Method for flexibly sorting particles

• US 5,998,212 A
• Filed: 08/26/1996
• Issued: 12/07/1999
• Est. Priority Date: 04/05/1991
• Status: Expired due to Fees

• Current Assignee: The University of Texas Medical Branch at Galveston (University of Texas System)
• Original Assignee: The University of Texas Medical Branch at Galveston (University of Texas System)
• Inventors: Leary, James F., Corio, Mark A.
• Primary Examiner(s): Pyon, Harold Y.
• Application Number:
  US08/697,296
• Time in Patent Office: 1,198 Days
• Field of Search: 436/8, 436/63, 436/800, 209/906, 209/579, 209/3.1, 422/82.01, 422/68.1
• US Class Current: 436/63
• CPC Class Codes: G01N 15/1427 with the synchronisation of components, a time gate for operation of components, or suppression of particle coincidences
• CPC Class Codes: G01N 15/1429 Signal processing
• CPC Class Codes: G01N 15/1459 the analysis being performed on a sample stream
• CPC Class Codes: G01N 15/149 specially adapted for sorting particles, e.g. by their size or optical properties
• CPC Class Codes: G01N 2015/1488 Methods for deciding
• CPC Class Codes: Y10S 209/906 Pneumatic or liquid stream feeding item

Abstract

This invention relates to a method and apparatus for flexibly controlling sorting decisions for a flow cytometer or similar instrument at a purity vs. yield ratio of sorted particles, particularly at high event rates. The system monitors distances between sequential objects to determine if they are in close enough proximity to be within a single resolution unit of the sorting device. The "friend" or "foe" status of neighboring events is considered by this system in dealing with detected "coincident" events. The system operates on information of the desirability to sort the object, i.e. droplet, based upon the properties of the individual object. A storage and retrieval method is provided for making the information available at the time a sort operation based on a sorting logic condition is performed. Accordingly, an easily reconfigurable mode of operation control is provided to allow customized sorting strategies, based on the needs of individual applications or experiments. This system may be included as an integral part of a flow cytometer/cell sorter or similar instrument and may also be provided as an outboard module to such systems.

Claims

1. A method for sorting particles comprising:

receiving detection signals representing selected parameters of moving particles from a sensor;

generating respective trigger signals and a respective individual sort decision in response to the detection signals received from said sensor;

detecting an overlap condition of successive respective trigger signals in response to time separation between trigger signals of less than selected intervals and producing respective overlap detecting signals in response to the overlap condition;

determining a logic condition in response to a selected combination of the respective individual sort decisions and the overlap detecting signals; and

applying a sort pulse to the moving particles when a selected yield/purity ratio which includes intermediate values between maximum yield and maximum purity correspond to a selected logic condition.

2. A method for sorting particles as in claim 1 further comprising:

defining the value of the sort pulse based on the logic condition.

3. A method for sorting particles as in claim 1, wherein said steps for sorting particles are performed with a control system comprising:

timing circuitry receiving said detection signals generated by said sensor and generating a trigger signal after a predetermined time interval for each of [the input] said detection signals generated by said sensor;

inter-event counting circuitry for receiving the trigger signals generated by said timing circuitry and incrementing an inter-event counter in response to said detection signals generated by said sensor received within said predetermined time interval;

inter-event storage circuitry for storing values of said inter-event counter;

sort decision storage circuitry for storing sort decision values for respective characteristics of said particles;

sort decision control circuitry receiving the trigger signal generated by said timing circuitry and thereby updating an availability level variable in response to the trigger signal generated by said timing circuitry;

said sort decision control circuitry generating a read storage signal for respectively reading sort decision values from said sort decision storage circuitry and values of said inter-event counter from said inter-event storage circuitry in response to the trigger signal generated by said timing circuitry;

comparing circuitry coupled to said inter-event storage circuitry, for comparing said respective values of said inter-event counter with a predetermined value to thereby generate compared values when said respective values of said inter-event counter are less than said predetermined value; and

logic decision circuitry receiving said respective sort decision values from said sort decision circuitry, said availability level variable updated by said sort decision control circuitry, and said compared values generated by said comparing circuitry, and generating said sort pulse.

4. A method for sorting particles as in claim 1, wherein said steps for sorting the particles are performed with a control system comprising:

a timing circuit which receives the detection signals from said sensor and generates a respective trigger signal;

an overlap detection circuit responsive to successive trigger signals generated by said timing circuit, to generate respective overlap detecting signals in response to time separation of less than selected intervals;

a sort logic circuit responsive to the trigger signals generated by said timing circuit, the detection signals and the overlap detecting signals generated by said overlap detection circuit, to generate respective sort pulses to be applied to the respective particles.

5. A method for sorting particles comprising:

generating input signals for particles from a sensor;

receiving said input signals generated by said sensor using timing circuitry and generating a trigger signal with said timing circuitry after a predetermined time interval for each of the input signals generated by said sensor;

receiving the trigger signals generated by said timing circuitry with inter-event counting circuitry and incrementing an inter-event counter in response to said input signals received within said predetermined time interval;

storing values of said inter-event counter in said inter-event storage circuitry;

storing sort decision values for respective characteristics of the particles;

receiving the trigger signal generated by said timing circuitry with sort decision control circuitry and updating an availability level variable in said sort decision control circuitry in response to the trigger signal generated by said timing circuitry;

generating a read storage signal with said sort decision control circuitry for respectively reading sort decision values from said sort decision storage circuitry and values of said inter-event counter from said inter-event storage circuitry in response to the trigger signal generated by said timing circuitry;

comparing said respective values of said inter-event counter with a predetermined value to generate compared values when said respective values of said inter-event counter are less than said predetermined value; and

receiving said respective sort decision values from said sort decision circuitry, said availability level variable updated by said sort decision control circuitry, and said compared values generated by said comparing circuitry, with logic decision circuitry, and generating with said logic decision circuitry a sort pulse signal for the particles in response to the trigger signal generated by said timing circuitry whenever a selected yield/purity ratio which includes intermediate values between maximum yield and maximum purity occurs.

6. A method for sorting particles as comprising:

generating detection signals pertaining to selected parameters for respective particles in response to the respective particles passing a selected point;

receiving the detection signals with a timing circuit, and generating a respective trigger signal;

generating respective overlap signals in response to time separation of less than selected intervals, with an overlap detection circuit responsive to successive trigger signals generated by said timing circuit;

generating respective sort logic signals to be applied to the respective particles whenever a selected yield/purity ratio which includes intermediate values between maximum yield and maximum purity correspond to a selected logic condition, said sort logic signals being generated by a sort logic circuit responsive to the trigger signals generated by said timing circuit, the detection signals and the overlap signals.