JP2008128677A - Marker for biosensor, biosensor, and marker detection method for biosensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a marker for a biosensor, a biosensor, and a marker detection method for the biosensor, capable of inexpensive and highly-sensitive detection without using an expensive sensor having ultra-high sensitivity or the like. <P>SOLUTION: The marker used for the biosensor comprises magnetic particle species 5 immobilized near a detection position of the biosensor together with a target biomaterial 4, and a plurality of magnetic particles 20 adsorbed in a pillar shape onto the magnetic particle species 10 to form a magnetic particle pillar 30 by application of an external magnetic field H. The magnetic particle pillar 30 is formed by application of an external magnetic field H, and the marker comprising the magnetic particle species 10 and the magnetic particle pillar 30 is detected by the biosensor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a biosensor marker, a biosensor, and a biosensor marker detection method, and more particularly, a biosensor marker, biosensor, and biosensor marker detection in which detection accuracy by the sensor is improved by increasing the number of markers. Regarding the method.

  Today, biosensors are used in a wide range of fields such as protein interaction analysis, cancer treatment, DNA analysis, pathogen detection, disease diagnosis, and measurement of environment-related substances. The biosensor measures the binding between an antigen (biomaterial) that is a substance to be measured and an antibody that is a test reagent that specifically binds to the antigen, thereby qualitatively and quantitatively measures the substance to be measured.

  As a technique for measuring the binding between an antigen and an antibody, for example, there is a DNA chip that measures by color shading using a fluorescent substance. However, since the amount of fluorescent material is not stable, it is not suitable for highly accurate measurement.

  In addition, there is a biosensor using a measurement of mass change using a surface plasmon resonance measurement method (SPR) or a quartz crystal microbalance measurement method (QCM). However, sufficient sensitivity for measuring a biomaterial with a very small mass cannot be obtained, and the apparatus becomes complicated, resulting in cost problems.

  As biosensors that have been attracting attention recently, there are known methods using a magnetic sensor using a giant magnetoresistive (GMR) element or Hall element that measures this magnetism using magnetic fine particles to which a biomaterial is fixed as a marker. (Patent Document 1, Patent Document 2, etc.). These are techniques that are stable in comparison with phosphors and the like, can be measured with high accuracy by using a highly sensitive magnetic measurement technique, and are also attracting attention from the viewpoint of automation.

  A conventional measurement method using magnetic fine particles as a biosensor marker will be described with reference to FIG. FIG. 1 is a schematic side view for explaining a marker measurement method of a conventional biosensor. A sensor unit 2 made of a GMR element, a Hall element or the like is provided on the substrate 1. A probe 3 is fixed to the upper part of the sensor unit 2. The probe 3 is selected so as to form a complementary strand with the target biomaterial 4 that may be present in the sample. When the target biomaterial 4 is present in the sample, the biomaterial 4 is complementarily bound to the probe 3. On the other hand, the magnetic fine particles 5 are surface-treated so as to be bonded to the biomaterial 4, and the magnetic fine particles 5 are configured to be caught by the biomaterial 4. Therefore, when the biomaterial 4 is present in the sample, the magnetism of the magnetic fine particles 5 bonded to the biomaterial 4 and fixed in the vicinity of the sensor unit is measured by the sensor unit 2. Thereby, the presence or absence of the marker is detected.

Japanese translation of PCT publication No. 2003-524781 JP 2005-188950 A

  The size of the magnetic fine particles used as a marker for a biosensor is preferably as small as possible with respect to the biomaterial in order to be fixed to the biomaterial. If the magnetic particles are too large for the biomaterial, it may happen that the magnetic particles are not caught and measured even though there is a biomaterial that should originally be bound. This is because this is unlikely to occur if the size is as large as. However, when the magnetic fine particles are made smaller, the magnetism of the magnetic fine particles is proportional to the size of the magnetic fine particles. Therefore, the smaller the magnetic fine particles are, the more difficult it is to be detected by the magnetic sensor. It can happen that the presence or absence of magnetic fine particles cannot be measured.

