FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
“MICROPARTICLE SORTING DEVICE AND METHOD FOR
CONTROLLING POSITION IN MICROPARTICLE SORTING
DEVICE”
SONY CORPORATION, of 1-7-1, Konan, Minato-ku, Tokyo
108-0075, Japan
The following specification particularly describes the invention and the manner in
which it is to be performed.
2
DESCRIPTION
Title of Invention: MICROPARTICLE SORTING DEVICE AND METHOD FOR CONTROLLING POSITION IN MICROPARTICLE SORTING DEVICE
Technical Field
[0001]
The present technology relates to a microparticle
sorting device and a method for controlling a position in a
microparticle sorting device and, in particular, to, for
example, a microparticle sorting device automatically
adjusting the position of a fluid stream generated from an
orifice and the position of a collection container that
receives the fluid stream.
Background Art
[0002]
Microparticle sorting device that optically,
electrically, or magnetically detects the characteristics of
microparticles, such as cells, and sorts and collects only
the microparticles having a predetermined characteristic
have been known (e.g., a flow cytometer).
[0003]
In cellular fractionation performed by the flow
cytometer, the fluid stream (the laminar flow of a sample
fluid and a sheath fluid) is generated by an orifice formed
3
in a flow cell. By applying vibration to the orifice, the
fluid stream is converted into droplets, and electrical
charge is imparted to the droplets. Thereafter, by
electrically controlling the direction in which each of the
droplets including a cell ejected from the orifice moves, a
target cell having a desired characteristic and a non-target
cell are collected into different collection containers.
[0004]
For example, PTL 1 describes "a microparticle sorting
device including a microchip having a flow path that allows
fluid including microparticles to flow therethrough and an
orifice that ejects the fluid flowing through the flow path,
a vibrating element for converting the fluid into droplets
at the orifice, charging means for imparting electrical
charge to the ejected droplets, optical detection means for
detecting the optical characteristics of the microparticles
that flow through the flow path, a pair of electrodes that
are disposed in the moving direction of the droplets ejected
into a space outside the chip and that face each other with
the moving droplets therebetween, and at least two
containers for collecting the droplets that have passed
between the electrodes" and serving as a microchip type flow
cytometer.
Citation List
Patent Literature
4
[0005]
PTL 1: Japanese Unexamined Patent Application
Publication No. 2010-190680
Summary of Invention
Technical Problem
[0006]
In microparticle sorting devices, in order for the
fluid stream generated from an orifice formed in the flow
cell or a microchip to accurately enter the collection
container, it is required to adjust the position of the flow
cell or microchip to align the positions of the fluid stream
and the collection container. If the position adjustment is
improper, the droplets including the microparticles do not
enter the collection container and, thus, sorting of the
microparticles is not available, or the amount of collection
is decreased. In addition, if the droplets including cells
does not accurately drop onto the center of the collection
container, the cell collide with the inner wall of the
collection container and are damaged. Accordingly, the
surviving rate of the cells decreases.
[0007]
In existing methods, the position adjustment is
performed by a user who adjusts the positions of the flow
cell and the microchip by hand while viewing the position of
the fluid stream. Accordingly, the user needs to be
5
proficient in the operation and, thus, a problem of the
reliability and stability arises. In addition, each time
the flow cell or the microchip is replaced with a new one,
the alignment that is significantly troublesome is required.
[0008]
Accordingly, it is a main object of the present
technology to provide a microparticle sorting device that
automatically and accurately adjust the positions of the
flow cell and the microchip.
Solution to Problem
[0009]
To solve the above-described problem, the present
technology provides a microparticle sorting device including
a pair of deflecting plates that face each other with a
passage area of a fluid stream therebetween, a camera that
captures an image of the fluid stream, and a fluid stream
detection light source that emits light parallel to a
direction in which the deflecting plate faces each other and
that is movable in a direction perpendicular to the fluid
stream and the light. In the microparticle sorting device,
a collection container that receives the fluid stream can be
mounted so as to be movable in the direction perpendicular
to the fluid stream and the light.
The microparticle sorting device further includes a
control unit that detects a bright point in an image
6
captured by the camera by image recognition and stores the
position of the fluid stream detection light source obtained
when the image having the detected bright point therein is
captured. In the microparticle sorting device, since the
control unit adjusts the position of the collection
container on the basis of the position of the fluid stream
detection light source obtained when the image having the
detected bright point therein is captured, the position of
the fluid stream generated from the orifice and the position
of the collection container can be automatically adjusted.
In the microparticle sorting device, the control unit
may be configured to move the fluid stream detection light
source in the direction perpendicular to the fluid stream
and the light until the bright point is detected in an image
captured by the camera. In addition, a plurality of the
fluid stream detection light sources may be disposed so as
to be separated from each other in the direction of the
fluid stream.
