Chemistry: electrical and wave energy – Processes and products – Electrophoresis or electro-osmosis processes and electrolyte...
Reexamination Certificate
1999-08-31
2002-03-05
Warden, Jill (Department: 1743)
Chemistry: electrical and wave energy
Processes and products
Electrophoresis or electro-osmosis processes and electrolyte...
C204S451000, C204S455000, C204S601000, C204S604000, C204S605000
Reexamination Certificate
active
06352633
ABSTRACT:
TECHNICAL FIELD
This invention relates to an automated apparatus for performing multiplexed Capillary Electrophoresis. It is especially useful in an automated Capillary Zone Electrophoresis (CZE) system for loading samples into a plurality of capillaries from wells of commercially available, microtitre trays of standard size.
BACKGROUND
The contents of commonly-owned U.S. patent application Ser. No. 09/105,988, which issued as U.S. Pat. No. 6,027,627 and also was published as WO 99/00664 are incorporated by reference to the extent necessary to understand the present invention. This reference discloses an automated apparatus for capillary electrophoresis.
FIG. 1
illustrates a prior art automated electrophoretic apparatus discussed in the above-referenced patent application for capillary electrophoresis. The apparatus includes a light source
452
, a processor/controller
404
, a dual carrousel arrangement having an upper carrousel
601
and a lower carrousel
602
which are aligned and spaced apart along a common axis and operated by a rotor
604
, a DC motor
605
having a movable member
603
to move a tray
214
place on one of the carrousels along a common axis toward or away from an array of capillary ends belonging to a capillary cartridge
300
, a detector
408
for detecting, at a window region
130
of the capillaries, the fluorescence emitted by samples migrating along the capillaries, and a computer monitor
406
to view the results of the migration. An electrophoretic medium, such as a gel, can be introduced into the capillaries via a conduit
606
in preparation for an electrophoretic run.
FIG. 2
illustrates a prior art plumbing system in accordance with the above-identified reference, for performing capillary electrophoresis using the device of FIG.
1
. In particular,
FIG. 2
shows the integration of a gel syringe
804
5
and an HPLC wash solvent system
807
into the solvent/gel delivery module. A solvent manifold
850
connects three inlets from the feeder tubes
806
of the solvent containers
801
,
802
,
803
to an outlet. Feeder tubes
806
from the solvent containers
801
,
802
,
803
are connected to the inlets of the solvent manifold
850
by tubing
860
. The controller
404
pictured in
FIG. 1
controls the solvent manifold
850
to select solvent from one of the three solvent containers
801
,
802
,
803
. The inlet of the HPLC pump
807
is connected to the outlet of the solvent manifold
850
by tubing
861
and the outlet of the HPLC pump
807
is connected to an inlet of a valve manifold
851
by tubing
862
.
The valve manifold
851
connects two inlets and an outlet. One inlet of the valve manifold
851
is connected to the gel syringe
804
by tubing
863
and the other inlet of the valve manifold
851
is connected to the outlet of the HPLC pump
807
. The outlet of the valve manifold
851
is connected to the solvent/gel input port
606
by tubing
864
. The controller
404
pictured in FIG. 11 causes the valve manifold
851
to select either the inlet connected to the gel syringe
804
or the inlet connected to the HPLC pump
807
. In this manner, gel and solvents are delivered to the capillary cartridge
909
in preparation for capillary gel electrophoresis of samples in microtitre tray
852
.
In the preferred embodiment, the tubing connecting the feeder tubes
806
of the solvent containers
801
,
802
,
803
to the inlets of the solvent manifold
850
is standard teflon tubing with a diameter of ⅛ inches. The tubing
861
connecting the outlet of the solvent manifold
850
to the inlet of the HPLC pump
807
is PEEK tubing with a diameter of {fraction (1/16)} inches. The tubing
861
connecting the outlet of the solvent manifold
850
to the inlet of the HPLC pump
807
, the tubing
862
connecting the outlet of the HPLC pump
807
to an inlet of the valve manifold
851
, the tubing
863
connecting the gel syringe
804
to an inlet of the valve manifold
851
and the tubing
864
connecting the outlet of the valve manifold
851
to the solvent/gel input port are PEEK tubing with a diameter of {fraction (1/16)} inches.