  Many of the magnetic sensors that detect a minute magnetic field from magnetic fine particles are composed of GMR sensors. However, this has a problem of low sensitivity, and sufficient measurement sensitivity for the above-mentioned extremely small magnetic fine particles. Could not get. In addition, even a Hall sensor that can be expected to have higher measurement accuracy than a GMR sensor, for example, to measure the magnetism of extremely small magnetic particles having a particle size of 100 nm or less corresponding to the size of a single molecule DNA. However, it still cannot be said to have sufficient measurement sensitivity.

  In view of such circumstances, the present invention intends to provide a biosensor marker, a biosensor, and a biosensor marker detection method that can be detected inexpensively and with high sensitivity without using an ultra-sensitive and expensive sensor or the like. Is.

  In order to achieve the above-described object of the present invention, a biosensor marker according to the present invention includes a magnetic fine particle species fixed together with a target biomaterial in the vicinity of a detection position of the biosensor, and a magnetic fine particle species by applying an external magnetic field. A plurality of magnetic fine particles adsorbed in a columnar shape to form magnetic fine particle columns.

  Here, the applied external magnetic field may be in the vertical direction or the horizontal direction with respect to the surface of the detection position.

  Further, the applied direction of the external magnetic field may be variable.

  In addition, the marker may be detected using a magnetic sensor.

  Here, the magnetic sensor may have a ferromagnetic part that forms a magnetic circuit between the magnetic fine particle column and the detection position.

  Further, the marker may be conductive, and the magnetic fine particle column may constitute an electric switch for forming an electric circuit between the magnetic particle column and the detection position.

  Furthermore, the marker may be detected using a quartz crystal microbalance sensor.

  The marker may be detected using a surface plasmon resonance sensor.

  The marker may be detected using an optical microscope.

  The biosensor for detecting a marker according to the present invention includes a magnetic fine particle species fixed together with a target biomaterial in the vicinity of the detection position of the biosensor, and a magnetic fine particle column adsorbed to the magnetic fine particle species by application of an external magnetic field. A plurality of magnetic fine particles, an external magnetic field applying means for applying an external magnetic field to the plurality of magnetic fine particles, and a detecting means for detecting a marker composed of a magnetic fine particle species and a magnetic fine particle column.

  Here, the external magnetic field applying means may be any means that applies an external magnetic field in a vertical direction or a horizontal direction with respect to the surface of the detection position.

  Further, the external magnetic field applying means may be capable of changing the application direction of the applied external magnetic field.

  Furthermore, the detection means may be composed of a magnetic sensor that detects the magnetism of the marker.

  Here, the magnetic sensor may have a ferromagnetic part that forms a magnetic circuit between the magnetic fine particle column and the detection position.

  Further, the marker may be conductive, and the detection means may include an electric switch configured such that the magnetic fine particle column forms an electric circuit between the magnetic fine particle column and the detection position.

  Further, the detecting means may be a quartz vibrator microbalance sensor that detects a marker as a change in resonance frequency.

  Further, the detection means may be a surface plasmon resonance sensor that detects a marker as a change in surface plasmon resonance.

  Furthermore, the detection means may comprise an optical microscope.

  Further, the marker detection method using the biosensor of the present invention includes a process of fixing a magnetic fine particle species together with a target biomaterial in the vicinity of a detection position of the biosensor, and a step of providing a plurality of magnetic fine particles in the vicinity of the magnetic fine particle type. A process of applying an external magnetic field to a plurality of magnetic fine particles, a process of forming a magnetic fine particle column by adsorbing a plurality of magnetic fine particles in a columnar shape to the magnetic fine particle species by the external magnetic field, a magnetic fine particle species and a magnetic fine particle column, And a step of detecting a marker consisting of:

  Here, the process of applying the external magnetic field may be a process of applying the external magnetic field in the vertical direction or the horizontal direction with respect to the surface of the detection position.

