Method for studying floating, living cells

Abstract

Disclosed is a method of studying floating living cell by confining the cells floating in an aqueous medium in picowells located on a bottom surface of a top wall of a chamber. Disclosed is also a picowell-bearing device for the study of cells comprising a chamber having at least one picowell on a bottom surface of the chamber. Also disclosed is a picowell-bearing device for the study of cells comprising a chamber having at least one picowell on an internal surface and at least one moveable wall, a force applicator configured to removeably apply a substantially uniformly distributed force around the periphery of the moveable wall in a direction to retain the moveable wall secured to the chamber.

What is claimed is: 
     
         1 . A picowell-bearing device for the study of living cells, comprising:
 a) a chamber having a first wall and a second wall, respectively defining top and bottom walls for the chamber, wherein each wall has a first surface inside the chamber and a second surface outside the chamber; and   b) a first picowell inside the chamber, a bottom of which is on the first surface of the top wall,   wherein the device is configured such that the picowell is oriented with an open end of the facing downward when a living cell therein is being studied.   
     
     
         2 . The device of  claim 1 , wherein the first picowell is comprised in a first picowell array, all the picowells of which have their open ends facing downward when living cells therein are being studied. 
     
     
         3 . The device of  claim 1 , further comprising a second picowell inside the chamber, a bottom of which is on the top surface of the bottom wall of the chamber, and which has an open end facing upward when a living cell therein is being studied. 
     
     
         4 . The device of  claim 3 , wherein the second picowell is comprised in a second picowell array, all the picowells of which have their open ends facing upward when living cells therein are being studied. 
     
     
         5 . The device of  claim 1 , further comprising at least one fluid inlet path located below the open end of the first picowell in fluid communication with the chamber when a living cell in the first picowell is being studied. 
     
     
         6 . The device of  claim 5 , wherein the fluid inlet path is a capillary channel located below the open end of the first picowell. 
     
     
         7 . The device of  claim 1 , further comprising at least one fluid outlet path in fluid communication with the chamber when a living cell in the first picowell is being studied configured for removal of liquid from the chamber. 
     
     
         8 . The device of  claim 7 , wherein the fluid outlet path is a capillary channel located below the open end of the first picowell. 
     
     
         9 . The device of  claim 8 , including a further fluid outlet path configured for removal of gas from the chamber. 
     
     
         10 . The device of  claim 1 , wherein the top wall of the chamber is defined, at least in part, by a component that carries the first picowell. 
     
     
         11 . The device of  claim 2 , wherein the top wall of the chamber is defined, at least in part, by a component that carries the first picowell array. 
     
     
         12 . The device of  claim 1 , further comprising a base that defines, at least in part, the bottom wall of the chamber. 
     
     
         13 . The device of  claim 12 , further including a body positioned above the base, to which the first picowell array is attached. 
     
     
         14 . The device of  claim 13 , wherein the base is moveable relative to the body to provide access to the interior of the chamber. 
     
     
         15 . The device of  claim 13 , wherein the body includes transversely spaced longitudinally extending portions that define a sliding path for movement of the base. 
     
     
         16 . The device of  claim 13 , further including a base holder that cooperates with the body to retain the base in contact with a bottom surface of the body, while permitting sliding motion of the base. 
     
     
         17 . The device of  claim 16 , wherein the contact between the base and the body is such as to substantially prevent leakage of fluid from the chamber. 
     
     
         18 . The device of  claim 13 , wherein a bottom surface of the body includes a hollow in which the first picowell array is located. 
     
     
         19 . The device of  claim 13 , wherein the interior of the chamber is in communication with a fluid inlet path and a fluid outlet path formed by opposite ends of a capillary channel defined by a portion of the body and a portion of the base. 
     
     
         20 . The device of  claim 18 , further including a downwardly extending portion of the body on which the hollow is located, and which cooperates with the base to form at least part of the capillary channel. 
     
     
         21 . The device of  claim 20 , wherein the portion of the capillary channel downstream of the first picowell array provides a waste removal path. 
     
     
         22 . The device of  claim 21 , further including a waste reservoir at the downstream end of the waste removal path portion of the capillary channel. 
     
     
         23 . The device of  claim 16 , wherein the base holder is configured to resiliently engage the device body to retain the base in place vertically between device body and base holder. 
     
