Abstrict A system to reduce moisture in a device having at least one integrated
desiccant housing to hold desiccant materials. The integrated desiccant
housing protects a desiccant bag or tablet from being damaged in
the process of packaging, transporting and storing the device. In
particular, an diagnostic assay tray assembly having sample wells
with active biochemical coatings can be better preserved by implementing
one or a plurality of integrated desiccant housing therein.
Claims What is claimed is:
1. A sample holding device including a moisture-reducing element,
comprising:
a sample holding area having a plurality of sample wells configured
to hold samples;
at least one desiccant-holding well defined by a perimeter surrounding
said sample holding area and separated from said sample wells, said
desiccant-holding well configured to have a plurality of surfaces
that define first and second openings at opposing ends, each of
said openings extending through said perimeter, said desiccant-holding
well designated to hold an amount of desiccant material; and
at least one air conduit, connecting said desiccant-holding well
to said sample holding area;
wherein said desiccant-holding well and said desiccant material
are operable to reduce moisture from said sample holding area.
2. A device as in claim 1 wherein said air conduit includes at
least one of said first and second openings in said desiccant-holding
well.
3. A device as in claim 1 wherein said plurality of surfaces of
said desiccant-holding well include a first surface having a top
flat portion and a bottom bent portion which forms an obtuse angle
with respect to said top flat portion; a second surface being substantially
identical to and opposing said first surface, said second surface
being arranged relative to said first surface such that said bottom
bent portions thereof bend towards to each other and maintain a
gap therebetween; a third flat surface disposed between said first
and second surfaces; and a fourth flat surface opposing said third
surface and disposed between said first and second surface;
wherein said first surface, said second surface, said third surface,
and said fourth surface form said first opening and said second
opening smaller than said first opening.
4. A device as in claim 1 further including:
a first wall in said desiccant-holding well;
a second wall in said desiccant-holding well opposing said first
wall;
a first holding arm attached to said first wall and configured
to have a first arc portion and a first bottom extension that is
connected to and perpendicular to a bottom portion of said first
arc portion; and
a second holding arm substantially similar to said first holding
arm and having a second arc portion and a second bottom extension
that is connected to and perpendicular to a bottom portion of said
second arc portion, said first bottom extension and said second
bottom extension forming a spatial gap therebetween which is smaller
than said first and second openings of said desiccant well;
wherein said first and second holding arms form a desiccant holder
operable to hold said amount of desiccant material.
5. A sample holding device including a moisture-reducing element,
comprising:
a sample holding area having a plurality of sample wells configured
to hold samples;
at least one desiccant-holding well defined by a perimeter surrounding
said sample holding area and separated from said sample wells, said
desiccant-holding well having a top opening and a plurality of supporting
surfaces and being designated to hold an amount of desiccant material,
wherein said plurality of supporting surfaces include a first surface
having a top flat portion and a bottom bent portion which forms
an obtuse angle with respect to said top flat portion; a second
surface being substantially identical to and opposing said first
surface, said second surface being arranged relative to said first
surface such that said bottom bent portions thereof bend towards
to each other and maintain a gap therebetween; a third flat surface
disposed between said first and second surfaces; and a fourth flat
surface opposing said third surface and disposed between said first
and second surface; and
at least one air conduit, connecting said desiccant-holding well
to said sample holding area;
wherein said first surface, said second surface, said third surface,
and said fourth surface form a rectangular topped opening and a
bottom opening which is smaller than said top opening and said desiccant-holding
well and said desiccant material are operable to reduce moisture
from said sample holding area.
6. A sample holding device including a moisture-reducing element,
comprising:
a sample holding area having a plurality of sample wells configured
to hold samples;
at least one desiccant-holding well defined by a perimeter surrounding
said sample holding area and separated from said sample wells, said
desiccant-holding well configured to have a top opening and designated
to hold an amount of desiccant material;
a first wall in said desiccant-holding well;
a second wall in said desiccant-holding well opposing said first
wall;
a first holding arm attached to said first wall and configured
to have a first arc portion and a first bottom extension that is
connected to and perpendicular to a bottom portion of said first
arc portion;
a second holding arm substantially similar to said first holding
arm and having a second arc portion and a second bottom extension
that is connected to and perpendicular to a bottom portion of said
second arc portion, said first bottom extension and said second
bottom extension forming a spatial gap therebetween which is smaller
than said top opening, wherein said first and second holding arms
construct a desiccant holder to hold said amount of desiccant material;
and
at least one air conduit, connecting said desiccant-holding well
to said sample holding area.