  Further, in the process of applying the external magnetic field, the application direction of the external magnetic field may be variable.

  The biosensor marker according to the present invention uses various kinds of sensors at low cost even for a micro magnetic particle species of a size equivalent to DNA by using magnetic particle species and magnetic particle columns adsorbed in a columnar shape to the magnetic particle marker. Therefore, there is an advantage that it can be measured with high sensitivity.

  The best mode for carrying out the present invention will be described below with reference to the drawings. 2A and 2B are side views for explaining the biosensor marker of the present invention. FIG. 2A is a side view in a state where no external magnetic field is applied, and FIG. It is a side view at the time of applying to. In the figure, the same reference numerals as those in FIG. 1 denote the same parts. First, the probe 3 is fixed to the upper part of the sensor part 2 formed in the board | substrate 1 like the conventional method. A predetermined surface treatment is applied to the upper part of the sensor unit 2 so that the probe 3 is fixed. Examples of the sensor shown in the figure include a sensor using a magnetic sensor such as a GMR element, a tunnel magnetoresistive effect (TMR) element, or a Hall element. The probe 3 is pre-selected so as to form a complementary strand with the target biomaterial 4 that may be present in the sample to be measured. When the target biomaterial 4 is present in the sample, the biomaterial 4 is complementarily bound to the probe 3. In this way, the biomaterial 4 is fixed near the detection position of the sensor unit.

  On the other hand, the magnetic fine particle seed 10 is surface-treated so as to bind to the biomaterial 4, and the magnetic fine particle seed 10 is configured to be caught by the biomaterial 4. In the above description, the example in which the magnetic fine particle species is bound to the immobilized biomaterial has been described. However, the present invention is not limited to this, and the biomaterial is bound to the magnetic fine particle species in advance, and this is used as a sample. As a matter of course, the probe may be provided on the detection surface on which the probe is fixed. Any conventional or future-developed technique can be applied to the method of immobilizing the magnetic fine particle species in the vicinity of the detection position of the sensor, and the presence of a biomaterial can be detected indirectly by measuring the magnetic fine particle species. Any method may be used as long as it is configured as described above. Further, a technique disclosed in Japanese Patent Application No. 2006-007138 by the same applicant as the present applicant, in which a magnetic particle moving wiring is disposed in the vicinity of the sensor unit in order to appropriately guide the magnetic particle species to the vicinity of the probe or biomaterial. Of course, it is also possible to apply.

  The magnetic fine particle seed 10 preferably has a particle size of 100 nm or less, which is a size corresponding to, for example, monomolecular DNA. By setting the size to this level, the difference in size between the magnetic fine particle species 10 and the biomaterial 4 does not increase, and the coupling between them becomes easy. The magnetic fine particle species 10 may be ferromagnetic or paramagnetic, and various magnetic materials such as ferrite and alnico, more specifically, FePt, Co, Ni, Fe, MnSb, MnAs, and the like. Can be applied. As the magnetic fine particle seed 10, a commercially available one can be used, for example, Dynabeads MyOne Streptavidin of Invitrogen Corporation, which is a magnetic fine particle having a particle diameter of 1 μm, can be used.

  As an example of specific immobilization of magnetic fine particle species, as a substrate, for example, CYTOP CTL-809M manufactured by Asahi Glass Co., Ltd. having a hydrophobic surface can be used, and a hydrophilic gold film is formed on this substrate. Then, a probe composed of a sulfur atom and a thiol group is fixed thereto, and an oligo or the like as a target biomaterial to which biotin is attached is bound to the probe. In this state, a magnetic fine particle species using Dynabeads MyOne Streptavidin of Invitrogen Corporation having a hydrophilic surface is provided on the substrate, and the magnetic fine particle species is immobilized on the substrate.

