JPH09155235A - Swing rotor for centrifuge and centrifugal separation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a swing rotor for centrifugally separating a liquid sample injected into a microplate or a microplate-shaped microtube assembly under high centrifugal acceleration with respect to rotors of centrifuges used in the field of medicine, pharmacy, genetic engineering or the like. SOLUTION: The structure of a bucket 2 to which a microplate is fitted is made to have the form adapted to the bottom surface of the microplate, allowing a centrifugal load of the microplate to be burdened in contact with the rear bottom surface of a sample injection hole part of the microplate. Besides, by a shell 16 surrounding a rotor body 1 and the bucket 2 and rotated with them in one body, wind loss is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifuge rotor used in fields such as medicine, pharmacy and genetic engineering, and more particularly to a swing rotor for centrifuging a microplate.

[0002]

2. Description of the Related Art First, a microplate will be described with reference to FIG. The microplate 4 may be used in various experiments in the field of tissue culture or genetic engineering, including, for example, dropping a reaction reagent into a body fluid such as blood and then centrifuging it, or including a centrifugation step as an intermediate step. It is being used. Such a microplate 4 is
Generally, it is made of a plastic material such as polystyrene or polypropylene and is formed by molding. The size is a box-shaped container having a length of about 130 mm, a width of about 90 mm, and a height of about 10 to 50 mm, and a large number of small concave sample injection holes 5 for injecting a sample are provided on the upper surface thereof in a vertical and horizontal manner. Has been. The microplate 4 is provided with a cutout portion 8 in the lower portion of the box-shaped outer wall 7 of the microplate 4 in consideration of the case where the microplates are vertically stacked. The dimensions of the cutout portion 8 are substantially the same as the dimensions of the upper surface portion of the microplate 4, so that the microplates 4 stacked vertically are
Prevents misalignment between each other. If the notch 8 is not provided at a position lower than the plate bottom surface 9 of the microplate 4, it is impossible to prevent the positional displacement between the microplates 4 when they are vertically stacked. The box-shaped outer wall 7 of No. 4 is configured to extend to a position lower than the plate bottom surface 9.

Next, a centrifuge rotor for centrifuging the sample in the microplate 4 will be described. Such a microplate centrifuging rotor is also shown in, for example, Japanese Utility Model Publication No. 57-934, but this description will be given with reference to FIGS. 6 and 7.
FIG. 6 is an external perspective view of a swing type rotor, and FIG.
3 is an external perspective view of a metal adapter mounted on the swing rotor shown in FIG. In FIG. 6, the rotor is basically composed of a rotor body 1 and a bucket 2, and a rotational force is applied to the rotor body 1 by a centrifugal separator (not shown). The bucket 2 swings outward, and centrifugal acceleration is applied to the sample held in the bucket 2.

In order to use such a swing rotor for separating a sample contained in the microplate 4, it is common to mount a metal adapter 3 on the bucket 2. The external dimensions of the adapter 3 are such that there is no rattling against the bucket 2, and the adapter 3 has a microplate for eliminating rattling with the microplate 4 when the microplate 4 is held. Bent portions 12 and 13 for holding the outer circumference of the sheet 4 are provided. The adapter 3 is manufactured by processing a metal plate such as a stainless steel plate or an aluminum plate, and its bottom 11 is flat.

When such an adapter 3 is loaded with the above-mentioned microplate 4, the structure shown in FIG. 8 is obtained. As described above, the box-shaped outer wall 7 of the microplate 4 is configured to extend to a position lower than the plate bottom surface 9, and the bottom portion 11 of the adapter 3 is configured to be flat. A gap 10 was present between the adapter 3 and the adapter 3. In such a state, the rotation speed is usually about 2,000 rpm, and the maximum centrifugal acceleration is usually about 700 × g.

[0006] In recent years, various tests in the field of tissue culture and examination of various symptoms related to human health have been actively carried out using microplates, and a centrifugal separation step required in the intermediate step of the examination and experiment. Is required to improve efficiency. The improvement in efficiency of the centrifugation step can be achieved by increasing the centrifugal acceleration by increasing the rotation speed for rotating the row.

