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FIELD OF THE INVENTION
The invention relates to a cuvette for doing reactions, preferably while
completely confined against leakage, and particularly to an improved
closure for an access port of the cuvette.
BACKGROUND OF THE INVENTION
EPA Publication No. 381,501, commonly-owned with this application,
describes a containment cuvette that is presupplied and sealed with the
reagents necessary to detect selected nucleic acids that are multiplied in
the cuvette. In addition, a patient's sample is injected through a port,
which port is then sealed such as by heat-sealing the plastic around the
port or inserting a stopper. As a result, a complete containment occurs,
even through the detection stage, so that there is no risk of any
multiplied nucleic acid (hereinafter, "amplified" nucleic acid) from
straying from the cuvette as an aerosol to contaminate yet-to-be used
cuvettes.
Such a cuvette has been very effective in testing for DNA, by allowing PCR
amplification to be done safely and without contamination. However, a
minor drawback exists in that the patient sample port has to be carefully
sealed to ensure nucleic acid does not leak out. Whether or not
heat-sealing or a mechanical stopper is used, in either case, care must be
exercised as otherwise a complete seal may not occur.
Still further, other, temporary seals of the cuvette have not always held
as desired.
Therefore, there has been a need prior to this invention for a method, and
for features in a flexible cuvette, that allow for automatic closure of
passageways such as that extending from the patient sample port after
sample insertion, without requiring special care.
SUMMARY OF THE INVENTION
I have constructed closure means that solve the aforementioned problem.
More specifically, in accord with one aspect of the invention, there is
provided a flexible cuvette defined by opposed flexible sheets sealed
together to define at least one compartment between them for holding a
liquid, and a passageway leading to or from the one compartment;
the improvement wherein the cuvette further includes means for sealing off
flow through the passageway, the means comprising a fold line extending
across the passageway at at least one location,
so that the cuvette can be folded about the hinge line sufficiently to
pinch off flow through the passageway,
and further including means for retaining the folded condition for as long
as necessary.
In accord with another aspect of the invention, there is provided a method
for sealing off flow through a passageway in a flexible cuvette to or from
a compartment, the method comprising
a) providing a fold line extending across the passageway at least once,
b) folding the cuvette about the fold line so as to pinch off flow through
the passageway, and
c) holding the cuvette folded as set forth in step b) for as long as flow
is to be sealed off through the passageway.
Therefore, it is an advantageous feature of the invention that the access
port of a cuvette is easily sealed off simply by attaching the cover that
is an integral part of the cuvette.
It is a related advantageous feature of the invention that such sealing as
described above does not rely solely on the cover that fits over the
access port, but on a pinching effect created in the act of applying the
cover.
Other advantageous features will become apparent upon reference to the
following "Description of the Preferred Embodiments", when read in light
of the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a cuvette constructed in accord with the prior
art;
FIG. 2 is a section view taken generally along the line II--II of FIG. 1;
FIG. 3 is a plan view similar to that of FIG. 1, but of the cuvette of the
invention;
FIG. 4 is a fragmentary section view taken generally along the line IV--IV
of FIG. 3;
FIG. 5 is a fragmentary plan view similar to that of FIG. 3, showing the
cover in place on the access port;
FIG. 6 is a section view similar to that of FIG. 4, but of another
embodiment of the invention;
FIG. 7 is a fragmentary plan view similar to that of FIG. 3, but
illustrating yet another alternative embodiment;
FIG. 8 is a fragmentary plan view similar to that of FIG. 1, but
illustrating a still further alternative embodiment;
FIG. 9 is a fragmentary plan view similar to that of FIG. 8, of still a
further embodiment;
FIG. 10 is a fragmentary section view taken along the line X--X of FIG. 9;
FIG. 11 is a fragmentary isometric view of a cuvette showing yet another
embodiment;
FIG. 12 is a section view similar to that of FIG. 10, of still another
embodiment;
FIG. 13 is a fragmentary isometric view of yet another embodiment, in
association with a heater for the cuvette, shown here raised;
FIG. 14 is a fragmentary elevational view in section, taken along the line
XIV--XIV of FIG. 13 but with the heater lowered into contact;
FIG. 15 is a fragmentary section view similar to that of FIG. 10, but of
still another embodiment;
FIG. 16 is an isometric view of the piece 500 shown in FIG. 15; and
FIG. 17 is a fragmentary section view similar to that of FIG. 15, but of
still another embodiment, wherein pinching off of flow has already been
achieved.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention is described for preferred embodiments in which nucleic acid
is amplified and detected while completely contained, to prevent
contamination, such as by using PCR amplification to detect DNA from a
patient sample. In addition, it can be used in any flexible cuvette for
any processing reaction whatsoever, whether or not nucleic acid is being
amplified, provided there is a need to close off an access port prior to
doing reactions.
