U.S. patent number 3,773,647 [Application Number 05/252,817] was granted by the patent office on 1973-11-20 for low voltage electrophoretic testing system.
This patent grant is currently assigned to Electro-Nucleonics Laboratories, Inc.. Invention is credited to Frank Karsai, Richard Max Mandle.
United States Patent |
3,773,647 |
Mandle , et al. |
November 20, 1973 |
LOW VOLTAGE ELECTROPHORETIC TESTING SYSTEM
Abstract
A low voltage electrophoretic testing system is provided
incorporating the various individual components thereof, the system
being adapted especially for use with the electrophoresis test kit
units, including the various modifications thereof, disclosed and
claimed in our copending application, filed even date herewith and
entitled "Electrophoresis Test Kits and Method of Making the
Same."
Inventors: |
Mandle; Richard Max (Pompton
Lake, NJ), Karsai; Frank (Dover, NJ) |
Assignee: |
Electro-Nucleonics Laboratories,
Inc. (Bethesda, MD)
|
Family
ID: |
22957678 |
Appl.
No.: |
05/252,817 |
Filed: |
May 12, 1972 |
Current U.S.
Class: |
204/607 |
Current CPC
Class: |
G01N
27/44756 (20130101) |
Current International
Class: |
G01N
27/447 (20060101); B01k 005/00 () |
Field of
Search: |
;204/18S,18G,299 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mack; John H.
Assistant Examiner: Prescott; A. C.
Claims
What is claimed is:
1. An electrophoretic testing apparatus, comprising, in
combination,
a unitary structure having a base wall,
a first vertical wall dividing said structure into an electrolyte
compartment having a length and into an outer compartment,
two horizontally spaced, substantially parallel, rigid and
clyindrical electrodes extending supportably through said first
vertical wall in fluid-sealing relation therewith and extending
substantially throughout the said length of said electrolyte
compartment,
a second vertical wall positioned generally parallel to said first
vertical wall and spaced therefrom by substantially said
length,
two parallel side walls joined to said base wall and said two
vertical walls in fluid-sealing relation,
a third vertical wall extending substantially parallel to said
electrodes and positioned within said electrolyte compartment
between said electrodes and dividing said electrolyte compartment
into two side-by-side electrolyte compartments,
each of said side-by-side compartments containing one of said
electrodes, and
a supporting saddle member for said electrodes positioned adjacent
to and parallel to said second vertical wall.
2. The combination of claim 1 wherein said first vertical wall has
positioned substantially adjacent and parallel thereto a second
supporting saddle member for said electrodes.
3. The combination of claim 1 wherein said first saddle member is
integral with said second vertical wall.
4. The combination of claim 4 wherein said second saddle member is
integral with said first vertical wall.
5. The combination of claim 1 wherein said parallel side walls have
separate top surfaces adapted to support an electrophoresis test
kit unit.
6. The combination of claim 1 wherein said electrolyte compartment
has positioned thereon orienting means adapted to insure properly
oriented positioning of an electrophoresis test kit unit
positionable thereon.
7. The combination of claim 7 wherein at least one of said top
surfaces has a vertical projection thereon, said projection serving
to orient said supported test kit unit.
8. The combination of claim 1 wherein a baffle and shield member is
positioned substantially within said electrolyte compartment.
9. The combination of claim 8 wherein said third vertical wall has
a top surface and said baffle and shield member is supported on
said top surface on said third vertical wall.
10. The combination of claim 9 wherein said top surface has
projections and said baffle and shield member has passages adapted
to frictionally fit over said projections.
11. The combination of claim 8 wherein said baffle and shield
member has a substantially horizontal top shelf wall and a
depending vertical wall supported from each edge of said shelf
wall.
12. The combination of claim 11 wherein said vertical walls diverge
downwardly.
13. The combination of claim 14 wherein each separate diverging
portion of said baffle and shield member walls substantially covers
one of said electrodes.
14. The combination of claim 43 wherein said saddle member has two
spaced positoning slots, and said electrolyte chamber has
positioned therein a baffle and shield member having separate
diverging vertical leg portions, each of said separate leg portions
being positioned within a separate one of said slots.
15. The combination of claim 43 wherein each of said saddle members
has two spaced positioning slots, and said electrolyte chamber has
positioned therein a baffle and shield member having separate
diverging vertical leg portions, the opposite ends of said leg
portions being separately positioned within a separate one of said
slots.