Description FIELD OF THE INVENTION
The present invention relates to techniques for holding moisture-reducing
material. More particularly, the present invention describes an
improved assay tray assembly used in testing or analysis of liquids
which includes a desiccant element.
BACKGROUND AND SUMMARY OF THE INVENTION
An assay tray assembly is used for detection of an analyte. Common
analytes include antigens or antibodies in a liquid sample, usually
of chemical, biochemical or biological nature. A variety of different
kinds of assay trays are known. A typical assay tray assembly includes
a tray frame and a plurality of sample wells that are either permanently
molded into the frame or built in a sample unit which is removable
from the tray frame. FIG. 1 shows an example of a typical assay
tray assembly. A rectangular frame 100 of the assay tray has four
sides 102 104 106 and 108. A plurality of sample wells are enclosed
in the frame 100. A sample well 110 usually has a cylindrical wall
and a closed end bottom plate that is preferably transparent to
allow spectroscopic testing. Each sample well is coated with a chemical
or biologically active substance associated with a particular analyte
in a liquid sample to be tested. For example, the active coating
can include antibodies or antigens. Commercial assay trays are often
coated with various active materials for commonly performed tests.
The activity of a chemical or biological active substance used
for coating in the sample wells is often adversely affected by moisture.
Therefore, once these substances are bound to the sample wells,
it has been desirable to control the humidity environment. This
minimizes the denaturation and degradation thereof that may be caused
by moisture in the air.
Widely adapted methods to reduce the moisture in an assay tray
assembly include using a dry room for storage and sealing a coated
assay tray in an air-tight package bag with water-absorbent desiccant
materials. The latter is more convenient and flexible for shipping
and storage. Therefore, it has been used by both research institutes
and industrial sectors. The desiccant materials are usually in the
form of powder or crystal packed in a bag or molded into a tablet.
A conventional method for packing the desiccant materials includes
pouching the desiccant material into small desiccant bags and packing
the bagged desiccants with an assay tray sealed in an air-tight
package bag. This allows a desiccant bag to move around within the
package. The package bag is usually designed to tightly wrap the
assay tray so that the amount of material used is minimized. This
is inconvenient for packaging because a separate desiccant bag has
to be packed with the assay tray. Contamination of the active substances
coated in the wells caused by the desiccant material occurs when
the desiccant material comes into contact with the active coating
substance. This happens if a desiccant bag leaks due to the compression
in packaging, storing or transporting process. This proves to be
problematic in preserving the quality of the coated assay trays.
Moreover, additional space in the air-tight package is needed for
the desiccant bags.
In recognition of the above limitations of a conventional assay
tray and package for minimizing moisture, the present invention
discloses an improved assay tray design. In particular, the present
invention provides a secure and convenient way to minimize the moisture
in an assay tray package by integrating a desiccant holding element
therein.
The inventor of the present invention recognized the importance
of maintaining the chemical or biological activities of coating
substances in a sample well in a low moisture environment by using
desiccant materials. Importantly, the inventor recognized that physical
contact between the desiccant materials and the coating substances
in a sample well can induce undesired biochemical reactions therebetween
and thereby contaminate the coating substances. The inventor further
recognized that the separation between the desiccant materials and
sample wells in an assay tray should be maintained under normal
storage and transportation conditions.
In view of these recognitions, the present invention describes
an assay tray with at least one integrated desiccant holder. The
desiccant holder is built into the tray assembly and has surfaces
that securely retain either a desiccant tablet or a pack of powder
desiccant materials therein. An opening of the desiccant holder
allows desiccant materials therein to absorb moisture from the air
in the assay tray assembly.
The present invention provides important improvements in the conventional
assay tray design and moisture protection known to the art. The
desiccant materials are securely held within the integrated desiccant
wells so that they do not move around within a packaged assay tray.
This provides convenience and ease in packaging and reduces the
amount of packaging materials used in the air-tight packing bags.
The desiccant material is held within the desiccant well that is
made of a rigid plastic material. There is preferably no contact
between the packaging bag and the desiccant and hence damage to
a desiccant tablet or powder pack in packing process, storage and
transportation is minimized. This further minimizes the possibility
that the desiccant material is in physical contact with the coating
substance inside sample wells and therefore the deleterious effects
in the coating substances due to their biochemical reactions with
desiccant materials are minimized. Moreover, the present invention
includes structure allowing replacement of desiccant materials as
their moisture-absorbing capability decays after some time of use.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a conventional assay tray known to the art.
FIG. 2a shows the preferred embodiment of the improved assay tray
of the present invention.
