Patent ID: 12209944

MODE(S) FOR CARRYING OUT THE INVENTION

Embodiments according to the present technology will now be described below with reference to the drawings.

1. First Embodiment

1.1) Configuration of Sample Liquid-Sending Apparatus

FIG.1primarily illustrates a sample liquid-sending apparatus according to a first embodiment, and a configuration of a flow cytometer100that includes this sample liquid-sending apparatus50. The flow cytometer100includes the sample liquid-sending apparatus50and an analyzer41.

The analyzer41includes a function to analyze the characteristics of a sample detected in the sample liquid-sending apparatus50. In other words, the flow cytometer100typically serves as a cell analyzer.

The sample liquid-sending apparatus50includes a placement portion30in which a sample tube (a sample container)38is placed, a nozzle15that can be inserted into the sample tube38, and a nozzle arm26that serves as a nozzle support that supports and fixes the nozzle15. A suspension of a sample is contained in the sample tube38. The sample is typically a biological cell. The placement portion30is configured such that a plurality of sample tubes38can be placed in the placement portion30, but the placement portion30may be configured such that only one sample tube38can be placed in the placement portion30.

The sample liquid-sending apparatus50includes a vibrator25that vibrates the nozzle15. Also illustrated inFIG.2, the vibrator25is provided to, for example, the nozzle arm26. Examples of the vibrator25include an eccentric motor, a piezoelectric element, a solenoid, and a magnetostrictor.

The sample liquid-sending apparatus50includes a sheath tank10, a waste-liquid tank19, pumps11and12that create flow in liquid, and a detector20that detects a sample by creating a sheath stream using a sheath liquid from the sheath tank10. The sample liquid-sending apparatus50further includes a sheath stream tube16that connects the pump11and the detector20, a sample stream tube17that connects the nozzle15and the detector20, and a joining stream tube18that connects the detector20and the pump12(a buffer13provided before the pump12).

The two pumps11and12are respectively provided upstream and downstream, and, for example, their driving pressures and driving timings are controlled. This results in precisely controlling the flow of liquid in the sheath stream tube16, the sample stream tube17, the detector20, and the joining stream tube18.

A “suction mechanism” is formed primarily by piping of, for example, the nozzle15, the pumps11and12, and the sample stream tube17.

The detector20primarily includes a cuvette. The creation of a sheath stream in the cuvette using a sheath liquid enable samples from the sample stream tube17to be aligned to flow. A sample detection is performed by a laser being irradiated by a laser generator (not illustrated) onto samples that are aligned to flow in the cuvette. A biological cell is primarily used as the sample.

The detector20and the analyzer41are connected to each other through, for example, an optical fiber43. The analyzer41includes a function to analyze the optical characteristics of, for example, scattered light and fluorescence generated by laser irradiation. The analyzer41includes a computer.

A portion of or the entirety of the sample stream tube17is made of a flexible material such as silicon rubber. For example, a three-dimensional drive mechanism (not illustrated) that drives the nozzle arm26is connected to the nozzle arm26. The three-dimensional drive mechanism is capable of moving the nozzle15to insert into a plurality of two-dimensionally arranged sample tubes38.

The sample liquid-sending apparatus50includes a controller45. The controller45is configured to control driving of the respective mechanisms such as the vibrator25, the pumps11and12, and the others. In particular, the controller45is configured to control at least one of the strength of a vibration caused by the vibrator25or the length of time of the vibration. In addition to these drivers, the controller45includes a central processing unit (CPU), a random access memory (RAM), and a read only memory (ROM) in principle. Instead of the CPU, the controller45may include a programmable logic device (PLD) such as a field programmable gate array (FPGA). Further, the controller45includes a driver (not illustrated) that drives, for example, the vibrator25and the pumps11and12.

1.2) Operation of Sample Liquid-Sending Apparatus

FIG.3is a time chart of an operation of the sample liquid-sending apparatus50and a voltage applied on the vibrator25. The sample tube38is placed in the placement portion30, and the nozzle15is inserted into the sample tube38. In other words, the nozzle15moves to a measurement position. Then, the controller45causes the vibrator25to vibrate by applying a drive voltage on the vibrator25. The drive voltage keeps on being applied for a specified time period (a length of time Ta), with a timing of starting the application of the drive voltage being used as a start point, and the vibration of the nozzle is maintained during the specified time period. Accordingly, a suspension in one sample tube38into which the nozzle15has been inserted, is stirred.

The strength of a vibration (such as the magnitude of a drive voltage) is set such that the nozzle15does not come into contact with the sample tube38. Further, the controller45can also control a drive voltage such that the drive voltage varies in a range in which the nozzle15does not come into contact with the sample tube38.