The preferred method of amplification of the nucleic acid is PCR
amplification, the details of which are set forth in the aforesaid EPA
publication.
The prior art form of the cuvette set forth in said EPA publication can be
briefly summarized as follows. (Further details are found in that
publication, and those are expressly incorporated herein by reference).
The cuvette 10 features flexible compartments, FIG. 1, that cooperate with
an external pressurizing means 60, such as a pressure roller. More
particularly, cuvette 10 comprises two relatively thin sheets 12, 14
formed such as by molding to mate together with pockets or compartments
and connecting passageways protruding from the plane of the contacting
sheets, FIG. 2. The sheets are secured together at least along their outer
periphery 16, and preferably at all points surrounding compartments or
passageways, such as by heat- and/or ultrasonic pressure-sealing. A
heat-activatable adhesive such as ethylene vinyl acetate is useful for
such joining operation. A liquid injection access port 22 is the exception
to the sealed periphery 16, for use with a mating pipette 24. Such port 22
optionally includes a rigid rim 23, FIG. 1, extending into it, within
which a pipette 24 seats.
The compartments are as follows: compartment 26 is the reaction
compartment, and optionally has the amplifying reagents 28
pre-incorporated therein, FIG. 2, in liquid or dried form. Compartment 30,
FIG. 1, is a storage compartment for the first wash compartment containing
wash water as a pre-incorporated reagent. Compartment 32 is a storage
compartment containing at least one of the detection materials
pre-incorporated therein. A biotinylated primer having at one end a
complementary nucleotide for attachment to the amplified DNA is placed in
compartment 26, whereas compartment 32 stores a signal generating moiety,
for example, avidin bound to the horseradish peroxidase discussed above.
Storage compartment 34 is a second wash-containing storage compartment,
which preferably has a much larger volume than the volume of storage
compartment 32. Storage compartment 36 has pre-incorporated therein, the
remaining detection reagents, namely a peroxide and a leuco dye, for
example 2-(4-hydroxy-3,5- dimethoxyphenyl)-4,5-bis
(4-methoxyphenyl)imidazole, preferably in combination with poly(viny
pyrrolidone) as a stabilizer. Storage compartment 38 has pre-incorporated
therein a stop solution to prevent too much leuco dye from converting to
the dye, for example, a solution of sodium azide.
Finally, compartment 40 is the detection site, and compartment 42 is the
waste compartment, preferably initially deflated to provide for expansion
as liquid is forced into it. Compartment 42 connects to compartment 40 via
passageway 43. Optionally, a one-way check valve (not shown) can be
included in passageway 43, FIG. 1, to prevent waste liquid from
backwashing into compartment 40, thus creating undesirable background
color.
The interconnections are as follows: passageway 21 connects injection port
22 with compartment 26, passageway 44 connects reaction compartment 26
with detection compartment 40, except that a temporary seal is provided at
46 to keep introduced DNA in compartment 26 until pressure is generated by
roller 60. Optionally, a temporary seal can also be applied at 25 across
passageway 21 to hold in the amplifying reagents. Passageway 48 connects
compartment 30, passageway 49 connects compartment 32, passageway 50
connects compartment 34, passageway 52 connects compartment 36 and
passageway 54 connects compartment 38, all with detection compartment 40,
again each preferably with a temporary seal 56, FIG. 2, interrupting flow
out of the respective compartment until roller 60 breaks the seal.
Passageway 54 serves as the trunk line to which the others (48, 49, 50 and
52) are joined.
The compartments are deliberately positioned, FIG. 1, so that each one will
empty into compartment 40 in the proper sequence as roller 60 advances
along path A in the direction of arrows 63.
As noted above, care must be taken after the injection of patient sample,
to seal off access port 22, as otherwise this becomes a path of leakage.
In accord with the invention, the problem with sealing the cuvette of the
prior art, and specifically, the access port, is solved as follows
(FIGS. 3-5). (In this description, parts identical to those previously
described bear the same reference numeral, and those that are similar have
the same reference numeral with "100" added). Thus, cuvette 110 comprises
a bottom sheet 12 and a top sheet 14, FIG. 4, sealed together generally as
discussed for the prior art embodiment. Compartments 26, 30, 32, 34, 36,
38, 40 and 42 are provided, along with their interconnecting passageways
43, 44, 48, 49, 50, 52 and 54, as previously described. Temporary seals
are formed at 46 and 56.
