Method for manufacturing a sample loading plate

Abstract

To provide a sample loading plate and a manufacturing method thereof capable of appropriately holding a sample on a sample loading portion.SOLUTION: In a sample loading plate 10 provided with a sample loading portion 6 having a hydrophilic surface on a substrate 1, in which a hydrophilic member 5 having higher hydrophilicity than the hydrophilic surface is partially embedded in the hydrophilic surface. The sample loading plate 10 is made by projecting the hydrophilic member 5 to embed the hydrophilic member 5 in the sample loading portion 6.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sample loading plate for loading samples and a method for manufacturing the same.

Background Art

[0002] As one of the ionization methods of mass spectrometry that enables rapid and accurate diagnosis of pathogenic bacteria and bacteria, the matrix-assisted laser desorption ionization (MALDI) method is known.

[0003] In the MALDI method, in order to analyze an analyte that is difficult to absorb laser light or is easily damaged by laser light, the sample is premixed with a substance (matrix) that is easily absorbent and ionizable by laser light, and the sample is ionized by irradiating this with laser light.

[0004] In a mass spectrometer using the MALDI method, generally, a metal plate called a target plate (hereinafter referred to as a "sample loading plate") on which an analyte and a matrix are premixed and liquefied with a solvent (hereinafter referred to as a "sample") is placed in the apparatus, and laser light is irradiated onto the sample loaded on the sample loading plate for a predetermined time to desorb and ionize the sample. At this time, a voltage is applied to the metal sample loading plate, and an electric field is applied to the desorbed and ionized sample to make it easier for the desorbed and ionized sample to fly toward the acceleration electrode.

[0005] The sample loading plate has a plurality of sample placement areas for loading samples. A plurality of samples to be measured are dropped into a predetermined sample loading section, dried (crystallized), and placed in a mass spectrometer, and the sample loading plate is moved to irradiate the plurality of samples with a laser.

[0006] For example, Patent Document 1 discloses a technique of holding a dropped sample in a sample loading portion by providing a hydrophilic modification layer having a surface corresponding to the sample loading portion on a sample loading plate made hydrophilic.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The sample loading plate is transported for drying or the like with a liquid sample loaded on the sample loading portion of the sample loading plate. At this time, the sample loading plate may not be held horizontally and may be inclined or vibrated due to the conveyance. In the sample loading plate, due to the inclination of the sample loading plate or the application of vibration, the sample to be held in the sample loading portion may fall out of the sample loading portion, or the sample may spread wet over an area other than the sample loading portion. In that case, the analysis of the sample cannot be properly performed. Conventionally, attempts have been made to make the sample loading portion hydrophilic. However, in mass spectrometry by, for example, the MALDI method, since laser light is irradiated onto the sample, there are also restrictions on the material of the sample loading portion, and there has been a problem in ensuring sufficient hydrophilicity to hold the sample in the sample loading portion.

[0009] The present invention has been made in view of the above problems, and an object thereof is to provide a sample loading plate capable of appropriately holding a sample in a sample loading portion and a method for manufacturing the same.

Means for Solving the Problems

[0010] In a sample loading plate provided with a sample loading portion having a hydrophilic surface on a substrate, the sample loading plate is such that a hydrophilic member having a higher hydrophilicity than the hydrophilic surface is partially embedded in the hydrophilic surface. The hydrophilic surface may be a rough surface having a larger surface roughness than the surface of the substrate around the sample loading portion. The sample loading portion may be formed by blasting a part of the substrate, and the hydrophilic member may be a projection material in the blasting process. The sample loading portion may be a well having a bottom surface and a side surface. A configuration may be adopted in which a water-repellent film is provided on the substrate surface around the sample loading portion. Further, in a method for manufacturing a sample loading plate provided with a sample loading portion having a hydrophilic surface on a substrate, the method includes a blasting process of projecting a hydrophilic member having a higher hydrophilicity than the hydrophilic surface onto the hydrophilic surface to form the sample loading portion, and the blasting process is a method for manufacturing a sample loading plate which is a process of embedding the hydrophilic member in the hydrophilic surface. The blasting process may be a process of roughening the surface roughness of the hydrophilic surface. Before or after the blasting process, a water-repellent film forming process of forming a water-repellent film on the surface of the substrate may be provided.