FIG. 2b shows the top view of the top opening of a first preferred
embodiment of the desiccant well 200 shown in FIG. 2a.
FIG. 2c shows the sectional view of the first embodiment of the
desiccant well 200 along the line 2c--2c in FIG. 2a.
FIG. 2d shows the sectional view of the first embodiment of the
desiccant well 200 along the line 2d--2d in FIG. 2a.
FIG. 3 shows the sectional view of a second embodiment of the desiccant
well 200 along the line 2e--2e in FIG. 2a.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2a is a schematic which illustrates one preferred embodiment
of the present invention. At least one desiccant well 200 is included
in the tray frame 100 of an assay tray as shown in the top plane
view. The desiccant well 200 has a shape that is designed to hold
a disk-shaped desiccant tablet. The desiccant well 200 is preferably
located in such a position in the assay tray that it will neither
affect the assay tray assembly in a testing procedure nor obscure
the labels of sample wells often marked on the tray frame.
The first embodiment of the desiccant well 200 is shown in FIGS.
2b, 2c, and 2d. A top view of the top opening of the desiccant well
200 is shown in FIG. 2b. FIG. 2c shows the sectional view of the
first embodiment of the desiccant well 200 along the line 2c--2c
in FIG. 2a and FIG. 2d shows the sectional view of the first embodiment
thereof along the line 2d--2d in FIG. 2a, respectively. The desiccant
well 200 has a rectangular top opening 202 four side walls 210
220 230 and 240 and a bottom opening 204. Each side wall has
an inner surface within the desiccant well 200 and an outer surface.
Each side wall 210 220 230 and 240 includes inner surface 212
222 232 and 242 respectively. The outer surface of side wall
210 220 230 and 240 includes 211 221 231 and 241 respectively.
The side walls 210 and 220 oppose each other to form a first pair
of holding surfaces and are shaped to hold a first part of a desiccant
tablet with their inner surfaces 212 and 222 respectively. The
side walls 230 and 240 oppose each other to form a second pair of
holding surfaces and are shaped to hold a second part of the desiccant
tablet with their inner surfaces 232 and 242 respectively.
All four side walls are attached to the top surface 201 of the
frame 100 to form the top opening 202 of the desiccant well 200.
The bottom part 213 of the wall 210 extends to form a first bent
structure 214. The bottom part 223 of the wall 220 extends to form
a second bent structure 224 facing the first bent structure 214.
Both bent structures 214 and 224 bend symmetrically with an inner
surface 216 of the bent structure 214 and an inner surface 226 of
the bent structure 224 facing each other. The inner surface 216
forms a first obtuse angle with respect to the inner surface 212
and the inner surface 226 forms a second obtuse angle with respect
to the inner surface 222 respectively. The first obtuse angle is
substantially identical to the second obtuse angle. The bottom opening
206 is formed with the two bent structures 214 and 224 the bottom
ends 233 and 243 of side walls 230 and 240. The bottom opening 204
is smaller than the top opening 205 due to the presence of the bent
structures 214 and 224. The bent structures 214 and 224 function
to form a third pair of holding surfaces to the desiccant tablet
in a third way with inner surfaces 216 and 226 thereof.
The thickness of a desiccant tablet to be used with the assay tray
assembly in FIGS. 2a and 2b is slightly less than the spacing between
the inner surfaces 232 and 242 of the opposing side walls 230 and
240. The diameter of the desiccant tablet is approximately equal
to the spacing between the inner surfaces 212 and 222 of the opposing
side walls 203 and 204. The depth of the well 200 i.e., the spacing
between the top opening 202 and the bottom opening 204 is larger
than the diameter of the desiccant tablet.
In operation, the desiccant tablet is inserted into the desiccant
well 200 with its both circular surfaces parallel to the opposing
side walls 230 and 240 from the top opening 202. The inner surfaces
212 and 222 of the opposing side walls 210 and 220 may exert a compressive
force on the inserted desiccant tablet in the desiccant well 200
to secure the tablet therewithin.
Both the top opening 202 and the bottom opening 204 function as
air conduit from the desiccant well 200 to the sample wells in the
assay tray packaged in an air-tight packing bag and facilitate the
inserted desiccant tablet to absorb moisture from the environment
of the coated sample wells thereof. This allows maintaining a low
moisture condition inside the assay tray. Being entirely hidden
in the desiccant well 200 the desiccant tablet is protected by
the tray frame 100 and the desiccant well 200. This avoids damage
to the desiccant tablet during packaging, transporting, and storage.
