Patent Application
20230191392
This disclosure relates to a test chip and a method for manufacturing the same.
There is an idea that diagnosis carried out in the immediate vicinity of patients or the like (on-the-spot diagnosis) is highly important, and such an idea is being generally accepted in clinical practice. Based on such idea, test chips have been developed that enable practical analysis by providing a sheet-shaped substrate with micro-sized passages and reaction spots.
One example of such test chip includes a mechanism wherein, when a test liquid containing a target substance such as antigen is introduced, the test liquid flows through a passage and reacts with a labeling medium, such as antibody that has been charged in advance, thereby allowing the presence of the target substance to be confirmed by means of color development (revelation). A typical example is pregnancy test drug.
As the test chip described above, there has been reported a microfluidic device in which a paper is used as a base material and a passage or a reaction spot is formed on the paper using a wax printer or an inkjet printer (Whiteside et al., Analytical Chemistry, Vol. 82, No. 1, Jan. 1, 2010 (NPL 1)). Such devices are also referred to as µ-PADs (microfluidic paper-based analytical devices)″ and have many advantages, such as (1) low cost, (2) pumpless, (3) no requirement for large-scale equipment, and (4) easy disposal. Research for improvement in such µ-PADs is being promoted globally.
For example, WO 2012/160857 A (PTL 1) discloses that the test tip can be manufactured easily and at low cost, by printing the outer edge of the passage or reaction spot as described above on a paper with ultraviolet curable ink, and curing the ink by irradiating with ultraviolet rays.
PTL 1: WO 2012/160857 A
NPL 1: Whiteside et al., Analytical Chemistry, Vol. 82, No. 1, Jan. 1, 2010
However, in the conventional test chip including the technology disclosed in PTL 1 described above, unevenness in color development (color development) tends to occur and cause fluctuation in the inspection results (insufficient reproducibility). For example, as the color development occurs near the end of the detection area, there is a problem that visual observation is difficult. Such a problem may adversely affect the diagnosis of important diseases, etc. Thus, the conventional test chip has a room for improvement in terms of suppressing uneven color development.
Further, for the above-mentioned test chips such as µ-PADs, in addition to confirmation of the presence or absence of the substance to be detected, it is desirable to realize the quantification thereof. In this regard, if it is unevenness of color development (color development) as described above can be suppressed, then it is possible to realize quantification by specifying the area of the color-developed part in the test chip and applying the pixel analysis technology. From this viewpoint also, it is desired to suppress uneven color development.
The task underlying the present disclosure is to solve the above-mentioned problems in the conventional device and to achieve the objects as follows. That is, it is an object of the present disclosure to provide a test chip wherein the target substance contained in the test liquid is reacted with the pre-charged labeling medium for confirming the presence of the target substance by the reaction between, and wherein uneven color development is significantly suppressed. It is another object of the present disclosure to provide a method for manufacturing the above-mentioned test chip, with which the test tip can be manufactured easily, high accurately and at low cost.
In the course of solving the above problem, the inventors found for the first time that the problem in the conventional test chip of the occurrence of color development near the end of the detection area is caused by the momentum of the liquid flow reaching the detection area.
Further, the inventors conducted extensive studies and found that color development could be induced near the center of the detection area if the liquid passage is optimized so that the liquid can reach the detection area from the thickness direction of the sheet, which led to the completion of the present disclosure.
The means for achieving the above object is summarized in the following clauses.
< 1 > A sheet-shaped test chip comprising:
<2> A sheet-shaped test chip comprising:
<3> A sheet-shaped test chip comprising:
<4> The test chip according to <3>, wherein at least two of the liquid passages E are connected to the liquid flow section D so as to face each other.
<5> The test chip according to <3> or <4>, wherein at least two of the liquid passages E have substantially the same shape.
<6> The test chip according to any one of < 1> to <5>, wherein:
<7> The test chip according to any one of < 1> to <5>, wherein:
<8> The test chip according to any one of <1> to <5>, wherein the second layer comprises the liquid receiving portion A.
<9> The test chip according to any one of <1> to <8>, wherein:
< 10> The test chip according to <9>, wherein the material M is a filter paper.
< 11 > The test chip according to <9> or < 10> wherein, in the material M′, an impregnation rate of the hydrophobic material into the material M is 14% or more and 32% or less.