In the microparticle sorting device, an orifice that
generates the fluid stream may be configured as a microchip
type flow cytometer provided in a microchip.
[0010]
Furthermore, the present technology provides a method
for adjusting a position of a fluid stream and a position of
a collection container for use in a microparticle sorting
7
device. The method including the steps of emitting light
that is parallel to a direction in which a pair of
deflecting plates that face each other with a passage area
of a fluid stream therebetween face each other while moving
the light in a direction perpendicular to the fluid stream
and the light, acquiring an image of the fluid stream,
detecting a bright point in the image by image recognition,
and adjusting the position of the collection container that
receives the fluid stream in the direction perpendicular to
the fluid stream and the light on the basis of an
irradiation position of the light when the image having the
detected bright point therein is acquired.
[0011]
According to the present technology, the term
"microparticle" widely refers to a biologically-relevant
microparticle, such as a cell, a microorganism, or a
liposome, or a synthetic particle, such as a latex particle,
a gel particle, or an industrial particle.
Examples of the biologically-relevant microparticle
include a chromosome, a liposome, a mitochondria, and an
organelle that form a variety of cells. Examples of the
cell include an animal cell (e.g., a blood cell) and a plant
cell. Examples of microorganism include bacteria (e.g.,
bacteria coliform), viruses (e.g., a tobacco mosaic virus),
and fungi (e.g., a yeast cell). In addition, examples of
8
the biologically-relevant microparticle can include a
biologically-relevant high molecule, such as nucleic acid,
protein, or a complex thereof. Furthermore, examples of the
industrial particle include an organic or inorganic highpolymer
material and a metal. Examples of the organic highpolymer
material include polystyrene, styrene, divinylbenzen,
and polymethylmethacrylate. Examples of the inorganic highpolymer
material include glass, silica, and magnetic
material. Examples of the metal include gold colloid and
aluminum. In general, these microparticles are spherical in
shape. However, these microparticles may be non-spherical
in shape. In addition, these microparticles may have any
sizes and masses.
Advantageous Effects of Invention
[0012]
The present technology provides a microparticle sorting
device that automatically and accurately adjusts the
positions of the fluid stream and the collection container.
Brief Description of Drawings
[0013]
[Fig. 1] Fig. 1 is a schematic illustration of the
configuration of a sorting system of a microparticle sorting
device 1 (a flow cytometer 1) configured as a microchip type
flow cytometer according to a first embodiment of the
present technology.
9
[Fig. 2] Fig. 2 illustrates the configuration of an
example of a microchip 2 mountable in the flow cytometer 1.
[Fig. 3] Fig. 3 is a schematic illustration of the
configuration of an orifice 21 of the microchip 2.
[Fig. 4] Fig. 4 is a flowchart illustrating a control
step for adjusting the position of a fluid stream S and the
position of a collection tube 3 in the flow cytometer 1.
[Fig. 5] Fig. 5 schematically illustrates the position
of a stream detection unit 43 when the laser beam L is
located at the irradiation position of the fluid stream S in
the flow cytometer 1.
[Fig. 6] Fig. 6 schematically illustrates the position
of the collection unit 33 when the fluid stream S is aligned
with the collection tube 3 in the flow cytometer 1.
[Fig. 7] Fig. 7 illustrates a modification of the
configuration of the stream detection unit 43 of the flow
cytometer 1.
[Fig. 8] Fig. 8 is a schematic illustration of the
configuration of a sorting system of a microparticle sorting
device 10 (a flow cytometer 10) configured as a microchip
type flow cytometer according to an embodiment related to
the present technology.
[Fig. 9] Fig. 9 is a flowchart illustrating a control
step for adjusting the position of the fluid stream S and
the position of the collection tube 3 in the flow cytometer
10
10.
[Fig. 10] Fig. 10 is a schematic illustration of an
example of an image captured by a droplet camera 5 of the
flow cytometer 10.
Description of Embodiments
[0014]
Exemplary embodiments of the present technology are
described below with reference to the accompanying drawings.
Note that the embodiments described below are only typical
examples of the present technology and, therefore, do not
narrow the scope of the present technology. The
descriptions are made in the following order:
1. Device Configuration of Microparticle Sorting Device
According to First Embodiment
(1-1) Chip Loading Module
(1-2) Microchip
(1-3) Deflecting Plate
(1-4) Collection Unit
(1-5) Stream Detection Unit
(1-6) Control Unit and Others
2. Position Control Performed by Microparticle Sorting
Device According to First Embodiment
(2-1) Collection Unit Position Initialization Step S1
(2-2) Fluid Stream Generation Step S2
(2-3) Stream Detection Unit Z-Axis Scanning/Fluid Stream
11
Imaging Step S3
(2-4) Image Recognition Step S4
(2-5) Detected Position Storing Step S5
(2-6) Z-Axis Stage Movement/Position Adjustment Step S6
3. Device Configuration of Microparticle Sorting Device
According to Embodiment Related to Present Technology
4. Position Control Performed by Microparticle Sorting
Device According to Related Embodiment
(4-1) Collection Unit Position Initialization Step S1/Fluid
Stream Generation Step S2
(4-2) Fluid Stream Imaging Step S3
(4-3) Image Recognition/Angle  Detection Step S4
(4-4) Z-Axis Stage Movement/Position Adjustment Step S5
[0015]
1. Device Configuration of Microparticle Sorting Device
According to First Embodiment
Fig. 1 is a schematic illustration of the configuration
of a sorting system of a microparticle sorting device 1
(hereinafter also referred to as a "flow cytometer 1")
configured as a microchip type flow cytometer according to a
first embodiment of the present technology.