16. The combination of claim 14 wherein said diverging leg portions
have separate leg portion ends each terminating a spaced distance
from said base wall.
17. The combination of claim 15 wherein said diverging leg portions
have separate leg portion ends each terminating a spaced distance
from said base wall.
18. The combination of claim 8 wherein said baffle and shield
member is formed of transparent electrically insulative
material.
19. The combination of claim 8 wherein said baffle and shield
member has formed therein at least one gas and heat escape
passage.
20. The combination of claim 1 wherein a light source is positioned
beneath said base wall.
21. The combination of claim 20 wherein said third vertical wall
constitutes a light conductor.
22. The combination of claim 21 wherein reflective surfaces are
positioned angularly adjacent to said light source.
23. The combination of claim 21 wherein said third vertical wall
and a horizontal shelf wall on the top of said baffle and shield
member have opaque surfaces adapted to provide dark background
illumination for said electrophoresis test kit unit.
24. The combination of claim 1 wherein said outer compartment has
two vertical side walls, and a timer and a substantially constant
direct current housing unit is positioned within said
compartment.
25. The combination of claim 24 wherein said outer compartment side
walls frictionally engage said housing unit.
26. The combination of claim 24 wherein said housing unit has two
horizontally spaced electrical sockets and each of said electrodes
has a separate end for electrical connection for each separate one
of said sockets.
27. The combination of claim 24 wherein said housing unit has an
adjustable timing setting knob positioned thereon.
28. The combination of claim 24 wherein said housing unit has
positioned therein a direct current adjusting circuit.
29. The combination of claim 24 wherein said housing unit has an
electrical connection, and
a source of substantially constant substantially low direct current
voltage in series with said electrical connection.
30. The combination of claim 29 wherein said voltage source is
adjustable.
31. The combination of claim 29 wherein said direct current voltage
source is series connected to a rectifier and to a step-down
transformer.
32. The combination of claim 30 wherein a plurality of separate
substantially constant current units are separately parallel
connected to said voltage source.
33. The combination of claim 31 wherein a plurality of separate
substantially constant current units are separately parallel
connected to said rectifier.
34. The combination of claim 32, wherein an electrical measuring
device is provided together with means to selectively connect said
device to each of said units.
35. The combination of claim 33 wherein an electrical measuring
device is provided together with means to selectively connect said
device to each of said units.
36. The combination of claim 34 wherein said measuring instrument
is current responsive.
37. The combination of claim 34 wherein said measuring instrument
is voltage responsive.
38. The combination of claim 32 wherein said voltage source
includes separate means to individually adjust the voltage to each
of said units.
39. The combination of claim 30 wherein said voltage source is
adjustable from about 15 volts to about 30 volts.
Description
Such electrophoresis test kit units include an integral gel or
gel-like unit, preferably of U-shape, and having relatively thick
elongated gel legs and a relatively thinner integral bridging gel
layer, the bridging gel unit being formed with integral wells,
preferably in matched or paired rows. The entire gel unit is
preferably hermetically sealed to prevent syneresis and
contamination.
The system of the invention provides a preferably adjustable
constant current, constant voltage supply for electrodes which
extend into electrolyte compartments.
The electrolyte compartments are adapted for insertion therein of
the lower portions of the gel legs, the integral gel unit of the
test kit serving to complete the electrical path of the system and
provide electrophoretic migration for testing.
RELATED U.S. APPLICATION DATA
Application filed even date herewith entitled "Electrophoresis Test
Kits and Methods of Making Same." U.S. Pat. Ser. No. 252,639.
BACKGROUND OF THE INVENTION
The present invention relates to electrophoretic test systems,
including the coactive components thereof, which produce an
adjustable low electrical voltage, accurately controllable and
preferably constant as to voltage and amperage.
The testing of fluids such as blood sera and similr sera, or other
similar liquids, for analytic and research purposes has increased
many hundred-fold in recent years and, as a consequence, a large
variety of systems for testing such sera, both qualitatively and
quantitatively, have been investigated and produced by the prior
art.
Among the most promising of such systems is that generally
denominated as electrophoresis. In its most generic sense
electrophoresis is a process involving the movement of a charged
particle suspended in a liquid due to the presence of an electrical
field in electrically coacting relationship with the particle.
While a variety of systems are available to the researcher or to
clinical testing personnel in the generic field of electrophoresis,
those systems which have been found to be generally most attractive
from the standpoint of economics and of dependability, i.e.,
reproduceable results, and of similar desirable features have
related to what is generally designated as gel electrophoresis or
gellified immunoelectrophoresis.
