Sample carrier for absorbing dried blood components and method for obtaining a membrane element with dried blood components

Abstract

The invention relates to a sample carrier. The sample carrier has an absorbent film layer, which is based on a nonwoven polyolefin and has at least one absorption region with dried blood components. The sample carrier also has a plastic-based foil layer, wherein the foil layer is pretreated in an antistatic manner. The film layer and the foil layer are mechanically connected to one another in a subregion of the sample carrier, wherein the layers are otherwise not mechanically connected to one another in the absorption region. When the sample carrier is placed on a flat surface, the film layer preferably covers the foil layer at least in the absorption region.

Description

[0001] The invention relates to a sample carrier. The sample carrier has an absorbent film layer, which is based on a nonwoven polyolefin and has at least one absorption region with dried blood components. The sample carrier also has a plastic-based foil layer, wherein the foil layer is pretreated in an antistatic manner. The film layer and the foil layer are mechanically connected to one another in a subregion of the sample carrier, wherein the layers are otherwise not mechanically connected to one another in the absorption region. When the sample carrier is placed on a flat surface, the film layer preferably covers the foil layer at least in the absorption region.

[0002] The invention further relates to a method for obtaining a membrane element with dried blood components. For the method, a sample carrier is provided, which is placed on a support area. A container is provided below the support area. The membrane element is punched out of the absorption area of ​​the sample carrier by means of a punching device, so that the punched-out membrane element and the foil element punched out of the foil layer fall into the container.

[0003] For many qualitative determinations in the field of analysis and in particular laboratory diagnostics, the main point is only whether the analyte can be correctly determined to be present or absent, rather than in what concentration it is present in the patient's blood. This is the case, for example, when studying a blood sample to show whether the patient suffers from a metabolic disease associated with a defective gene. It is then only necessary to study the blood sample to show whether such a gene is present, rather than how much genetic material containing the gene is contained in the sample.

[0004] In the case of other analytes, it is necessary to determine in which concentration the analyte is present in the blood, since diagnostic reference concentration ranges are known. If the concentration of the analyte is within this range, this indicates that the patient is healthy. Therefore, for such semiquantitative or also purely quantitative determinations, it is important to correctly determine the amount or concentration of the analyte.

[0005] In order to measure the concentration of a specific analyte in the patient's blood, venous blood is usually taken from the patient and then processed into serum. In addition to this invasive intervention, which is uncomfortable for the patient and to a lesser extent even carries health risks (such as nausea or weakness), blood sampling can only be performed by qualified professionals such as physicians or at least by nurses or experienced laboratory staff. For this purpose, the patient must go to a physician's office or hospital.

[0006] On the contrary, it is much easier and gentler to obtain capillary blood. After piercing the patient's fingertip or earlobe with a sharp object, a few drops of capillary blood flow out, which are collected with a dropper and added to an absorbent sample carrier. Once the blood dries on the carrier and completely dries at room temperature for a few hours when appropriate, the carrier can be transported without further processing, even very simply by mailing. Therefore, there is no need to visit a physician's clinic. Due to the dried blood sample or dried blood components, the sample carrier and the sample located thereon are no longer considered as dangerous goods. A carrier with blood can be separated from a carrier with dried blood, preferably capillary blood. This can be achieved, for example, with a device as described in US14 / 900,360 or by punching. This separated carrier with dried blood is usually referred to as "dried blood spot" or "DBS".

[0007] The carrier mentioned here can be produced, for example, by a film layer which can absorb blood or blood components in a liquid aggregate state and then also allow the blood or blood components to dry thereon, and then the carrier is transported in the form of an absorbent film.

[0008] The blood component absorbed by the membrane can be whole blood, especially capillary blood. Alternatively, the blood component can be serum or plasma.

[0009] If a film element or a carrier is then punched out of the film in the above-mentioned manner, it may happen that the punching out may not have been successful.

[0010] Typically, the sample carrier is placed in the form of a film on a support device or a support area, and the film is then mechanically acted upon from above by means of a punching device or a punching knife in such a way that a membrane element is cut out of the film, wherein the membrane element then falls due to gravity into a container located below the sample carrier or below the film. This container can then be used later for biochemical analyses.