After the length of time Ta passes from the start point (after the vibrator25stops vibrating), the length of time Ta being longer than a length of time Tb from the start point, the controller45starts boosting the pumps11and12. The boosting means pulsing a pump for a short time period of, for example, about one second to a few seconds. In other words, a suction operation performed by the nozzle15is started by starting the boosting.

The suction pressure of the nozzle15upon boosting is, for example, a few kPa. This results in quickly suctioning a suspension in the sample tube38through the nozzle15, and in guiding a large number of samples to the detector20.

When a boost is performed and then the boost is released, the state in which the boost has been released is referred to as a steady state. In the steady state, the stream of a sample in the nozzle15and the sample stream tube17is steady. This enables the detector20to accurately detect samples one by one, the samples being aligned due to a sheath stream from the sheath stream tube16. The analyzer41analyzes data of the optical characteristics of a sample obtained by the detector20.

For convenience, a series of processes from a start of a boost to at least a detection of a sample that is performed by the detector20is hereinafter referred to as “measurement”.

FIG.4Aillustrates the entirety of the sample tube38being moved by a stirring method used in the past, the method moving an entire sample container integrally.FIG.4Billustrates the nozzle15being vibrated by the vibrator25. As described above, the nozzle vibration caused by the vibrator25results in efficiently transmitting the nozzle vibration to a suspension in the sample tube since its amplitude is small.

1.3) Verifications

The inventors performed four verifications, Verifications 1 to 4 described below, in order to prove effects provided by the first embodiment. In the verifications, the inventors used a cell analyzer (SA3800) from Sony Corporation for comparison examples. In other words, the vibrator25is provided to a nozzle arm of the cell analyzer for the verifications. The cell analyzer used for the verifications includes a stirring unit at a lower portion of a stage provided with a plurality of sample containers (the sample tubes38, or a well plate not illustrated), the stirring unit moving the entirety of the plurality of sample containers integrally.

1.3.1) Verification 1

Verification 1 is a verification of an effect that a nozzle vibration caused by the vibrator25has on EPS (the number of events per second). Needless to say, in Verification 1, the stirring unit of the cell analyzer described above was not used, and the vibrator25was used.

FIG.5is a graph illustrating a temporal change in a suction pressure of the nozzle15(kPa) and in EPS. The event means a detection of one sample performed by the detector20, and the number of events is the number of samples detected by the detector20. Referring to the graph ofFIG.5, just after starting measurement, the suction pressure of the nozzle15was lower than −5 kPa due to a boost (Bst1), and after the measurement was finished, the suction pressure of the nozzle15was close to +20 kPa due to back washing in the sample stream tube17and the nozzle15. The negative value means suction. This change in a value of a suction pressure makes it possible to determine the timings of starting and finishing measurement.

A well plate (96 wells) was charged with samples and liquid for verification. Beads of a dried inorganic material (flow check beads) were used as the samples, and deionized water (DIW) was used as the liquid. Here, the inventors checked the liquid in the well plate, where the liquid in the well plate was not stirred (the vibrator25did not vibrate), and it was confirmed that the samples remained pooled in the lower portion of the liquid. In other words, the samples were not dispersed in the liquid. It was confirmed that the EPS was small when the samples were detected in this state (EPS1inFIG.5).

When a nozzle vibration was caused by the vibrator25for one second (VB1), a large EPS was detected in the process of measurement performed with respect to a next boost, the second boost (Bst2) (EPS2).

Next, the nozzle15was moved into a next well in which samples were also pooled in the lower portion of the liquid, and a sample measurement was performed with respect to a boost (Bst3). It was confirmed that the EPS was small (EPS3). Then, a sample measurement was performed again with respect to a boost (Bst4), and it was also confirmed that the EPS was small (EPS4). This proved that, when the nozzle15is inserted into a sample container (a well) and measurement is performed, the EPS is not improved in a state in which the vibrator25does not vibrate.

After that, when a vibration was further caused by the vibrator25for one second (VB2), a large EPS was confirmed in the process of subsequently performed measurement (EPS5and EPS5′).

As a result of the verification described above, clearly different results of the EPS were obtained before and after the nozzle vibration caused by the vibrator25, which shows the effect of the nozzle vibration.

1.3.2) Verification 2

Verification 2 is a verification of an effect that a nozzle vibration caused by the vibrator25has on a cell. The inventors verified the effect that a nozzle vibration has on a cell using Jurkat cells.FIG.6Aillustrates a distribution of life and death of cells before a suspension of the cells is vibrated, andFIG.6Billustrates a distribution of life and death of the cells after the suspension of the cells are vibrated for three minutes. In the graphs, the cells plotted in a boxed range are living cells. As illustrated in the graphs, there is no change in the distribution of life and death of the cells between before and after the vibration. This demonstrates that the three-minute vibration has no effect on the cells.

