim 1, wherein the functional groups are protected in step (a), and wherein the functional groups are deprotected following reaction of the focusing fluid with the polymer solution.

15. The method according to claim 1, wherein the functional groups comprise carboxylic acid groups.

16. The method according to claim 1, wherein the focusing fluid is water.

17. The method according to claim 1, wherein in step (a), the particles comprise fluorophores.

18. The method according to claim 1, wherein in step (a), the particles comprise nanoparticles.

19. The method according to claim 1, wherein in step (a), the particles comprise quantum dots.

20. The method according to claim 19, wherein in step (a), the polymer solution comprises a combination of one or more types of the quantum dots, and wherein the identifiable set of the quantum dots bound by each of the microbeads is adapted to, following irradiation, produce one or more identifiable spectral signals based on color and/or intensity.

21. The method according to claim 1, wherein in step (a) the particles comprise a combination of quantum dots and magnetic nanoparticles.

22. The method according to claim 1, wherein in step (d), the single flow stream flows out from the chamber into a focusing orifice;

wherein in step (e), the single flow stream flows out from the focusing orifice; and

wherein a wet diameter (d_g) of each of the microbeads is directly dependent upon a diameter of the polymer stream in step (e).

23. The method according claim 22, wherein the wet diameter (d_g) of each of the microbeads is determined according to the following equation:

d_g=1.89d_j

wherein d_j is the diameter of the polymer stream in step (e).

24. The method according to claim 1, wherein in step (d), the single flow stream flows out from the chamber into a focusing orifice;

wherein in step (e), the single flow stream flows out from the focusing orifice; and

wherein a diameter (d_j) of the polymer stream in step (e) is dependent upon;

a diameter of the focusing orifice in step (e);

a density and a flow rate of the polymer solution in step (a); and

a density and a flow rate of the focusing fluid in step (b).

25. The method according claim 24, wherein the diameter (d_j) of the polymer stream in step (e) is determined according to the following equation:

26. The method according to claim 25, wherein a wet diameter (d_g) of each of the microbeads is directly dependent upon a diameter of the polymer stream in step (e) and is determined according to the following equation:

d_g=1.89d_j

wherein d_j is the diameter of the polymer stream in step (e); and

wherein the density (ρ

₁) of the polymer solution in step (a), the density (ρ

₂) of the focusing fluid in step (b), and the diameter (D) of the exit orifice in step (e) are predetermined such that, when the flow rate (Q₁) of the polymer solution flowing into the chamber is about 1 milliliter per hour (mL/h) and the flow rate (Q₂) of the focusing fluid flowing into the chamber is about 180 milliliters per hour (mL/h), the method operatively forms microbeads about 6 micrometers (μ

m) in diameter.

27. The method according to claim 25, wherein a wet diameter (d_g) of each of the microbeads is directly dependent upon a diameter of the polymer stream in step (e) and is determined according to the following equation:

d_g=1.89d_j

wherein d_j is the diameter of the polymer stream in step (e); and

wherein the density (ρ

₁) of the polymer solution in step (a), the density (ρ

₂) of the focusing fluid in step (b), and the diameter (D) of the exit orifice in step (e) are predetermined such that, when the flow rate (Q₁) of the polymer solution flowing into the chamber is about 0.5 milliliters per hour (mL/h) and the flow rate (Q₂) of the focusing fluid flowing into the chamber is about 180 milliliters per hour (mL/h), the method operatively forms microbeads about 5 micrometers (μ

m) in diameter.

28. The method according to claim 1, further comprising a first polymer narrowing step of reducing a cross-sectional profile of the polymer stream before step (a).

29. The method according to claim 28, further comprising a second polymer narrowing step of further reducing the cross-sectional profile of the polymer stream after the first narrowing step and before step (a).

30. The method according to claim 1, wherein in step (b), the focusing fluid flows into the chamber in a focusing stream;

and further comprising a focusing fluid narrowing step of reducing a cross-sectional profile of the focusing stream before step (b).

