Microparticle fractionating apparatus and method of fractionating microparticle

• US 9,784,659 B2
• Filed: 10/03/2013
• Issued: 10/10/2017
• Est. Priority Date: 11/08/2012
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Tanase, Hironobu, Itou, Takayuki, Yata, Toru, Tsuji, Akiko, Tago, Takashi
• Primary Examiner(s): Rodriguez, Joseph C
• Application Number:
  US14/440,765
• Publication Number:
  US 20150285726A1
• Time in Patent Office: 1,468 Days
• CPC Class Codes: B01L 2200/0652 Sorting or classification of particles or molecules
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2400/027 electrostatic forces between substrate and tip
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 3/0268 using pulse dispensing or spraying, eg. inkjet type, piezo actuated ejection of droplets from capillaries
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: B03C 7/003 Pretreatment of the solids prior to electrostatic separation
• CPC Class Codes: B03C 7/12 with material falling free
• CPC Class Codes: B07C 5/02 Measures preceding sorting, e.g. arranging articles in a stream orientating sorting and transport of caps B67B3/06
• CPC Class Codes: B07C 5/344 according to electric or electromagnetic properties sorting according to size measured electrically or electronically B07C5/08; material testing by magnetic means G01N24/00, G01N27/00, by electrical means G01N27/00; electrical measuring devices in general G01R; coin testing G07D5/00
• CPC Class Codes: G01N 15/14 Optical investigation techniques, e.g. flow cytometry
• CPC Class Codes: G01N 15/1459 the analysis being performed on a sample stream
• CPC Class Codes: G01N 15/1484 microstructural devices
• CPC Class Codes: G01N 15/149 specially adapted for sorting particles, e.g. by their size or optical properties
• CPC Class Codes: G01N 2015/1006 for cytology
• CPC Class Codes: G01N 2015/1028 Sorting particles

Abstract

Described are microparticle fractionating apparatus and methods of fractionating microparticles. Multiple electrodes may be used to charge droplets when separating and collecting microparticles based on a result analyzed by an optical methodologies. A first electrode may be used to charge a sample fluid, and a second electrode used to apply additional charge near a droplet break-off point.

Claims

1. A charging apparatus for charging droplets discharged from an orifice of a microparticle fractionating apparatus, the charging apparatus comprising:

a first electrode configured to apply a first bias from a bias source to a sample liquid supplying the orifice; and

a second electrode and circuit configured to apply a second bias other than ground potential and referenced to the first bias to the droplets formed from the sample liquid, wherein the second electrode is spaced less than or equal to 5 millimeters from a droplet break-off-point in a fluid stream discharged into air from the orifice.

2. The charging apparatus of claim 1, wherein the second electrode extends at least 30 millimeters downstream from the droplet break-off-point.

3. The charging apparatus of claim 1, wherein the second bias has a potential opposite in phase to the first bias.

4. The charging apparatus of claim 1, wherein the second bias has a value that is approximately equal in magnitude to the first bias.

5. The charging apparatus of claim 4, wherein application of the second bias to the second electrode is configured to cancel a noise component of the bias source.

6. The charging apparatus of claim 4, wherein application of the second bias to the second electrode is configured to substantially double an amount of charge in a droplet that was applied by the first electrode.

7. The charging apparatus of claim 1, wherein a majority of the second electrode extends downstream of a droplet break-off-point.

8. The charging apparatus of claim 7, wherein the second electrode is formed as at least one electrode plate.

9. The charging apparatus of claim 7, wherein the second electrode is formed as a cylinder.

10. The charging apparatus of claim 7, wherein the second electrode is formed as a hole in a plate.

11. The charging apparatus of claim 7, wherein the second electrode is formed as a ring electrode.

12. The charging apparatus of claim 1, further comprising:

a microchip in which the orifice is located; and

a vibration device arranged to cause formation of the droplets.

13. A method for charging droplets discharged from an orifice of a microparticle fractionating apparatus, the method comprising:

applying a first bias from a bias source to a first electrode arranged to be in contact with a sample liquid supplying the orifice that is arranged to produce the droplets;

referencing a second bias to the first bias; and

applying the second bias other than ground potential to a second electrode spaced less than or equal to 5 millimeters from a droplet break-off-point in a fluid stream discharged into air from the orifice.

14. The method of claim 13, wherein the second electrode extends at least 30 millimeters downstream from the droplet break-off-point.

15. The method of claim 13, further comprising setting the second bias to have a value that is opposite in phase to the first bias.

16. The method of claim 15, further comprising applying the second bias to the second electrode to cancel a noise component of the bias source.

17. The method of claim 13, further comprising applying the second bias at the second electrode so as to substantially double an amount of charge in a droplet that was applied by the first electrode.

18. A microparticle fractionating apparatus comprising:

a droplet-forming device having an orifice and arranged to receive a sample liquid containing microparticles and produce a stream of separated droplets;

a first electrode configured to apply a first bias from a bias source to the sample liquid supplying the orifice;

a second electrode and circuit configured to apply a second bias other than ground potential and referenced to the first bias to the separated droplets formed from the sample liquid, wherein the second electrode is spaced less than or equal to 5 millimeters from a droplet break-off-point in a fluid stream discharged into air from the orifice; and

deflection plates located after the second electrode and arranged to subject the separated droplets to an electric field so as to deflect the paths of the separated droplets.