[0011] Since the film or film layer has a certain mechanical flexibility, it may happen that during the punching process the film layer is somewhat offset from the punching knife, so that a practically clean cut to cut out the film element is not possible, but rather tears of the film material occur in the edge region of the film element or in the cut edge. As a result, additional forces may act on the film element due to the tearing process, so that the film element does not fall vertically, but is deflected in the falling direction. The electrostatic charging of the film element and the deflection due to electrostatic forces are reduced or in some cases avoided by antistatic foils. It may happen that the film element does not fall into the desired and provided container.

[0012] If the film layer is too thick or too large, it may happen that the punching knife does not completely and unsuccessfully penetrate the film layer, so that the film element is not completely cut out from the film layer. Then, it is also impossible to achieve that the film element falls into the provided container.

[0013] When applying the blood component in a liquid aggregate state to the absorption region of the film layer, it may be desirable that the film layer is not in direct contact with other layers on its upper side and on its lower side in order not to influence the distribution of the liquid blood component in the film layer or away from the film layer. It is advantageous for this purpose if the film layer and the foil layer are also not mechanically connected to each other in the absorption region so that the foil layer can be deflected away from the film layer during the drying process of the blood component in the absorption region.

[0014] However, by mechanically connecting the foil layer to the film layer in a sub-region of the sample carrier, preferably in an edge region, it is ensured that the foil layer can also be provided in a simple manner for the punching process later. That is, the user only needs to cover the foil layer with the film layer during the drying process.

[0015] With regard to the sample carrier, the membrane layer may also be referred to as the upper side or upper layer of the sample carrier, whereas the foil layer may be referred to as the lower side or lower layer of the sample carrier.

[0016] The object of the present invention is to provide a sample carrier which, when carrying out a punching method known from the prior art, allows a membrane element with dried blood components to be punched out successfully, so that the punched-out membrane element falls into a container provided and, in particular, located below the membrane layer.

[0017] This object is achieved by a sample carrier according to the invention. The sample carrier has an absorbent film layer, which is based on a nonwoven polyolefin and has at least one absorption region with dried blood components. In addition, the sample carrier has a foil layer based on plastic, wherein the foil layer is pretreated in an antistatic manner. The film layer and the foil layer are mechanically connected to each other in a subregion of the sample carrier, wherein the layers are otherwise not mechanically connected to each other in the absorption region. When the sample carrier is placed on a flat surface, the film layer preferably covers the foil layer at least in the absorption region.

[0018] The sample carrier according to the invention has the advantage that, due to the provision of a foil layer in addition to the film layer, a mechanical stabilization of the film layer can be achieved during the punching process, so that the edge-back of the film layer during the punching or cutting process is reduced. This can in some cases achieve that the film material does not produce burrs in the region of the punching edge or cutting edge and thus that the film element can be cut precisely from the film layer. In other words, by avoiding the formation of burrs in the region of the cutting edge or punching edge, it is avoided that the punched film element is deflected in the wrong direction and in some cases does not fall into a container positioned below the punching device.

[0019] By not having a mechanical connection between the membrane layer and the foil layer in the punched-out absorption region, it is also achieved that after falling into the provided container, the punched-out membrane element can come into contact with the reactants or biochemical liquids in the container over its entire surface (i.e. on its back side or the side facing the foil layer), so that the expected treatment result is not falsified.

[0020] However, by mechanically connecting the foil layer to the film layer in a sub-region of the sample carrier, preferably in the edge region of the sample carrier, a simple operability is created for the user. That is, the user only needs to contact a certain position of the sample carrier, for example a sub-region or an edge region mentioned in this article, and can then position the foil layer and the film layer together on the support area of ​​the punching device in a single working step, so that the film layer and the foil layer are arranged or oriented relative to each other in a desired manner. That is, it is not necessary for the user to first place a separate foil layer and then place the film layer on the foil layer. The sample carrier can be used in the laboratory, in the doctor's office or at the patient's residence to absorb blood components in a liquid aggregate state and then be sent or carried to the laboratory work site after the blood components have dried, without the need to provide a separate foil layer.

