Electrostatic deceleration system for flow cytometer

• US 6,211,477 B1
• Filed: 02/26/1998
• Issued: 04/03/2001
• Est. Priority Date: 02/26/1998
• Status: Expired due to Fees

• Current Assignee: Becton, Dickinson & Co, California Institute of Technology
• Original Assignee: Becton, Dickinson & Co
• Inventors: Stewart, Carleton C., Duckett, Larry D., Cardott, John N.
• Primary Examiner(s): Nguyen, Tuan N.
• Application Number:
  US09/030,928
• Time in Patent Office: 1,132 Days
• Field of Search: 209/3.1, 209/3.2, 209/127.1, 209/127.4, 209/130, 209/128, 436/43, 436/50, 436/164
• US Class Current: 209/127.4
• CPC Class Codes: G01N 15/1404 Handling flow, e.g. hydrodynamic focusing
• CPC Class Codes: G01N 15/149 specially adapted for sorting particles, e.g. by their size or optical properties
• CPC Class Codes: Y10T 436/115831 Condition or time responsive

Abstract

An electrostatic deceleration system is provided for use with a flow cytometer to decelerate the movement of electrically charged droplets formed by the flow cytometer in order to minimize damage to the cells contained in the droplets when the droplets are collected in corresponding collection vessels. The deceleration system includes a plurality of deceleration devices which are each used to decelerate droplets charged to a particular magnitude and polarity. Each deceleration device includes a steering plate arrangement and a deceleration ring arrangement. The steering plate arrangement directs the droplets having a particular magnitude and polarity of charge into the corresponding deceleration ring arrangement. The deceleration ring arrangement includes a plurality of deceleration rings to which are applied electrical potentials of a polarity the same as the polarity of the charged droplet. These potentials apply an electrostatic force gradient to the droplet as it passes through the rings, and thus reduce the speed at which the droplet travels. As the droplets passing through the deceleration ring arrangement are slowed, the droplets reform into a continuous stream prior to entering a collection vessel where the cells contained in the droplets are collected.

Claims

1. A device for influencing movement of an electrically charged droplet that has passed through an electric field, the device comprising:

a conductive element system disposed at a location traversed by the droplet after the droplet passes through the electric field; and

a potential source which applies at least one electrical potential to the conductive element system, said electrical potential influencing the movement of the droplet when the droplet traverses the conductive element system to selectively decelerate the droplet.

2. A device as claimed in claim 1, wherein:

the potential source applies the at least one electrical potential to the conductive element system such that the at least one electrical potential influences the path of movement of the droplet.

3. A device as claimed in claim 1, wherein:

the potential source applies the at least one electrical potential to the conductive element system such that the at least one electrical potential influences the speed of movement of the droplet.

4. A device as claimed in claim 1, wherein:

the conductive element system comprises a first conductive element arrangement and a second conductive element arrangement; and

the potential source is adaptable to apply a first potential to the first conductive element arrangement to influence the path of movement of the droplet, and a second potential to the second conductive element arrangement to influence the speed of movement of the droplet.

5. A device as claimed in claim 4, wherein:

the potential source applies the second potential to the second conductive element arrangement to decelerate the droplet.

6. A device as claimed in claim 1, wherein:

the conductive element system comprises a pair of conductive elements between which the droplet passes; and

the potential source is adaptable to apply the potential to the conductive element system as a potential difference between the conductive elements in the pair, so that the potential difference influences the path of movement of the droplet.

7. A device as claimed in claim 1, wherein:

the conductive element system comprises first and second pairs of conductive elements disposed such that the droplet passes between the conductive elements of the first pair and subsequently passes between the conductive elements of the second pair; and

the potential source applies said potential to the conductive element system as first and second potential differences between the conductive elements in the first and second pairs, respectively, so that the first and second potential differences and influence the path of movement of the droplet.

8. A device as claimed in claim 1, wherein:

the conductive element system comprises at least one conductive element having an opening therein, adaptable to allow passage of the droplet therethrough; and

the potential source applies the potential to the conductive element system as a respective potential for each said conductive element, to influence the speed of movement of the droplet.

9. A device as claimed in claim 8, wherein:

the respective potential of each said conductive element has a polarity the same as the polarity at which the droplet is charged, in order to repel the droplet and thereby decrease the speed of movement of the droplet.

10. A device as claimed in claim 9, wherein:

the respective potential of any said conductive element is different from that of any other said conductive element.

11. A device as claimed in claim 8, wherein:

at least one said conductive element comprises a plurality of sections, spaced from each other and configured to form said opening.

12. A device as claimed in claim 8, wherein:

the conductive element system comprises a plurality of said conductive elements, disposed in succession from a first said conductive element to a last said conductive element, such that the droplet passes successively through the openings in the conductive elements in a direction from the first to the last said conductive element.

13. A device as claimed in claim 12, wherein:

the voltage source applies said potential to the conductive element system as a respective potential for each of said conductive elements, with the respective potentials increasing successively such that the respective potential of the first said conductive element is the smallest and the respective potential of the last said conductive element is the largest.