The generic term double diffusion is commonly used to describe gel
tests, whether such tests are electrophoretic in nature or not,
wherein two components, capable of reaction with each other, are
placed in contiguous wells, or other similar openings, contained
within a gel layer. In such systems the forces of movement cause
the two components to diffuse in a generally universal direction;
hence, if the starting wells are placed sufficiently close
together, the materials placed therein will meet at a boundary
line. At this line the materials may, if properly selected,
precipitate and form a precipitin line, or they may form one or
more boundary lines of long chain agglutinated molecules. In most
cases, these boundary lines are visible to the naked eye, and, if
they are not, they can be made visible or their position determined
by known methods. Such an immunodiffusion process, when occurring
in an applied electrical field, is generally termed
immunoelectrophoresis.
In systems utilizing such electrophoresis, a first composition is
placed in a well which is formed in a layer of gel and a second
composition is placed in an adjacent, or paired well formed in the
same layer of gel. By placing the two wells between sources of
opposite electrical polarities the materials in the wells are
caused to migrate towards each other through the gel. If, for
example, one of the materials is an antigen, hereinafter referred
to as Ag, and the other material is an antibody, hereinafter
referred to as Ab, and these materials are reactive with each
other, then if Ab is placed in one well and Ag is placed in the
other paired well, and an electrical field is positioned with the
wells placed therein between sources of opposite polarity so as to
cause the migration of the Ag and Ab towards each other, there will
be a position or band of positions in the gel layer in which the
molecules of these two meet. If, as stated, Ab and Ag are mutually
reactive, then a detectable precipitin line or lines will form
wherever the Ag and Ab meet. Such a line or lines may be straight
or acruate, depending upon the conditions utilized.
Accordingly, such a system of electrophoresis may be used to
analyze known Ab against unknown Ag and vice-versa, in order to
determine the identities or presences thereof.
As one specific example of such a material which is commonly
tested, reference is made to Hepatitis-associated (Australian)
Antigen (HAA). This antigen is associated with the disease
generally called Serum Hepatitis, in contrast to Viral Hepatitis.
It has only been in the most recent years that the wide prevalence
of Serum Hepatitis has become fully evident. Studies made in this
field indicate that the so-called Australian Ag (HAA) is associated
with the causative agent for Serum Hepatitis.
Since Serum Hepatitis and HAA are more prevalent in the blood of
professional donors or in the blood of individuals who have been
subjected to frequent exposure to hypodermic techniques, it is
becoming increasingly important before transfusion of blood to
human patients that all such supplies of blood be tested to make
certain they are not contaminated with Serum Heptatis.
It is essential to the utilization of such tests that an accurate
testing system for supply of electrolyte and electricity be
available.
SUMMARY OF THE INVENTION
The present invention discloses and embraces a system for rapid
utilization by relatively inexperienced technicians which furnishes
a low voltage electrophoretic testing system, providing an
electrical system which is capable of the simultaneous supply of
preferably adjustable, preferably constant current, preferably
constant voltage electricity to a plurality of simultaneously
operating electrolyte cells each of which is of compact unique
construction for coaction with the test units of the above
discussed copending application or with any electrophoretic test
unit which is of similar shape.
The invention provides an electrode supporting structure which is
minimal in size and simultaneously provides support for a unique
baffle structure, whose baffles also serve as electrode
shields.
Means are provided for locating the test kit units in properly
oriented position as to the wells thereof and for supporting the
test unit in operative position. Also provided is an alternative
embodiment incorporating means to transmit light directly to the
test well site during the electrophoretic test run.
Obviously, since HAA and similar electrophoretic tests must be
performed in the millions, it is equally essential that a test
apparatus and system be available therefor which is economical,
dependable as to repeatability, and capable of efficient operation
by relatively inexperienced personnel. This is accomplished by the
present invention by simultaneously minimizing the chances of
danger to such personnel from both the electrical portion of the
equipment and the possibly infectious material containing portions
thereof.
The test kit units of the invention of the copending application
are preferably so inexpensive that they are single-use units; i.e.,
the enire test kit may be discarded after a single test run.
A large variety of gel materials may be utilized in the test kit
units described herein. The most common gel for such use is an agar
or agarose which has been buffered with a mildly alkaline buffer
such as a tris buffer or a barbituate buffer or the like.