[0021] By pre-treating the foil layer in an antistatic manner, electrostatic charging or electrostatic force is avoided during the punching process. Because the film layer and the foil layer are stacked on each other, the punching knife cuts through the film layer and the foil layer during the punching process. Such a punching knife is usually made of metal. During the punching process, the friction of the metal on the plastic may cause the electrostatic charging of the foil and in some cases also cause the electrostatic charging of the membrane element, so that the electrostatic force may act on the punched foil element and in some cases also may act on the membrane element. It may be caused that the punched foil element and in some cases also the membrane element deviates in its falling direction and does not fall into the positioned container. If, for example, the punched foil element falls into another container near the desired container, then when the multiple absorption areas of the sample carrier are repeatedly punched, cross contamination between different blood components or different blood samples in the corresponding container is caused. By pre-treating the foil layer in an antistatic manner, the punched membrane element and / or the undesirable wrong deflection of the punched foil element that may be caused by electrostatic force is avoided.

[0022] The foil layer is preferably pretreated on both sides in an antistatic manner.

[0023] The term "quantitative determination" is understood in the sense of the present application as a determination method for giving a conclusion about the absolute concentration of the analyte (more preferably given with a numerical value). Alternatively, a semi-quantitative determination may be involved, in which the concentration may be associated with a range from at least three, as far as possible four concentration ranges, such as negative, weakly positive and positive, or a relative concentration determination. The concentration determination is especially carried out by means of a calibrator, wherein the calibrator is preferably a preferred solution of two or more, preferably four units or a solid analyte coated on a carrier that can be used for diagnosis, the units respectively comprising a known amount of analyte, wherein the two or more units respectively comprise other known amounts.

[0024] The quantitative determination is preferably carried out by a method selected from the group consisting of immunodiffusion, immunoelectrophoresis, light scattering, agglutination and an immunoassay using a marker, for example from the group consisting of an immunoassay using a radioactive marker, an enzyme marker (preferably ELISA), a chemiluminescent marker (preferably an electrochemiluminescent marker) and an immunofluorescent marker (preferably an indirect immunofluorescent marker), preferably ELISA.

[0025] By contacting the punched-out membrane element with a liquid suitable for receiving the analyte from the dried blood component, the dried blood component is eluted from the punched-out membrane element. Here, aqueous buffers with suitable pH and salt content, such as PBS, are particularly considered. The exact composition and conditions of the liquid and the contact time can be found by conventional experiments for stability and optimization (the purpose is to receive the analyte into the liquid as completely as possible) and depend on the properties of the analyte. Similarly, the liquid is selected as much as possible so that the liquid is compatible with the subsequent method for detecting the analyte. The analyte of interest in the liquid is then detected. The analyte is determined to be present or absent, or whether it is present at a concentration higher than the detection limit of the detection method used. The analyte is preferably detected in a semi-quantitative or quantitative manner. Various options for carrying out the method have been described in the prior art, for example Grüner, N., Stambouli, O. und Ross, RS (2015) Dried Blood Spots—Preparing and Processing for Use in Immunoassays and in Molecular Techniques, J. Vis. Exp 97, 52619.

[0026] Advantageous embodiments of the invention are the subject matter of the dependent claims and are explained in greater detail in the following description, partly with reference to the drawings.

[0027] The plastic is preferably polyester.

[0028] The polyester is preferably polyethylene terephthalate.

[0029] The foil layer is preferably pretreated in an antistatic manner in the sense that it has an antistatic agent at least in a subregion of its surface. The foil layer preferably has an antistatic agent on both sides in at least one subregion in each case.

[0030] The polyolefin is preferably selected from the group comprising polyethylene, polypropylene, polymethylpentene, polyisobutylene and polybutene.

[0031] The polyolefin is preferably polypropylene.

[0032] The sample carrier preferably has at least one adjustable positioning element, which can be adjusted between a first configuration and a second configuration. In the first configuration, the positioning element enables the film layer to be spaced apart from the foil layer when the sample carrier is placed on a flat surface. In the second configuration, when the sample carrier is placed on the flat surface, the film layer covers the foil layer at least in the absorption region.

