Chemistry: electrical and wave energy – Processes and products – Electrophoresis or electro-osmosis processes and electrolyte...
Patent
1996-12-20
1998-04-07
Gorgos, Kathryn L.
Chemistry: electrical and wave energy
Processes and products
Electrophoresis or electro-osmosis processes and electrolyte...
204466, 204616, 204618, 204619, G01N 2726, G01N 27447
Patent
active
057360227
DESCRIPTION:
BRIEF SUMMARY
This application is a national stage application of PCT/SE95/00762 filed Jun. 21, 1995 published as WO95/35496 Dec. 28, 1995.
TECHNICAL FIELD
The invention relates to a spacer in the form of an elongated, rectangular parallelepiped for use between the two glass plates of a gel cassette to delimit a space for receiving an electrophoresis gel between the glass plates, an arrangement at a gel cassette having two glass plates which are kept apart by means of at least two spacers to define a space for receiving an electrophoresis gel, said spacers being in the form of elongated, rectangular parallelepipeds, and use of such a gel cassette.
BACKGROUND OF THE INVENTION
From U.S. Pat. No. 4,675,095 such a spacer is known in an electrophoresis apparatus of the fluorescence detection type, where light from an excitation light source is projected from the side into the electrophoresis gel to enable detection of fluorophor labelled fragments in samples that migrate along electrophoretic paths in the gel. From this U.S. patent it is apparent that the spacer is to be transparent with respect to the excitation light. In a commercial embodiment, this spacer is a plastic spacer. A disadvantage of a plastic spacer is that it is very difficult to produce the optical surfaces that are necessary in order to project the excitation light into the gel with high efficiency. Moreover, tensions in the plastic material can give rise to unwanted optical effects. Furthermore, the useful life of such spacers will be very short since the plastic material is easily scratched. Another disadvantage is that the separation medium used is not polymerized homogeneously enough adjacent to plastic spacers upon casting, which causes so called "smiling" and a skew migration of the samples in the gel during an electrophoresis run. Also, a poorly polymerized gel can cause refractions that deflect the excitation light.
An attempt to eliminate these problems is known from WO 87/07719, where the spacers are divided and separate light guides are inserted between the respective spacer parts to guide the excitation light into and out of the gel. In a commercial embodiment the spacer parts are of plastic while the light guides are of glass.
However, the handling of divided spacers of plastic with separate light guides is problematic in view of the fact that a number of separate parts are to be fitted together. The light guides can namely easily end up misaligned and, moreover, sealing problems can appear upon casting of the gel.
BRIEF DESCRIPTION OF THE INVENTION
The object of the invention is to bring about a spacer of the type mentioned in the introductory portion, which does not possess the disadvantages of the spacers known so far.
This is attained by means of the spacer according to the invention in that it is of glass.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is an end view of a gel cassette having spacers in accordance with the present invention.
PREFERRED EMBODIMENT
The single figure (FIG. 1) is an end view of a gel cassette having two glass plates 1 and 2, which are kept separate by means of two spacers 3a and 3b according to the invention to delimit, in a manner known per se, a space 4 for receiving an electrophoresis gel (not shown).
The spacers 3a and 3b comprise separate, elongated, rectangular parallelepipeds and, in accordance with the invention, in the gel cassette shown, at least one of the spacers is completely made of glass, e.g. a boron silicate glass, in order for the gel cassette to be usable in electrophoresis apparatuses where excitation light is projected from the side into the gel for automatic direct detection of e.g. fluorephor labelled samples.
By making the spacers 3a and 3b completely of glass a more homogenous polymerization of a gel which is cast in the space 4 between the plates 1 and 2, is obtained in that it polymerizes better against glass than against plastic. In an electrophoresis run this will appear in the form of considerably less so called "smiling" and skew migration of the samples in the gel adjacent
REFERENCES:
patent: 4518476 (1985-05-01), Delony et al.
patent: 4675095 (1987-06-01), Kambara et al.
patent: 4839016 (1989-06-01), Anderson
patent: 5186807 (1993-02-01), Sanford et al.
Gorgos Kathryn L.
Pharmacia Biotech AB
Starsiak Jr. John S.
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