Vertical slab type electrophoresis apparatus

A novel vertical slab type electrophoresis apparatus, characterized by the provision of a gel holding glass sheet couple detachably fitted in a pair of tapered fitting groove formed opposingly on and along the entire length of glass support column portions of a buffer solution chamber by means of wedge-like fixing bars having an outer shape corresponding to the internal wall shape of said fitting groove. The electrophoresis apparatus precludes distortion of the gel which is gripped between the coupled glass sheets, permitting to obtain excellent migration images while preventing fracture of the glass sheets.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a vertical slab type electrophoresis apparatus, 
and more particularly to a vertical slab type electrophoresis apparatus 
which is capable of fixedly holding a gel holding glass sheet couple with 
uniform force and in a facilitated manner. 
2. Description of the Prior Art 
The vertical slab gel electrophoresis system which is superior to the disk 
type electrophoresis system in operationability and resolution and which 
is capable of two-dimensional development is frequently used these days as 
a means suitable for separation and analysis of biological components such 
as proteins, nucleic acids and the like. The conventional apparatus 
employed for such electrophoresis processes usually have a gel holding 
glass sheet couple connected to a buffer liquid chamber by fixing the 
opposite sides of the glass sheets to support column portions by the use 
of clips 10 or screws or by fixing arbitrary points by the means of wedges 
(FIG. 10). 
However, electrophoresis apparatus with such fixing means are found to be 
unsatisfactory because of the problems arising from uneven force of 
retention and fixation, e.g. distortion of gels, deterioration of 
migration images and fracture of glass sheets. 
SUMMARY OF THE INVENTION 
The present inventors have conducted an intensive study in search for a 
solution to the above-mentioned problems, and as a result found that the 
migration image can be improved to a marked degree by fixing the paired 
gel holding glass sheets with uniform force by the means of tapered 
fitting groove in combination with wedge-like fixing bars. 
More particularly, in accordance with the present invention, there is 
provided a vertical slab type electrophoresis apparatus including a gel 
holding glass sheet couple, characterized in that the apparatus comprises: 
a pair of tapered fitting groove formed opposingly on and along the entire 
length of glass support column portions of a liquid buffer chamber for 
receiving the opposite sides of the couple of gel holding glass sheets; 
and wedge-like fixing bars having an outer shape corresponding to the 
inner wall shape of the glass fitting groove and engageable in the fitting 
groove to fix the glass sheets detachably therein.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS 
Hereafter, the invention is described more particularly by way of preferred 
embodiments shown in the drawings. 
In the various figures, indicated at 1 is a gel holding glass sheet couple 
for grippingly holding a migration gel between two glass sheets. This gel 
holding glass couple may be constructed in an arbitrary form, for example, 
may be constituted by; a pair of glass sheets 1a and 1b which are bonded 
to each other through spacers 1c, one glass sheet 1a having an indented 
upper edge connecting the column portion 3 while the other glass sheet 1b 
is provided with a straight upper edge (FIG. 8); or a pair of 
straight-edged glass sheets 1d of different heights or lengths, which are 
bonded to each other through spacers 1c in such a manner that the upper 
edge of one glass sheet falls short of the other glass sheet (FIG. 9). 
The reference numeral 2 denotes a chamber forming structure cooperating 
with the gel holding glass sheet couple to form a chamber of a buffer 
liquid trough which may be of the type having inner and outer chambers or 
of the type having upper and lower chambers. 
Indicated at 3 are elongated glass support column portions which are formed 
in suitable positions depending upon the shape of the buffer liquid 
chamber. 
The glass support column portions 3 are each provided with tapered fitting 
groove 4 for receiving therein the glass sheet couple 1 and wedge-like 
fixing bars as will be described hereinlater, the fitting groove 4 being 
formed opposingly and tapered along the entire length of the glass support 
column portions 3. The tapered fitting groove 4 is broadened toward an 
opening through which the wedge-like fixing bar is inserted, for instance, 
toward the upper side (FIGS. 4 and 6), toward the lower side (FIG. 7) or 
toward the lateral side (FIG. 5). 
Designated at 5 are the wedge-like fixing bar which have an outer shape 
corresponding to the inner wall shape of the glass fitting groove 4, and 
inserted into the latter after fitting the opposite sides of the gel 
holding glass sheet couple 1 in the groove 4, thereby detachably fixing 
the glass sheet couple 1 in the groove 4. The column portions 3 and wedge 
like fitting 5 together form means for detachably securing the glass sheet 
couple to the cooperating chamber forming structure 2. 
For fixation of the gel holding glass sheet couple 1, it is desirable to 
provide packing 6 between the glass sheet couple 1 and the inner wall 
surface of the fitting groove 4. For this purpose, the glass fitting 
groove 4 are preferably provided with groove 41 on the inner wall surfaces 
for receiving the packing 6. 
With the apparatus of the invention as described above, the gel holding 
glass sheet couple is fixedly retained in the glass fitting groove on the 
glass support columns of the liquid buffer chamber by the wedge-like 
fixing bars, so that substantially uniform pressure is exerted on the 
glass sheet couple as a whole. 
Accordingly, the electrophoresis apparatus of the invention precludes 
distortion of the gel which is gripped between the coupled glass sheets, 
permitting to obtain excellent migration images while preventing fracture 
of the glass sheets. 
Besides, in case of the electrophoresis apparatus shown in FIG. 1 as an 
exemplary embodiment of the invention, it is possible to increase the 
height of the outer buffer liquid chamber 21 and cool the gel holding 
glass sheet couple from both of the inner and outer buffer liquid chambers 
22 and 21, allowing to conduct the electrophoresis with higher voltage and 
current as compared with conventional counterparts. For example, 
electrophoresis for a 10.times.8.6.times.0.1 cm SDS-polyacrylamide gel 
using 3 mm thick glass sheets can be conducted with a voltage and a 
current as high as 500 V and 60 mA, respectively, in a shortened migration 
time of about 30 minutes without a smile phenomenon of the migration 
image. When packing is used in combination with the glass sheet couple as 
shown in FIG. 9, it becomes possible to employ higher voltage (800 V) and 
current (1000 mA) for the electrophoresis thereby to shorten the migration 
time and obtain an improved migration image free of the smile phenomenon.