< 12> The test chip according to any one of < 1 > to < 11>, wherein a ratio of the thickness of the second layer to the thickness of the first layer (thickness of the second layer / thickness of the first layer) is 0.56 or more and 2.2 or less.
<13> The test chip according to any one of < 1> to < 12>, wherein a color development reaction due to a substance to be detected takes place in the detection confirmation section B.
< 14> A method for manufacturing a test chip of any one of < 1> to < 13 >, comprising:
<15> The method for manufacturing a test chip according to <14>, wherein a ratio of the thickness of the second hydrophobic membrane to the thickness of the first hydrophobic membrane (thickness of the second hydrophobic membrane / thickness of the first hydrophobic membrane) is 0.56 or more and 2.2 or less.
According to the present disclosure, it is possible to provide a test chip wherein the target substance contained in the test liquid is reacted with the pre-charged labeling medium for confirming the presence of the target substance by the reaction between, and wherein uneven color development is significantly suppressed. Furthermore, according to the present disclosure, it is also possible to provide a method for manufacturing the above-mentioned test chip, with which the test tip can be manufactured easily, high accurately and at low cost.
I
Hereinafter, the present disclosure will be described in detail based on the embodiments.
According to the present disclosure, there is provided a sheet-shaped test chip, which is basically characterized in that it includes
Further, the test chip according to one embodiment of the present disclosure is further characterized in that, in addition to the basic features noted above, the liquid flow section D has an annular structure formed with a liquid non-flow section D′ therein. The details of this feature will be described later.
The test chip according to another embodiment of the present disclosure is further characterized in that, in addition to the basic features noted above, the second layer is provided with a plurality of the liquid passages E. The details of this feature will be described later.
The test chip according to still another embodiment of the present disclosure is further characterized in that, in addition to the basic features noted above, the first layer is formed on one surface of a single sheet-like material, and the second layer is formed on the other surface of the sheet-like material. The details of this feature will be described later.
According to these test chips, it is possible to significantly suppress uneven color development.
In the test chip of the present disclosure, the liquid receiving portion A is a portion where the test liquid is dropped. Further, in the test chip of the present disclosure, the detection confirmation section B is a portion where confirmation is made as to whether or not a target substance, such as an antigen, is present in the test liquid dropped on the liquid receiving section A, by means of the presence or absence of color development. Thus, the test chip 1 of the present disclosure may be provided with a medium that reacts with the substance to be detected and / or a labeling medium adapted to cause a color reaction due to the substance to be detected. Furthermore, it is preferred that, in the test chip 1 of the present disclosure, the color development reaction due to the substance to be detected takes place in the detection confirmation section B.
More specifically, the aspects of the above-mentioned basic features common to the test chips of the present disclosure may include an aspect wherein the liquid receiving section A is provided in the first layer and the second layer has the liquid flow section C (first aspect), an aspect wherein the liquid receiving section A is provided in the first layer, and the first layer is further provided with a liquid passage F connected to the liquid receiving portion A (second aspect), and an aspect wherein the liquid receiving portion A is provided in the second layer (third aspect).
The first layer 10 of the test chip 1 is provided with a liquid non-flow section X as a portion other than the liquid receiving section A and the detection confirmation section B. The liquid receiving section A and the detection confirmation section B are made, for example, of a material M that permits flow of the test liquid by capillary action. Further, the liquid non-flow section X is made, for example, of a material M′ that prohibits (does not permit) flow of the test liquid.
As illustrated in
Here, in the conventional test chip, since the liquid receiving section and the detection confirmation section (detection area) are simply connected by a passage on the base material, when the test liquid is dropped into the liquid receiving section, there is a problem of unevenness of the color development such that the color development is distributed unevenly near the end of the detection area (particularly near the end that is remote from the liquid receiving section), due to the momentum of the liquid flow flowing along the surface direction of the material and reaching the detection area. On the other hand, in the test tip 1 as described above, since the test chip 1 has the above-mentioned configuration, the test liquid dropped into the liquid receiving section A is flows eventually in the thickness direction of the test chip 1 (the direction from the liquid flow section D to the detection confirmation section), and reaches the detection confirmation section B. Thus, in the test chip 1 according to the first aspect, the color development site can be maintained near the center of the detection confirmation section B, thereby significantly suppressing unevenness of the color development.
