Particle rotation method and particle rotation device

Abstract

To provide a particle rotation method that can rotate particles.SOLUTION: A particle rotation method gives bubbles vibration to cause a flow in the liquid, thereby rotating particles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a particle rotation method. [Background technology]

[0002] Patent Document 1 discloses a particle separation device. This particle separation device includes a plate, multiple pillars, and a drive unit. Each pillar stands at an equal distance on the plate. The drive unit drives the plate so that it moves in an orbit around the pillars. In this particle separation device, when a liquid containing cells is supplied onto the plate and the drive unit is driven to move the plate in an orbit, a vibration-induced flow is generated in the fluid around each pillar. This particle separation device can separate cells by varying the direction of movement depending on the size of the cells due to the vibration-induced flow of the fluid around each pillar. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-208418 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, with the increasing demand for artificial insemination, there is a demand for technology that can rotate cells faster and more accurately than manual methods, and position the cells accurately. The particle separation device in Patent Document 1 aims to separate cells in a fluid according to their size, and therefore Patent Document 1 does not disclose or suggest how to control the rotation of the cells.

[0005] The present invention has been made in view of the above-mentioned conventional circumstances, and an object to be achieved is to provide a particle rotation method capable of rotating particles. [Means for solving the problem]

[0006] The particle rotation method of the present invention rotates particles by applying vibration to bubbles to generate a flow in the liquid.

[0007] In this particle rotation method, when bubbles vibrate, the surrounding liquid is affected by the vibrations, causing a flow. Particles in the liquid are rotated by the fluid around the bubbles, which has caused a flow due to the vibrations of the bubbles. By utilizing this phenomenon, it is possible to position particles in three dimensions.

[0008] Therefore, the particle rotation method of the present invention can rotate particles. [Brief explanation of the drawings]

[0009] [Figure 1] 1A is a plan view showing a structure used to confirm the particle rotation method of Example 1, and FIG. 1B is a cross-sectional view showing a cross section taken along the arrow XX in FIG. 1A. [Figure 2] 1 is a graph showing the change in rotation speed depending on frequency. [Figure 3] FIG. 10 is an explanatory diagram showing how bubbles vibrate. DETAILED DESCRIPTION OF THE INVENTION

[0010] A preferred embodiment of the present invention will now be described.

[0011] The radius of the bubbles in the particle rotation method of the present invention can be 0.05 mm to 0.3 mm, which allows for good rotation of particles with a diameter of about 0.15 mm, which is roughly the same size as a cow's egg.

[0012] The vibration frequency of the bubbles in the particle rotation method of the present invention can be from 100 Hz to 1 KHz, which can effectively rotate particles with a diameter of about 0.15 mm, which is roughly the same size as a bovine egg.

[0013] Next, a first embodiment of the particle rotation method of the present invention will be described with reference to the drawings.

[0014] Example 1 The particle rotation method of Example 1 was confirmed using the structure 10 shown in FIG. 1. In a plan view from above, the structure 10 is a square with sides of approximately 5.0 mm. The thickness of the structure 10 is approximately 1.0 mm. The structure 10 has nine holes 11 formed on its upper surface. In a plan view from above, each hole 11 is circular with a diameter of approximately 0.5 mm. The depth of each hole 11 is approximately 0.5 mm. When the structure 10 is arranged with one pair of sides extending vertically and the other pair of sides extending horizontally in a plan view from above, the holes 11 are arranged at equal intervals, three vertically and three horizontally. The structure 10 is vibrated by a vibrator 20 disposed below. The vibrator 20 can be vibrated using a smartphone speaker. In this case, by using a microscope application on the smartphone in combination, a device capable of confirming particle rotation can be constructed.

[0015] <How to rotate particles> This section describes a method for generating bubbles in pure water containing multiple microbeads using structure 10, and then vibrating the generated bubbles to create a flow in the pure water and rotate the microbeads. First, glycerin is applied to each hole 11 of structure 10 to prevent the pure water from entering. Then, structure 10 is immersed in pure water containing multiple microbeads and vibrated using vibrator 20. Each microbead has a diameter of approximately 0.15 mm, roughly the same as the diameter of a bovine egg. Vibrating structure 10 causes the bubbles generated in hole 11 to vibrate, creating a flow in the pure water around the bubbles, and vertical rotation of the microbeads near the bubbles within hole 11 was observed. The radius of the bubbles was approximately 0.08 mm. When the vibration frequency of vibrator 20 was changed, as shown in Figure 2, the rotation rate of the microbeads increased as the frequency decreased, but the stability decreased.