Additional known gel-like materials having such utility for
electrophoretic purposes are silica, pectin, starch, acrylamide,
agar-acrylamide, etc. However, the use of agar is generally
recommended because of its relative inexpensiveness and of its
availability, if desired, in pure form. Additionally, it should be
noted that the percentage of water in gelled agar is extremely
high, so that the gel agar does not offer high molecular sieve
resistance to the migration of particles therethrough. Accordingly,
buffered purified agar or agarose gel is the preferred material for
use in the present invention.
For a more complete description of such gels, including the details
of manufacture and composition thereof, reference is made to
Immunoelectrophoretic Analysis by Pierre Grabar, Methods of
Biochemical Analysis, Volume VII, pages 3-12 (1959),
Immunodiffusion and Immunoelectrophoresis by Orjan Ouchterlony, Ann
Arbor Science Publishers, Inc., pages 4-8 (1968), Methods in
Immunology and Immunochemistry, edited by Williams and Chase,
Academic Press, Volume II, Appendix II, and Volume III, pages
118-198 and 237-292 and 357-365 (1971).
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of the overall electrophoretic testing
system with a test kit unit in operable position;
FIG. 2 is a top plan view of the combined timer and constant
current unit and electrolyte compartmental housing of the testing
system;
FIG. 3 is a vertical sectional view taken on the line 3--3 of FIG.
2;
FIG. 4 is a vertical sectional view taken on the line 4--4 of FIG.
2;
FIG. 5 is a vertical sectional view of the overall housing unit for
the constant current and timer unit and electrode and electrolyte
tank with the units carried thereby removed;
FIG. 6 is a vertical sectional view of an alternative embodiment of
the electrode and electrolyte compartment with a means for
illuminating the test unit;
FIG. 7 is a vertical sectional view taken on the line 7--7 of FIG.
6; and
FIG. 8 is a schematic flow diagram of the electrical components of
the system of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference is made to the figures of the drawing, wherein the
overall electrophoretic test system, indicated in its entirety at
10, is illustrated with the electrophoresis test kit unit of the
copending application, indicated in its entirety at 100, in
position on the test system for a test run. Basically, such a
system includes a supply contained within a housing 11 of standard
alternating current voltage of 110-120 volts which is fed to a
step-down, isolation, transformer producing up to, for example 30
volts AC output, and then to an AC/DC rectifier, which feeds a
plurality of controllable outputs, each of which connects to a
separate voltage outlet 14, 14', each outlet having, for example,
an adjustable available voltage of less than 30 volts of DC
potential, such voltage being capable of regulation, such as over a
range of about 15 to about 30 volts. It is to be understood,
however, that the voltage available at each of the outlets 14, 14'
may range from 0 to about 30 volts or over a similar preset desired
range, the outlets being connected in parallel electrical
relationship.
This series of connecting sockets or outlets 14, 14' is preferably
provided on the front panel of supply unit 11. Each of these
outlets is connected, by appropriate leads, indicated at 12, to a
separate control and timer unit housing 13 and to an electrode unit
15 and carried by a housing member 17, forming a separate
electrophoretic electrical supply unit 20 for each test kit unit
100 being run.
Each control and timer unit 13 produces for a desired time set by a
manual or other timer of any appropriate type known to the prior
art and controlled by a settable knob, indicated at 19, a constant
current output. One preferred embodiment of such a constant current
system includes a bridge arrangement in which one of the legs of
the bridge constitutes a measuring resistance, the output of the
bridge being utilized to control an amplifier, which, in turn,
controls the output available from this unit and maintains such
output at, for example, 19 milliamps, plus or minus one.
In Agar Gel Electrophoresis by R. J. Wieme, Elvisier Publishers,
page 72 (1965) there is shown an adjustable constant current and
constant voltage supply whose general circuitry is suitable for use
in electrophoretic systems such as that of the invention. It is to
be understood that any conventional constant current and any
conventional constant voltage circuitry may be utilized, as may be
any known conventional voltage and/or current adjustment means.