However, when the rotational speed of the rotor constructed as described above is increased in order to improve the efficiency, the boundary portion 6 between the group portion of the sample injection hole portion 5 of the microplate 4 and the box-shaped outer wall 7 is removed. The group portion of the sample injection hole 5 is crushed and damaged, and the purpose of centrifugation cannot be achieved. The reason for this is that when a centrifugal load due to centrifugal acceleration is applied to the microplate 4, there is a gap portion 10 between the plate bottom surface 9 of the microplate 4 and the bottom portion 11 of the adapter 3, so that the sample injection hole portion 5 has a centrifugal load. As a result, a large bending moment is applied to the boundary portion 6 between the group of sample injection hole portions 5 and the box-shaped outer wall 7 due to bending toward the gap portion 10 side, and the boundary portion 6 is damaged. According to the applicant's test, when a commercially available ordinary microplate 4 was tested, it was about 1,000.
The boundary portion 6 was damaged at × g (1,000 times the gravitational acceleration). Polystyrene is generally used as the material for the microplate 4, and the fact that polystyrene is a characteristic of being weak in strength is also a cause of the damage.

For this reason, in the conventional rotor having such a structure, the maximum rotation speed is 2,000 rpm and the maximum centrifugal acceleration is 60, which is within a range where the microplate is not damaged.
The thing of about 0-800xg is marketed.

The intended use and application field of the present invention are DNAs which have been actively studied in the field of genetic engineering and the like.
It is aimed at improving the efficiency of research on RNA and RNA. In the DNA sequencing process in this field, centrifugation using DNA as a sample is one of the important process steps. In particular, in the DNA recovery method by ethanol precipitation, which is carried out by adding an appropriate amount of ethanol or the like to a solution containing DNA, a higher recovery rate is desired, but the conventional maximum rotation speed is 2,000 r.
The recovery rate was about 75% for a rotor having a pm and maximum centrifugal acceleration of about 600 to 800 × g.

In order to increase this recovery rate, it is necessary to carry out the separation under higher centrifugal acceleration, and therefore
Conventionally, using a plastic microtube (test tube) of about 0.2 ml to 2 ml, 12,000 rpm (10,
Centrifugation was performed for about 10 minutes at about 000 × g).

However, in this operation, since each microtube is handled one by one, the operation is complicated, and since microtubes are used instead of microplates, the operation is limited to one time due to the limitation of the apparatus in centrifugation. In operation, the throughput was about 48 at most.

[0012]

[Problems to be Solved by the Invention] Various tests in the field of human health tests, DNA- and RNA-related studies, and tissue culture fields have been actively carried out using a centrifuge, and the tests and experiments have been carried out. It is required to improve the efficiency of the centrifugal separation step required in the intermediate step. The efficiency improvement of the centrifugation step can be achieved by increasing the centrifugal acceleration given to the sample by increasing the number of rotations to improve the recovery rate of the target substance and by increasing the number of samples that can be processed at one time. .

However, in the conventional rotor for centrifuge, the efficiency can be improved by using the microplate which has the merit of being able to process 96 specimens at a time. If the number of rotations of the microplate rotor is further increased to improve the efficiency of the centrifugation step, the microplate will be damaged as described above, and the object cannot be achieved.

Therefore, the applicant invented a microplate adapter having a seating surface that contacts the back bottom surface of the microplate in order to eliminate the gap portion existing on the back bottom surface side of the microplate, and is different from the present case. Filed as an invention. By providing a seat surface that contacts the back bottom surface of the microplate in the microplate adapter, eliminating the gap existing on the back bottom surface side of the microplate, and receiving the centrifugal force applied to the microplate on the seat surface of the adapter, When a rotation test was performed on a microplate, which had been destroyed at about 1,000 × g, it was possible to add centrifugal acceleration up to 2,000 × g without any problem. I was able to confirm that I could withstand.

However, if an even higher centrifugal acceleration is applied to the microplate, the microplate itself is supported by the adapter and is not destroyed, but the rotor has the structure shown in FIG. When it is set higher, the wind loss due to the rotation of the rotor also increases, and the wind energy consumes rotational energy, making it difficult to increase the rotation.

The object of the present invention is to remedy the above-mentioned drawbacks,
The present invention aims to improve the efficiency of the centrifugation process by allowing the current microplate or microplate-like microtube assembly to be used under high centrifugal acceleration.

