JP2010208885A - Silicon structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silicon structure having a large surface area and exhibiting magnetic characteristic which is used for recovering a target material in a bioscreening and uses silicon having high machinability, low melting point and low density. <P>SOLUTION: The silicon structure 10 is provided with a base material 11 and a plurality of fibrous projecting materials 12 containing silicon dioxide as an essential component and directly joined to the surface of the base material 11 which contains silicon as an essential component. A magnetic body is supported by the fibrous projecting material 12. The surface area is increased by forming the plurality of the fibrous projecting materials 12 comprising silicon dioxide to be densely entangled and magnetic separation and highly efficient recovery are available by supporting the magnetic body 13 on the fibrous projecting materials 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a silicon structure used for bioscreening technology.

  In bioscreening such as protein purification, antibody purification, cell separation, and DNA sequencer, a technique for recovering a target substance by using particle beads is used. By using the particle beads, not only the target substance can be immobilized on the surface in a large amount, but also nonspecific adsorption other than the target substance can be suppressed. Furthermore, development of a so-called high-throughput technology that enables high-speed and large-volume processing by imparting magnetic properties to such particle beads has been actively conducted. The use of such bioscreening technology is expected to enable the development of drugs based on genetic information related to epidemics and so-called tailor-made treatments based on individual differences in genetic information. Is done.

As prior art document information relating to this application, for example, Patent Document 1 is known.
JP 2006-131771 A

  In recent years, there has been a demand for particle beads having a size as small as possible and a surface area as large as possible in order to immobilize on the surface as much as possible a substance that specifically reacts with a target substance. That is, when the surface area is small, there is a problem in that the target substance cannot be recovered with high efficiency, a large number of particle beads and target substances are required, and a desired target substance amount cannot be obtained. Furthermore, in order to enable screening by magnetic adsorption, it was necessary to give magnetic properties to the particle beads. A technique for forming fibers from SiC as a technology enabling these is described in Journal of Materials Chemistry, 1998, 8, 8, p. 1859-1864. By using this technique, it is possible to form a structure having both more surface area and magnetic properties by forming a fiber containing a magnetic material. However, since this method uses SiC for the layer serving as the base material, the processability is low, and it is difficult to process the base material into a structure with a large surface area. In addition, since the melting point is high, it is difficult to obtain a substrate having a three-dimensional structure even in the melting method. Furthermore, since SiC has a high density, it has been difficult to effectively perform magnetic adsorption unless a strong magnet is used for magnetic adsorption.

  Accordingly, an object of the present invention is to realize a silicon structure having a large surface area and magnetic properties by using silicon having a high workability or a low melting point and a low density.

  In order to achieve this object, the present invention includes a base material and a plurality of fibrous protrusions mainly composed of silicon dioxide directly bonded to a surface of the base material mainly composed of silicon. The silicon structure is a silicon structure in which a magnetic material is supported on the fibrous protrusions.

  Thereby, this invention can implement | achieve the area | region where a surface area is large and hydrophilic property and / or water retention property are very high. Therefore, it is possible to immobilize many substances that react specifically with the target substance on the surface even though it has a complicated shape. Therefore, it should be applied to bioscreening devices such as protein purification, antibody purification, cell separation, and DNA sequencer. Can do. Furthermore, since the magnetic substance is supported on the fibrous protrusions, separation and purification by magnetic separation is possible. In other words, a silicon structure for high-speed bioscreening can be provided because the target substance can be recovered with high efficiency by quickly separating using a magnet and easily redispersing when the magnet is removed. Can do.

(Embodiment 1)
Hereinafter, silicon structure 10 according to the first embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, the silicon structure 10 according to the first embodiment is composed mainly of a base material 11 and silicon dioxide directly bonded to the surface of the base material 11 mainly composed of silicon. And a plurality of fibrous protrusions 12. The base material 11 is made of a silicon substrate made of single crystal silicon.

  Here, the direct bonding refers to a state in which atoms or molecules constituting the substrate 11 and the fibrous protrusions 12 are directly bonded, and usually a state in which molecules are covalently bonded. Further, these bonding surfaces do not use an adhesive or the like, and do not include materials other than atoms or molecules constituting the substrate 11 and the fibrous protrusions 12. Since the fibrous protrusions 12 can be formed on the base material 11 without using an adhesive or the like, it is possible to improve the heat resistance and to realize the silicon structure 10 in which impurities or the like are not mixed. it can.