As described above, the liquid receiving section A and the detection confirmation section B in the first layer 10, and the liquid flow section C, the liquid flow section D, and the liquid passage E in the second layer 20 are made, for example, of the material M that permits flow of the test liquid due to the capillary action. On the other hand, the liquid non-flowing section X in the first layer 10 and the liquid non-flowing section Y in the second layer 20 are made, for example, of the material M′ in which the material M is impregnated with a hydrophobic material, and flow of the test liquid is prohibited.
The material M is not particularly limited as long as it causes a capillary action, and may include paper, such as filter paper, non-woven fabric, nitrocellulose, polypropylene, etc. Among these, from the viewpoint that a test chip can be produced more easily and at low cost, the material M is preferably a filter paper. Furthermore, the thickness and the basis weight (density) of the material M may be appropriately selected in consideration of the viscosity of the test liquid, etc.
The hydrophobic material is not particularly limited as long as it can be impregnated into the material M and inhibits the capillary action in the material M, and examples thereof may include wax or a composition containing the same. Further, from the viewpoint of easy production, the hydrophobic material preferably has a melting point of 90° C., or lower.
In the test chip described above, it is preferred that the material M′ of the liquid non-flow section X on the front surface side is colored so that the inspector can easily observe the liquid receiving section A and the detection confirmation section B on the front surface side. On the other hand, the material M′ of the liquid non-circulation portion Y on the back surface side of the test chip may be colored, white or transparent, or may not be colored.
The coloring of the material M′ may be carried out for example, by impregnating the material M with a colorant in addition to the hydrophobic material. Such a colorant is preferably hydrophobic, and examples thereof may include pigments such as carbon black (black pigment). Further, it is preferred to select a colorant that does not adversely affect the reagent used for the test chip.
The shape of the liquid receiving portion A in a plan view is not particularly limited and may be appropriately selected depending on the intended purpose; for example, it may be circular as illustrated in
The shape of the detection confirmation section B in a plan view is not particularly limited and may be appropriately selected depending on the intended purpose; it may be circular as illustrated in
The shape of the liquid flow section C in a plan view is not particularly limited and may be appropriately selected depending on the intended purpose; preferably, it is the same shape as the liquid receiving section A. Further, it is preferred that the liquid flow section C has a shape that substantially matches the liquid receiving section A in the plan view of the test chip.
The shape of the liquid flow section D in a plan view is not particularly limited and may be appropriately selected depending on the intended purpose; preferably, it is the same shape as the detection confirmation section B. Further, it is preferred that the liquid flow section D has a shape that substantially matches the detection confirmation section B in the plan view of the test chip.
The thickness of the test chip according to the present disclosure is not particularly limited, and may be 100 to 300 µm, for example.
Although not illustrated, the test chip of the present disclosure may have a plurality of sets of combination of the detection confirmation section B, the liquid flow section D, and the liquid passage E. In this case, the presence or absence of a plurality of substances to be detected can be confirmed at the same time, through a single inspection.
Further, the first layer 10 of the test chip 1 is provided with a liquid non-flow section X, as a portion other than the liquid receiving section A, the detection confirmation section B, and the liquid passage F. The liquid receiving section A, the detection confirmation section B, and the liquid passage F are made, for example, of a material M that permits flow of the test liquid by the capillary action. Further, the liquid non-flow section X is made, for example, of a material M′ that prohibits flow of the test liquid.
As illustrated in
As described above, the liquid receiving section A, the detection confirmation section B and the liquid passage F in the first layer 10, and the liquid flow section D and the liquid passage E in the second layer 20 are made, for example, of a material M that permits flow of the test liquid due to the capillary action. On the other hand, the liquid non-flow section X in the first layer 10 and the liquid non-flow section Y in the second layer 20 are made, for example, of the material M′ in which the material M is impregnated with a hydrophobic material, which prohibits the flow of the test liquid.
In the test chip described above, it is preferred that the material M′ of the liquid non-flow section X on the front surface side is colored so that the inspector can easily observe the liquid receiving section A and the detection confirmation section B on the front surface side. On the other hand, the material M′ of the liquid non-circulation portion Y on the back surface side of the test chip may be colored, white or transparent, or may not be colored.
