Methods and apparatus for electrophoresis of prior-cast, hydratable separation media

Abstract

Methods and apparatus are presented that facilitate electrophoresis of prior-cast, hydratable separation media, usefully immobilized pH gradient (IPG) strips. The method exploits the swelling of prior-cast, hydratable separation media upon rehydration to help lodge the media in an enclosing member that permits spaced electrical communication with the enclosed separation media. The electrical communication permits a voltage gradient to be established in the enclosed separation medium sufficient to effect separation of analytes therein. Cassettes, buffer cores, electrophoresis systems and kits are presented for effecting the methods of the invention.

1 . A method for performing electrophoresis, comprising: 
 hydratingly lodging a prior-cast hydratable electrophoretic separation medium within an enclosing member that permits spaced electrical communication with said enclosed medium; and then    using said spaced electrical communication to establish a voltage gradient in said medium sufficient to effect electrophoretic separation of analytes therein.    
   
   
       2 . The method of  claim 1 , further comprising the antecedent step of inserting said prior-cast hydratable electrophoretic separation medium in its dehydrated state within said enclosing member.  
   
   
       3 . The method of  claim 2 , wherein said step of hydratingly lodging comprises: 
 contacting said enclosed dehydrated prior-cast hydratable electrophoretic separation medium with an aqueous solution for a time sufficient to lodge said separation medium within said enclosing member.    
   
   
       4 . The method of  claim 3 , wherein said aqueous solution comprises a sample to be separated in said prior-cast hydratable separation medium.  
   
   
       5 . The method of  claim 1 , further comprising a later step of removing said prior-cast hydratable electrophoretic separation medium from said enclosing member.  
   
   
       6 . The method of any of claims  1 - 5 , wherein said prior-cast hydratable electrophoretic separation medium has an immobilized pH gradient.  
   
   
       7 . A cassette for performing electrophoresis, comprising: 
 means for hydratingly lodging a prior-cast electrophoretic separation medium within an enclosing member; and    means for spaced electrical communication with said enclosed medium,    wherein said spaced electrical communication means can be used to establish a voltage gradient in said enclosed separation medium sufficient to effect electrophoretic separation of analytes therein.    
   
   
       8 . A cassette for performing electrophoresis, comprising: 
 a form-retaining member; and    at least one channel, wherein    said form-retaining member imparts dimensional integrity to said at least one channel;    said at least one channel has a first channel entry, a second channel entry, and a cavity therebetween, said channel cavity being so dimensioned as to permit insertion of a hydratable prior-cast electrophoretic separation medium in its dehydrated state and lodgingly enclose said hydratable prior-cast electrophoretic separation medium in its rehydrated state; and    said first and second channel entries permit spaced electrical communication with said channel cavity.    
   
   
       9 . The cassette of  claim 8 , wherein said cassette comprises a plurality of said channels.  
   
   
       10 . The cassette of  claim 8 , wherein said form-retaining member contributes the entire circumferential wall of the cavity of each of said at least one channel.  
   
   
       11 . The cassette of  claim 8 , further comprising: 
 a laminate cover,    wherein said laminate cover adheres directly or indirectly to said form-retaining member and contributes at least part of the circumferential wall of each of said at least one channels.    
   
   
       12 . The cassette of  claim 11 , wherein adherence of said laminate cover to said form-retaining member is reversible.  
   
   
       13 . The cassette of  claim 8 , further comprising: 
 a first well-forming member,    wherein said first well-forming member adheres, directly or indirectly, to said form-retaining member and defines a separate fluid reservoir at the first channel entry of each of said at least one channel.    
   
   
       14 . The cassette of  claim 13 , further comprising: 
 a second well-forming member,    wherein said second well-forming member adheres, directly or indirectly, to said form-retaining member and defines a separate fluid reservoir at the second channel entry of each of said at least one channel.    
   
   
       15 . The cassette of  claim 14  wherein adherence of said well-forming members to said form-retaining member is reversible.  
   
   
       16 . The cassette of  claim 8 , wherein, for each of said at least one channel, said first and second channel entries permit electrical communication with the cavity therebetween through a common surface of said cassette.  
   
   
       17 . The cassette of  claim 8 , wherein, for each of said at least one channel, said first and second channel entries permit electrical communication with the cavity therebetween through separate surfaces of said cassette.  
   
   
       18 . The cassette of any of claims  8 - 17 , further comprising: 
 at least one prior-cast hydratable electrophoretic separation medium,    wherein each of said at least one prior-cast separation medium is engaged in a separate channel of said cassette.    
   
   
       19 . A kit for electrophoresing prior-cast hydratable electrophoretic separation media, comprising: 
 a cassette according to  claim 9;  and    at least one prior-cast hydratable electrophoretic separation medium suitably dimensioned as to be hydratingly lodgeable in said cassette.    
   
   
       20 . A kit for electrophoresing prior-cast hydratable electrophoretic separation media, comprising: 
 a cassette according to  claim 9;  and    at least one conductive wick.    
   
   
       21 . A buffer core for vertical electrophoresis of prior-cast hydratable separation media, comprising: 
 a substantially inflexible frame, said frame having a first cassette engagement face;    an anode; and    a cathode,    wherein said anode and cathode are positioned to effect simultaneous spaced contact with a common surface of a cassette operationally contacted to said first cassette engagement face.    
   
   
       22 . A buffer core according to  claim 21 , further comprising: 
 a second cassette engagement face;    wherein operational engagement of a first and second cassette respectively to said first and second frame engagement faces creates a chamber internal to said frame that is sealed on 5 sides;    wherein said cathode and said anode are each in electrical communication with the interior of said internal chamber; and    wherein operational contact of a first and second cassette to said respective first and second frame engagement faces causes spaced contact of said anode and said cathode to a common surface of at least one of said cassettes.