Moreover, the desiccant well 200 physically separates the desiccant
tablet from the sample wells that are coated with active substances.
This way, the possibility of the desiccant material physically contacting
the coated substances is reduced. Therefore, adverse effects on
the biochemical activity of the coated substances due to reactions
between the desiccant and the coated substances are significantly
reduced.
Another important feature of the desiccant well 200 is that a desiccant
tablet therein can be conveniently replaced. A desiccant tablet
can be taken out of the desiccant well 200 by pushing the tablet
from the bottom opening 204.
Furthermore, the present invention reduces the amount of material
used for making the air-tight packaging bag since the desiccant
tablets are entirely hidden inside the tray frame 100 of an assay
tray assembly.
Multiple desiccant wells 200 can be built in the tray frame 100
to increase the moisture absorbing capability of an assay tray assembly.
Three desiccant wells are shown in FIG. 2.
The desiccant well 200 can be made in many shapes and dimensions
other than the rectangular shape as described thereabove. This allows
a desiccant tablet to be molded into various convenient shapes (e.g.,
a cylindrical shape, a cubic or a rectangular block).
In addition, desiccant bags or packages of various shapes and dimensions
can be used in the present invention instead of molded desiccant
tablets.
According to the present invention, there are several advantages
to have an opened bottom 204 in the desiccant well 200 over a closed
bottom. First, the opened bottom 204 provides air conduit from the
desiccant well 200 to the environment of coated sample wells in
addition to the top opening 202. Secondly, it allows easy replacement
of a desiccant tablet. Thirdly, it facilitates the standard manufacturing
process since most commercial assay trays are made with molding
method.
FIG. 3 illustrates a second embodiment of the desiccant well 200
along the line 2d--2d in FIG. 2a. The desiccant well 200 include
a rectangular top opening 305 a rectangular bottom opening 306
four side walls, and two holding arms 310 and 320 for securing a
desiccant tablet or a desiccant bag within the well 200.
The first holding arm 310 is attached to a first side wall 302
of the desiccant well 200. A second holding arm 320 is attached
to a second side wall 304 opposing the first side wall 302. Both
holding arms 310 and 320 are shaped in arc and are curved away from
each other. The bottom portion 311 of the first holding arm 310
is preferably parallel to the side wall 302 and extends to a first
bottom extension 312 perpendicular to the bottom portion 311 thereof.
Similarly, the bottom portion 321 of the second holding arm 320
is preferably parallel to the side wall 302 and extends to a second
bottom extension 322 perpendicular to the bottom portion 321 thereof.
The holding arms 310 and 320 are shaped and sized so that an opening
330 is maintained between the first bottom extension 312 and the
second bottom extension 322.
The first holding arm 310 and the second holding arm 320 respectively
have two holding surfaces opposing each other to hold a desiccant
tablet or bag in a first way. The top surfaces of the first bottom
extension 312 and the second bottom extension 322 hold a desiccant
tablet or bag in a second way. The opening 330 is sized to be smaller
than the dimension of a desiccant tablet or desiccant bag.
In operation, a desiccant tablet or desiccant bag of a predetermined
dimension is inserted between the two arms 310 and 320 from the
top opening 305. The two holding arms 310 and 320 exert compression
force to secure the desiccant material inside the desiccant well
200. The four side walls such as 302 and 304 are made of rigid plastic
material to protect the desiccant material therein. The top opening
305 of the desiccant well 200 the opening 330 and the bottom opening
306 provide air conduits to the surrounding of the coated sample
wells in the assay tray.
The opening 330 and the bottom opening 306 also allow easy replacement
of a desiccant tablet or bag. In addition, they also facilitate
the molding process in manufacturing the assay tray that is widely
used in commercial production.
The desiccant well 200 can have various shapes and dimensions.
Some examples include square, rectangle, and circular.
A plurality of desiccant wells similar to the desiccant well 200
are implied by the present invention. One advantage of using multiple
desiccant wells is an increased moisture-absorbing capability of
the assay tray assembly.
Although the present invention has been described in detail with
reference to a number of particular embodiments, one ordinarily
skilled in the art to which this invention pertains will appreciate
that various modifications and enhancements may be made without
departing from the spirit and scope of the present invention. For
example, the desiccant well of the present invention can be implemented
in many other devices that require a low moisture environment. The
integrated desiccant well prevents a desiccant tablet or bag from
crashing and squeezing caused by the external compression and provides
a convenient way to reduce the moisture level. Importantly, a desiccant
well should be implemented so that the functionability of a device
is not adversely affected.
All these and other modifications are intended to be encompassed
within the following claims. |