Other than the above, description of the features of the second aspect common to the first aspect is omitted.
Further, the first layer 10 of the test chip 1 is provided with a liquid non-flow section X as a portion other than the detection confirmation section B. The detection confirmation section B is made, for example, of a material M that permits flow of the test liquid by the capillary action. Further, the liquid non-flow section X is made, for example, of a material M′ that prohibits flow of the test liquid.
Further, as illustrated in
As described above, the detection confirmation section B and the liquid passage F in the first layer 10, and the liquid flow section D and the liquid passage E in the second layer 20 are made, for example, of a material M that permits flow of the test liquid due to the capillary action. On the other hand, the liquid non-flow section X in the first layer 10 and the liquid non-flow section Y in the second layer 20 are made, for example, of a material M′ in which the material M is impregnated with a hydrophobic material, which prohibits flow of the test liquid.
In the test chip described above, it is preferred that the material M′ of the liquid non-flow section X on the front surface side and the liquid non-flow section Y on the back surface side is colored so that the inspector can easily observe the liquid receiving portion A and the detection confirmation portion B on the front surface side.
The test chip according to the third aspect is particularly useful, for example, when it is desired to arrange the liquid receiving section A and the detection confirmation section B on different surfaces from the viewpoint of fail-safe.
Other than the above, description of the features of the second aspect common to the first aspect is omitted.
Further, the test chip according to the present disclosure may appropriately include the features described below. Hereinafter, the description will be made with reference to the features according to the first aspect as the basic feature, though any of the features may be applied to the case of the second aspect and the third aspect.
In the test chip 1 as described above, the liquid flow section D having an annular structure may have any contour shape such as circle, ellipse, or rectangle, though it is preferred that the contour shape substantially matches the detection confirmation portion B in the plan view of the test chip. Further, it is preferred that the liquid non-flow section D′ in the plan view of the test chip has a shape obtained by scale-reduction of the contour shape of the liquid flow section D. Further, it is preferred that the liquid non-flow section D′ is colored in white, transparent, or uncolored so as not to disturb confirmation of the color development in the detection confirmation section B.
Regarding the abovementioned feature, in the case of the test chip according to the second aspect, a plurality of liquid passages F may be provided as many as the number of liquid passages E, and the plurality of liquid passages F of the first layer 10 and the plurality of liquid passages E of the second layer 20 may be connected to each other, respectively.
In the test chip 1 as described above, from the viewpoint of suppressing an increase in the amount of test liquid required for inspection, the number of the liquid passages E (and the liquid passages F in the case of the second aspect) is preferably four or less, more preferably three or less, and further preferably two or less. Further, the number of connection(s) of the liquid passages E to the liquid flow section D is preferably four or less, more preferably three or less, and further preferably two or less.
Further, in the test chip 1 as described above, as illustrated in
Further, in the test chip 1 as described above, as illustrated in
When the above-mentioned test chip 1 is comprised of the material M (the material that permits flow of the test liquid by capillary action) and the material M′ (the material in which the material M is impregnated with the hydrophobic material to prohibit flow of the test liquid), it is preferred for the material M′ that the impregnation rate of the hydrophobic material into the material M is preferably in the range of 14% or more and 32% or less. By manufacturing the test chip so that the impregnation rate is 14% or more, the passage wall surface (interface between the material M and the material M′) of the test liquid becomes sufficiently uniform, and the flow of the test liquid from the liquid receiving section A to the detection confirmation section B can be made smoother. Further, by manufacturing the test chip so that the impregnation rate is 32% or less, it is possible to sufficiently avoid the problem such as blockage when impregnating the material M with the hydrophobic material are sufficiently avoided, and more reliably obtain a test chip with a desired passage structure.
The above-mentioned impregnation rate refers to the impregnation rate of the material M′ in the region of the test chip 1 that is made of that material M′ over the entire thickness direction.
The impregnation rate may be regarded as 100% for the material M′ which is obtained by immersing the material M in a hydrophobic material that is heated (e.g., heated to 120° C.) to have a sufficiently low viscosity, and maintaining this temperature for a sufficient time (e.g., for 3 minutes). More specifically, the impregnation rate may be determined by the method described hereinafter with reference to the examples.
The impregnation rate may be adjusted, for example, by regulating the amount of the hydrophobic material to be impregnated (the thickness of the hydrophobic film, etc.).