[0017]

SUMMARY OF THE INVENTION The above object is to provide a rotor body which is attached to a drive shaft of a centrifuge and has a plurality of bucket accommodating portions, and a rotor body in each of the accommodating portions. A swing rotor for a centrifuge, which comprises a bucket swingably engaged with the centrifuge swing rotor for centrifuging a sample stored in the bucket by a centrifugal force generated by rotation. In the above, by making the structure of the bucket into a shape compatible with the bottom surface of the microplate, the centrifugal load of the microplate is brought into contact with the back bottom surface of the sample injection hole portion of the microplate, and the rotor body and This is accomplished by having a shell that encloses the bucket and rotates integrally.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION First, the structure of an adapter 3 for holding a microplate will be described with reference to FIGS.
FIG. 4 is an external perspective view showing the adapter 3 mounted on the rotor of FIG. The adapter 3 has a macro plate 4
Is provided with bent portions 12 and 13 for supporting the outer side of the macro plate 4, and the bottom surface of the bent surface 12 is in contact with the back bottom surface of the macro plate 4 and the box-shaped outer wall 7 of the macro plate 4 is inserted. The stepped portion 18 is provided. The adapter 3 itself does not necessarily have to be as shown in FIG. 4, and as shown in FIG. 5, the pad 19 having the seat surface 17 and the step portion 18 is placed on the adapter of the conventional type having a flat bottom. It may be configured. As a method for manufacturing the adapter 3, there are a method for bending the bent portions 12 and 13 of a metal plate, a method for manufacturing and bonding the pad 19 with rubber or plastic, and a method for molding the entire adapter 3 with plastic.

A swing rotor for a centrifuge having such an adapter 3 will be described with reference to FIG. FIG. 1 is an external perspective view showing a swing rotor according to a first embodiment of the present invention. In FIG. 1, the rotor body 1 has two bucket storages 14 and the bucket storage 1
4 has a pin 15 between the bucket 2 and the rotor body 1.
It is swingably attached via. An adapter 3 for holding the microplate 4 is inserted into the bucket 2 from above. Further, a shell 16 is attached so as to surround the assembly of the rotor body 1 and the bucket 2. The size of the shell 16 is determined so that the tip of the bucket does not come into contact with the shell when the bucket 2 swings. Further, the shell 16 is integrally formed with the rotor body 1 on the lower side, and the shell 16 has an outer peripheral surface. It has no irregularities and is configured to minimize wind loss during rotation. More shell 1
The upper part of 6 has an opening 20 for facilitating the mounting and removal of the microplate 4. In addition,
The tab body 1, the bucket 2, and the shell 16 are processed and shaped using an aluminum alloy. Of course, a plastic material or a composite material can be used if the strength permits.

When the swing rotor for a centrifuge constructed as described above is rotationally driven by a centrifuge (not shown), wind is generated on the outer peripheral portion of the rotor where the highest wind loss occurs as compared with the conventional construction without the shell 16. The loss is extremely small, and it is possible to rotate at a higher rotation speed.

The opening 2 of the shell 16 shown in FIG.
If 0 is closed, wind loss can be further reduced. FIG. 2 shows an example in which the opening 20 is closed by the lid 21. FIG. 2 is a vertical sectional view showing a swing rotor according to a second embodiment of the present invention, in which the left half is in a state where the rotor is stationary and the right half is in a state where the rotor is rotating. Note that FIG. 3 is a top view in which FIG. 2 is cross-sectioned.

The configuration shown in FIG. 2 has the swing roll shown in FIG.
A center pin 22 is fixed to the center of the rotor body 1 of the rotor by screwing or bonding, and a lid 21 having an engaging member 23 that engages with the center pin 22 is attached. The lid 21 is removable from the shell 16, and the lid 21 is removed from the shell 16 when the microplate 4 is attached and detached, and the lid 21 is attached to the shell 16 during centrifugation. The swing rotor configured as described above can reduce the wind loss on the upper surface of the swing rotor as compared with the swing rotor shown in FIG. 1, and thus can rotate at a higher rotational speed.

The shell 16 of the swing rotor shown in FIGS. 1 and 2 has a hole 24 at the bottom thereof. When the swing rotor shown in FIG. 1 or the swing rotor shown in FIG. 2 forgets to mount the lid 21 and rotates, the air in the shell 16 is discharged to the outside of the shell 16 by the centrifugal force. Then, the air inside the shell 16 has a low density, and the air outside the shell 16 has a high density. That is, a difference in air density (a difference in pressure) occurs inside and outside the shell 16, and due to this difference, a force that lifts the entire swing rotor upward in the state of FIG. 2 is generated. When the rotor is lifted upward, it disengages from the drive unit of the centrifuge (not shown), which is extremely dangerous. In order to avoid this, in order to eliminate the difference in air density inside and outside the shell 16, a hole 24 is provided at the bottom of the shell 16. Since air flows from the outer side to the inner side of the shell 16 in the hole 24, it is not desirable to provide it on the outer peripheral side of the rotor that acts to discharge the air inside the shell 16 to the outside by centrifugal force, and it is close to the rotation axis. Is better.

