Target cell capture filter and target cell capture method

Abstract

The present invention provides a target cell capture filter for easily, quickly, and efficiently separating and capturing target cells contained in a biological sample such as blood, which has an improved capture rate per unit area. [Solution] A target cell capture filter having a capture surface that captures target cells in a liquid, the target cell capture filter having a plurality of notches that allow a portion of the capture surface to elastically deform in a direction perpendicular to the capture surface to form gaps, at least a portion of the plurality of notches being a first notch group consisting of a plurality of notches that differ from one another in the shortest distance from the point of maximum deformation of the notches to the outer edge of the capture surface, and characterized in that the amount of elastic deformation relative to the impulse per unit area is equal.

Description

[Technical field]

[0001] The present invention relates to a target cell capture filter and a target cell capture method, and in particular to a target cell capture filter having a capture surface that captures target cells in a liquid. [Background technology]

[0002] Selective extraction of target substances (mainly cells, microorganisms, proteins, exosomes, etc.) from liquids has become a very important issue in the fields of life science and biotechnology, including medicine, health, and agriculture, and there is a demand for a method to capture only the target substances easily, quickly, and efficiently.

[0003] The present inventors have previously proposed a target cell trapping device that easily, quickly and efficiently separates and traps target cells contained in a biological sample such as blood (Patent Document 1).

[0004] Furthermore, Patent Document 2 discloses a method in which, using "a microfluidic chip with avidin fixed in a cell capture passage," "a nucleic acid aptamer modified with biotin is added to a sample in advance, followed by incubation," and "the mixed solution after incubation is filled into the microfluidic chip, and the target cancer cells in the mixed solution are bound to avidin via biotin, thereby achieving separation of the target cancer cells." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-83265 A [Patent Document 2] China Patent Application Publication No. 103087899 Summary of the Invention [Problem to be solved by the invention]

[0006] However, while the conventional capture methods (Patent Documents 1 and 2) are capable of capturing target cells, they have a problem in that the capture rate per unit area is not improved.

[0007] Therefore, an object of the present invention is to propose a target cell capture filter with an improved capture rate per unit area. [Means for solving the problem]

[0008] A first aspect of the present invention is a target cell capture filter having a capture surface that captures target cells in a liquid, the target cell capture filter comprising a plurality of notches that enable a portion of the capture surface to elastically deform in a direction perpendicular to the capture surface to form gaps, at least a portion of the plurality of notches being a first notch group that is a plurality of notches having different shortest distances from the maximum deformation point of the notches to the outer edge of the capture surface, and characterized in that the amount of elastic deformation with respect to the impulse per unit area is equal.

[0009] A second aspect of the present invention is a target cell capture filter of the first aspect, wherein the multiple notches belonging to the first group of notches are arranged to form a geometric shape, and further, the geometric shape is formed in a nested manner, and the nested geometric shapes are arranged more densely from the inside to the outside.

[0010] A third aspect of the present invention is a target cell capture filter according to the second aspect, comprising a plurality of the geometric shapes arranged in a nested manner.

[0011] A fourth aspect of the present invention is a target cell capture filter according to any one of the first to third aspects, wherein the line segments of the multiple incisions belonging to the first incision group have equal lengths.

[0012] A fifth aspect of the present invention is a target cell capture filter of any of the first to fourth aspects, wherein the multiple notches belonging to the first group of notches are arranged to form concentric circles.

[0013] A sixth aspect of the present invention is a target cell capture filter of the fifth aspect, wherein the concentric circles have, in order of decreasing radius, a first circle having a first radius, a second circle having a second radius, and a third circle having a third radius, and the difference in length between the second radius and the first radius is greater than the difference in length between the third radius and the second radius.

[0014] A seventh aspect of the present invention is a method for target cell capture using a target cell capture filter having a capture surface for capturing target cells in a liquid, the target cell capture filter having a plurality of notches that enable a portion of the capture surface to elastically deform in a direction perpendicular to the capture surface to form gaps, at least a portion of the plurality of notches being a first notch group consisting of a plurality of notches having different shortest distances from the maximum deformation point of the notches to the outer edge of the capture surface, and having equal amounts of elastic deformation with respect to impulse per unit area, the method including a target cell capture step in which the target cell capture filter captures the target cells in the liquid. Effect of the Invention

[0015] According to the first aspect of the present invention, by making the deformation amount of the gaps equal when the target cell capture filter elastically deforms, liquid passes evenly over the entire surface of the target cell capture filter, enabling capture over the entire surface of the filter, thereby making it possible to improve the capture rate per unit area of ​​the filter.