  With the above-described configuration, a plurality of the fibrous projections 12 mainly composed of silicon dioxide are formed in a moquette shape or a mesh shape, so that the surface area of silicon dioxide is increased. In such a region having a large surface area, a liquid material, such as water, that receives a large surface tension of silicon dioxide is strongly pulled by the surface of silicon dioxide and is retained around the fibrous protrusions 12.

  Therefore, it is possible to realize a silicon structure 10 that realizes a region having extremely high hydrophilicity and / or water retention and further has a very large surface area per unit area.

  Furthermore, since the fibrous protrusions 12 mainly composed of silicon dioxide have a large surface area and can take a complicated shape, a probe scaffold imitating the cell surface or the inside can be formed. For example, in the case of analyzing a virus infection using a sugar chain as a probe, not only the type of sugar chain but also the density is important for screening. Immobilizing the probe enables screening in a situation that mimics the actual infection.

  In addition, the fibrous protrusions 12 mainly composed of silicon dioxide and the base material 11 mainly composed of silicon are made of materials that are standardly used in biochips. Existing probe fixing methods such as those used can be applied as they are.

  Here, the reason for having large hydrophilicity and water retention due to the presence of the fibrous protrusions 12 will be described.

  Silicon dioxide is originally a highly hydrophilic material, but when silicon dioxide is formed in a thin film and external dirt such as in the air adheres to the surface, the thin film made of silicon dioxide has a surface that pulls water. When the tension is reduced and the surface area is small, the result is a relative loss of hydrophilicity. On the other hand, since the fibrous protrusion 12 in the silicon structure 10 of the first embodiment has a very large surface area per unit area, the surface tension per unit area is small due to adhesion of dirt or the like. Even if it becomes, since the surface area as a whole is large, the force pulled by water is not lost so much, and as a result, it is possible to realize the silicon structure 10 that can maintain hydrophilicity and water retention for a long period of time. Can do.

  Since it is such a structure, since the fibrous protrusion 12 in Embodiment 1 of this invention is excellent in affinity with a liquid substance, bubble generation | occurrence | production can be reduced. That is, in the first embodiment of the present invention, since the liquid substance quickly spreads along the side surface of the fibrous protrusion 12, the wettability of the fluid is increased at the time of bioscreening in various analyses, and bubbles are generated. Can be suppressed.

  Here, since some probes and antibodies change in quality when dried, biochips having hydrophilicity and water retention are also excellent in terms of adaptability.

  In addition, these fibrous protrusions 12 are in close contact with each other so as to be intertwined with each other, and may have a mixture of things that are branched in a free direction as well as having a contracted shape. . Since the fibrous protrusions 12 are intertwined with each other and branched into a plurality of parts, the fibrous protrusions 12 are more firmly formed. Furthermore, with this structure, even when water pressure is generated from the fluid, the plurality of fibrous protrusions 12 disperse external stress due to water pressure, so that a structure that does not easily break can be achieved. Further, by using the region where the fibrous protrusions 12 are formed as a reaction part and binding the reactive substances to the fibrous protrusions 12, the amount of the reactive substances can be increased, thereby further promoting the reaction. be able to.

  In addition, the composition of the fibrous protrusions 12 is configured to be harder to break than single crystal silicon dioxide. This is because the fibrous protrusions 12 in Embodiment 1 of the present invention are amorphous dioxide dioxide. This is probably because it is made of silicon. When the region where the fibrous protrusions 12 are formed is measured by X-ray spectroscopic analysis, as shown in FIG. 4, 2θ / degree resulting from Si (110) used as the base material 11 is about 47 degrees. There is no large peak except for the peak in the region, and this result suggests that the fibrous protrusion 12 is made of amorphous silicon dioxide.

  In Embodiment 1 of the present invention, a silicon substrate made of single crystal silicon is used as the base material 11, but the surface may be formed of silicon, and the material up to the inside of the base material 11 does not matter. .

  Further, the surface silicon may be in a state of single crystal silicon, polycrystalline silicon, amorphous, or the like. However, silicon is desirable because it has excellent workability and is convenient in the cutting process and has a low melting point, so that it can easily form a three-dimensional structure.