However, access port 122, FIGS. 3 and 4, comprises a raised boss on sheet
14 having a central aperture 180 that fluidly connects to passageway 121
left unsealed in the seal between sheets 12 and 14. Passageway 121 extends
from port 122 and aperture 180 first away from the reaction compartment
26, along portion 182, and then it doubles back to that reaction
compartment. Portion 182 extends into a closure portion 184 of the cuvette
that is joined to the remainder of the cuvette only at a hinge line 190,
FIG. 3, identified in FIG. 4 by arrow 192. Hence, hinge line 190 cuts
across portion 182 of passageway 121 twice. Hinge line 190 extends from an
outside edge 194 of cuvette 110, FIG. 3, to an end 196 where it joins a
cut portion comprising a line of severance 198 extending completely
through sheets 12 and 14 to isolate cover portion 184 except for hinge
line 190. (Line of severance 198 is heat-sealed at 16, just as the rest of
the periphery of the cuvette is sealed).
Portion 184 also includes a closure or cap means 200 projecting upward from
sheet 14. Preferably, such means comprise a boss 202 having an aperture
204 that is closed off at its bottom by sheet 14, FIG. 4. Given an outside
diameter d.sub.2 for port 122, the inside diameter d.sub.1 of aperture 204
is selected to provide a friction fit of closure means 200 on port 122.
However, this friction fit is not necessarily a seal, as will become
apparent.
To seal off passageway 121 after patient sample is injected into
compartment 26, closure portion 184 is bent about hinge line 192, FIG. 4,
to cause closure means 200 to engage and cover the boss of port 122. (The
heights of port 122 and boss 202 are exaggerated in FIG. 4 for clarity. In
reality they are reduced sufficiently to allow such connection.) This
bending acts to pinch sheets 12 and 14 together across portion 182 of
passageway 21, at two locations A and B, FIG. 5, thus sealing off that
passageway against leakage. The friction fit of closure means 200 is
provided on port 122 to ensure that, once covered, port 122 remains so
covered. Other known alternative closure mechanisms can be used to keep
closure means 200 covering port 122, for the duration of the test, or
permanently if desired.
After sealing off passageway 121, roller 60, FIG. 3, can be passed over the
non-cover portions of the cuvette to cause sequential release of the
contents of the various compartments. Since only the cover portion of the
cuvette is bent to seal off passageway 121, the roller does not have to
press against access port 122 and its cover. Alternatively, not shown,
cuvette 110 can be positioned between two plates provided with opposed
pistons that press against the compartments to burst them in sequence.
It is not necessary that the cap be integral with the rest of the pouch, as
that can be slipped over the access port separately, as shown in FIG. 6.
Parts similar to those previous described bear the same reference numeral
to which the distinguishing suffix "A" is appended.
Thus, cuvette 110A has an access port 122A with an aperture 180A that feeds
to a passageway portion 182A that passes through a hinge line, arrow 192A,
around which closure portion 184A is folded to pinch closed passageway
portion 182A. However, in this case, the closure means comprises, in
portion 184A, an aperture 204A, which extends completely through sheets
12A and 14A. The cover boss 202A is a cap piece separate from portion
184A. After aperture 204A is slipped around port 122A, arrow 210A, cover
202A is also inserted over port 122A, arrows 310, thus completing the
closure. However, cap 202A, as before, is not the means that seals off
passageway portion 182A, since that occurs from the pinching of that
portion at 192A. Rather, cap 202A serves to ensure that portion 184A stays
in place on port 122A to maintain that pinching of portion 182A.
An additional option of the invention is to include an air vent passageway
from the chamber into which the patient sample is injected, FIG. 7. Parts
similar to those previously described bear the same reference numeral, to
which the distinguishing suffix "B" is appended.
Thus, FIG. 7, cuvette 110B includes an access port 122B wherein an aperture
180B connects to a feed passageway 121B that connects to a reaction
compartment 26B having a sealed outlet passageway 44B. (Hatched portions
represent the portions of the cuvette wherein the two opposed sheets are
sealed together.) Closure portion 184B with aperture 204B features a hinge
line 190B and a cut line 198B that allows closure aperture 204B to slip
over portion 122B when portion 184B is folded about line 190B, as
described heretofore. Because hinge line 190B passes through portion 182B
of passageway 121B, the folding of portion 184B acts to pinch shut
passageway 121B.
In addition, an air vent passageway 321 extends from compartment 26B back
to a suitable vent aperture on the exterior surface 330 of pouch 110B, for
example an aperture 340, or to the waste chamber (not shown here).