[0016] Furthermore, according to the second, third or fifth aspect of the present invention, the rigidity of the target cell capture filter is made uniform, and the amount of deformation upon elastic deformation is more uniform than with conventional filters, making capture across the entire filter surface even easier.

[0017] The inventors discovered that the amount of cells captured on the outer portion of conventional target cell capture filters was extremely small, and believed that this was due to an imbalance in the structural rigidity of the filter, with problems arising from gaps that form when the filter elastically deforms.

[0018] Furthermore, according to the fourth aspect of the present invention, by making the lengths of the line segments of the cuts equal, the deformation amounts of the gaps during elastic deformation are made equal, making it even easier to capture particles over the entire surface of the filter.

[0019] According to the fifth aspect of the present invention, by making the cuts form concentric circles, gaps can be arranged evenly over the entire surface of a target cell capture filter suitable for commonly used conical containers. [Brief description of the drawings]

[0020] [Figure 1] FIG. 13 is a diagram showing an example of a cut in a target cell capture filter. [Diagram 2] 1 is a graph showing the results of measuring the capture density of target cells depending on the filter cut depth. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments. EXAMPLES

[0022] The present invention relates to a three-dimensional filter that primarily classifies target substances present in a liquid in a size-selective and affinity-specific manner, and a method for capturing target cells using the same, and in particular to a three-dimensional filter that effectively captures target cells present in a liquid.

[0023] 1(A) is a diagram illustrating a target cell capture filter 1 and a target cell capture filter 21 according to this embodiment. The target cell capture filter 1 and the target cell capture filter 21 have a plate-like shape when not in use. Furthermore, the target cell capture filter 1 and the target cell capture filter 21 are each an example of the "target cell capture filter" in the claims of this application.

[0024] The target cell capture filter 1 (hereinafter referred to as the "composite 3D filter 1") shown in FIG. 1(A) has cuts 3 (an example of the "cuts" in the claims) in the shape of different concentric circles (an example of the "figure shape" and "concentric circle" in the claims) in one surface (an example of the "capture surface" in the claims). The target cell capture filter 21 (hereinafter referred to as the "equally spaced filter 21") in FIG. 1(B) has a cut 3 in the shape of one concentric circle (an example of the "figure shape" and "concentric circle" in the claims). The presence of the cut 3 allows a part of the surface to elastically deform in a direction perpendicular to the surface to form a gap. The intervals that form the gaps in the surface become narrower as the gaps move concentrically from the center to the outside, so that the width of the gaps when elastically deformed by fluid force becomes equidistant.

[0025] FIG. 2 is a graph showing the results of measuring the capture density of target cells depending on the difference in the cut of the target cell capture filter. Here, the measurement will be described. The target cells are modified with a nucleic acid aptamer in advance, and the binding with the filter is considered to utilize biotin-avidin binding. Specifically, a nucleic acid aptamer modified with biotin at the end is introduced into a sample solution containing target cells, the target cells are bound to the nucleic acid aptamer, and the filter is modified with avidin. Then, by introducing the sample solution into the filter, the target cells are captured by biotin-avidin binding. As shown in FIG. 2, when the evenly-spaced filter 21 according to this embodiment is compared with the conventional filter 51, the capture density of target cells is improved by more than three times in the evenly-spaced filter 21. Furthermore, it can be seen that the capture density of target cells is improved by about 20 times in the composite 3D filter 1 compared with the conventional filter 51.

[0026] The target cell capture filters 1 and 21 have a plurality of slits 3 that elastically deform to form gaps, and at least some of the plurality of slits 3 have the following characteristics. That is, (1) Multiple cuts; (2) The shortest distance from the maximum deformation point of each cut to the outer edge 5 of the target cell capture filter is different from each other. Hereinafter, a plurality of cuts having such characteristics will be referred to as a "first cut group" (an example of the "first cut group" in the claims of the present application).