  Note that if only the silicon is used for the base material 11, the silicon can be processed into a fine and complicated shape. However, since silicon is hydrophobic, bubbles may be generated due to low liquid wettability. However, it is useful for reducing bubbles in the fine silicon structure 10 that the surface is covered with the fibrous protrusions 12 having a high hydrophilicity as in the first embodiment of the present invention.

  Further, the shape of the base material 11 according to the first embodiment of the present invention is desirably particulate in order to keep a large surface area. Furthermore, it is preferable to have a substantially spherical shape because it has the largest surface area. In addition, any structure may be used as long as it has a three-dimensional structure and a large surface area, such as a polyhedron and a cylinder.

  Furthermore, in Embodiment 1 of this invention, it was set as the structure which carries the magnetic body 13 on the fibrous projection 12. FIG. Here, Co which is a ferromagnetic material was used for the magnetic material 13. Here, “supporting” indicates a state in which the magnetic body 13 is contained in the fibrous protrusions 12 or directly joined thereto. The above configuration enables separation and purification by magnetic separation.

  Specifically, as shown in FIG. 3, it is more desirable that the magnetic body 13 is supported at the tip of the fibrous protrusion 12. This is because the outermost surface of the silicon structure 10 can have magnetic properties, so that the separation and purification ability by magnetic separation is improved. With this configuration, the silicon structure 10 according to the first embodiment of the present invention is dispersed without being aggregated in the liquid, but can be quickly separated using a magnet and easily redispersed when the magnet is removed. By doing so, since the target substance can be recovered with high efficiency, the silicon structure 10 having excellent functionality for high-speed bioscreening can be provided.

  Co is used for the magnetic body 13, but Fe and Ni metals, and iron and iron group transition metals such as Fe—Ni, Fe—Co, Fe—Ni—Co—Al, and Fe—Ni—Cr are used. Separation and refining by magnetic separation can be facilitated if it is a ferromagnetic material that adsorbs to the magnet, such as contained alloys, compounds such as samarium magnets and neodymium magnets, and oxides such as magnetite, magnetite and barium magnets. it can.

  Next, a method for manufacturing the silicon structure in the first embodiment of the present invention will be described.

  First, as the first step, silicon particles are formed as the base material 11. Specifically, silicon is melted in a crucible, and silicon is dropped from a nozzle by pressurization. The dropped silicon is spheroidized by surface tension. Furthermore, it becomes a substantially spherical silicon particle by solidifying while allowing it to fall freely. At this time, the diameter of the silicon particles is about 1 to 1.5 mm.

  In addition, the formation method of a silicon particle is not restricted to said method, You may form by reducing the surface of a glass bead. In addition to this, a thin film containing silicon as a main component may be formed on a material to be a base material by a film forming method such as a CVD method.

  In addition, the shape of the base material 11 is desirably particulate in order to keep a large surface area. Furthermore, it is preferable to have a substantially spherical shape because it has the largest surface area. In addition, any structure may be used as long as it has a three-dimensional structure and a large surface area, such as a polyhedron and a cylinder.

  Further, these shapes may be formed by a cutting method such as blade dicing or stealth dicing, etching or polishing. In order to increase the surface area per unit mass, it is desirable to make the particle size smaller. In this case, the particle size can be controlled by precisely controlling the amount of molten silicon dropped.

  Next, as a second step, the magnetic material 13 is injected as a catalyst into the silicon particles to form the magnetic material-containing silicon particles. The magnetic substance 13 serves as a catalyst, and the fibrous protrusions 12 mainly composed of silicon dioxide can be grown on the silicon particles.

  An ion implantation method is suitable for injecting the magnetic material into the silicon particles. The ion implantation method is a method in which a specific element is implanted into a substrate by electrically accelerating ions and hitting an individual, and the control of the concentration distribution in the depth direction is good. Thereby, the magnetic body 13 which becomes a catalyst can be injected with higher accuracy.

  Although ion implantation is used this time, the magnetic body 13 can be implanted all over the silicon particles at once by using thermal diffusion such as vapor phase diffusion or solid phase diffusion.

  Further, by using patterning, it is possible to inject the magnetic body 13 only in a specific part.