14. A device as claimed in claim 12, wherein:

the conductive element system further comprises dielectric spacers which are disposed between adjacent said conductive elements.

15. A device for influencing movement of a plurality of electrically charged droplets that have passed through an electric field, the device comprising:

a plurality of conductive element systems, each disposed at a respective location traversed by any of said droplets after said droplets pass through the electric field; and

a potential source which applies a respective at least one electrical potential to each of the conductive element systems, each said respective at least one electrical potential influencing the movement of any of the droplets that traverses its respective conductive element system to selectively decelerate the droplet.

16. A device as claimed in claim 15, wherein:

the plurality of conductive elements systems are relocatable to different respective locations which are to be traversed by any of said droplets after passing through the electric field.

17. A device as claimed in claim 15, wherein:

the potential source applies the respective at least one electrical potential to the conductive element systems such that each said respective at least one electrical potential influences the path of movement of any of the droplets that traverses its respective conductive element system.

18. A device as claimed in claim 15, wherein:

the potential source applies the respective at least one electrical potential to the conductive element systems such that each said respective at least one electrical potential influences the speed of movement of any of the droplets that traverses its respective conductive element system.

19. A device as claimed in claim 15, wherein:

at least one of the conductive element systems comprises a first conductive element arrangement and a second conductive element arrangement; and

the potential source is adaptable to apply a first potential to the first conductive element arrangement of said at least one conductive element system to influence the path of movement of any of the droplets that traverses the first conductive element arrangement, and a second potential to the second conductive element arrangement of said at least one conductive element system to influence the speed of movement of any of the droplets that traverses the second conductive element arrangement.

20. A device as claimed in claim 15, wherein:

at least one of the conductive element systems comprises a pair of conductive elements between which any of the droplets pass; and

the potential source applies the respective potential to said at least one conductive element system as a potential difference between the conductive elements in the pair, so that the potential difference influences the path of movement of any of the droplets traversing the pair.

21. A device as claimed in claim 15, wherein:

at least one of the conductive element systems comprises first and second pairs of conductive elements disposed such that any of the droplets passes between the conductive elements of the first pair and subsequently passes between the conductive elements of the second pair; and

the potential source applies the respective potential to said at least one conductive element system as first and second potential differences between the conductive elements in the first and second pairs, respectively, so that the first and second potential differences each influences the path of movement of any of the droplets.

22. A device as claimed in claim 15, wherein:

at least one of the conductive element systems comprises at least one conductive element having an opening therein, adaptable to allow passage of any of the droplets therethrough; and

the potential source applies the respective potential to said at least one conductive element system as a respective voltage for each said at least one conductive element, to influence the speed of movement of any of the droplets.

23. A device as claimed in claim 22, wherein:

the respective potential of each said conductive element has a polarity the same as the polarity at which said any of the droplets are charged, in order to repel and thereby decrease the speed of movement of said any of the droplets.

24. A device as claimed in claim 23, wherein:

the respective potential of any said conductive element is different from that of any other said conductive element.

25. A device as claimed in claim 22, wherein:

at least one said conductive element comprises a plurality of sections, spaced from each other and configured to form said opening.

26. A device as claimed in claim 22, wherein:

said at least one conductive element system comprises a plurality of said conductive elements, disposed in succession from a first said conductive element to a last said conductive element, such that any of the droplets passes successively through the openings in the conductive elements in a direction from the first to the last said conductive elements.

27. A device as claimed in claim 26, wherein:

the voltage source applies the respective potential to said at least one conductive element system as a respective potential for each of said conductive elements, with the respective potentials increasing successively such that the respective potential of the first said conductive element is the smallest and the respective potential of the last said conductive element is the largest.

28. A device as claimed in claim 26, wherein:

said at least one conductive element system further comprises dielectric spacers which are disposed between adjacent said conductive elements.

29. A method for influencing movement of an electrically charged droplet that has passed through an electric field, comprising the steps of:

placing a conductive element system at a location to be traversed by the droplet after the droplet passes through the electric field; and

applying at lest one electrical potential to the conductive element system to cause the conductive element system to create an electrostatic force which influences the movement of the droplet to selectively decelerate the droplet.

30. A method as claimed in claim 29, wherein:

the potential applying step applies the at least one electrical potential to the conductive element system to create the electrostatic force such that it influences the path of movement of the droplet.

31. A method as claimed in claim 29, wherein:

the potential applying step applies the at least one electrical potential to the conductive element system to create the electrostatic force such that it influences the speed of movement of the droplet.

32. A method as claimed in claim 30, further comprising the steps of:

placing a second conductive element system at a location to be traversed by the droplet after its path of movement has been influenced by the electrostatic force; and

applying at least one second electrical potential to the second conductive element system to cause the second conductive element system to create a second electrostatic force which influences the speed of movement of the droplet.

33. A method as claimed in claim 32, wherein:

the step of applying the at least one second electrical potential causes the second conductive element system to create the second electrostatic force such that the second electrostatic force decelerates the speed of movement of the droplet.