[0027] The first cut group also has the characteristic that the amount of elastic deformation with respect to the impulse per unit area in the central portion 7, which is a region including the center of the filter, is equal to the amount of elastic deformation with respect to the impulse per unit area in the outer edge portion 9, which is a region in contact with the outer edge of the filter.

[0028] Here, the amount of deformation is represented by the area of ​​the gap, and can be roughly calculated as the product of the length of the gap and the distance of deformation.

[0029] Furthermore, the cuts 3 of the target cell capture filter 21 are all the same length. Compared to the conventional filter 51, in which the cuts are longer on the outer concentric circles, the stiffness of the filter has been increased, making it easier for clogging to occur before the filter is deformed into a three-dimensional shape, and making it easier for the capture target to remain on the target cell capture filter 21. This is also thought to have led to an improvement in the capture rate of target cells.

[0030] On the other hand, in the target cell capture filter 1, the smaller the circular arc of the cut, the shorter the cut length.

[0031] The cell capture filter according to this embodiment elastically deforms to the same extent at the center and the outer edge, making it easier for liquid to pass through the entire surface of the filter. As a result, the amount of capture target material that comes into contact with the filter per unit area is the same at both the center and the outer edge, making it possible to significantly improve the capture rate of the capture target material compared to conventional filters.

[0032] In this embodiment, the target cell capture filter is plate-shaped, but it may be in a shape other than a plate, for example, a thin film, as long as it has a capture surface. In addition, the capture surface is not limited to a flat surface, and may be a curved surface. [Explanation of symbols]

[0033] 1; target cell capture filter, 3; notch, 5; outer edge, 7; center, 9; outer edge, 21; target cell capture filter

Claims

1. A target cell capture filter having a capture surface for capturing target cells in a liquid, the target cell capture filter has a plurality of cuts that allow a portion of the capture surface to elastically deform in a direction perpendicular to the capture surface to form gaps; At least some of the plurality of cuts are a first cut group including a plurality of cuts, the first cut group being a plurality of cuts having mutually different shortest distances from the maximum deformation points of the cuts to the outer edge of the capture surface; The deformation amount of the elastic deformation with respect to the impulse per unit area is equal, Each of the plurality of cuts belonging to the first cut group is arranged to form a circle, The plurality of cuts belonging to the first cut group include arranged to form a nested geometric shape; the geometric shapes are multiple, Each of the geometric shapes is a group of concentric circles having a plurality of circles with different radii and sharing a single center, the length of the cut in each of the geometric shapes increases as the cut is spaced apart from the center of each of the concentric circles; The centers of the concentric circles are different from each other, A target cell capture filter, wherein the multiple geometric shapes are arranged symmetrically with respect to a straight line connecting the center of the filter and the center of any of the multiple concentric circles, the center of which is different from the center of the filter and the center of any of the multiple concentric circles.

2. A method for capturing target cells using a target cell capture filter having a capture surface for capturing target cells in a liquid, comprising: the target cell capture filter has a plurality of cuts that allow a portion of the capture surface to elastically deform in a direction perpendicular to the capture surface to form gaps; At least some of the plurality of cuts are a first cut group including a plurality of cuts, the first cut group being a plurality of cuts having mutually different shortest distances from the maximum deformation points of the cuts to the outer edge of the capture surface; The amount of elastic deformation per unit area is equal to the impulse. Each of the plurality of cuts belonging to the first cut group is arranged to form a circle, The plurality of cuts belonging to the first cut group include arranged to form a nested geometric shape; the geometric shapes are multiple, Each of the geometric shapes is a group of concentric circles having a plurality of circles with different radii and sharing a single center, the length of the cut in each of the geometric shapes increases as the cut is spaced apart from the center of each of the concentric circles; The centers of the concentric circles are different from each other, the plurality of geometric shapes are arranged in line symmetry with respect to a straight line connecting the center of the filter and the center of any one of the groups of concentric circles, the center of the filter being different from the center of the plurality of concentric circles; A method for target cell capture, comprising a target cell capture step in which the target cell capture filter captures the target cells in the liquid.

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