[0016]
(1-1) Chip Loading Module
In the drawing, a reference numeral 11 represents a
chip loading module that holds a microchip 2. The chip
12
loading module 11 includes a chip loading unit that delivers
the microchip 2 inserted from the outside to a predetermined
position and hold the microchip 2 and a fluid sending
connector unit that supplies, for example, sample fluid
including cells and sheath fluid to the microchip 2 that is
held (neither is shown). In addition, the chip loading
module 11 includes a chip vibrating unit and a charging unit
(neither is shown). The chip vibrating unit applies
vibration to an orifice 21 that is formed in the microchip 2
to generate a laminar flow of the sample fluid and the
sheath fluid (a fluid stream S) and causes the orifice 21 to
eject droplets of the fluid stream S. The charging unit
imparts electrical charge to the ejected droplets.
[0017]
(1-2) Microchip
Figs. 2 and 3 illustrate an example of the microchip 2
mountable in the flow cytometer 1. Fig. 2A is a schematic
illustration of the top surface, and Fig. 2B is a schematic
illustration of a cross section corresponding to a P - P
cross section of Fig. 2A. In addition, Fig. 3 schematically
illustrates the structure of the orifice 21 of the microchip
2, where Fig. 3A is a top view, Fig. 3B is a cross-sectional
view, and Fig. 3C is a front view. Fig. 3B corresponds to
the P - P cross section of Fig. 2A.
[0018]
13
The microchip 2 is formed by bonding substrate layers
2a and 2b having a sample flow path 22 formed therein. The
sample flow path 22 can be formed in the substrate layers 2a
and 2b by using injection molding of thermoplastic resin.
Examples of the thermoplastic resin include plastics that
are well-known as a material of existing microchips, such as
polycarbonate, polymethylmethacrylate resin (PMMA), cyclic
polyolefin, polyethylene, polystyrene, polypropylene, and
polymethyldisilazane (PDMS).
[0019]
The sample fluid is introduced from the fluid sending
connector unit to a sample inlet 23. Thereafter, the sample
fluid merges with the sheath fluid introduced from the fluid
sending connector unit to a sheath inlet 24 and is delivered
to the sample flow path 22. The sheath fluid introduced
from the sheath inlet 24 branches in two directions and is
delivered. Thereafter, the sheath fluid merges with the
sample fluid so as to sandwich the sample fluid in two
directions at a merge point at which the sheath fluid merges
with the sample fluid introduced from the sample inlet 23.
In this manner, a three-dimensional laminar flow in which
the sample fluid laminar flow is located at the center of
the sheath fluid laminar flow is formed.
[0020]
A reference numeral 25 represents a suction flow path
14
used for, if clogging occurs or bubbles are generated in the
sample flow path 22, eliminating the clogging or the bubbles
by applying a negative pressure to the inside of the sample
flow path 22 and temporarily causing the sample fluid to
flow backward. The suction flow path 25 has a suction
outlet 251 formed at one end. The suction outlet 251 is
connected to a negative pressure source of, for example, a
vacuum pump via the fluid sending connector unit. The other
end is connected to the sample flow path 22 at a
communication port 252.
[0021]
The width of the three-dimensional laminar flow is
narrowed in a narrowing portion 261 (refer to Fig. 2) and a
narrowing portion 262 (refer to Fig. 3) each having the
cross-sectional area that is perpendicular to a fluid
delivery direction and that decreases from the upstream to
downstream in the fluid delivery direction gradually or in a
stepwise manner. Thereafter, the three-dimensional laminar
flow is discharged from the orifice 21 formed at one end of
the flow path in the form of a fluid stream S (refer to Fig.
1). In Fig. 1, the direction in which the fluid stream S is
discharged from the orifice 21 is represented by a positive
Y-axis direction.
[0022]
The characteristics of a cell are detected between the
15
narrowing portion 261 and the narrowing portion 262 of the
sample flow path 22. For example, in optical detection, a
laser beam is emitted from a light irradiation detecting
unit (not shown) to cells flowing in single file through the
core of the three-dimensional laminar flow in the sample
flow path 22, and scattered light or fluorescence generated
from each of the cells is detected by a light detector.
