Electrophoresis system

Abstract

A method for separating a sample into components by two-dimensional electrophoresis uses an IPG strip, and a gel slab which are spaced apart and carried on a single generally planar support means. The planar support means is first oriented in a generally vertical plane and the first electrophoretic separation medium is oriented in a horizontal plane spaced above or below the second electrophoretic separation medium by a gap. A first dimension separation of a sample mixture in the strip is then carried out while the strip and slab are separated by a non-electrically conducting liquid which is substantially immiscible with water and is non-extractive of water preferably paraffin oil. After the first separation has been carried the support means is tilted so that the first strip is at an angle to the horizontal and the paraffin is flushed out from the gap between the strip and the slab. Next agarose gel containing buffer is flowed into the gap to allow transfer of sample molecules from the strip to the slab under the influence of an electric field.

What is claimed is:  
     
         1 . An apparatus for carrying out a two-dimensional electrophoretic separation of a sample, said apparatus comprising: 
 a first electrophoretic separation medium comprising an elongate strip;    a second electrophoretic separation medium, both said media being spaced apart and carried on a single generally planar support means, said elongate strip having a top surface which lies above a surface of the planar support means; and    a thin film which sealingly attaches to the surface of the planar support means and, in conjunction with the planar support means, encloses the elongate strip.    
     
     
         2 . An apparatus according to  claim 1 , wherein the thin film is an electrically conductive thin film.  
     
     
         3 . An apparatus according to  claim 2 , wherein the thin film comprises a conductive plastic layer.  
     
     
         4 . An apparatus according to  claim 1 , wherein the thin film comprises a metal foil.  
     
     
         5 . An apparatus according to  claim 1 , wherein the media are spaced apart by a gap of from 1 to 4 mm.  
     
     
         6 . An apparatus according to  claim 1 , wherein the generally planar support means is comprised by a cassette, wherein the cassette further comprises a front wall, a rear wall and opposed side walls.  
     
     
         7 . An apparatus according to  claim 6 , wherein the elongate strip comprises ends which are separated from the adjacent side walls of the cassette by a gap of about 5 mm.  
     
     
         8 . An apparatus according to  claim 6 , wherein the cassette defines electrode bridge portions adjacent the ends of the strip.  
     
     
         9 . A two dimensional electrophoresis gel cassette comprising: 
 a cassette shell comprising a planar support surface;    a first electrophoretic separation medium comprising an elongate strip supported on the planar support surface, said elongate strip having a top surface which lies above a surface of the planar support surface;    a second electrophoretic separation medium comprising a slab supported on the planar surface; and    a removable thin film cover which sealingly attaches to the surface of the planar support surface of the cassette shell, and, in conjunction with the planar support surface, encloses the first medium,    wherein the cassette shell defines a fluid retaining space between the first medium and the second medium.    
     
     
         10 . A two dimensional electrophoresis gel cassette according to  claim 9 , wherein the removable thin film is an electrically conductive thin film.  
     
     
         11 . A two dimensional electrophoresis gel cassette according to  claim 10 , wherein the thin film comprises a conductive plastic layer.  
     
     
         12 . A two dimensional electrophoresis gel cassette according to  claim 9  wherein the removable thin film cover comprises a metal foil.  
     
     
         13 . A two dimensional electrophoresis gel cassette according to  claim 9 , wherein the first medium is in a dehydrated state.  
     
     
         14 . A two dimensional electrophoresis gel cassette according to  claim 9 , wherein the removable thin film cover comprises an electrically conductive plastic foil.  
     
     
         15 . A two dimensional electrophoresis gel cassette comprising: 
 a cassette shell having a planar support surface;    a first electrophoretic separation medium comprising an elongate strip supported on the planar support surface, said elongate strip having a top surface which lies above a surface of the planar support;    a second electrophoretic separation medium comprising a slab supported on the planar surface; and    a removable, thin film cover which sealingly attaches to the planar support surface and encloses the first medium in conjunction with the planar support surface,    wherein the cassette shell defines a fluid retaining space between the first medium and the second medium, wherein the fluid retaining space can retain a non-electrically conducting liquid whereby the first medium can be used to conduct an electrophoretic separation upon removal of the cover.    
     
     
         16 . A two dimensional electrophoresis gel cassette according to  claim 15 , wherein the removable thin film is an electrically conductive thin film.  
     
     
         17 . A two dimensional electrophoresis gel cassette according to  claim 16 , wherein the thin film comprises a conductive plastic layer.  
     
     
         18 . A two dimensional electrophoresis gel cassette according to  claim 15 , wherein the removable thin film cover comprises a metal foil.  
     
     
         19 . A two dimensional electrophoresis gel cassette comprising: 
 a cassette shell having a planar support surface;    a first electrophoretic separation medium comprising an elongate strip supported on the planar support surface, said elongate strip having a top surface which lies above a surface of the planar support;    a second electrophoretic separation medium comprising a slab supported on the planar surface; and    a removable thin film which sealingly attaches to the surface of the planar surface and, in conjunction with the planar support surface of the cassette shell, encloses the first medium,    wherein between the first and second mediums, the cassette shell defines a fluid retaining space for disposition of a bridging material, whereby the second medium can be used for electrophoretic separation of materials electrophoretically separated electrophoretically separated in the first medium.    
     
     
         20 . A two dimensional electrophoresis gel cassette according to  claim 19 , wherein the removable thin film is an electrically conductive thin film.  
     
     
         21 . A two dimensional electrophoresis gel cassette according to  claim 20 , wherein the thin film comprises a conductive plastic layer.  
     
     
         22 . A two dimensional electrophoresis gel cassette according to  claim 19 , wherein the removable thin film cover comprises a metal foil.  
     
     
         23 . A method of separating a sample into components by two dimensional electrophoresis using a cassette comprising a shell comprising a planar support surface, a first electrophoretic separation medium comprising an elongate strip supported on the planar support surface, said elongate strip having a top surface which lies above a surface of the planar support; a second electrophoretic separation medium comprising a slab supported on the planar surface; and a removable thin film cover which sealingly attaches to the surface of the planar support surface and which, in conjunction with the planar support surface encloses the first medium, the method comprising: 
 removing the cover;    introducing the sample into the first medium;    introducing a non-electrically conducting fluid between the first medium and the second medium;    electrophoretically separating in the first medium, material comprised by the sample;    replacing the non-electrically conducting fluid with a bridging material; and    electrophoretically separating in the second medium material electrophoretically separated in the first medium.    
     
     
         24 . A method according to  claim 23 , wherein the removable thin film is an electrically conductive thin film.  
     
     
         25 . A method according to  claim 24 , wherein the thin film comprises a conductive plastic layer.  
     
     
         26 . A method according to  claim 25 , wherein the removable thin film cover comprises a metal foil.  
     
     
         27 . A method according to  claim 23 , further comprising rehydrating the first medium.