Advantages of the Invention

[0011] According to the sample loading plate and its manufacturing method of the present invention, it is possible to provide a sample loading plate that can appropriately hold a sample mounted on the sample loading portion.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying out the Invention

[0013] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, in order to make each configuration easy to understand, the actual shape, the actual structure, the scale, the number, etc. in each structure may be made different. FIG. 1 is a diagram showing an embodiment of a sample loading plate of the present invention, (a) is a plan view of the sample loading plate, and (b) is a cross-sectional view taken along line A-A of (a).

[0014] The sample loading plate 10 shown in FIG. 1 includes a plurality of wells 6 having a bottom surface portion 6a and a side surface portion 6b on a substrate 1. The well 6 is a sample loading portion for holding a sample containing an object to be analyzed on the substrate 1. On the surfaces of the bottom surface portion 6a and the side surface portion 6b of the well 6, a hydrophilic member 5 having hydrophilic properties is partially embedded. The substrate 1 is a member having hydrophilicity and conductivity, for example, made of a metal such as stainless steel, aluminum, or an aluminum alloy, and is a substantially rectangular flat plate having an outer shape of about 120 mm × 80 mm and a thickness of about 2 mm. The well 6 formed in the substrate 1 has a diameter of 0.8 mm and a depth of 0.1 mm. The arithmetic mean roughness Ra of the surface of the portion of the substrate 1 excluding the well 6 is 0.1 μm, the arithmetic mean roughness Ra of the bottom surface portion 6a of the well 6 is 2.0 μm, and the arithmetic mean roughness Ra of the side surface portion 6b is 2.5 μm. The well 6 has a rougher surface compared to the portion excluding the well 6, and the side surface portion 6b of the well 6 is rougher than the bottom surface portion 6a. Further, the hydrophilic member 5 is made of silicon dioxide, aluminum oxide, or titanium oxide particles having a particle size of about 27 to 74 μm, which is more hydrophilic than the substrate 1, and a part of its outer surface is embedded in the well 6 in a state of being exposed to the outside.

[0015] Figure 2 is a cross-sectional view showing a state in which a sample is loaded on the sample loading plate 10. The sample 30 dropped into the well 6, which is a sample loading portion, spreads radially by gravity and surface tension, and the wetting stops when the balance of the surface free energy between the sample 30 and the surface of the well 6 and the substrate 1 around it is achieved. Here, in the sample loading plate 10 of this embodiment, the bottom surface portion 6a and the side surface portion 6b of the well 6 have a rougher surface than the surface of the substrate 1 around the well 6, and the hydrophilicity is higher than that around the well 6 of the substrate 1. Therefore, the effect of holding the sample 30 in the well 6 (anchor effect) is high. Further, in this embodiment, the hydrophilic member 5 is embedded in the bottom surface portion 6a and the side surface portion 6b of the well 6 so that a part of its surface is exposed to the outside. The hydrophilic member 5 is a member having higher hydrophilicity than the surface of the substrate 1 (and the surface of the well 6). Further, by embedding it in the well 6, the surface exposure area of the sample loading portion increases as compared with the case where the hydrophilic member 5 is not embedded, and in addition to the well 6 having a rough surface, a higher anchor effect is realized. Further, by adopting titanium oxide or the like, which is a photocatalyst, for the hydrophilic member 5, it is also possible to obtain stable hydrophilicity (obtain an anchor effect) in the long term.

[0016] Next, a method for manufacturing the sample loading plate 10 will be described with reference to the drawings. Figure 3 is a schematic diagram showing a method for manufacturing the sample loading plate 10. The sample loading plate 10 shown in Figure 1 is manufactured by the following steps.