  In the present invention, a plurality of magnetic fine particles 20 are further provided for the magnetic fine particle species 10 thus immobilized. The size of the magnetic fine particle 20 is not particularly limited, but may be as large as that of the magnetic fine particle seed 10. However, it is possible to select various kinds of larger magnetic particles and smaller magnetic particles depending on the formation conditions of the magnetic particle columns described later and the strength of the applied external magnetic field. The magnetic fine particles 20 may be ferromagnetic or paramagnetic, and may be made of various magnetic materials such as ferrite, alnico, and more specifically FePt, Co, Ni, Fe, MnSb, MnAs, and the like. Can be applied. In addition, as the plurality of magnetic fine particles 20, commercially available ones can be used, for example, Dynabeads MyOne Streptavidin of Invitrogen Corporation, which is a magnetic fine particle having a particle diameter of 1 μm, can be used.

  With such a plurality of magnetic fine particles 20 provided in the vicinity of the magnetic fine particle seed 10, an external magnetic field H is applied to the plurality of magnetic fine particles 20 by, for example, a magnet or a coil. Then, as shown in FIG. 2B, along the direction in which the external magnetic field is applied, the plurality of magnetic fine particles 20 are adsorbed to the magnetic fine particle seed 10 in a columnar shape, and the magnetic fine particle column 30 is formed. In the illustrated example, only one magnetic fine particle column is shown. However, the present invention is not limited to this. For example, if a plurality of magnetic fine particle types are fixed on a plurality of sensor units, a plurality of magnetic fine particle columns are provided. The column is adsorbed and fixed to each magnetic fine particle species. Further, there may be magnetic fine particle columns that are not fixed to the magnetic fine particle species, but these may be removed by washing or the like.

  As shown in the figure, the magnetic fine particle columns 30 stand along the direction of the external magnetic field H, and are generally assembled so that the center is thicker than both ends. Such a phenomenon is described in, for example, “Field-induced structure in magnetic fluid”, Physical Review Letters, Vol. 74, no. 14, April 3, 1995 (Jing Liu et al., “Field-Induced Structures in Ferrofluid Emulsions” Physical Review Letters, Volume 74, Number 74, Ill.

  FIG. 2B shows a state where an external magnetic field H is applied in a direction perpendicular to the surface of the detection position, but the present invention is not limited to this, and the external magnetic field is the surface of the detection position. May be applied in the horizontal direction, or the application direction may be varied as necessary. The plurality of magnetic fine particles 20 are adsorbed to the magnetic fine particle seed 10 in a columnar shape, but the plurality of magnetic fine particles 20 may collect in a columnar shape even when the magnetic fine particle seed 10 is not present. Therefore, in order to remove such unnecessary columnar magnetic fine particles, for example, when the application direction of the external magnetic field is horizontal, these flow in the horizontal direction and are adsorbed on the fixed magnetic fine particle species. And can be separated. In addition, magnetic fine particles and magnetic fine particle columns that are not fixed to the magnetic fine particle species can be efficiently removed by washing while changing the application direction of the external magnetic field.

  The strength of the external magnetic field varies depending on the magnetic properties such as the magnetic moment of the magnetic fine particles, but may be appropriately set in consideration of the size of the magnetic fine particle columns that can be formed and the attractive force with the magnetic fine particle species. For example, the applied magnetic field may be about 71.6 kA / m (about 900 Oe) at the maximum, and the magnetic fine particle column can be formed even with a smaller magnetic field.

  The sensor unit 2 indirectly detects the presence or absence of a biomaterial by measuring the magnetism of the marker composed of the magnetic fine particle species 10 and the magnetic fine particle column 30 thus fixed. The marker according to the present invention has a magnetism that cannot be detected by a single magnetic fine particle species because the magnetic fine particle column has a length of, for example, about several μm and the magnetism is enhanced even if the magnetic fine particle has a particle size of 100 nm. Can be easily detected.