Passageway 321 also extends across hinge line 190B so as to be pinched
shut when the access passageway 121B is sealed. Although passageway 321 is
shown as crossing hinge line 190B twice, it could cross only once, by
locating aperture 340 at dotted position 340', for example.
It is not essential that the hinge line used to seal the sample injection
passageway must cross that passageway twice. The cuvette can be
constructed so that it crosses it once, FIG. 8. Parts similar to those
previously described bear the same reference numeral, to which the
distinguishing suffix "C" has been appended.
Thus, cuvette 110C is formed from two opposing sheets by sealing them
together to leave a reaction compartment 26C connected to access port 122C
and to other compartments via passageways 121C and 44C, as previously
described. Closure portion 184C is also formed by a line of severance 198C
and a hinge line 190C, also as previously described, so that port 122C can
be inserted into a closure means 200C comprising a raised boss 202C also
as previously described. However, the positions of port 122C and closure
means 200C have been reversed, so that passageway 121C is crossed by hinge
line 190C only once.
For the corner fold embodiment of FIG. 8, it is not necessary that a
portion of the cuvette be especially modified to allow hinging and folding
to occur. Such modification, such as severance of the cuvette at an angle
to the hinge line, can be eliminated if the pouch is constructed as per
FIGS. 9-10. Parts similar to those previously described bear the same
reference numerals, to which the distinguishing suffix "D" is appended.
Thus, cuvette 110D has an access port 122D that feeds into a passageway
121D extending to reaction compartment 26D, with hinge line 190D crossing
passageway 121D at at least one location, as described heretofore. Capping
of the access port to hold it in the folded-over, pinched-off condition,
is provided, as before, by dead-end closure cap means 200D, to ensure that
the pinching of passageway 121D by the folding at arrow 192D, FIG. 10,
remains for the duration of the assay. However, unlike the previous
embodiments, hinge line 190D extends at an angle alpha and gamma to the
two sides of the cuvette, rather than parallel to one of the sides,
thereby allowing the hinging at line 190D to occur without having to sever
the cuvette along a line intersecting the hinge line.
If for some reason, hinge line 190 cannot extend across a corner as shown
in FIGS. 9 and 10, other ways can be provided to allow hinging and folding
to occur, as shown in FIG. 11, besides by severing the cuvette. Parts
similar to those previously described bear the same reference numeral, to
which the distinguishing suffix "E" is appended. Thus, cuvette 110E
comprises an access port 122E for feeding sample via a passageway 121E to
reaction compartment 26E and beyond, as described heretofore, with a hinge
line 190E crossing passageway 121E (here, at two locations) to pinch it
off when portion 184E is folded over to allow capping shoulder 200E to
friction fit over port 122E. However, to allow the folding over of portion
184E at line 190E, no severance of the cuvette is needed. Instead, portion
184E is joined to the rest of the cuvette by a flexible fan-fold 300,
which allows portion 184E to be coplanar with the rest of the cuvette, or
folded over in the direction of arrow 210E.
Still further, when fastening the folded-over portion in place to maintain
the pinching of the passageway, it is not necessary that the
friction-fitting cap engage the access port. Instead, it can engage a
dead-end boss provided for that purpose, FIG. 12. Parts similar to those
previously described bear the same reference numeral to which the
distinguishing suffix "F" is appended.
Thus, FIG. 12, cuvette 110F is provided exactly as before, with a hinge
line 190F crossing over passageway 121F (shown as a dotted line) that
extends from access port 122F to the subsequent compartment(s) (not
shown). Also as before, a cap 200F is provided on fold-over portion 184F
to lock the latter to the rest of the cuvette with passageway 121F pinched
off. However, unlike the previous embodiments, a dead-end boss 310 is
provided separate from access port 122F, and it is this boss over which
cap 200F is friction-forced to hold portion 184F in its folded-over
configuration (shown in phantom).
Still further, it is not necessary that the hinge line, and subsequent
pinching off, occur only across the passageway leading from the access
port to the reaction compartment. It can also be used to pinch off
unwanted flow away from the reaction or any other compartment during
heating, downstream towards the detection compartment or site, FIGS. 13
and 14. Parts similar to those previously described bear the same
reference numeral, to which the distinguishing suffix "G" is appended.