31. A system for forming microbeads comprising:

(a) a polymer solution comprising particles and a polymer dissolved in a solvent;

(b) a focusing fluid capable of reacting with the polymer solution to form functional groups adapted to bind with biorecognition molecules;

(c) a flow focusing apparatus comprising a flow focusing body shaped to define an interior chamber and an exit opening, with the chamber operatively receiving the focusing fluid and a polymer stream of the polymer solution, with the focusing fluid operatively contacting and focusing the polymer stream in the chamber, so as to focus the polymer stream, and with the focusing fluid and the polymer stream focused thereby operatively flowing, as a single flow stream out from the chamber through the exit opening;

wherein pendant droplets operatively detach from a leading end portion of the single flow stream so as to form the microbeads;

wherein each of the microbeads binds an identifiable set of the particles, and

wherein the focusing fluid operatively reacts with the polymer solution to form one or more of the functional groups at a surface of each of the microbeads, such that the microbeads are adapted to bind with the biorecognition molecules.

32. The system according to claim 31, wherein the flow focusing apparatus further comprises a polymer supply subassembly which includes a first polymer nozzle having an entry portion shaped to define an entry opening, an exit portion shaped to define a tip aperture, and a neck portion shaped to define an internal channel running between the entry opening and the tip aperture;

wherein the polymer stream operatively flows into the entry opening, through the internal channel, and out from the tip aperture towards the chamber; and

wherein the first polymer nozzle is adapted to operatively reduce a cross-sectional profile of the polymer stream during passage therethrough.

33. The system according to claim 32, wherein the polymer supply subassembly additionally includes a second polymer nozzle connected in series after the first polymer nozzle;

wherein the polymer stream operatively flows from the tip aperture of the first polymer nozzle into an entry opening defined by an entry portion of the second polymer nozzle, through an internal channel defined by a neck portion of the second polymer nozzle, and out from a tip aperture defined by an exit portion of the second polymer nozzle towards the chamber.

34. The system according to claim 33, wherein the second polymer nozzle comprises a needle member engaging the exit portion of the second polymer nozzle and extending out from the tip aperture of the second polymer nozzle;

and wherein the needle member is shaped to define an internal needle channel and a needle tip aperture;

wherein the polymer stream operatively flows from the tip aperture of the exit portion of the second polymer nozzle through the needle channel, and out from the needle tip aperture towards the chamber.

35. The system according to claim 33, wherein the second polymer nozzle is adapted to operatively further reduce the cross-sectional profile of the polymer stream during passage therethrough.

36. The system according to claim 32, wherein the flow focusing body is shaped to define a polymer supply opening leading to the chamber;

and wherein the polymer supply subassembly securely engages the flow focusing body, with at least part of the polymer supply subassembly being securely received within the polymer supply opening, such that the polymer stream operatively flows from the polymer supply subassembly into the chamber.

37. The system according to claim 31, wherein the flow focusing apparatus further comprises a focusing fluid supply nozzle having an entry portion shaped to define an entry opening, an exit portion shaped to define a tip aperture, and a neck portion shaped to define an internal channel running between the entry opening of the focusing fluid supply nozzle and the tip aperture of the focusing fluid supply nozzle;

wherein a focusing stream of the focusing fluid operatively flows into the entry opening of the focusing fluid supply nozzle, through the internal channel of the focusing fluid supply nozzle, and out from the tip aperture of the focusing fluid supply nozzle towards the chamber; and

wherein the focusing fluid supply nozzle is adapted to operatively reduce a cross-sectional profile of the focusing stream during passage therethrough.

38. The system according to claim 37, wherein the flow focusing body is shaped to define a focusing fluid supply opening leading to the chamber;

and wherein the focusing fluid supply nozzle securely engages the flow focusing body, with at least the exit portion of the focusing fluid supply nozzle being securely received within the focusing fluid supply opening, such that the focusing fluid stream operatively flows from the tip aperture of the focusing fluid supply nozzle into the chamber.

39. The system according to claim 31, further comprising a fluid bath and a receptacle containing the fluid bath to operatively collect the microbeads after detachment from the leading end portion of the single flow stream.