  In the above example, the sensor of the sensor unit 2 is exemplified by a sensor using a magnetic sensor such as a GMR element, a TMR element, or a Hall element, but the present invention is not limited to this. In the marker according to the present invention, not only the magnetic fine particle column 30 enhances magnetism but also the mass and size as compared with the single magnetic fine particle species. Therefore, in addition to the magnetic sensor, it is possible to easily detect the presence or absence of a marker using, for example, a quartz crystal microbalance sensor or a surface plasmon resonance sensor.

  Here, the quartz crystal microbalance sensor is a mass sensor that uses the characteristic that the frequency decreases when a substance adheres to the surface of the quartz crystal. The surface plasmon resonance sensor is a sensor that utilizes the phenomenon of surface plasmon resonance in which the intensity of reflected light attenuates as the angle of incidence of the laser on the gold thin film changes. In a crystal microbalance sensor or surface plasmon resonance sensor, even if the magnetic fine particle species alone is too small to measure the change in frequency or refractive index, the magnetic fine particle column Since the mass is enhanced, the measurement can be easily performed.

  In addition, since the size of the marker according to the present invention is increased, it is also possible to detect the marker with an optical microscope. Since the optical microscope has a theoretical resolution of about 100 nm and actually about 250 nm, fine particles smaller than that could not be observed. However, if the marker of the present invention is used, the size becomes about several μm due to the magnetic fine particle column, so that it can be easily observed with an optical microscope without using an expensive and large electron microscope. Of course, it is also possible to emphasize the shading using a fluorescent material or the like if necessary.

  FIG. 3 shows a photograph taken with an optical microscope of the marker of the present invention in which magnetic fine particle columns are formed on a magnetic fine particle seed having a particle diameter of 10 nm. The magnetic fine particle seed having a particle diameter of 10 nm was created by the inventors of the present application, and the surface thereof is hydrophilic. Similarly, a plurality of magnetic fine particles for the magnetic fine particle column were 10 nm magnetic fine particles. The applied external magnetic field is about 71.6 kA / m (about 900 Oe). As shown in the drawing, the marker is magnified by the magnetic fine particle column, so that it can be seen that the marker of the present invention can be confirmed regardless of the magnetic fine particle type smaller than the resolution of the optical microscope.

  Next, another embodiment of the biosensor using the marker of the present invention will be described. FIG. 4 is a schematic diagram for explaining another embodiment of the biosensor using the marker of the present invention. FIG. 4A is a side view when an external magnetic field is applied in the vertical direction, and FIG. ) Is a side view when an external magnetic field is applied in the horizontal direction, and FIG. 4C is a top view of FIG. In the figure, the parts denoted by the same reference numerals as those in FIG. 2 represent the same items and will not be described in detail. As shown in FIG. 4, in this embodiment, the probe 3 is fixed in the vicinity of the side of the sensor unit 2, and the biomaterial 4 and the magnetic fine particle species 10 are bonded thereto. A plurality of magnetic fine particles 20 are provided here, and an external magnetic field H is applied in a direction perpendicular to the surface of the detection position, thereby forming magnetic fine particle columns 30 that are adsorbed in a columnar shape to the magnetic fine particle species (FIG. 4 (a) state).

  As a feature of the present embodiment, as shown in the figure, the sensor unit 2 has a ferromagnetic unit 40 provided in the vicinity thereof. The ferromagnetic portion 40 is made of, for example, permalloy or the like, and is disposed so as to form a magnetic circuit between the magnetic fine particle column 30 and the sensor portion 2. When the external magnetic field in the vertical direction as shown in FIG. 4A is switched in the horizontal direction, the state shown in FIGS. 4B and 4C is obtained. As shown in the figure, when an external magnetic field is applied in the horizontal direction, the magnetic fine particle column 30 is inclined in the horizontal direction along the direction in which the external magnetic field is applied, and comes into contact with the ferromagnetic portion 40. Then, the magnetism of the marker composed of the magnetic fine particle seed 10 and the magnetic fine particle column 30 is amplified via the ferromagnetic portion 40 and reaches the sensor portion 2, so that the sensor portion 2 can measure the magnetism of the marker with higher accuracy. Become.