In the test chip 1 as described above, it is preferred that the ratio of the thickness (t2) of the second layer 20 to the thickness (t1) of the first layer 10 (the thickness of the second layer / the thickness of the first layer), i.e., the ratio t2/t1 is 0.56 or more and 2.2 or less. By manufacturing the test chip so that the ratio t2/tl is 0.56 or more and 2.2 or less, a desired passage structure can be more reliably formed in the obtained test chip. In particular, when the test chip is manufactured by the test chip manufacturing method described later, if the test chip is manufactured so that the ratio t2/tl is 0.56 or more and 2.2 or less, it is possible to sufficiently avoid problems such as blockage when impregnating the sheet-like material with the hydrophobic material, and effectively improve the speed and/or speed stability of the liquid flow from the liquid receiving section A to the detection confirmation section B. From the same viewpoint, the ratio t2/tl is preferably more than 1.0, i.e., the thickness t2 of the second layer 20 is larger than the thickness t1 of the first layer 10 as illustrated in
The above-mentioned test chip 1 may be manufactured, for example, by providing a predetermined portion (detection confirmation section B, etc.) on a sheet-shaped material to form the first layer 10, and a predetermined portion (liquid flow section D, etc.) on another sheet-shaped material to form the second layer 20, and then laminating these two sheet-like materials. Alternatively, the above-mentioned test chip 1 may also be manufactured by providing a predetermined portion on a part of a single sheet-like material to form the first layer 10, and a predetermined portion on another part of the single sheet-like material to form the second layer 20, and folding the single sheet-like material which positioning the first layer and the second layer. However, it is preferred that the test chip 1 according to of the present embodiment is manufactured by forming a first layer on one surface side of a single sheet-like material and forming a second layer on the other surface side. The test chip of the present embodiment, in which the first layer and the second layer are formed on both sides of one sheet-like material, provides various advantages, such as (1) the labor and cost of lamination process (or folding process) can be saved; (2) the flow of the test liquid due to the capillary action between the first layer and the second layer is ensured; and (3) no jigs or the like for holding the laminated body (or the folded body) of the sheet-like material are required so that the disposal becomes easy.
The test chip 1 in which the first layer and the second layer are formed on both sides of a single sheet-like material may be manufactured, for example, by the method for manufacturing a test chip described below.
According to one embodiment of the present disclosure, there is provided a method for manufacturing a test chip as described above, which is characterized in that the method comprises:
With such manufacturing method, it is possible to manufacture the above-described test chip easily, with high accuracy and at low cost.
In the film forming step, a hydrophobic material is used to form a first hydrophobic film on a first substrate and a second hydrophobic film on a second substrate.
A colorant may be added to the hydrophobic material. Further, the hydrophobic material may be appropriately blended with a viscosity adjusting component (e.g., resin or the like), a dispersion aid, a filler, etc. The hydrophobic material and the colorant are as described above with reference to the test chip.
The above-mentioned hydrophobic material is preferably heated and melted in forming the films. The heating temperature may be appropriately set in consideration of the melting point of the hydrophobic material and the viscosity adjusting component. In addition, the viscosity of the hydrophobic material at the time of melting may be appropriately selected so that the sheet-like material can be impregnated as desired, in consideration of the thickness and basis weight (density) of the sheet-like material to be used later.
The viscosity of the hydrophobic material is not particularly limited; however, from the viewpoint of sufficiently avoiding problems such as blockage during impregnation, the viscosity at 140° C. and a shear rate of 3000 s-1 is preferably 100 mPa·s or less, 50 mPa·s or less, more preferably 30 mPa·s or less.
The first substrate and the second substrate are not the constituent members of the finally obtained test chip, but one of the members used for manufacturing the test chip. As the first substrate and the second substrate, for example, there may be used a film made of polyesters, such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), as well as polyphenylene sulfide (PPS), cellophane or the like. The first substrate and the second substrate may have any shape such as a ribbon shape and a film shape. Further, the same substrate may be used as the first substrate and the second substrate.
In the film forming step, the hydrophobic film may be formed on the first substrate and the second substrate by applying the above-mentioned hydrophobic material. At the time of coating, it is preferred to heat and hold the first substrate and the second substrate in advance. The thickness of the first hydrophobic film and the second hydrophobic film to be formed may be appropriately selected, in consideration of the thickness of the sheet-like material to be used later.