40. The system according to claim 39, wherein the fluid bath contains the focusing fluid.

41. The system according to claim 31, wherein the solvent comprises an organic solvent.

42. The system according to claim 31, wherein the polymer is substantially hydrophobic.

43. The system according to claim 31, wherein the polymer comprises a polystyrene powder or a derivative thereof.

44. The system according to claim 31, wherein the polymer comprises a polystyrene-acid anhydride copolymer.

45. The system according to claim 31, wherein in the polymer solution, the functional groups are protected before operative reaction of the focusing fluid with the polymer solution, and wherein the functional groups are deprotected following operative reaction of the focusing fluid with the polymer solution.

46. The system according to claim 31, wherein the functional groups, at least following operative reaction of the focusing fluid with the polymer solution, comprise carboxylic acid groups.

47. The system according to claim 31, wherein the focusing fluid is water.

48. The system according to claim 31, wherein the particles comprise fluorophores.

49. The system according to claim 31, wherein the particles comprise nanoparticles.

50. The system according to claim 31, wherein the particles comprise quantum dots.

51. The system according to claim 50, wherein the polymer solution comprises a combination of one or more types of the quantum dots, and wherein the identifiable set of the quantum dots bound by each of the microbeads is adapted to, following irradiation, produce one or more identifiable spectral signals based on color and/or intensity.

52. The system according to claim 31, wherein the particles comprise a combination of quantum dots and magnetic nanoparticles.

53. The system according to claim 31, wherein the flow focusing apparatus further comprises a focusing gate shaped to define a focusing orifice therethrough, with the focusing gate substantially obstructing the exit opening of the flow focusing body, and with the focusing orifice leading out from the chamber, such that the single flow stream operatively flows out from the chamber through the focusing orifice, and such that the single flow stream operatively flows out from the focusing orifice.

54. The system according to claim 53, wherein a wet diameter (d_g) of each of the microbeads is directly dependent upon a diameter of the polymer stream exiting the focusing orifice.

55. The systems according to claim 54, wherein the wet diameter (d_g) of each of the microbeads is determined according to the following equation:

d_g=1.89d_j

wherein d_j is the diameter of the polymer stream exiting the focusing orifice.

56. The system according to claim 53, wherein a diameter (d_j) of the polymer stream flowing out from the focusing orifice is dependent upon:

a diameter of the focusing orifice as the polymer stream exits therefrom;

a density and a flow rate of the polymer solution entering the chamber; and

a density and a flow rate of the focusing fluid entering the chamber.

57. The system according claim 56, wherein the diameter (d_j) of the polymer stream flowing out from the focusing orifice is determined according to the following equation:

58. The system according to claim 57, wherein a wet diameter (d_g) of each of the microbeads is directly dependent upon a diameter (d_j) of the polymer stream exiting the focusing orifice and is determined according to the following equation:

d_g=1.89d_j

wherein the density (ρ

₁) of the polymer solution entering the chamber, the density (ρ

₂) of the focusing fluid entering the chamber, and the diameter (D) of the focusing orifice as the polymer exits therefrom, are predetermined such that, when the flow rate (Q₁) of the polymer solution flowing into the chamber is about 1 milliliter per hour (mL/h) and the flow rate (Q₂) of the focusing fluid flowing into the chamber is about 180 milliliters per hour (mL/h), the system operatively forms microbeads about 6 micrometers (μ

m) in diameter.

59. The system according to claim 57, wherein a wet diameter (d_g) of each of the microbeads is directly dependent upon a diameter (d_j) of the polymer stream exiting the focusing orifice and is determined according to the following equation:

d_g=1.89d_j

wherein the density (ρ

₁) of the polymer solution entering the chamber, the density (ρ

₂) of the focusing fluid entering the chamber, and the diameter (D) of the focusing orifice as the polymer exits therefrom, are predetermined such that, when the flow rate (Q₁) of the polymer solution flowing into the chamber is about 0.5 milliliters per hour (mL/h) and the flow rate (Q₂) of the focusing fluid flowing into the chamber is about 180 milliliters per hour (mL/h), the system operatively forms microbeads about 5 micrometers (μ

m) in diameter.