Robotic syringe system utilizing a liquid piston for the measurement and dispensing of fluid samples

Abstract

Described here is a mechanical and electronic device which can accurately draw up and dispense a volume of fluid. A novel syringe is described which can replace (and overcome some of the shortfalls) of the traditional mechanical syringe by way of a liquid syringe. The syringe system is designed to be used in conjunction with modern liquid handling systems used in biological and biochemical research as related to drug screening. However, the syringe system is not limited to such applications. Also of key importance to this invention, is the use of a monitoring system to accurately monitor and record the actual volumes being drawn up and dispensed. The liquid piston has the advantage of reduced friction and removes the necessity for there to be any o-ring or sealing system which requires periodic replacement and/or maintenance.

1 . A syringe pump comprising a mechanism for engaging and driving a plunger of a syringe inside a syringe barrel and where said plunger is comprised of a liquid.  
   
   
       2 . The system according to  claim 1 , wherein said mechanism for engaging and driving the said liquid plunger consists of two reservoirs of the same liquid and one reservoir is under a pressure greater then the ambient pressure (a pressure source) and one reservoir is under a pressure less then the ambient pressure (a vacuum source); and 
 a. where said mechanism consists of two valves connecting the said reservoirs to the said plunger such that the said plunger's motion can be controlled inside the said syringe barrel using the valves; and    b. where the pressures of the said reservoirs are kept constant; and    c. where the position of the said plunger can be monitored to control the volume delivered by the syringe pump.    
   
   
       3 . The system according to  claim 1 , wherein said mechanism for engaging and driving the said liquid plunger consists of a gear pump.  
   
   
       4 . The system according to  claim 2 , wherein the said syringe pump can aspirate a solution by opening of the valve connected to the said vacuum source, effectively moving the said plunger out of the syringe barrel.  
   
   
       5 . The system according to  claim 2 , wherein the said syringe pump can dispense a solution by opening of the valve connected to the said pressure source, effectively moving the said plunger into the syringe barrel.  
   
   
       6 . The system of  claim 5 , wherein the time the said valve is open is proportional to the total volume that is dispensed by the syringe.  
   
   
       7 . The system of  claim 2 , wherein the said valves are controlled using solenoids and pulsed width modulation.  
   
   
       8 . The system according to  claim 1 , wherein the said barrel is of diameter 0.1 millimeter to 20 millimeter.  
   
   
       9 . The system according to  claim 1 , wherein the said barrel is composed of a transparent glass or plastic.  
   
   
       10 . The system according to  claim 1 , wherein said liquid is composed of a liquid with a suitable opacity, viscosity, and boiling point.  
   
   
       11 . The system according to  claim 1 , wherein the said liquid is one of water and oil.  
   
   
       12 . An optical detection system to monitor the position of a syringe plunger consisting of: 
 a. a charge-coupled device (CCD) camera able to detect the position of the liquid piston; and    b. where the distance that the piston moves can be related by mathematical equations to the volume of liquid either aspirated or dispensed.