FIG. 3
illustrates a preferred embodiment of capillary cartridge
1180
in accordance with the above-identified application. In this embodiment, the capillary tubes run from their first ends
1188
disposed in an electrode/capillary array
1181
. The capillary tubes then run inside multilumen tubing
1183
. The multilumen tubing is taught in detail in U.S. patent application Ser. No. 08/866,308, which is incorporated by reference herein. The multilumen tubing
1183
is held firmly in place by tubing holders
1185
. The capillary tubes, without the protection the multilumen tubing, pass through an optical detection region
1187
. Beyond the optical detection region
1187
, the capillary tubes have a common termination and are bundled together and cemented into a high pressure T-shaped fitting
1182
made from electrically conductive material, which, during electrophoresis, is connected to electrical ground.
The tubing holders
1185
and the T-fitting
1182
are fixed to a cartridge base
1186
. The cartridge base
1186
is made from polycarbonate plastic for its dielectric characteristic. The base
1186
in turn is removably attached to a shuttle
1179
which includes a set of rail couplings
1184
protruding from its bottom. These rail couplings
1184
are arranged so that they fit on to a railing system (not shown in FIG. 18) of the apparatus in FIG.
1
. The railing system allows the shuttle
1184
to move between an in position and out position. The base
1186
is detached from the shuttle
1179
so that the cartridge
1180
is disposed (or cleaned) and a new (or cleaned) capillary cartridge is attached when the shuttle
1179
is in its out position. The combination of the railing system and the shuttle
1179
allows the newly attached capillary cartridge to be repeatedly located at the same position as that of the disposed capillary cartridge in relation to a camera and a laser (not shown in
FIG. 3
) when the shuttle
1179
is in its in position. In a preferred embodiment, the shuttle
1179
extends the length of the base
1186
with an opening to accommodate the electrode/capillary array
1181
; the shuttle
1179
is attached to the base
1186
by a plurality of removable fasteners
1178
.
The prior art plumbing system of FIG.
2
and T-fitting of
FIG. 3
are best suited for capillary gel electrophoresis. In capillary gel electrophoresis, the gel is fairly viscous, on the order of 50,000 centi-poise. This requires a system which can create pressure sufficient to load gel into the capillaries in preparation for a capillary electrophoresis run, and sufficient to expel the gel from the capillaries during reconditioning.
In contrast to the gels that are used in capillary gel electrophoresis, buffers are used to load the capillaries in capillary zone electrophoresis (CZE). These buffers have a viscosity on the order of that of water, i.e., about 1 centi-poise. While the low viscosity of buffers has the advantage of not needing high pressure to load and unload the electrophoretic medium, CZE with buffers does have the disadvantage of capillary siphoning. Capillary siphoning is characterized by the buffer solution at one end of the capillaries being completely drawn into the capillaries, thereby depleting the buffer at that one end. Like siphoning of any tubing, this problem occurs when the two ends of the capillaries terminate at different heights. The obvious solution to this problem is to ensure that opposite ends of the capillaries are maintained at the same level. This, however, is less than an ideal solution.
SUMMARY OF THE INVENTION
The present invention is directed to an automated parallel capillary zone electrophoresis (CZE) system. The CZE system of the present invention is realized by modifying the prior art capillary gel electrophoresis (CGE) system of the above-reference prior art. More particularly, the present invention is principally realized by modifying the plumbing at the ends of the cap
Kane Thomas E
Li Qingbo
Liu Changsheng
Pennie & Edmonds LLP
Spectrumedix Corporation
Starsiak Jr. John S.
Warden Jill
LandOfFree
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