[0023]
A connection portion of the sample flow path 22 to the
orifice 21 is formed as a straight portion 27 extending in a
line. The straight portion 27 functions to eject the fluid
stream S from the orifice 21 straight in the positive Y-axis
direction.
[0024]
The fluid stream S ejected from the orifice 21 is
converted into fluid droplets by vibration applied to the
orifice 21 by the chip vibrating unit. The orifice 21 is
open in the end surface direction of the substrate layers 2a
and 2b. A notch 211 is provided between the opening
position of the orifice 21 and the end surface of each of
the substrate layers. The notch 211 is formed by cutting
off the substrate layers 2a and 2b between the opening
position of the orifice 21 and the end surface of each of
the substrates so that a diameter L of the notch 221 is
greater than the opening diameter l of the orifice 21 (refer
16
to Fig. 3C). In order not to disturb the movement of the
droplet ejected from the orifice 21, it is desirable that
the diameter L of the notch 211 be greater than or equal to
twice the opening diameter l of the orifice 21.
[0025]
(1-3) Deflecting Plate
In Fig. 1, reference numerals 12, 12 represent two
deflecting plates disposed so as to face each other with the
fluid stream S (or the ejected droplets) ejected from the
orifice 21 therebetween. The deflecting plates 12, 12 are
configured to include electrodes for controlling the
movement direction of the droplet ejected from the orifice
21 using an electrical force acting on the electrical charge
imparted to the droplet. In addition, the deflecting plates
12, 12 control the trajectory of the fluid stream S
generated from the orifice 21 using an electrical force
acting on the electrical charge imparted to the fluid stream
S. In Fig. 1, the direction in which the deflecting plates
12, 12 face each other is represented by an X-axis direction.
[0026]
(1-4) Collection Unit
In the flow cytometer 1, the fluid stream S (or the
droplet of the fluid stream S) is received from one of a
plurality of collection tubes (the collection containers) 3
arranged in a line in the direction in which the deflecting
17
plates 12, 12 face each other (the X-axis direction). The
collection tubes 3 may be plastic tubes and glass tubes that
are widely used for experiments. The number of the
collection tubes 3 is not limited to any particular number.
In this example, five collection tubes 3 are illustrated.
The fluid stream S generated from the orifice 21 is led to
one of the five collection tubes 3 in accordance with the
presence of an electrical acting force between the
deflecting plates 12, 12 or the magnitude of the force and
is collected by the collection tube 3.
[0027]
The collection tubes 3 are replaceably disposed in a
collection tube holder 31. In addition, the collection tube
holder 31 is disposed on a Z-axis stage 32 configured to be
movable in a direction (a Z-axis direction) that is
perpendicular to the direction in which the fluid stream S
is emitted from the orifice 21 (the Y-axis direction) and
that is perpendicular to the direction in which the
deflecting plates 12, 12 face each other (the X-axis
direction). In Fig. 1, an arrow F represents the direction
in which the Z-axis stage 32 moves. In the drawing, a
reference numeral 321 represents a waste fluid exit port
provided in the Z-axis stage 32. In the flow cytometer 1,
the collection tube holder 31 and the Z - axis stage 32 form
a collection unit (a collection container moving stage unit)
18
33 that is driven by a Z-axis motor (not shown).
[0028]
(1-5) Stream Detection Unit
The flow cytometer 1 includes a CCD camera 41 that
captures the image of the fluid stream S. In addition, the
flow cytometer 1 includes a stream detection unit 43. The
stream detection unit 43 includes a fluid stream detection
light source 42 that emits a laser beam L that is parallel
to the direction in which the deflecting plates 12, 12 face
each other (the X-axis direction) and a Z-axis motor 431
that moves the fluid stream detection light source 42 in a
direction (a Z-axis direction) that is perpendicular to the
direction in which the fluid stream S is ejected (the Y-axis
direction) and that is perpendicular to the direction of the
laser beam L (the X-axis direction). In Fig. 1, an arrow f
indicates a direction in which the stream detection unit 43
moves. Note that the CCD camera 41 may be imaging means,
such as a photoelectric conversion element (e.g., a line
sensor or a single-plate photodiode). In addition to a
laser source, such as an LED or an LD, xenon light or an
incandescent lamp, for example, can be used as the fluid
stream detection light source 42.
[0029]
In the flow cytometer 1, due to individual difference
in the microchip 2 mounted, the trajectory of the fluid
19
stream S emitted from the orifice 21 varies. Each time the
microchip 2 is replaced with a new one, the position of the
fluid stream S in the Z-axis direction (and the X-axis
direction) in the drawing may vary. Similarly, even for the
same microchip 2, each time measurement is performed, the
position of the fluid stream S may vary. The CCD camera 41,
the stream detection unit 43, and the collection unit 33
function to detect such a change in position in the Z-axis
direction (and the X-axis direction) and adjust the
positions of the fluid stream S and the collection tubes 3
in the Z-axis direction.
