Microparticle fractionating apparatus and method of fractionating microparticle

Patent metadata

Field	Value
Publication number	US-9784659-B2
Application number	US-201314440765-A
Country	US
Kind code	B2
Filing date	Oct 3, 2013
Priority date	Nov 8, 2012
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

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.

First claim

The invention claimed is:

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.

Assignees

• Sony Corp

Inventors

• Tanase Hironobu
• Itou Takayuki
• Yata Toru
• Tsuji Akiko
• Tago Takashi

Classifications

• B03C7/003

  Pretreatment of the solids prior to electrostatic separation · CPC title

• G01N2015/149

  Physics · mapped topic

• B01L2400/027

  electrostatic forces between substrate and tip · CPC title

• B01L3/5027

  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 · CPC title

• B03C7/12

  with material falling free · CPC title