Devices and methods for overlaying blood or cellular suspensions

Abstract

A device is described that overlays a first fluid, such as blood or a cellular suspension onto a base material, such as a Ficoll liquid density gradient. In some embodiments, the fluid layering device includes a cylindrical reservoir, a fluid barrier, a coupling extension, one or more helical channels in fluid communication with the reservoir, and an exhaust vent. The fluid layering device can be coupled through its coupling extension to an open end of a container, such as a conical centrifuge tube, including the base material. Once attached, the device regulates flow of the first fluid from the reservoir into the conical tube so that a suitable overlay is formed without substantially disturbing a surface of the base material, regardless of the care and skill of the user.

1 . A fluid layering device configured to control a flow of fluid into an open-ended container, comprising:
 a fluid barrier configured to prevent passage of fluid from a proximal reservoir toward a distal end of the open-ended container;   a peripheral seal extending along an outer perimeter of the fluid barrier, the peripheral seal configured for sealing engagement along an interior surface of the open-ended container;   at least one groove formed in the peripheral seal, configured to provide a controlled flow of fluid across the fluid barrier and along the interior surface of the open-ended container; and   an exhaust vent configured to vent from the open-ended container gas displaced by the controlled flow of fluid.   
     
     
         2 . The fluid layering device of  claim 1 , further comprising a proximal reservoir defined at least partially by a proximal surface of the fluid barrier. 
     
     
         3 . The fluid layering device of  claim 2 , wherein the reservoir is open-ended, defined by an elongated cylindrical wall extending proximally from the fluid barrier. 
     
     
         4 . The fluid layering device of  claim 3 , further comprising a coupling arrangement adjacent to the open end of the reservoir. 
     
     
         5 . The fluid layering device of  claim 4 , wherein the coupling arrangement comprises a thread. 
     
     
         6 . The fluid layering device of  claim 1 , wherein the fluid barrier comprises at least one drain port in fluid communication with a proximal end of each of the at least one grooves. 
     
     
         7 . The fluid layering device of  claim 1 , further comprising a proximal handle allowing for insertion and removal of the fluid layering device with respect to the open-ended container. 
     
     
         8 . The fluid layering device of  claim 1 , wherein the exhaust vent terminates in an exhaust port disposed along an outer surface of the fluid layering device. 
     
     
         9 . The fluid layering device of  claim 1 , wherein each of the at least one grooves extends helically along a cylindrical surface defining the peripheral seal. 
     
     
         10 . The fluid layering device of  claim 1 , further comprising a shoulder positioned to abut at least a portion of a rim of the open-ended container when the fluid layering device is inserted therein, the shoulder position with respect to a proximal end of the fluid layering device to control height of the fluid barrier along a longitudinal axis of the open-ended container. 
     
     
         11 . The fluid layering device of any of the above claims, wherein the fluid layering device is sterilized. 
     
     
         12 . The fluid layering device of any of the above claims, wherein the fluid layering device is formed from material selected from the group consisting of: plastics; polymers; resins; glass; ceramics; metals; and combinations thereof. 
     
     
         13 . The fluid layering device of any of the above claims, wherein fluid stored within the fluid layering device is observable through a sidewall of the device. 
     
     
         14 . The fluid layering device of  claim 13 , wherein at least a portion of the fluid layering device is translucent or transparent. 
     
     
         15 . A method for controlling a flow of fluid into an open-ended container, comprising:
 positioning a fluid barrier above a surface of a base material disposed in a distal end of the open-ended container;   adding a first fluid into a reservoir positioned proximal to the fluid barrier;   directing a flow of fluid from the reservoir across the fluid barrier and into the distal end of the open-ended container, fluid passing the fluid barrier flowing toward the base material along an interior surface of the open-ended container; and   exhausting from the distal end of the open-ended container gas displaced by the controlled flow of fluid,   wherein a layer of the first fluid is deposited over the base material without substantially disturbing a surface of the base material.   
     
     
         16 . The method of  claim 15 , wherein positioning the fluid barrier comprises inserting at least a proximal portion of a fluid layering device into an open end of the open-ended container. 
     
     
         17 . The method of any of  claims 15 - 16 , further comprising removing the fluid barrier from the open-ended container. 
     
     
         18 . The method of  claim 17 , further comprising centrifuging the layered material. 
     
     
         19 . The method of any of  claims 15 - 17 , wherein the base material is Ficoll. 
     
     
         20 . The method of any of  claims 15 - 18 , wherein the fluid is a cellular suspension. 
     
     
         21 . The method of  claim 20 , wherein the cellular suspension is blood. 
     
     
         22 . A fluid layering device configured to control a flow of fluid into an open-ended container, comprising:
 means for positioning a fluid barrier above a surface of a base material disposed in a distal end of the open-ended container;   means for adding a first fluid into a reservoir positioned proximal to the fluid barrier;   means for directing a flow of fluid from the reservoir across the fluid barrier and into the distal end of the open-ended container, fluid passing the fluid barrier flowing toward the base material along an interior surface of the open-ended container; and   means for exhausting from the distal end of the open-ended container gas displaced by the controlled flow of fluid.   
     
     
         23 . A fluid layering device configured to control a flow of fluid into an open-ended container containing a base material, comprising:
 a longitudinally extending cylindrical side wall open at its proximal end;   a fluid barrier disposed across a distal end of the cylindrical side wall, a proximal surface of the fluid barrier and an interior surface of the cylindrical side wall forming an open-ended reservoir;   an insertable portion extending distally from the fluid barrier; the insertable portion comprising:
 a longitudinally extending sealing wall positioned to form a fluid-tight seal along a peripheral interior surface of a proximal portion of the open-ended container; 
 at least one groove extending along the sealing wall and terminating in a peripheral fluid port configured to ensure fluid flowing into the open-ended container flows along an interior surface of the open-ended container; 
   at least one drain in fluid communication between the reservoir and a proximal end of each of the at least one grooves; and   an exhaust vent in fluid communication with the open-ended container, wherein the vent regulates the flow of gas displaced by the controlled flow of fluid, thereby contributing to a rate of fluid flow.   
     
     
         24 . The fluid layering device of  claim 23 , wherein at least one groove extends helically along the sealing wall. 
     
     
         25 . The fluid layering device of  claim 23 , further comprising a threaded coupling engagement along a distal portion of the cylindrical wall.