[0030]
(1-6) Control Unit and Others
In addition to the above-described configurations, the
flow cytometer 1 includes a light irradiation detecting unit
for detecting the optical characteristics of a cell, a data
analyzing unit for determining the characteristics, a tank
unit that stores the sample fluid and the sheath fluid, and
a control unit for controlling such configurations, which
widely used flow cytometers also include.
[0031]
The control unit can be configured from a generalpurpose
computer including, for example, a CPU, a memory,
and a hard disk. The hard disk stores, for example, an OS
and a program that performs the steps of position control
20
described below.
[0032]
In addition, the light irradiation detecting unit
includes an irradiation system and a detection system. The
irradiation system includes a laser source, a light
collecting lens or a dichroic mirror that collects and emits
a laser beam onto a cell, and a bandpass filter. The
detection system detects measurement target light generated
from the cell in response to the emission of the laser beam.
For example, the detection system is configured from, for
example, a PMT (photo multiplier tube) or an area imaging
element, such as a CCD or a CMOS element.
[0033]
The measurement target light detected by the detection
system of the light irradiation detecting unit is generated
by a cell due to emission of the measurement light. For
example, the measurement target light can be forwardscattered
light, side scattered light, or one of scattered
light and fluorescence of Rayleigh scattering or Mie
scattering. Such measurement target light is converted into
an electric signal, which is output to the control unit. In
the control unit, the electric signal is used for
determining the optical characteristics of the cell.
[0034]
Note that the flow cytometer 1 may magnetically or
21
electrically detect the characteristic of a cell. In this
case, microelectrodes are disposed so as to face each other
in the sample flow path 22 of the microchip 2 to measure,
for example, the resistance value, the capacity value (the
capacitance value), the inductance value, the impedance, the
value of change in an electric field between the
microelectrodes, a change in magnetization, a change in a
magnetic field, or a change in a magnetic field.
[0035]
2. Position Control Performed by Microparticle Sorting
Device According to First Embodiment
(2-1) Collection Unit Position Initialization Step S1
Fig. 4 is a flowchart illustrating a control step for
adjusting the position of the fluid stream S and the
position of the collection tube 3 in the flow cytometer 1.
The control step includes the procedures of "collection unit
position initialization step S1", "fluid stream generation
step S2", "stream detection unit Z-axis scanning/fluid
stream imaging step S3", "image recognition step S4",
"detected position storing step S5", and "Z-axis stage
movement/position adjustment step S6". The procedures are
described below.
[0036]
First, in the collection unit position initialization
step S1, the position of the collection unit 33 is
22
initialized. More specifically, the Z-axis stage 32 is
moved in the Z-axis direction (refer to an arrow F in Fig.
1). The Z-axis stage 32 is moved to a position (an
initialization position) at which the fluid stream S emitted
from the orifice 21 enters the waste fluid exit port 321
provided in the Z-axis stage 32. The control unit outputs a
signal to the Z-axis motor (not shown) to move the
collection unit 33 to the initialization position.
[0037]
(2-2) Fluid Stream Generation Step S2
In step S2, the fluid sending connector unit starts
delivering the sample fluid and the sheath fluid to the
sample inlet 23 and the sheath inlet 24 of the microchip 2,
respectively, and the fluid stream S is emitted from the
orifice 21. The control unit outputs a signal to the fluid
sending connector unit to start delivering the sample fluid
and the sheath fluid. The fluid stream S emitted from the
orifice 21 is collected by the waste fluid exit port 321 and
is discharged.
[0038]
(2-3) Stream Detection Unit Z-axis Scanning/Fluid Stream
Imaging Step S3
In step S3, the control unit causes the Z-axis motor 431
to move the stream detection unit 43 in the Z-axis direction
(refer to the arrow f in Fig. 1). During the movement, the
23
control unit captures the image of the fluid stream S using
the CCD camera 41. Due to the movement of the stream
detection unit 43, the fluid stream detection light source
42 is also moved in the Z-axis direction. Thus, the laser
beam L emitted from the fluid stream detection light source
42 is scanned in the Z-axis direction.
[0039]
(2-4) Image Recognition Step S4
The image of the fluid stream S captured by the CCD
camera 41 is output to the control unit, and the control
unit detects a bright point in the image in the image
recognition step S4.
[0040]
When the stream detection unit 43 is moved in the Zaxis
direction and the laser beam L is scanned in the same
direction, the laser beam L is emitted to the fluid stream S
at some position. Fig. 5 illustrates the position of the
stream detection unit 43 when the laser beam L is located at
the irradiation position of the fluid stream S.
