Method and apparatus for syringe-based sample introduction within a flow cytometer

Abstract

An apparatus for introducing a specimen into a flow cytometer comprises: a syringe having a hollow barrel containing the specimen, a plunger partially within the barrel and a needle that extends into a volume of a nozzle of the flow cytometer; a one-way port in the nozzle forming a seal against the needle; a mounting platform coupled to both the syringe and to the flow cytometer; and a syringe pump coupled to the plunger, the syringe pump comprising a motor, a drive mechanism coupled to the motor; and a clamping mechanism coupled to the drive mechanism, wherein the motor operates the drive mechanism so as to cause the clamping mechanism to depress the plunger into the barrel.

1 . An apparatus for introducing a specimen into a flow cytometer, the apparatus comprising: 
 a syringe having a hollow barrel containing the specimen, a plunger partially within the barrel and a needle that extends into a volume of a nozzle of the flow cytometer;    a one-way port in the nozzle forming a seal against the needle;    a mounting platform coupled to both the syringe and to the flow cytometer; and    a syringe pump coupled to the plunger and comprising: 
 a motor,  
 a drive mechanism coupled to the motor; and  
 a clamping mechanism coupled to the drive mechanism and to an element of the group consisting of the syringe barrel, the mounting platform and the flow cytometer, wherein the motor operates the drive mechanism so as to cause the clamping mechanism to depress the plunger into the barrel.  
   
     
     
         2 . The apparatus of  claim 1 , further comprising: 
 a pressure sensor coupled to a sheath fluid line of the flow cytometer; and    a controller module electronically coupled to the pressure sensor and to the motor, wherein the pressure sensor transmits a signal based upon sheath fluid pressure in the sheath fluid line to the controller module.    
     
     
         3 . The apparatus of  claim 2 , wherein the controller module operates the motor in response to the signal to maintain a constant pressure differential between the sheath fluid pressure and a pressure of the specimen.  
     
     
         4 . The apparatus of  claim 2 , wherein the controller module varies the sheath fluid pressure in response to the signal to maintain a constant pressure differential between the sheath fluid pressure and a pressure of the specimen.  
     
     
         5 . The apparatus of  claim 1 , wherein the drive mechanism comprises a lead screw and the clamping mechanism comprises a plate engaged to the plunger and another plate engaged to an element of the group consisting of the syringe barrel, the mounting platform and the flow cytometer.  
     
     
         6 . An apparatus for introducing a specimen into a flow cytometer, the apparatus comprising: 
 a syringe having a hollow barrel containing the specimen, a plunger partially within the barrel and a needle that extends into a volume of a nozzle of the flow cytometer;    a hollow receptacle in the nozzle receiving and forming a seal against the needle;    a mounting platform coupled to both the syringe and to the flow cytometer; and    a syringe pump coupled to the plunger and comprising: 
 a motor,  
 a drive mechanism coupled to the motor; and  
 a clamping mechanism coupled to the drive mechanism and to an element of the group consisting of the barrel, the mounting platform and the flow cytometer, wherein the motor operates the drive mechanism so as to cause the clamping mechanism to depress the plunger into the barrel.  
   
     
     
         7 . The apparatus of  claim 6 , further comprising: 
 a pressure sensor coupled to a sheath fluid line of the flow cytometer; and    a controller module electronically coupled to the pressure sensor and to the motor, wherein the pressure sensor transmits a signal based upon sheath fluid pressure in the sheath fluid line to the controller module.    
     
     
         8 . The apparatus of  claim 7 , wherein the controller module operates the motor in response to the signal to maintain a constant pressure differential between the sheath fluid pressure and a pressure of the specimen.  
     
     
         9 . The apparatus of  claim 7 , wherein the controller module varies the sheath fluid pressure in response to the signal to maintain a constant pressure differential between the sheath fluid pressure and a pressure of the specimen.  
     
     
         10 . The apparatus of  claim 6 , wherein the drive mechanism comprises a lead screw and the clamping mechanism comprises a plate engaged to the plunger and another plate engaged to an element of the group consisting of the syringe barrel, the mounting platform and the flow cytometer.  
     
     
         11 . An apparatus according to  claim 1 , wherein the volume of specimen introduced into the nozzle is determined or calculated from the distance by which the plunger is depressed into the barrel.  
     
     
         12 . An apparatus according to  claim 1 , wherein the rate of introduction of specimen into the nozzle is determined or calculated from the rate by which the plunger is depressed into the barrel.  
     
     
         13 . An apparatus according to  claim 12 , wherein a rate of particle introduction into the nozzle is determined or calculated from a particle density of the specimen.  
     
     
         14 . A method for introducing a specimen into a flow cytometer comprises the steps of: 
 providing a syringe having a hollow barrel containing the specimen, a plunger partially within the barrel and a needle extending into a volume of a nozzle of the flow cytometer;    providing a one-way port in the nozzle container forming a seal against the needle;    providing a mounting platform coupled to both the syringe and to the flow cytometer;    providing a syringe pump coupled to the plunger and comprising: 
 a motor;  
 a drive mechanism coupled to the motor; and  
 a clamping mechanism coupled to the drive mechanism and to an element of the group consisting of the barrel, the mounting platform and the flow cytometer; and  
   operating the motor so as to operate the drive mechanism so as to cause the clamping mechanism to depress the plunger into the barrel.    
     
     
         15 . The method of  claim 14 , further comprising the steps of: 
 providing a pressure sensor coupled to a sheath fluid line of the flow cytometer;    providing a controller module electronically coupled to the pressure sensor and to the motor;    determining variations in sheath fluid pressure with the pressure sensor; and    transmiting a signal based upon sheath fluid pressure to the controller module.    
     
     
         16 . The method of  claim 15 , further comprising the step of using the controller module to operate the motor in response to the signal to maintain a constant pressure differential between the sheath fluid pressure and a pressure of the specimen.  
     
     
         17 . The method of  claim 15 , further comprising the step of using the controller module to control the sheath fluid pressure in response to the signal to maintain a constant pressure differential between the sheath fluid pressure and a pressure of the specimen.  
     
     
         18 . The method of  claim 14 , further comprising the step of determining or calculating the volume of specimen introduced into the nozzle from the distance by which the plunger is depressed into the barrel.  
     
     
         19 . The method of  claim 14 , further comprising the step of determining or calculating the rate of introduction of specimen into the nozzle from the rate by which the plunger is depressed into the barrel.  
     
     
         20 . The method of  claim 19 , wherein a rate of particle introduction into the nozzle is determined or calculated from a particle density of the specimen.