[0016] <How bubbles vibrate> As shown in Figure 3, the vibration of bubbles is such that under normal circumstances, the pressure inside the bubbles is constant and the bubbles are spherical. When vibrating vibrator 20 to vibrate structure 10, pressure is applied to the bubbles from the inside, causing them to deform, and the bubbles try to return to their original spherical shape. When vibrating vibrator 20 to vibrate structure 10, pressure is applied to the bubbles from the outside, causing them to deform, and the bubbles try to return to their original spherical shape. When this process is repeated, the bubbles vibrate, and the liquid around the bubbles is also affected by the vibration of the bubbles, causing a flow, and the microbeads rotate vertically.

[0017] <Flow generation around bubbles due to vibration> The forces acting on the bubbles and the deformation of the bubbles were investigated using theoretical formulas. The sound pressure level of the transducer 20 used in this study was 30 dB. The formula for calculating the sound pressure generated from the transducer 20 is shown in equation (1). Here, L is the sound pressure level, p is the observed value, and p0 is the reference value.

[0018]

number

[0019] The reference value p0 is 2.0 × 10 ―5 Since [Pa], the observed value p is expressed by equation (2-2).

[0020]

number

[0021] The formula for Young's modulus is given by equation (3), where ε is strain, E is Young's modulus, and δ is stress.

[0022]

number

[0023] If the calculated sound pressure is used as stress and Young's modulus is used as the surface tension of water, the strain can be calculated using equation (4).

[0024]

number

[0025] The strain ε can also be expressed by another formula: ε = ΔL / L, where ΔL is the amount of deformation and L is the size of the original bubble. Therefore, if the radius of the original bubble is 0.1 mm, then equation (5) can be obtained.

[0026]

number

[0027] Since the movement of a bubble is similar to that of a spring, Hooke's law (6) is applied. Here, k is the spring multiplier, which corresponds to the surface tension of the bubble, and x is the displacement.

[0028]

number

[0029] To obtain the deformation amount calculated above, we use equation (7).

[0030]

number

[0031] Therefore, 1.2 x 10 -4 It is thought that if a force of more than N is applied, vibrations with an amplitude of 1.7 μm will occur, generating a flow that rotates the particles vertically.

[0032] As described above, the particle rotation method of Example 1 rotates the microbeads by applying vibrations to the bubbles to generate a flow in the pure water. In this particle rotation method, when the bubbles vibrate, the surrounding pure water is affected by the vibrations and a flow is generated. The microbeads in the pure water are rotated by the pure water around the bubbles, which has generated a flow due to the vibrations of the bubbles.

[0033] Therefore, the particle rotation method of Example 1 can rotate microbeads.

[0034] The radius of the bubbles is 0.08 mm in the particle rotation method of Example 1. In this case, microbeads with a diameter of about 0.15 mm, which is roughly the same size as a cow's egg, can be rotated well.

[0035] The vibration frequency of the bubbles in the particle rotation method of Example 1 is from 100 Hz to 1 KHz. In this case, microbeads with a diameter of about 0.15 mm, which is roughly the same size as a bovine ovum, can be rotated well.

[0036] The present invention is not limited to the first embodiment described above with reference to the drawings, and the following embodiments are also included within the technical scope of the present invention. (1) The outer diameter and dimensions of the structure can be changed as appropriate. (2) The shape and dimensions of the holes formed in the structure can be changed as appropriate. (3) The vibrator that vibrates the structure may be a smartphone speaker or the like. [Explanation of symbols]

[0037] 10...Structure 11...hole 20...Oscillator

Claims

1. A particle rotation method for rotating particles by applying vibration to bubbles to generate a flow in a liquid, the method comprising: Particle rotation method, where the bubble vibration frequency is from 100 Hz to 1 KHz.

2. 2. The particle rotation method according to claim 1, wherein the radius of the bubbles is from 0.05 mm to 0.3 mm.

3. A particle rotation device that generates a flow in a liquid by applying vibration to bubbles to rotate particles, a structure having a plurality of holes formed on an upper surface thereof, the structure being immersed in pure water containing a plurality of particles to generate bubbles in the holes; an oscillator that vibrates the structure to vibrate the bubbles; A particle rotation device comprising:

Images