Each of the constant current and timer units 13, best shown in
FIGS. 1 and 2, has electrically connected to the output thereof two
preferably cylindrical electrodes 21 and 22, formed of material
such as porous carbon or the like, and these are substantially
contained within an electrolyte compartment 24 forming a part of
the preferably integrally formed housing member 17. The housing
member 17, preferably cast or molded from a noncorrosive plastic,
has a first vertical wall 26 which carries in fluid sealing
relation electrodes 21 and 22 and which divides this compartment 24
from the other or outer compartment 28 containing the timer and
control elements electrically connected to the electrodes by
sockets 23, 23 or the like. The entire housing member 17 has a base
wall 30 having an outer compartment portion 31 and an electrolyte
compartment portion 31', which are shown as being on different
levels, but may be uniplanar if desired. The base wall 31 and side
walls 32 and 33 of the outer compartment preferably frictionally
support the power control unit 13 in oriented position with the
electrodes connected thereto and sealingly extending into the
forward electrolyte compartment 24 through wall 26, any suitable
form of sealing being utilized.
The electrolyte compartment 24 is provided with side walls 35, 36
having substantially equal height and an end wall 38, also,
preferably of the same height, as is wall 26. Walls 26, 31, 35, 36
and 38 define the electrolyte compartment, leaving an open top
thereto, indicated at 40.
Unit 17 is supported at appropriate portions of bottom wall 30 by
legs 39, 39, if desired. These legs may be formed of electrically
insulative material as are preferably all of the above described
walls.
Positioned within the electrolyte compartment 24 is a second
vertical, longitudinal dividing wall 42 positioned substantially at
right angles to first vertical wall 26, as best shown in FIGS. 2
and 3, and which is joined to walls 30, 26 and 38 in fluid sealing
relation and may be integrally formed therewith. The electrolyte
tank 24 is thus divided into two electrolyte compartments or tanks
44 and 46, one for each of the electrodes 21 and 22, one of which
is an anode and the other of which is a cathode.
This second vertical wall 42, which is longitudinally extending in
the direction of the axes of the electrodes 21 and 22, as shown,
electrically isolates these two electrodes from each other, so as
to divide the forward compartment into these two side-by-side
separate liquid proof compartments 44 and 46. Both of these
compartments are filled to or near the top thereof with an
appropriate electrolyte solution, containing an appropriate buffer,
the composition of the solution being compatible with the selected
test. As explained, one side compartment and the electrode and
electrolyte contained therein are of positive polarity, while the
opposite side compartment and the electrode and electrolyte
contained therein are of opposite, negative polarity, the choice of
polarity being optional.
Positioned adjacent the bottom of the electrolyte compartment 24
contiguous to wall 26 is a vertically extending member 50 extending
parallel to wall 26 and which member 50 may have formed as part
thereof a slot 51 for wall 42 and support saddles 52, 54 for
electrodes 21 and 22. Also formed thereon are slots 56 and 58. A
member 60 substantially identical to member 50 is positioned
adjacent and parallel to wall 38 within compartment 24, member 60
having slots and saddles similar to those of member 50. Members 50
and 60 may be integrally formed with the wall elements 26 and 28
respectively, if desired; they serve as supports for the electrodes
21 and 22, for dividing wall 42 and for a baffle and electrode
shield member 62, preferably formed of transparent, electrically
insulative, plastic material, which member serves as a baffle
member for directing convection circulation of the electrolyte
around the electrodes 21 and 22 which it shields.
Member 62 has an upper horizontally extending shelf or wall 64
supported on the top 66 of dividing wall 42. Generally vertical
baffle legs 68 and 69 extend downwardly from shelf 64 and, as
shown, preferably have slanting portions 70 and 72 and outer
vertical portions 74 and 76 which fit into slots 56 and 58 and
their mating slots at the opposite ends of tank 24. Circulation
holes for the electrolyte and heat, indicated at 80, are provided
and the electrolyte is free to circulate between the top of bottom
wall 31 and the bottoms 77, 78 of vertical legs 68 and 69. If
desired, holes 82 and 84 may be provided in shield 62 to
frictionally fit on pegs 86 and 88 formed on top 66 of wall 42.
Legs 68 and 69 diverge downwardly.
Holes 80 also serve as escape vents for any gases which may be
evolved at or near the surfaces of electrodes 21 and 22.
The tops 90 and 92 of side walls 35 and 36 preferably serve as
supports for the test kit units of the present invention during the
actual electrophoretic test runs; the shelf 64 may also be used for
support purposes. A projection or the like, indicated at 94, is
provided on one of the walls to provide a registration positioning
means for insuring positioning of the test kit units in proper
orientation relative to the cathodic and anodic tanks.