[0041]
If the laser beam L is located at the irradiation
position of the fluid stream S, an irradiation point of the
laser beam L in the fluid stream S is detected as a highluminance
pixel (a bright point) in the image of the fluid
stream S captured by the CCD camera 41. However, if the
24
laser beam L is not located at the irradiation position of
the fluid stream S, a point at which the laser beam L is
emitted in the fluid stream S does not appear. Accordingly,
no bright point is detected in the image of the fluid stream
S captured by the CCD camera 41.
[0042]
That is, if a bright point is detected in the image of
the fluid stream S, the stream detection unit 43 is located
at the irradiation position of the laser beam L in the fluid
stream S. The position of the stream detection unit 43 (the
same as the position of the fluid stream detection light
source 42) in the Z-axis direction corresponds to the
position of the fluid stream S in the same direction.
[0043]
While description has been made with reference to step
S3 in which the stream detection unit 43 is scanned in the
Z-axis direction and step S4 in which the position at which
the laser beam L is emitted to the fluid stream S is
detected, detection of the position may be made by moving
the chip loading module 11 holding the microchip 2 in the Zaxis
direction. In the case in which the chip loading
module 11 is moved, the position of the stream detection
unit 43 is predetermined so that the position of the laser
beam L emitted from the fluid stream detection light source
42 is the same as the position of the collection tube 3 in
25
the Z-axis direction. Note that when the chip loading
module 11 is moved, the need for the following detected
position storing step S5 and Z-axis stage movement/position
adjustment step S6 may be eliminated.
[0044]
(2-5) Detected Position Storing Step S5
If a bright point is detected in the image of the fluid
stream S, the control unit stores the position information
of the stream detection unit 43 in the Z-axis direction as
the position information of the fluid stream S in the same
direction.
[0045]
If no bright point is detected in the image of the
fluid stream S, movement of the stream detection unit 43 in
the Z-axis direction, capturing of the image of the fluid
stream S (step S3) using the CCD camera 41 and image
recognition performed by the control unit (step S4) are
repeatedly performed. In this manner, the stream detection
unit 43 is moved in the Z-axis direction until the laser
beam L reaches the irradiation position in the fluid stream
S and a bright point is detected in the image of the fluid
stream S. Note that in the case in which the chip loading
module 11 is moved, movement of the chip loading module 11
in the Z-axis direction, capturing of the image of the fluid
stream S using the CCD camera 41, and image recognition
26
performed by the control unit are repeatedly performed until
a bright point is detected in the image of the fluid stream
S.
[0046]
(2-6) Z-axis Stage Movement/Position Adjustment Step S6
In Z-axis stage movement/position adjustment step S6,
the control unit adjusts the position of the collection tube
holder 31 on the basis of the position information of the
stream detection unit 43 in the Z-axis direction when the
bright point is detected. More specifically, the position
information of the stream detection unit 43 in the Z-axis
direction is converted into the position information of the
collection unit 33 in the same direction, and the Z-axis
stage 32 is moved to the position corresponding to the
converted position information. In this manner, the
collection tube 3 disposed in the collection tube holder 31
is aligned with the fluid stream S in the Z-axis direction
and, thus, the fluid stream S can accurately reach the
collection tube 3. Fig. 6 illustrates the position of the
collection unit 33 when the fluid stream S is aligned with
the collection tube 3.
[0047]
As described above, in the flow cytometer 1, the
position of the collection tubes 3 is automatically adjusted
with respect to the position of the fluid stream S.
27
Accordingly, in the flow cytometer 1, the need for manual
position adjustment of the microchip that is previously
required each time the microchip is replaced with a new one
or measurement is performed can be eliminated. Consequently,
easy and highly accurate analysis can be performed.
[0048]
Note that in this example, the stream detection unit 43
includes only one fluid stream detection light source 42.
However, in the flow cytometer 1, two or more fluid stream
detection light source 42 may be disposed. Fig. 7
illustrates a configuration in which the stream detection
unit 43 has a fluid stream detection light source 421
disposed therein in addition to the fluid stream detection
light source 42. The fluid stream detection light source
421 is disposed so as to be separated from the fluid stream
detection light source 42 in the direction of the fluid
stream S (the Y-axis direction in the drawing). The fluid
stream detection light source 421 outputs a laser beam L1
that is parallel to the laser beam L output from the fluid
stream detection light source 42. In this manner, by
disposing a plurality of fluid stream detection light
sources so as to be separated from each other in the Y-axis
direction, one of the laser beams to be used can be selected
in accordance with the height (the capacity) of each of the
collection tubes 3 disposed in the collection container 31.
28
More specifically, for example, for a 5-ml tube having a
small height, the laser beam L of the fluid stream detection
light source 42 is used. In contrast, for a 15-ml tube
having a large height, the laser beam L1 of the fluid stream
detection light source 421 disposed at a higher position is
used. In this manner, even when a tube having a large
height is used, the occurrence of a situation in which the
laser beam is blocked by the tube and, thus, position
detection of the fluid stream S is unavailable can be
prevented.