[0017] [Substrate preparation step: Figure 3(a)] First, the substrate 1 is prepared. The substrate 1 in this embodiment is a substrate having an outer shape of about 120 mm × 80 mm and a thickness of about 2 mm. The substrate 1 is preferably, for example, stainless steel, aluminum, or an aluminum alloy.

[0018] [Blasting process: Figure 3(b)] Next, a well 6, which is a sample loading portion, is formed on the substrate 1 by blasting (see Fig. 3(c) for the state after processing). In this step, from the nozzle 4 of the blasting apparatus, the hydrophilic member 5 is projected onto the substrate 1 to form the well 6, the surface of the well 6 is roughened, and further, the hydrophilic member 5 is embedded in the bottom surface portion 6a and the side surface portion 6b of the well 6. The well 6 is formed by the substrate 1 being scraped by the hydrophilic member 5 projected from the nozzle 4. The projection of the hydrophilic member 5 onto the substrate 1 is determined by the projection speed, projection distance, projection angle, etc., such that a part of the hydrophilic member 5 projected from the nozzle 4 is embedded in the surfaces of the bottom surface portion 6a and the side surface portion 6b of the well 6 and remains on the surface of the well 6. Also, in this embodiment, the hydrophilic member 5 is projected while being inclined with respect to the substrate 1. Therefore, more of the hydrophilic member 5 is embedded in the side surface portion 6b than in the bottom surface portion 6a. As a result, the hydrophilicity of the side surface portion 6b is higher than that of the bottom surface portion 6a. The well 6 formed by such blasting has a rougher surface with a surface roughness of the bottom surface portion 6a and the side surface portion 6b larger than that of the surface of the substrate 1, and the side surface 6b is rougher than the bottom surface 6a due to the hydrophilic member 5 being projected while inclined. In this step, the hydrophilic member 5 is embedded in the well 6 simultaneously with the formation of the well 6, and the formation of the sample loading portion can be performed more efficiently than when each is performed as a separate step. In this step, a mask having an opening at a position corresponding to the well 6 of the substrate 1 may be disposed, and the hydrophilic member 5 may be projected from the nozzle 4. By doing so, processing with higher accuracy becomes possible.

[0019] [Washing step: Fig. 3(c)] Finally, the sample loading plate 10 is washed with a cleaning liquid to remove the hydrophilic member 5 that is not embedded but adhered to the surfaces of the bottom surface portion 6a and the side surface portion 6b of the well 6. In this washing step, since the hydrophilic member 5 embedded in the well 6 is embedded in the well 6 with sufficient energy, most of it is not removed. Through the above steps, the sample loading plate 10 of this embodiment is obtained.

[0020] Next, another embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a diagram showing the sample loading plate 20 of the present invention, where (a) is a plan view of the sample loading plate, and (b) is a cross-sectional view taken along the line A-A of (a). Here, the same reference numerals are used for the same configurations as those in the embodiments described above, and the description of the overlapping parts is omitted. The sample loading plate 20 in this embodiment includes a well 6 serving as a sample loading portion on the substrate 1, a hydrophilic member 5 embedded in the surfaces of the bottom surface portion 6a and the side surface portion 6b of the well, and a water-repellent film 2. The water-repellent film 2 is formed on the entire surface of the substrate 1 except for the well 6, and the periphery of the well 6 is surrounded by the water-repellent film 2. The water-repellent film 2 is, for example, a water-repellent material containing carbon (C), fluorine (F), or silicon (Si), or a composite water-repellent material thereof, and its thickness is, for example, 5 nm. In this embodiment, since the periphery of the well 6 is surrounded by the water-repellent film 2, it is advantageous in that the wet spreading of the sample 30 can be reduced compared to the sample loading plate 10, thereby reducing the risk of contact between samples in each of the plurality of sample loading portions.