[0033] If the blood components in a liquid aggregate state are applied to the absorption region of the sample carrier, the spacing of the foil layer from the membrane layer can be achieved by the placement element in the first configuration, so that during the drying process, the blood components do not move from the membrane layer or the absorption region of the membrane layer to the foil layer and are not guided away from the absorption region or away from the membrane layer there. As a result, the residence of the initially liquid blood components in the absorption region or in the membrane layer during the drying process is maximized. In other words: the blood components do not move to the foil layer, so that as many liquid blood components as possible remain in the membrane layer during the drying process. This is therefore particularly advantageous, because the blood components as patient samples are usually only available to a limited extent or in a limited volume and are therefore a precious resource.

[0034] The sample carrier can then be fed into the punching process in the described manner in the second configuration by virtue of the film layer covering the foil layer in the absorbent region in the second configuration of the support element.

[0035] In addition, a method for obtaining a membrane element with dried blood components is proposed. In a first step, a sample carrier according to the invention is provided. The sample carrier is placed on a support area. A container is provided below the support area. A membrane element is then punched out of the absorption area of ​​the sample carrier by means of a punching device or by means of a punching knife, so that the punched-out membrane element and the foil element punched out of the foil layer fall into the container.

[0036] The method preferably further comprises the following steps

[0037] - contacting the membrane element with a liquid in the container, the liquid being suitable for absorbing analytes from the dried blood component, and

[0038] - detecting said analyte in said liquid.

[0039] In addition, the use of the sample carrier of the present invention is proposed. The sample carrier can be used to qualitatively determine whether the analyte in the dried blood component is present. Alternatively, it can be used to semi-quantitatively determine the concentration of the analyte in the dried blood component. Preferably, it can be used to quantitatively determine the concentration of the analyte in the dried blood component.

[0040] The present invention will be explained in detail below with the help of specific embodiments with the help of the accompanying drawings, without limiting the overall inventive concept. In the accompanying drawings:

[0041] Figure 1 A top view showing a preferred embodiment of a sample carrier of the present invention,

[0042] Figure 2 A side view showing a preferred embodiment of a sample carrier of the present invention,

[0043] Figure 3 Another embodiment of the sample carrier of the present invention is shown.

[0044] Figure 4a and 4b Further embodiments of the sample carrier according to the invention are shown in different configurations.

[0045] Figure 5 shows a first configuration during a punching process for punching out a film element,

[0046] Figure 6 shows a second configuration during a punching process for punching out a film element,

[0047] Figure 7 and Figure 8 A corresponding sample carrier is shown with one film layer and one foil layer respectively,

[0048] Fig. 9 A first graphical representation showing the experimental results in percentages,

[0049] Fig.10 A graphical representation of the experimental results is shown using absolute values ​​and percentages.

[0050] Figure 1 A sample carrier P is shown with a membrane layer M based on a high-grade polyolefin. The membrane layer M has at least one or more absorption regions A, wherein at least one of the absorption regions A has a dried blood component. Such a blood component can be whole blood, in particular capillary blood, or plasma or serum.

[0051] A subregion T, preferably an edge region, is indicated by a dashed line.

[0052] Figure 1 In addition, an arrow R1 indicating the side view angle is shown. Figure 2 The sample carrier P is shown from the perspective described.

[0053] Figure 2 A sample carrier P with a membrane layer M and an absorption region A is shown. Figure 1 The blood components in the test are not clearly labeled.

[0054] Below the membrane layer M there is a foil layer F.

[0055] The sample carrier P is placed on a plane E.

[0056] The foil layer F is based on plastic, wherein the foil layer F is pretreated on at least one side, preferably on the upper side and the lower side of the foil layer F, in an antistatic manner.

[0057] The membrane layer M and the foil layer F are mechanically connected to one another in the sub-region T. This can be produced by an adhesive tape in the sub-region T, for example.

[0058] In the absorption region A, the foil layer F and the membrane layer M are not mechanically connected to each other.

[0059] When the sample carrier P is placed on the plane E, the membrane layer M covers the foil layer F at least in the absorption region A.

[0060] Figure 5 Since Figure 2 The side view shows that when the sample carrier P is placed on the support area AB, Figure 2 and Figure 1 The support area AB preferably has a hole L.