  According to the present embodiment, since the probe is fixed to the side of the sensor unit, a predetermined surface treatment or the like for fixing the probe to the upper surface of the sensor unit is not necessary. For this reason, it becomes possible to expose a sensor part to the surface more, and it also becomes possible to enhance sensor sensitivity. The ferromagnetic part is not limited to permalloy as long as it can form a magnetic circuit, and various magnetic materials, more specifically, FePt, Co, Ni, Fe, MnSb, MnAs, etc. can be applied.

  Furthermore, still another embodiment of the biosensor using the marker of the present invention will be described with reference to FIG. FIG. 5 is a schematic side view for explaining still another embodiment of the biosensor using the marker of the present invention, and shows a state in which an external magnetic field is applied in the horizontal direction. In the figure, the parts denoted by the same reference numerals as those in FIG. 2 represent the same items and will not be described in detail. In this embodiment, the magnetic fine particle column is used as an electric switch by constituting the plurality of magnetic fine particles 20 with conductive fine particles. That is, the sensor unit 2 is configured by a pair of conduction terminals, for example, and is configured to be short-circuited by the magnetic fine particle column 30. As a result, the presence or absence of the marker composed of the magnetic fine particle column 30 adsorbed on the magnetic fine particle seed 10 can be determined only by confirming the conduction / non-conduction of the conduction terminal by changing the application direction of the external magnetic field. As described above, when the marker of the present invention is used, it is possible to detect the presence or absence of the marker at a very low cost and reliably without using a magnetic sensor.

  Note that the biosensor marker of the present invention is not limited to the illustrated examples described above, and it is needless to say that various modifications can be made without departing from the gist of the present invention. Also, it should be understood that the dimensions given in the above description are not limited to these, and may be larger or smaller.

  Of course, the magnetic fine particle species and the magnetic fine particles for the magnetic fine particle column may be the same. However, since the magnetic fine particles for the magnetic fine particle seed are surface-treated so as to bind to the biomaterial, the cost is high. However, the magnetic fine particles for the magnetic fine particle column need not be surface-treated. It is preferable to use untreated magnetic fine particles for the magnetic fine particle columns.

  Furthermore, the detection sensor to be applied is not limited to the above-described illustrated example, and a combination of these may be used to detect the marker by a plurality of means. Also, the detection sensor is not particularly limited, and any sensor that can detect general magnetic fine particles can be used. Furthermore, the application of the external magnetic field is not limited to applying a plurality of magnetic fine particles after supply, but may be applied constantly.

FIG. 1 is a schematic side view for explaining a marker measurement method of a conventional biosensor. 2A and 2B are schematic side views for explaining the biosensor marker of the present invention. FIG. 2A is a side view in a state where an external magnetic field is not applied, and FIG. 2B is an external magnetic field. It is a side view at the time of applying to a perpendicular direction. FIG. 3 is a photograph of the biosensor marker of the present invention taken with an optical microscope. FIG. 4 is a schematic diagram for explaining another embodiment of the biosensor using the marker of the present invention. FIG. 4A is a side view when an external magnetic field is applied in the vertical direction, and FIG. ) Is a side view when an external magnetic field is applied in the horizontal direction, and FIG. 4C is a top view of FIG. FIG. 5 is a schematic side view for explaining still another embodiment of the biosensor using the marker of the present invention, and shows a state in which an external magnetic field is applied in the horizontal direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Sensor part 3 Probe 4 Biomaterial 5 Magnetic fine particle 10 Magnetic fine particle seed | species 20 Several magnetic fine particle 30 Magnetic fine particle pillar 40 Ferromagnetic part

Claims (21)