A preferred embodiment of the test kit, particularly for use in
hepatitis testing, is partially shown in FIGS. 1 and 3 and is
indicated in its entirety at 100. This test unit 100 includes a
plate 102 which plate having an upper surface 107 and a lower
surface 108 extends generally horizontally, and has formed thereon
a locating means, shown here as a recess or notch 104, which coacts
with the described projection 94 or the like formed on one of the
walls of the compartment. This is done so that the test kit must be
properly positioned with the wells 106, 107 thereof in proper
polarity relationship with the electrolyte tanks 44 and 46
containing electrodes 21 and 22 of opposite polarity.
The test kit 100, which in a preferred embodiment is expendable and
is molded from plastic components, includes two, spaced depending
gel legs 110 and 112 which are interconnected by an integral gel
bridge 114 forming an integral gel unit. The gel legs 110 and 112
are in the form of relatively large blocks having their larger
horizontal dimension generally parallel to the rows of the wells
106, which wells are formed in gel bridge layer 114 under passages
170 in plate 102, as explained fully in the said copending
application.
The plastic legs 128 and 129 which depend downward from plate 102
into electrolyte compartments 44 and 46 respectively are, when the
test kit unit is being used in an electrophoretic test run, open at
the bottoms 130 thereof so as to provide free egress of the
electrolytes to the integral gel unit, including legs 110 and 112
and interconnecting gel bridge layer 114, closed or covered at the
top to prevent contamination.
It will be understood that the level of electrolyte in compartments
44 and 46 is maintained at a sufficient height during
electrophoretic operation, to immerse a substantial portion of legs
128 and 129 to insure electrolyte circulation through the gel unit
during the electrophoretic test run duration. As explained fully in
the copending application, the integral gel unit forms a low
electrical resistance to the flow of current, so that heat loss and
evaporation are minimized.
The plate and tank 24 are preferably so dimensioned that there is
virtually no space left at 40 or elsewhere for the inadvertent
insertion of the fingers of inexperienced technicians. The
extensions 156 and 158 aid in this goal. The use of the low voltage
and amperage described herein further reduces the chances of injury
to personnel operating the system.
It will be seen that each cell 24 has a continuous electrical flow
path of low electrical resistance comprising the first electrode
21, the buffered electrolyte in compartment 44, the integral gel
unit including legs 110 and 112 and bridge layer 114, all
substantially saturated with electrolyte, the buffered electrolyte
in compartment 46 and electrode 22.
While 15 volts is adequate to effectively operate the system at the
start of the electrical electrophoretic test run, the electrical
supply is capable of being increased to 30 volts during the run if
necessary to maintain a substantially constant voltage gradient in
the gel in the vicinity of the wells, particularly between pairs of
wells. This is frequently necessary because the formation of
undesirable byproducts of electrolysis increases the resistance
halating around the outer surfaces of the electrodes.
Shield 62 helps to insure that any such products fall by gravity to
the floor of the electrolyte compartments and are not freely
circulated to increase possible contamination or dirtying of the
equipment.
In use a well sealing cover is first removed and the left hand
wells are filled with a patient's sera and the right hand wells are
filled with antisera which will react with the sera during the
electrophoretic test run if they are mutually reactive to form a
centrally located precipitin line.
Each well 106 generally has an identical well 106 paired therewith
to form a well pair. Generally, as shown, there is a control pair
of wells at one end of the test unit in order to provide the user
with a simple and accurate means of determining that the unit is
functioning properly and to demonstrate the preferred reaction and
precipitin line between the components contained in the wells.
The test unit is then placed astride the electrolyte dividing wall
shelf 64 on the tops 90 and 92 of the side walls 35 and 36, and, if
desired, on the tops of the end walls 26, 28 with the locating
notch 104 in the proper position relative to element 94. The timer
and voltage control units and properly set and the necessary
electrical connections and adjustments are made to provide the
desired electrical field and field gradient across the gel bridge
114, the test kit unit wells and gel bridge being covered
preferably.