[0061] Below the support area AB a container G is provided.

[0062] With the aid of a punching device ST, a film element is punched out of the film layer M from the absorption region A of the sample carrier P, so that the punched-out film element is then to fall together with the foil element punched out of the foil layer F into the container G. For this purpose, the punching device or the punching knife ST is guided from above in a direction R2 extending perpendicularly to the support region AB.

[0063] Figure 6 Another configuration is shown, in which the punching knife or punching device ST has punched out the membrane element ME and the foil element FE from the sample carrier P. Punching is successful when both the membrane element ME and the foil element FE fall into the container.

[0064] The membrane element ME can then preferably be brought into contact with a biochemical liquid or a reactant liquid FL in a container G in order to determine the presence of the analyte or to determine the concentration of the analyte in the dried blood component semi-quantitatively or alternatively quantitatively.

[0065] Fig. 9 The results of a percentage analysis of a punching experiment are shown, in which a PantheraPuncher 9 device from the manufacturer PerkinElmer was used as a punching device. The film layer of the sample carrier is based on a nonwoven polyolefin and is here a film of the Porex BNW441435 type.

[0066] The punching process is considered successful when the membrane element and the foil element fall into the container provided for this purpose. The depressions ("wells") of a deep-well flat 96-well microtiter plate made of polypropylene, model Eppendorf 30501306, are used as containers. Alternatively, however, standard microtiter plates with a smaller height and made of other materials, preferably polystyrene, can also be used.

[0067] Error conditions can occur in the following ways:

[0068] - the membrane element cannot be punched out due to the high mechanical resistance of the underlying foil layer, or

[0069] - the membrane element and the foil element have been punched out but do not fall into the container positioned directly below but rather fall nearby, or

[0070] Although the punched-out membrane elements are received in the provided containers, the punched-out foil elements do not arrive in the containers but in containers of the microtiter plate located nearby, which can result in cross-contamination of samples with one another.

[0071] about Fig. 9 The percentage analysis results are as follows: Fig.10 The relevant absolute values ​​are shown. The corresponding configuration consisting of a film layer (POREX) and the relevant foil layer is entered in the first column SP1. Here, the exact product name of the corresponding foil layer and its corresponding thickness in micrometers are also included in the corresponding entry in column 1. It should be emphasized that only the foil Lumirror 45.11 is an antistatically coated foil.

[0072] The number of punching tests performed is recorded in column SP2. The absolute number of successfully performed punching tests is recorded in column SP3. The corresponding percentage of successfully performed punching tests is recorded in column SP4.

[0073] For the case where no foil or no foil layer was used, a successful blanking rate of 72.67% was obtained when only the POREX film with the film layer and no foil layer was used.

[0074] If different foils without antistatic pretreatment were used, less than 75% of successful punching tests were obtained. In embodiments with a foil layer thickness of 125 μm or 175 μm, no punching tests were successfully performed at all, because the mechanical properties of such foils made punching unsuccessful and the membrane element could not be punched out at all.

[0075] When using the antistatically pretreated foil Lumirror 45.11 with a thickness of 96 μm, a significantly higher success rate of the punching experiments was achieved, with a success rate of 95.76%.

[0076] It is evident that antistatic pre-treatment of the foil layer achieves significantly improved results.

[0077] The Lumirror 45.11 type foil used here is antistatically pretreated and is a polyester based foil.

[0078] Figure 3Another preferred embodiment P2 of the sample carrier of the present invention is shown. Figure 1 Compared to the first embodiment P of the sample carrier according to the invention, this embodiment P2 of the sample carrier additionally has one or more support elements AE. The support elements AE are preferably produced by cardboard elements or paper elements fastened to the edge region RB of the film layer M. The support elements AE can be folded along the edge region or the corresponding folded edge and oriented in this way. Figure 3 The sample carrier P2 is shown in a so-called second configuration in which the sample carrier is placed on a flat surface such that the membrane layer M covers the foil layer F in the absorption region A.

[0079] Figure 4a The sample carrier P2 is shown in the so-called second configuration, in which the support element AE is slightly bent upwards in the side view, so that the membrane M is Figure 2 The foil layer F covers the absorption region A marked in FIG. 1 (not directly visible here).