A case in which the swing rotor for a centrifuge constructed as described above is actually used will be described. FIG.
Using a centrifuge swing rotor configured as described above, a commercially available microplate was subjected to a rotation test.
It was possible to rotate up to 5,000 xg at 5,700 rpm without any problem. This means that it has been confirmed that it can endure about 6 times the centrifugal acceleration as compared with the conventional rotor.

Experiments were also conducted on the actual centrifugal separation effect. Lambda DNA solution containing lambda phage DNA
A DNA recovery experiment was carried out from (32 g / ml) by the ethanol precipitation method. At the time of collection, the number of rotations for centrifugation was changed (centrifugation time was constant for 10 minutes), and the effect of the number of rotations on the DNA recovery rate was examined. When the rotation speed is 2,000 rpm (maximum centrifugal acceleration 620xg), the recovery rate is about 75%, and the rotation speed is 3,000.
80% recovery rate at rpm (maximum centrifugal acceleration 1,390 xg)
On the other hand, at a rotation speed of 5,700 rpm (maximum centrifugal acceleration of 5,010 xg), the recovery rate was 100%.

Thus, it was found that the higher the rotation speed, the higher the recovery rate, and that the DNA recovery rate was 100% at the maximum centrifugal acceleration of 5,000 × g or more. Therefore, if the microplate is attached to the swing rotor for a centrifuge according to the present invention and the microplate is rotated so that the maximum centrifugal acceleration is 5,000 × g or more, the recovery rate is high and the microplate can be used. A large number of samples can be processed at one time, and as a result, the efficiency of the centrifugation step can be improved.

[0027]

According to the present invention, since the microplate or the microplate-like microtube assembly can be rotated under high centrifugal acceleration, the efficiency of the centrifugation step can be improved. You can

[Brief description of the drawings]

FIG. 1 is an external perspective view showing a swing rotor according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a swing rotor according to a second embodiment of the present invention.

3 is a cross-sectional top view of FIG.

4 is an external perspective view showing an adapter mounted on the rotor of FIG. 1. FIG.

5 is a cross-sectional view showing a modified example of the adapter of FIG.

FIG. 6 is an external perspective view showing a conventional swing rotor.

7 is an external perspective view of the adapter mounted on the swing rotor of FIG.

8 is a vertical cross-sectional view showing a state in which a microplate is placed on the adapter of FIG.

[Explanation of symbols]

1 is a rotor body, 2 is a bucket, 3 is an adapter, 4 is a microplate, and 16 is a shell.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Yamazaki 1060 Takeda, Hitachinaka City, Ibaraki Prefecture Hitachi Koki Engineering Co., Ltd.

Claims (6)

[Claims] 1. A rotor body attached to a drive shaft of a centrifuge and having a plurality of bucket storage portions, and swingably engaged with the rotor bodies in each of the storage portions. A swing rotor for a centrifuge, which comprises a bucket, wherein the structure of the bucket has a microstructure in a swing rotor for a centrifuge that centrifuges a sample stored in the bucket by a centrifugal force generated by rotation. By making the shape compatible with the bottom surface of the plate, the microplate is brought into contact with the back bottom surface of the sample injection hole portion to bear the centrifugal load of the microplate, and further, the rotor body and the bucket are wrapped and integrated. Swing roll for centrifuge characterized by having a rotating shell
Ta. 2. The swing rotor for a centrifuge according to claim 1, further comprising a lid that covers the opening of the shell. 3. The swing for a centrifuge according to claim 1, wherein the bucket has an adapter having a shape matching the bottom surface of the microplate, and the adapter is integrally formed with the bucket. Rotor. 4. The swing rotor for a centrifuge according to claim 1, wherein the microplate has a structure for accommodating a large number of plastic microtubes. 5. A rotor body, a bucket swingable with respect to the rotor body and having a shape matching the bottom surface of the microplate, the rotor body and the bucket are wrapped and integrated. Using a centrifuge swing rotor with a rotating shell, a gravitational acceleration of 5,0 is applied to the microplate injected with the liquid sample solution.
A centrifugal separation method, wherein the liquid sample solution is centrifugally separated by applying a centrifugal force of 00 times or more. 6. The centrifugation method according to claim 5, wherein the liquid sample is a suspension obtained by adding an appropriate amount of alcohol to a solution containing nucleic acid or protein.