A marker used in a biosensor, the marker being
Magnetic fine particle species fixed together with the target biomaterial in the vicinity of the detection position of the biosensor,
A plurality of magnetic fine particles that are adsorbed in a columnar shape to the magnetic fine particle species by application of an external magnetic field to form magnetic fine particle columns;
A biosensor marker comprising:   The biosensor marker according to claim 1, wherein the applied external magnetic field is in a vertical direction or a horizontal direction with respect to the surface of the detection position.   The biosensor marker according to claim 1 or 2, wherein the applied direction of the applied external magnetic field is variable.   The biosensor marker according to any one of claims 1 to 3, wherein the marker is detected using a magnetic sensor.   5. The biosensor marker according to claim 4, wherein the magnetic sensor has a ferromagnetic part that forms a magnetic circuit between the magnetic fine particle column and a detection position.   The biosensor marker according to any one of claims 1 to 3, wherein the marker has conductivity, and the magnetic particle column forms an electric circuit between the magnetic particle column and the detection position. A biosensor marker comprising a switch.   The biosensor marker according to claim 1, wherein the marker is detected by using a quartz crystal microbalance sensor.   The biosensor marker according to claim 1, wherein the marker is detected using a surface plasmon resonance sensor.   The biosensor marker according to any one of claims 1 to 8, wherein the marker is detected using an optical microscope. A biosensor for detecting a marker, the biosensor comprising:
Magnetic fine particle species fixed together with the target biomaterial in the vicinity of the detection position of the biosensor,
A plurality of magnetic fine particles that are adsorbed in a columnar shape to the magnetic fine particle species by application of an external magnetic field to form magnetic fine particle columns;
An external magnetic field applying means for applying an external magnetic field to the plurality of magnetic fine particles;
Detecting means for detecting a marker composed of the magnetic fine particle seed and the magnetic fine particle column;
A biosensor comprising:   The biosensor according to claim 10, wherein the external magnetic field application unit applies an external magnetic field in a vertical direction or a horizontal direction with respect to a surface of the detection position.   The biosensor according to claim 10 or 11, wherein the external magnetic field applying unit is capable of changing an application direction of an external magnetic field applied.   The biosensor according to any one of claims 10 to 12, wherein the detection means includes a magnetic sensor that detects magnetism of a marker.   14. The biosensor according to claim 13, wherein the magnetic sensor has a ferromagnetic portion that forms a magnetic circuit between the magnetic fine particle column and a detection position.   The biosensor according to any one of claims 10 to 12, wherein the marker has conductivity, and the detecting means forms an electric circuit between the magnetic fine particle column and the detection position. A biosensor comprising an electrical switch configured as described above.   The biosensor according to claim 10, wherein the detection unit includes a quartz crystal microbalance sensor that detects a marker as a change in resonance frequency.   The biosensor according to claim 10, wherein the detection unit includes a surface plasmon resonance sensor that detects a marker as a change in surface plasmon resonance.   The biosensor according to any one of claims 10 to 17, wherein the detection means includes an optical microscope. A marker detection method using a biosensor, the method comprising:
Immobilizing a magnetic fine particle species together with a target biomaterial in the vicinity of the detection position of the biosensor;
Providing a plurality of magnetic fine particles in the vicinity of the magnetic fine particle species;
Applying an external magnetic field to the plurality of magnetic fine particles;
A process in which the magnetic fine particle column is formed by adsorbing the plurality of magnetic fine particles in a columnar shape to the magnetic fine particle seed by the external magnetic field;
Detecting a marker composed of the magnetic fine particle seed and the magnetic fine particle column;
A marker detection method for a biosensor, comprising:   20. The biosensor marker detection method according to claim 19, wherein the step of applying the external magnetic field is a step of applying an external magnetic field in a vertical direction or a horizontal direction with respect to the surface of the detection position. Marker detection method for biosensor.   21. The biosensor marker detection method according to claim 19 or 20, wherein an application direction of the external magnetic field is variable in the process of applying the external magnetic field.