     
         24 . The device of  claim 18 , further including a liquid inlet opening, wherein the base and the liquid inlet opening cooperate to form a liquid reservoir in fluid communication with the capillary channel. 
     
     
         25 . The device of  claim 24 , wherein the liquid inlet opening is formed by a hole through the device body. 
     
     
         26 . The device of  claim 2 , wherein the picowells of the first picowell array are porous. 
     
     
         27 . The device of  claim 26 , further comprising a second chamber located above the picowell-containing chamber when the device is oriented for study of cells in the picowell array, wherein the second chamber is, in fluid communication with the picowell-containing chamber through the pores of the picowells comprised in the first picowell array. 
     
     
         28 . The device of  claim 27 , further including an air vent in the second chamber, wherein the upper chamber is configured to allow escape through the air vent of excess gas accumulated in the upper chamber after introduction of the medium and living cells into the device. 
     
     
         29 . The device of  claim 1 , wherein the chamber includes at least one element that is moveable to provide access to the interior of the chamber; and wherein the device further includes a force applicator operable to apply a force to the moveable element to retain the moveable wall secured to the chamber. 
     
     
         30 . The device of  claim 29 , wherein the force is a magnetic force. 
     
     
         31 . The device of  claim 29 , wherein the force applicator includes a magnet located at least in proximity to the periphery of the moveable wall. 
     
     
         32 . The device of  claim 29 , wherein the force applicator includes threads on the moveable wall. 
     
     
         33 . The device of  claim 29 , wherein the force applicator includes a rigid force distributor contacting the periphery of the moveable wall. 
     
     
         34 . The device of  claim 29 , wherein the force is applied substantially uniformly around the periphery of the moveable wall. 
     
     
         35 . The device of  claim 21 , further including a body of absorbent material in fluid communication with the waste removal path. 
     
     
         36 . The device of  claim 1 , further including a medium loading opening in fluid communication with the chamber, and a removable component to substantially seal the medium loading opening subsequent to introducing a fluid medium and at least one living cell into the chamber for study. 
     
     
         37 . The device of  claim 2 , wherein the first picowell array is an integral part of the bottom surface of the top wall of the chamber. 
     
     
         38 . The device of  claim 3 , wherein the bottom wall of the chamber includes a hollow on the surface thereof inside the chamber that contains the second picowell or the second picowell array. 
     
     
         39 . A picowell-bearing device for the study of living cells that have a density lower than that of a medium in which they are contained, comprising:
 a) a chamber having a top and a bottom wall, each wall having a first surface inside the chamber, and a second surface outside the chamber;   b) a first picowell array on the first surface of the top wall, wherein the picowells comprised in the picowell array are open at the ends that face the bottom wall of the chamber when cells in the picowells are being studied, whereby cells introduced into the chamber that have a density lower than that of a medium in which they are contained float upward and are trapped in the picowells during study;   c) a fluid reservoir coupled to the chamber by an inlet flow path;   d) an outlet flow path from the chamber;   e) a first flow control element that controls the rate of liquid flow from the fluid reservoir to the chamber;   f) a gas reservoir coupled to the inlet flow path; and   g) a second flow control element that controls the rate of gas flow from the gas reservoir to the inlet flow path.   
     
     
         40 . The device of  claim 39 , further including a controller that controls the first and second flow control elements. 
     
     
         41 . The device of  claim 40 , wherein the controller includes a microprocessor. 
     
     
         42 . The device of  claim 40 , further including sensors connected to the controller for the temperature of the medium in the chamber, and for the flow rate and gas content of the liquid in the inlet flow path. 
     
     
         43 . The device of  claim 40 , further including a heater that controls the temperature of a medium in the chamber; and
 a temperature sensor connected to the controller that determines the temperature of the medium in the chamber, wherein the controller is operable to control the heater to maintain a desired temperature of the medium.   
     
     
         44 . The device of  claim 39 , wherein fluid exiting the chamber through the outlet flow path is fed back to reenter the chamber through the inlet flow path. 
     
     
         45 . The device of  claim 39 , further including a second picowell array on the first surface of the bottom wall of the chamber, wherein the picowells comprised in the second picowell array are open at the ends that face the top wall of the chamber when cells in the second picowell array are being studied, whereby cells introduced into the chamber that have a density higher than that of a medium in which they are contained sink downward and are trapped in the picowells of the second picowell array during study.