In particular, the ratio of the thickness of the second hydrophobic membrane (t2′) to the thickness of the first hydrophobic membrane (t1′) (thickness of the second hydrophobic film / thickness of the first hydrophobic film), that is, the ratio t2′/ t1′is preferably 0.56 or more and 2.2 or less. By setting the ratio t2′/t1′ to 0.56 or more and 2.2 or less, problems such as blockage when impregnating the sheet-like material with the hydrophobic material in the subsequent process are sufficiently avoided, and the speed and/or speed stability of the liquid flow from the liquid receiving section A to the detection confirmation section B can be sufficiently increased. From the same viewpoint, the t2′/t1′ is more preferably more than 1.0, further preferably 1.3 or more, and even more preferably 1.8 or more. However, the ratio t2′/t1′ is not particularly limited and may be 3.0 or less.
In the first printing step, the first hydrophobic film formed on the first substrate is used for carrying out printing on a first sacrificial substrate. Further, in the second printing step, the second hydrophobic film on the second substrate is used for carrying out printing on a second sacrificial substrate.
The first sacrificial substrate and the second sacrificial substrate are not the constituent members of the finally obtained test chip, but one of the members used for manufacturing the test chip. The first sacrificial substrate and the second sacrificial substrate are preferably for general-purposes, with which printing may be carried out with high accuracy, and may be high-quality paper, coated paper, synthetic paper, etc. The first sacrificial substrate and the second sacrificial substrate may be comprised of the same base material.
The printing on the first sacrificial substrate and the printing on the second sacrificial substrate are not particularly limited; for example, there may be preferably used a label writer widely used as office supplies. Then, in the first printing step, the first hydrophobic film on the first substrate is used to vary out printing on the first sacrificial substrate so as to have an inverted pattern of the first layer of the test chip. Further, in the second printing step, the second hydrophobic film on the second substrate is used to carry out printing on the second sacrificial substrate so as to have an inverted pattern of the second layer of the test chip. In this regard, taking the production of the test chip illustrated in
The pattern to be printed may be generated in advance by, for example, a personal computer or the like, and the data may be imported to the printing device. Further, the first printing step and the second printing step may be carried out simultaneously.
In the first transfer step, the first hydrophobic film after the first printing step is transferred to one surface of a single sheet-like material, and impregnated into the sheet-like material. Further, in the second transfer step, the second hydrophobic film after the second printing step is transferred to the other surface of the single sheet-like material, and impregnated into the sheet-like material. By this, a first layer derived from the first hydrophobic membrane, as well as a second layer derived from the second hydrophobic membrane are formed.
A transfer device, such as laminator, may be used for the transfer of the hydrophobic films. Further, in the transfer of the first hydrophobic film on the first substrate and the transfer of the second hydrophobic film on the second substrate, it is preferred that the respective transfer positions are appropriately adjusted according to the pattern of the desired test chip.
The sheet-like material is as described above with respect to the material M.
The impregnation of the hydrophobic membrane into the sheet-like material may be achieved, for example, by heating. In this regard, for example, if a transfer device such as a heatable laminator is used, it is possible to simultaneously carry out both the transfer and the impregnation of the hydrophobic films.
Here, in the first transfer step and the second transfer step, at least a part of the first hydrophobic film transferred from the first substrate and the second hydrophobic film transferred from the second substrate by means of the above-mentioned impregnation is made to contact in the material M. In other words, in the region of the sheet-like material where the hydrophobic films are transferred to both sides as seen in the thickness direction, the hydrophobic films are impregnated over the entire thickness direction. On the other hand, in the region of the sheet-like material where the hydrophobic films are transferred only to one surface as seen in the thickness direction, the other surface is not impregnated. Such adjustment may be carried out, for example, by appropriately adjusting the viscosity of the above-mentioned hydrophobic material, the thickness of the sheet-like material, the thickness of the hydrophobic membrane, etc.
In the first transfer step and the second transfer step, the entirety of the transferred hydrophobic films may be impregnated in the sheet-like material. In that case, the thickness of the sheet-like material does not significantly change before and after the first transfer step and the second transfer step (there is however a possibility that the thickness may decrease due to the influence of compression by the laminator, or the like).