[0021] Next, a method for manufacturing the sample loading plate 20 will be described with reference to the drawings. FIG. 5 is a schematic diagram showing the method for manufacturing the sample loading plate 20 of the present invention. The sample loading plate 20 shown in FIG. 4 is manufactured by the following steps. Note that the description of the same steps as those in the method for manufacturing the sample loading plate 10 shown in FIG. 3 may be partially omitted.

[0022] [Water-repellent film forming step: FIG. 5(a)] First, the substrate 1 is prepared, and the water-repellent film 2 is formed on the entire surface of one side of the substrate 1. The water-repellent film 2 is formed by a film-forming method such as vacuum deposition.

[0023] [Mask placement step: FIG. 5(b)] Next, a mask 3 having an opening is placed on the surface of the substrate 1 where the water-repellent film 2 is formed. The mask 3 having an opening is a metal mask 3 or a mask 3 made of a resist film using known photolithography technology. The opening of the mask 3 is an area including the well 6 of the sample loading plate 20 and corresponds to the projection area of the hydrophilic member 5 onto the substrate 1 described later. In this embodiment, the mask 3 is used when forming the well 6, but the hydrophilic member 5 may be projected onto the substrate 1 without using the mask 3.

[0024] [Blasting process: FIGS. 5(c-1) and 5(c-2)] Next, the hydrophilic member 5 is projected from the nozzle 4 to the position corresponding to the well 6 of the substrate 1 (the opening of the mask 3) (see FIG. 5(c-1)). In this process, the water-repellent film 2 at the well 6 forming site is removed, and the well 6 with a rough bottom surface 6a and side surface 6b is formed. At the same time, the hydrophilic member 5 is embedded in the well 6 (see the state after processing in FIG. 5(c-2)).

[0025] [Washing process: FIG. 5(d)] Finally, the mask 3 placed on the substrate 1 is removed, and the sample loading plate 20 is washed with a cleaning liquid to remove the hydrophilic member 5 that adhered to the surface of the bottom surface 6a and the side surface 6b of the well 6 without being embedded. In this washing, since the hydrophilic member 5 embedded in the well 6 is embedded in the well 6 with sufficient energy, most of it is not removed. Through the above steps, the sample loading plate 20 of this embodiment is obtained.

[0026] As described above, the sample loading plate and the method for manufacturing the sample loading plate of the present invention have been described based on the embodiments, but they can be arbitrarily changed within the scope of the technical idea of the present invention. For example, in the method for manufacturing the sample loading plate 20, the water-repellent film 2 is formed on the substrate 1 and then the well 6 is formed. However, after forming the well 6, a mask covering the well 6 may be placed to form the water-repellent film 2 around the well 6. Also, the sample loading portion is the well 6 having the bottom surface 6a and the side surface 6b, but it may be a mortar-shaped sample loading portion having an inclined surface toward the center of the sample loading portion.

Explanation of reference numerals

[0027] 1 Substrate 2 Water-repellent film 3 Mask 4 Nozzle 5 Projection material 6 Well 6a Bottom surface part 6b Side surface part 10, 20 Sample loading plate 30 Sample

Claims

1. In a method for manufacturing a sample loading plate having a sample loading portion with a hydrophilic surface on a substrate, the method comprises a blasting step of forming the sample loading portion by projecting a hydrophilic member having a higher hydrophilicity than the hydrophilic surface onto the hydrophilic surface, wherein the blasting step is a step of embedding the hydrophilic member in the hydrophilic surface. A method for manufacturing a sample loading plate, characterized by this.

2. The method for manufacturing a sample loading plate according to claim 1, wherein the blasting step is a step of roughening the surface roughness of the hydrophilic surface.

3. The method for manufacturing a sample loading plate according to claim 1 or 2, characterized by comprising a water-repellent film forming step of forming a water-repellent film on the surface of the substrate before or after the blasting step.

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