[0049]
3. Device Configuration of Microparticle Sorting Device
According to Embodiment Related to Present Technology
Fig. 8 is a schematic illustration of the configuration
of a sorting system of a microparticle sorting device 10
(hereinafter also referred to as a "flow cytometer 10")
according to an embodiment related to the present technology.
[0050]
Unlike the flow cytometer 1 according to the abovedescribed
first embodiment, the flow cytometer 10 includes a
droplet camera 5 instead of the CCD camera 41 and the stream
detection unit 43 provided in the flow cytometer 1. The
device configuration of the flow cytometer 10 other than the
droplet camera 5 is the same as that of the flow cytometer 1
and, therefore, description of the configuration is not
29
repeated. Note that in Fig. 8, the same reference symbols
are used for the same configurations of the flow cytometer
10 as those of the flow cytometer 1 in Fig. 1.
[0051]
The droplet camera 5 is a camera (e.g., a CCD camera)
for capturing the image of the fluid stream S ejected from
the orifice 21 of the microchip 2 or a discharged droplet.
The image captured by the droplet camera 5 is displayed on,
for example, a display unit. The image is used for user to
be aware of the state of formation of the droplet in the
orifice 2 (e.g., the size and the shape of the droplet and
formation intervals).
[0052]
As described above, the trajectories of the fluid
stream S injected from the orifice 21 of the microchips 2
differ from one another due to individual difference in the
microchip 2 mounted. Accordingly, each time the microchip 2
is replaced with a new one, the position of the fluid stream
S may vary in the Z-axis direction (and the X-axis
direction) in the drawing. In addition, even for the same
microchip 2, the position of the fluid stream S may vary in
each of measurements. In the flow cytometer 10, the droplet
camera 5 also functions to detect such a variation of the
position of the fluid stream S in the Z-axis direction.
[0053]
30
4. Position Control Performed by Microparticle Sorting
Device According to Related Embodiment
Adjustment of the positions of the fluid stream S and
the collection tube 3 using the droplet camera 5 and the
collection unit 33 is described below. Fig. 9 is a
flowchart illustrating a control step for adjusting the
position of the fluid stream S and the position of the
collection tube 3 in the flow cytometer 10. The control
step includes the procedures of "collection unit position
initialization step S1", "fluid stream generation step S2",
"fluid stream imaging step S3", "image recognition/angle 
detection step S4", and "Z-axis stage movement/position
adjustment step S5". The procedures are described below.
[0054]
(4-1) Collection Unit Position Initialization Step S1/Fluid
Stream Generation Step S2
The procedures of Collection unit position
initialization step S1/fluid stream generation step S2 are
the same as those in the flow cytometer 1 according to the
first embodiment. In these steps, the position of the
collection unit 33 is initialized to the position at which
the fluid stream S enters the waste fluid exit port 321
formed in the Z-axis stage 32. Thereafter, ejection of the
fluid stream S is started.
[0055]
31
(4-2) Fluid Stream Imaging Step S3
In this step S3, the control unit outputs a signal to
the droplet camera 5. Upon receiving the signal, the
droplet camera 5 captures the image of the fluid stream S.
[0056]
(4-3) Image Recognition/Angle  Detection Step S4
The image of the fluid stream S captured by the droplet
camera 41 is output to the control unit. An example of the
image is illustrated in Fig. 10. In a droplet camera image
P, the image of the fluid stream S is captured so as to be
inclined at a certain angle  with respect to the vertical
direction. In image recognition/angle  detection step S4,
the control unit performs image recognition and detects the
angle  from the droplet camera image P.
[0057]
The angle  corresponds to the output angle of the fluid
stream S injected from the orifice 21. The variation of the
trajectory of the fluid stream S injected from the orifice
21 is caused by the output angle  of the fluid stream S
injected from the orifice 21. Accordingly, by detecting the
angle , the position information of the fluid stream S in
the Z-axis direction can be obtained. To accurately detect
the angle , it is more desirable that a plurality of the
droplet cameras 5 be disposed so as to be separated from
each other in the Y-axis direction and, thus, capture the
32
images of the fluid stream S injected from the orifice 21 of
the microchip 2 at a plurality of positions. By using the
images of the fluid stream S captured at a plurality of
positions, the angle  can be more accurately calculated.
[0058]
(4-4) Z-Axis Stage Movement/Position Adjustment Step S5
In Z-axis stage movement/position adjustment step S5,
the control unit adjusts the position of the collection tube
holder 31 on the basis of the detected angle . More
specifically, the control unit moves the Z-axis stage 32 to
an appropriate position calculated using the angle  and a
predetermined distance between the orifice 21 and the
collection tube 3. In this manner, the collection tube 3
disposed in the collection tube holder 31 is aligned with
the fluid stream S and, thus, the fluid stream S can
accurately reach the collection tube 3.