The first transfer step may be carried out before the second transfer step or after the second transfer step. Alternatively, the first transfer step and the second transfer step may be carried out collectively and simultaneously. In that case, the sheet-like material may be sandwiched between the first substrate and the second substrate so that the hydrophobic films are brought into contact with the sheet-like material.
If the conditions of the first transfer step and the second transfer step are the same, the thicknesses ratio (t2/t1) of the first layer and the second layer formed after impregnation is maintained at the thickness ratio of each hydrophobic film before impregnation.
After the first transfer step and the second transfer step, the first substrate and the second substrate may be peeled off, as appropriate. In this way, it is possible to finally obtain the test chip of the present embodiment.
In the method for manufacturing a test chip according to the present embodiment, by carrying out the predetermined printing step and transfer step described above, even if a sheet-like material with a relatively rough surface such as a commercially available filter paper is used, transfer defects and voids are less likely to occur, and test chips can be manufactured with higher accuracy.
Further, in the method for manufacturing a test chip according to the present embodiment, since the first layer and the second layer having a desired pattern can be formed without using a mold or the like, on-demand manufacturing is made possible.
Further, in the test chip manufacturing method according to the present embodiment, since the test chip are manufactured by forming the first layer and the second layer on both sides of one sheet-shaped material, various advantages can be achieved as compared, for example, to the case where the test chip is manufactured by using two sheet-shaped materials (or where a single sheet-shaped material is folded), such as (1) the labor and cost of lamination process (or folding process) can be saved; (2) the flow of the test liquid due to the capillary action between the first layer and the second layer of the obtained test chip is ensured; and (3) no jigs or the like for holding the laminated body (or the folded body) of the sheet-like material are required so that the disposal becomes easy.
Next, the present disclosure will be described in further detail with reference to Examples and Comparative Examples, though the present disclosure is not limited to the following Examples.
First of all, the inventors examined the effects of the pattern (passage structure) of the first layer and the second layer of the test chip on the color unevenness.
Paraffin wax as a hydrophobic material (“Paraffin Wax – 155” manufactured by Nippon Seiki Co., Ltd.) 48 parts by mass, synthetic wax as a hydrophobic material (“Diacama® 80” manufactured by Mitsubishi Chemical Corp.) 48 parts by mass, ethylene-vinyl acetate copolymer resin (“Ultrasen® 681” manufactured by Toso Corp.) 2 parts by mass, and carbon black as a coloring agent (“MA-100” manufactured by Mitsubishi Chemical Corp.) 2 parts by mass were blended and melt-mixed at 100° C. At that time, each component was dispersed using a sand mill. In this way, the hydrophobic material was been prepared.
The above-mentioned hydrophobic material and a substrate (polyester film “Lumirror® #5A-F531” manufactured by Toray Ind. Inc., with one side subjected to heat-resistant treatment) have been placed on a hot plate maintained at 120° C., with the non-heat-resistant side upside. The above-mentioned hydrophobic material was maintained in a molten state at 120° C. and then applied onto the substrate with a Mayer bar to have a thickness of about 6 to 12 µm, so as to form ribbon-shaped hydrophobic films (the first hydrophobic film and the second hydrophobic film).
Next, by using a label writer (“TEPURA SR750” by King Jim Corp.), the above-mentioned hydrophobic film was printed on a high-quality paper as the first sacrificial substrate so as to have a desired pattern prepared in advance on a personal computer. Similarly, the above-mentioned hydrophobic film was printed on the high-quality paper as the second sacrificial substrate so as to have a desired pattern prepared in advance on a personal computer. The above two patterns printed on wood-free paper correspond to the inverted patterns of the front surface (first layer) and the back surface (second layer) of the finally obtained test chip, respectively. The high-quality paper after the printing is not for use in a subsequent process.