[0080] Figure 4b The sample carrier P2 is shown in a first configuration in which the positioning element AE is arranged from Figure 3 Based on the configuration of , it is bent downward so that it can be placed in such a way that when the sample carrier P2 is also placed on the plane E, the membrane layer M is spaced apart from the foil layer F.

[0081] This ensures that, after a blood component has been placed on the absorption region A of the membrane layer M, the blood component can dry into the membrane layer M without the foil layer F contacting the underside of the membrane layer M. This prevents a portion of the blood component from leaving the membrane layer M and drying on the surface of the foil layer F.

[0082] That is, the support element AE is preferably a folding element on the side of the sample carrier P2, so that the sample carrier P2 is supported by the folding element AE in such a way that the membrane layer M is spaced apart from the foil layer in the region of the absorption area A in the first configuration.

[0083] In a first embodiment, a spacing of the foil layer F from the membrane layer M is achieved by the support element AE or the support elements AE when the sample carrier P2 is placed on the plane E, so that the foil layer F lies on the plane E.

[0084] Figure 7 and 8 Here, the respective film layer M and foil layer F are shown, wherein due to the contact of the foil layer F with the film layer M during the drying process, a partial amount B2 of the blood component dries on the respective surface of the respective foil layer F. This is also to be avoided and is prevented by Figure 3 , 4a and the sample carrier P2 of 4b are implemented.

Claims

1. A sample carrier (P, P2) having: an absorbent film layer (M) based on a nonwoven polyolefin and having at least one absorbent region (A) with dried blood components (B), - and additionally, a plastic-based foil layer (F), wherein the foil layer is pretreated in an antistatic manner, wherein the plastic is a polyester, wherein the film layer forms an upper side of the sample carrier and the foil layer forms a lower side of the sample carrier, wherein the membrane layer (M) and the foil layer (F) are mechanically connected to one another in a subregion (T) of the sample carrier, wherein the film layer and the foil layer are additionally not mechanically connected to each other in the absorption region (A), And wherein when the sample carrier (P, P2) is placed on a plane (E), the film layer (M) covers the foil layer (F) at least in the absorption region (A), and the film layer and the foil layer overlap each other.

2. The sample carrier according to claim 1, The polyester is polyethylene terephthalate (PET).

3. The sample carrier according to claim 1, The foil layer (F) is pretreated in an antistatic manner in the sense that it comprises an antistatic agent at least in a subregion of its surface.

4. The sample carrier according to claim 1, Wherein the polyolefin is selected from the group consisting of polyethylene, polypropylene, polymethylpentene, polyisobutylene and polybutene.

5. The sample carrier according to claim 4, The polyolefin is polypropylene.

6. The sample carrier according to any one of claims 1 to 5, wherein the sample carrier (P2) has at least one adjustable positioning element (AE), which can be adjusted between a first configuration and a second configuration, wherein in the first configuration, when the sample carrier (P2) is placed on the plane, the positioning element (AE) enables the membrane layer to be spaced apart from the foil layer, And wherein in the second configuration, when the sample carrier (P2) is placed on the plane (E), the membrane layer (M) covers the foil layer (F) at least in the absorption area (A).

7. A method for obtaining a membrane element having a dried blood component, the method comprising: - providing a sample carrier (P, P2) according to one of claims 1 to 6, - placing the sample carrier (P, P2) onto the support area (AB), - providing a container (G) below said support area (AB), The membrane element (ME) is punched out of the absorption region (A) of the sample carrier by means of a punching device (ST), so that the punched-out membrane element (ME) and the foil element (FE) punched out of the foil layer (F) fall into the container (G).

8. The method according to claim 7, The method further comprises: - bringing the membrane element (ME) into contact with a liquid (FL) in the container (G), the liquid being suitable for absorbing analytes from the dried blood component, and - detecting said analyte in said liquid.

9. Use of a sample carrier according to any one of claims 1 to 6, - for qualitatively determining the presence or absence of an analyte in the dried blood component, - for semi-quantitative determination of the concentration of an analyte in the dried blood component, or - for quantitatively determining the concentration of an analyte in the dried blood component.

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