Thus, FIG. 13, cuvette 110G comprises the various compartments as described
in previous embodiments, and connecting passageways. However, for each
compartment that has to be heated, such as reaction compartment 26G, there
is a temporary seal 46G that is intended to not leak during heating until
a bursting pressure is applied. That seal is located opposite to any
incoming passageway such as passageway 121G (none being present for
reagent compartments). The difficulty is that, under some conditions, seal
46G can leak during heating, allowing liquid (patient sample or reagent,
depending on the compartment involved) to prematurely pass on to detection
sites in detection compartment 40G.
To avoid this, the hinge line of the invention, line 190G, is formed to
cross the passageway extending downstream of the burstable seal --
passageway 44G in the case of reaction compartment 26G. Furthermore,
cuvette 110G is severed along line 198G to form a fold-over portion 184G
located in the interior of the cuvette.
The operation is shown in FIG. 14. Prior to placing a heater 400 in contact
with the compartment to be heated, e.g., compartment 26G, a support 410
with a straight edge 412 is place aligned with hinge line 190G. When
heater 400 is lowered into contact, a pusher finger 420 on the heater
folds portion 184G along the hinge line, pinching off the passageway
downstream of the seal, thus preventing liquid from prematurely entering
the next compartment (e.g., compartment 40G), even if seal 46G should
leak. In this operation, unlike the pinching off of the passageway from
the access port, the pinching is temporary only and is released following
heating to allow flow to occur once again (when the upstream compartment
is deliberately burst immediately following the heating.)
The pinching shut of the passageway can be enhanced in several ways, by
either the cuvette itself, or the processing apparatus. These are
illustrated in FIGS. 15-17. Parts similar to those previously described
bear the same reference numerals, to which the distinguishing suffixes
"H"and "I" are appended, respectively.
Thus, FIG. 15, a corner fold such as is shown in FIGS. 9 and 10 can be
enhanced by an inflexible fold bar disposed adjacent to the hinge line, so
that as the corner is folded over, the edge of the fold bar acts to
further pinch shut the passageway. More specifically, device 110H is
formed by opposing sheets with a passageway 121H leading from inlet port
122H to a reaction compartment 26H, and a cap means 200H is provided to
cover port 122H when folding occurs about hinge line 190H, arrow 210H, as
is described previously for the embodiment of FIGS. 9 and 10.
Additionally, a relatively solid, inflexible member or piece of plastic
500 is inserted in corner portion 184H, so that one of its edges 502 is
beveled at 504 to form a relatively sharp edge, FIG. 16. Passageway 121H
in turn is formed over piece 500, either by dimpling sheet 14H to preform
a channel, or by grooving piece 500 as suggested by the phantom lines,
FIG. 16.
When portion 184H is folded over hinge line 190H, arrow 210H, piece 500
acts to enhance the pinching off of passageway 121H at line 190H, as will
be readily appreciated.
Alternatively, not shown, piece 500 can be replaced by an inflexible member
such as a bar placed on the exterior of the pouch, rather than in the
interior, to extend with an edge adjacent the fold line.
FIG. 15 also illustrates that the cap means can have thicknesses in excess
of the thickness of the single sheet 14H. E.g., base 506 of cap 200H is
thicker than the thickness of sheet 14H, as are the sidewalls 508. This is
readily achieved by manufacturing cap 200H as a separate component and
then adhesively securing it to sheet 14H in the position shown.
A similar increase can be achieved in the sidewalls of port 122H.
As is noted above, an external pressure member such as a roller is used to
burst at least the reaction compartment after suitable reactions occur.
This roller can also be useful in enhancing the pinching off of the
passageway, FIG. 17. In such an embodiment, cuvette 110I features an inlet
or access port 122I, a cap means 200I, a passageway (not shown) extending
between sheets 14I and 12I to a burstable compartment 26I, and a hinge
line 190I about which corner portion 184I can be folded to pinch off the
passageway, as described heretofore. (Unlike previous embodiments, port
122I and cap means 200I project from the cuvette in a direction opposite
to the projection of compartment 26I, as a further option.) Most
preferably, cuvette 110I is processed on a support 510 having a recess 512
that accommodates the protrusion of port 122I and cap means 200I, and a
roller 60I used to burst compartment 26I is also used to enhance the
pinching off of flow in the passageway by creasing with pressure, the
hinge line 190I. Once the creasing by roller 60I is achieved, it can be
rolled on to burst compartment 26I since the crease at hinge line 190I is
effective to hold the passageway pinched off. This embodiment can be used
with or without the enhancer shown in FIGS. 15-16.
The invention disclosed herein may be practiced in the absence of any
element which is not specifically disclosed herein.
The invention has been described in detail with particular reference to
preferred embodiments thereof, but it will be understood that variations
and modifications can be effected within the spirit and scope of the
invention.
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