Here, in Comparative Example 1, the patterns on the front surface (the first layer) and the pattern on the back surface (the second layer) are as illustrated in
Next, by using the printed substrate, a filter paper (Whatman grade 41) as the sheet-shaped material M was sandwiched while carrying out appropriate positioning, and bringing the hydrophobic films into contact with the filter paper. Then, by using the laminator maintained at 90° C., the hydrophobic films were collectively transferred onto both sides of the filter paper. Each hydrophobic film was substantially completely impregnated into the filter paper from both sides, to make the portion of the filter paper directly underneath hydrophobic. By this, the first layer having a predetermined pattern was formed on the front surface side of the filter paper, and the second layer having the predetermined pattern was formed on the back surface side of the filter paper. In the filter paper, in the region where the hydrophobic films were transferred onto both sides in the thickness direction, the hydrophobic films were impregnated over the entire thickness direction. Further, in the region where the hydrophobic film was transferred onto only one surface in the thickness direction, the impregnation did not reach the other surface. Then, the substrates on both sides were peeled off, to finally obtain a test chip. Since the first layer and the second layer in each example are derived from the same hydrophobic film, they had the same thickness.
For each of the obtained test chips, the front surface (the first layer) was placed on the upper side, and the center of the detection confirmation section B was marked with a water-based red highlight pen. Then, three drops of distilled water were dropped into the liquid receiving portion A with a dropper, and the change of the red mark due to the flow of water was observed.
As a result, in Comparative Example 1 (
In contrast, in Examples 1-1 to 1-7 (
Next, the inventors examined the relationship between the thicknesses of the first layer and the second layer, which can ensure good liquid flowability.
Hydrophobic materials (inks) were prepared according to the formulation as listed in Table 1.
Test chips were obtained in essentially the same way as above, except that ink 1 or ink 2 was used as the hydrophobic material, Watman grade 41 (filter paper # 41) or Whatman grade 40 (filter paper # 40) was used as the filter paper (material M), and the temperature of the laminator was appropriately adjusted. At that time, the patterns of the first layer and the second layer were as illustrated in
Each of the obtained test chips was placed, with the front surface (first layer) on the upper side. Next, about 0.3 mL of a liquid obtained by dissolving aqueous fluorescent ink in distilled water was dropped into the liquid receiving section A with a dropper, to measure the time (flow time) from the start of the dropping until the liquid reaches the detection confirmation section B. The same measurement was carried out eight times, for calculating the average value and the standard deviation. The results are listed in Tables 2 to 5 for each combination of the hydrophobic material and the filter paper.
10
10
20 (max)
It may be concluded that all of the examples in Table 2 and Table 5 have good liquid flowability. From this, as regards the ratio of the thickness of the second layer to the thickness of the first layer (the thickness of the second layer / the thickness of the first layer), as long as the ratio is within the range of at least 0.56 to 2.2, a good liquid flowability can be guaranteed.
Next, the inventors examined the impregnation rate of the hydrophobic material that can ensure good liquid flowability.
The same filter paper (the filter paper # 41 or the filter paper # 40) as used in Experiment 2 was cut into a size of 5 cm × 2 cm, and dried at 120° C. for 3 minutes, to measure the dry mass MO (g). Then, the filter paper was immersed in the same hydrophobic material (ink 1 or ink 2) as that used in Experiment 2, and left at 120° C. for 3 minutes. The filter paper after immersion was sandwiched between the same type of filter paper and slide glass, and left at 120° C. for 1 minute under a load of 100 gf to remove excess hydrophobic material. The mass M1 (g) of the filter paper was then measured. The maximum impregnation amount Pmax (g/m2) per unit section area was then calculated from (M1-M0) × 1000.
In each of Tables 2 to 5, examples with the maximum and minimum total thickness of the first hydrophobic film and the second hydrophobic film were selected, respectively, and the ink densities listed in Table 1 are used, to calculate the actual impregnation amount P (g/m2) per unit section area in the selected example. Then, the impregnation rate (%) of the hydrophobic material in the filter paper was calculated as (P/Pmax) × 100. The results are listed in Table 6.
From Table 6, it may be considered that good liquid flowability can be ensured if the impregnation rate of the hydrophobic material is at least in the range of about 14% to 32%.
The present disclosure provides a test chip wherein the target substance contained in the test liquid is reacted with the pre-charged labeling medium for confirming the presence of the target substance by the reaction between, and wherein uneven color development is significantly suppressed. Further, the present disclosure also provides a method for manufacturing a test chip, with which the above-mentioned test chip can be easily manufactured with high accuracy and at low cost.
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| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-079845 | Apr 2020 | JP | national |
| 2021-001630 | Jan 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/014245 | 4/1/2021 | WO |