[0059]
As described above, in the flow cytometer 10, the
position of the collection tubes 3 relative to the position
of the fluid stream S is automatically adjusted.
Accordingly, in the flow cytometer 10, the need for manual
position adjustment of the microchip that is previously
required each time the microchip is replaced with a new one
or measurement is performed can be eliminated. Thus, easy
and highly accurate analysis can be performed.
33
[0060]
In addition, in the flow cytometer 10, automatic
position adjustment of the fluid stream S and the collection
tubes 3 can be provided using a device design that is
simpler than that of the flow cytometer 1 according to the
above-described first embodiment.
[0061]
The microparticle sorting device according to the
present technology can have the following configurations:
(1) A microparticle sorting device includes a pair of
deflecting plates that face each other with a passage area
of a fluid stream therebetween, a camera that captures the
image of the fluid stream, and a fluid stream detection
light source that emits light parallel to a direction in
which the deflecting plate faces each other and that is
movable in a direction perpendicular to the fluid stream and
the light,
(2) The microparticle sorting device described in the above
(1) further includes a control unit that detects a bright
point in an image captured by the camera through image
recognition and stores the position of the fluid stream
detection light source obtained when the image having the
detected bright point therein is captured,
(3) In the microparticle sorting device described in the
above (2), a collection container that receives the fluid
34
stream is mountable so as to be movable in the direction
perpendicular to the fluid stream and the light, and the
control unit adjusts the position of the collection
container on the basis of the position of the fluid stream
detection light source obtained when the image having the
detected bright point therein is captured,
(4) In the microparticle sorting device described in the
above (2) or (3), the control unit moves the fluid stream
detection light source in the direction perpendicular to the
fluid stream and the light until the bright point is
detected in an image captured by the camera,
(5) In the microparticle sorting device described in any one
of the above (1) to (4), a plurality of the fluid stream
detection light sources are disposed so as to be separated
from each other in the direction of the fluid stream, and
(6) In the microparticle sorting device described in any one
of the above (1) to (5), an orifice that generates the fluid
stream is a microchip type flow cytometer provided in a
microchip.
Reference Signs List
[0062]
1, 10 microparticle sorting device (flow cytometer)
11 chip loading module
12 deflecting plate
2 microchip
35
21 orifice
3 collection tube
31 collection tube holder
32 Z-axis stage
321 waste fluid exit port
33 collection unit
41 CCD camera
42, 421 fluid stream detection light source
43 stream detection unit
431 Z-axis motor
5 droplet camera
L, L1 laser beam
S fluid stream
36
CLAIMS
[Claim 1]
A microparticle sorting device comprising:
a pair of deflecting plates that face each other with a
passage area of a fluid stream therebetween;
a camera that captures an image of the fluid stream;
and
a fluid stream detection light source that emits light
parallel to a direction in which the deflecting plate faces
each other and that is movable in a direction perpendicular
to the fluid stream and the light.
[Claim 2]
The microparticle sorting device according to Claim 1,
further comprising:
a control unit that detects a bright point in an image
captured by the camera through image recognition and stores
the position of the fluid stream detection light source
obtained when the image having the detected bright point
therein is captured.
[Claim 3]
The microparticle sorting device according to Claim 2,
wherein a collection container that receives the fluid
stream is mountable so as to be movable in the direction
perpendicular to the fluid stream and the light, and
wherein the control unit adjusts the position of the
37
collection container on the basis of the position of the
fluid stream detection light source obtained when the image
having the detected bright point therein is captured.
[Claim 4]
The microparticle sorting device according to Claim 3,
wherein the control unit moves the fluid stream detection
light source in the direction perpendicular to the fluid
stream and the light until the bright point is detected in
an image captured by the camera.
[Claim 5]
The microparticle sorting device according to Claim 4,
wherein a plurality of the fluid stream detection light
sources are disposed so as to be separated from each other
in the direction of the fluid stream.
[Claim 6]
The microparticle sorting device according to Claim 5,
wherein an orifice that generates the fluid stream is a
microchip type flow cytometer provided in a microchip.
[Claim 7]
A method for adjusting a position of a fluid stream and
a position of a collection container for use in a
microparticle sorting device, comprising the steps of:
emitting light that is parallel to a direction in which
a pair of deflecting plates that face each other with a
passage area of a fluid stream therebetween while moving the
38
light in a direction perpendicular to the fluid stream and
the light;
acquiring an image of the fluid stream;
detecting a bright point in the image through image
recognition; and
adjusting the position of the collection container that
receives the fluid stream in the direction perpendicular to
the fluid stream and the light on the basis of an
irradiation position of the light obtained when the image
having the detected bright point therein is acquired.