In actual practice, it has been found that optimum electrophoresis
of Serum Hepatitis Ag and Ab occurs with a voltage gradient between
the wells 106, 106 of approximately 6 volts per centimeter. With
the system described thus far, including wells spaced approximately
0.6 centimeters apart, the minimum potential which can provide such
a voltage gradient is about 15 volts. The system, as explained
above, can provide up to 30 volts maximum, so that an excess over
the required initial 15 volts is available, as needed, to
compensate for the described polarization of the electrodes and
electrolytic decomposition of the electrolyte in the electrolytic
tanks. The constant current regulating device described above and
shown in FIGS. 1 and 2, and connected in series with the 30 volt
power supply and the electrolyte tanks and the gel path, functions
to maintain the desired 6 volt per centimeter gradient between the
well sites and is adjustable
It will be appreciated that this system is operated at a much lower
voltage than most of the systems of the prior art, such prior art
systems generally operating at about at least 100 volts and
generally at about 200 to about 300 volts. Hence, the danger of
electrical shock to the operator is lessened to such a degree as to
be virtually negligible. As explained above, when the test unit is
positioned on top of the wall of the electrolyte tank compartments,
straddling the top wall 64 of the shield 62, with one leg immersed
in the anode compartment and the other leg immersed in the cathode
compartment, there is formed a closed electrical circuit through
the power supply, the electrodes, the electrolyte tanks, the agar
or other gel blocks and the preferably integral agar or other gel
bridge.
In FIGS. 6 and 7 there is illustrated a second embodiment of the
invention which enables the operator of the system to observe much
more distinctly, while the electrophoretic test is actually being
run, the wells 106 and the gel bridge layer 114 portions
therebetween to better notice or, if desired, photograph the
precipitin or the like formation. Sucn enhanced observation of test
run results in situ during the run may also be utilized to
determine the desirability of varying one or more of the parameters
of operation.
The overall housing unit 127 is substantially similar to previously
described unit 27 and includes a transverse vertical wall 26 having
openings through which electrodes 121 and 122 extend, these
elements corresponding, respectively, to 26, 21 and 22 of the first
embodiment. In like manner electrolyte compartments 144 and 146
correspond to compartments 44 and 46 and walls 130, 131, 131', 135,
136, and 138 correspond respectively to the walls 30, 31, 31', 35,
36 and 38 of the first embodiment. Legs 139 are similar to 39.
Saddle supports 150 and 160 and their elements are substantially
similar to 50 and 60 and the components thereof described above.
All of the parts 164, 168, 169, 170, 172, 174, 176, 177 and 178 of
baffle and shield member 162 correspond to member 62 and its
elements.
Positioned, however, beneath bottom wall 131 of compartment 124, is
a low heat source of illumination, indicated at 180, which is
preferably a monochromatic light source, such as sealed tungsten
filaments, connected to a suitable source of operating voltage, not
shown, such as 120 volts AC, preferably through any conventional
switch, not shown.
Preferably positioned on each side of the light source with their
axes generally parallel thereto are inclined reflectors 182 and
184. Vertical, longitudinal wall 142 serves as a light pipe and is
made from material such as lucite for this purpose. It may be
coated with opaque layers 143. It is understood that plate 102 may
be opaque so that the light directed up pipe 142 illuminates gel
layer 114 in sharp constant thereto. Also the shelf 164 may be a
light pipe open upwardly at its ends 167, 167 to conduct light
laterally to layer 114 against a dark background.
FIG. 8 shows schematically a simplified flow diagram of the
electrical circuitry of the system of the invention, it being
understood that all of the individual components are conventional
in the known art.
Housing unit 11 connects the line voltage source 210 with an
isolation transformer 220 which produces preferably 30 volts AC
output which is fed to an AC to DC rectifier or the like 230.
The 30 volt DC output of the rectifier 230 is preferably fed to a
plurality, here shown as six, of parallel connected, individual
variable voltage regulators 241 through 246. If desired, a single
variable voltage regulator may be substituted for this
plurality.
The outputs of regulators 241 through 246 appear at previously
described output sockets 14, 14', shown as six in number and these
are separately connected, as previously described, to the six
corresponding timer and constant current housing units 13, 13',
also shown here as six in number. These units have, as described,
individually settable timers. They may also each have a separate
and separately adjustable constant current regulator of any
suitable type known in the art. Units 13 feed preferably 19
milliamps to the six individual electrode pairs 21, 22 and 21',
22', etc., each pair of electrodes being connected electrically
through their surrounding electrolytes and the gel unit of the test
set during an electrophoretic run.
As shown in FIG. 1, unit 11 has associated therewith a suitable
switch 310, having a number of positions 320, 320', one for each
outlet 14, 14'. Switch 310 selectively connects by standard means,
not shown, an ammeter or voltmeter 330, having a scale and pointer
340, to each of the cell units, so that an operator may monitor the
cells as desired during the electrophoretic run.
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