  Further, the catalyst may be formed by partially protecting the resist film and forming a thin film mainly containing an element that becomes the magnetic body 13 on a part of the silicon particles. In this case, the film can be formed by any film forming method, but the CVD method is desirable from the viewpoint of coverage.

  Moreover, you may use what contained the element used as the magnetic body 13 in the base material 11 itself. In this case, an arbitrary raw material may be added to the molten raw material of silicon. In this case, since the inside of the base material 11 also has magnetic characteristics, screening with the magnetic body 13 can be performed more easily.

  At this time, if the magnetic substance 13 is dispersed at a high concentration only in a specific part of the silicon particle surface, or if it is contained only in a part of the silicon particle surface, the subsequent growth of the fibrous protrusions 12 occurs. As a result, the surface area can be increased. However, from the viewpoint of reactivity, it is possible to expect a further increase in the surface area by uniformly supporting the magnetic body 13 on the entire surface of the silicon particles.

Next, as a third step, a seed layer made of C, F, and H elements is formed on the magnetic substance-containing silicon particles. This seed layer is a layer made of an organic polymer made of C, F, and H elements, and by using a plasma CVD method or the like, CF ₄ , CHF ₃ , C ₂ F ₆ , C ₃ H ₈ , C ₄ F _{8 are used.} A seed layer made of an organic polymer film can be formed by decomposing in a plasma using at least one of fluorocarbon-based gases such as. In the plasma, the gas is decomposed into a state in which bonds such as CF, CF ₂ , CF ₃ are broken, and H atoms are added to these to recombine to form various combinations of polymer molecules. However, in order to form the fibrous projections 12 made of silicon dioxide in a later step, the arrangement order of the combination of these molecules in the seed layer is not particularly important, and C, F, and H are bonded. Any state is acceptable. Therefore, the C, F, and H elements at this time are not particularly limited here because various combinations of molecules are formed.

  Here, the magnetic body 13 can also be used as a catalyst by using a gas containing the magnetic body 13 together with the above gas. In this case, the above-described method such as ion implantation is not necessary. Further, by forming a resist film and performing patterning before forming the seed layer, silicon dioxide can be formed only at a specific portion. The same effect can also be obtained by providing a portion mainly composed of silicon and other portions on the surface to be the base material 11. Thereby, a target substance can be obtained preferentially only in a specific part.

  Thereafter, as a fourth step, the silicon particles containing the magnetic material 13 on which the seed layer has been formed are reattached on the surface after the silicon monoxide has evaporated by heat treatment at a high temperature of 1000 to 1100 ° C. and a low oxygen concentration. Aggregates and silicon dioxide grows. At this time, since silicon monoxide spreads and adheres again to the surface of the silicon particles, the fibrous protrusions 12 mainly composed of silicon dioxide grow on the surface of the silicon particles.

Here, the low oxygen concentration indicates that the oxygen partial pressure during the heat treatment is low, and it may be reduced in pressure or substituted by another gas. The other gas is, for example, N ₂ , Ar, CO or the like, and unlike O ₂ , O ₃ , H ₂ O, it is a gas having low oxidizability. Note that if the oxygen partial pressure is too low, silicon monoxide cannot be generated, so a desirable oxygen partial pressure is in the range of several thousand Pa to 10 ⁻⁶ Pa.

  By such a manufacturing method, the silicon structure 10 in which the fibrous protrusions 12 carrying the magnetic body 13 are formed on the surface of the base material 11 can be produced without forming a silicon dioxide thin film.

  As described above, the silicon structure according to the present invention is useful in, for example, bioscreening systems such as protein purification, antibody purification, cell separation, and DNA sequencer.

Sectional drawing of the silicon structure in Embodiment 1 of this invention SEM photo of the surface of the silicon structure Section A enlarged sectional view of FIG. The figure which shows the X-ray spectroscopic analysis result of the surface of the same silicon structure

DESCRIPTION OF SYMBOLS 10 Silicon structure 11 Base material 12 Fibrous protrusion 13 Magnetic body

Claims (2)

A substrate;
A silicon structure comprising a plurality of fibrous protrusions mainly composed of silicon dioxide directly bonded to a surface mainly composed of silicon of the base material,
A silicon structure in which a magnetic substance is supported on the fibrous protrusion. The shape of the substrate is
The silicon structure according to claim 1, which is in the form of particles.