1.3.3) Verification 3

Verification 3 is a verification of an effect in the case of the nozzle15being constantly (continuously) vibrated by the vibrator25upon detecting samples. The inventors used 40-μm beads as samples, and as illustrated inFIG.7, also after the second boost (Bst2) is finished, the nozzle15was continuously vibrated (VB) upon detecting the samples, and a large number of events were confirmed (EPS1).

FIG.8is a graph illustrating a temporal change in the number of the confirmed events and in the suction pressure of the nozzle15. The 40-μm bead easily sinks in liquid, and thus it is not easy to detect the event. However, as a result of this verification, after the second boost (Bst2) was started, the event was constantly detected when the vibrator25was vibrating.

1.3.4) Verification 4

Verification 4 is a verification regarding an amount of suspension containable in a sample container. The inventors performed verification regarding a containable amount of suspension with respect to the case of moving an entire sample container and the case of only stirring a suspension in the sample container using a nozzle vibration. A well plate (96 wells) was used as the sample container. One of the wells in the well plate was fully charged with a sample-containing liquid, and stirring was performed.

When using a stirring method that moves an entire well plate, about 40% of an amount of suspension with which a well is fully charged will spill from the well. Thus, the amount containable in a well is merely about 60%. On the other hand, according to the present technology, no suspension spills from a well fully charged with a suspension when the vibrator25vibrates. This indicates that it is possible to increase an amount of suspension containable in a well. Accordingly, it is possible to contain a large number of samples in one well.

1.4) Effects

The first embodiment makes it possible to efficiently stir a suspension in the sample tube38since the nozzle15is vibrated by the vibrator25. Compared to a large-scale stirring unit for driving an entire sample tube as disclosed in Patent Literature 1, the first embodiment makes it possible to make a vibration causing source smaller, and this results in being able to make the sample liquid-sending apparatus50smaller and to reduce costs.

Further, when using a stirring method that moves an entire sample tube, there is a need for a preliminary operation for performing the stirring, where about 10 seconds are necessary to perform the preliminary operation. On the other hand, the first embodiment has an advantage in there being no need for such a preliminary operation since the vibrator25can cause a vibration quickly.

When using a stirring method that moves the entirety of a plurality of sample tubes, the number of stirring performed before measurement starts to be performed, is larger with respect to a sample tube38into which the nozzle15is inserted later (with respect to a sample tube38on which measurement is performed later). Thus, a sample in a sample tube38on which measurement is performed later, is mechanically damaged more greatly due to stirring being performed (mechanical damage is accumulated to a greater extent due to stirring being performed). On the other hand, the first embodiment makes it possible to minimize such mechanical damage since only the nozzle15inserted into the sample tube38is vibrated.

For example, as illustrated inFIG.8with respect to Verification 3, it becomes possible to detect an event steadily by causing a nozzle vibration constantly (continuously) after boosting.

For example, as described in Verification 4, it is possible for a sample container (such as a well plate) to contain an amount of sample-containing liquid that is close to the upper limit of an amount of liquid containable in the sample container.

2. Second Embodiment

Next, the sample liquid-sending apparatus according to a second embodiment is described. In the following description, regarding, for example, the members and the functions included in the sample liquid-sending apparatus50according to the first embodiment described above, a substantially similar component is denoted by the same reference symbol, a description thereof is simplified or omitted, and the description is made focused on a point of difference.

FIG.9illustrates a primary portion of the sample liquid-sending apparatus. A nozzle65includes a mounting portion63to which the vibrator25is provided. For example, the mounting portion63is configured such that the vibrator25is embedded in the mounting portion63.

The second embodiment also provides an effect similar to that of the first embodiment described above. In addition, the nozzle65is directly vibrated, and this results in improving electrical and mechanical efficiency in vibrational transmission.

3. Third Embodiment

FIG.10illustrates a flow cytometer that includes a sample liquid-sending apparatus according to a third embodiment. This sample liquid-sending apparatus150is different from the first embodiment described above in that the controller45acquires information from the analyzer41and performs a feedback control. For example, the analyzer41is configured to output, to the controller45, information regarding a count value of detected samples (the number of samples), that is, information regarding the number of events.

The controller45is configured to control at least one of the strength of the vibrator25or the length of time of the vibrator25according to a threshold set for the input number of events.

FIG.11illustrates a temporal change in the number of events. As described above, for example, the controller45causes the vibrator25to vibrate, stops the vibration, and then starts boosting. Then, the number of events reaches a maximum just after starting the boost. The number of events starts to be decreased and then reaches a steady state. It is assumed that the number of events in the steady state is 100%. For example, a threshold TH can be set in a range of 30% to 80% of the number of events in the steady state.

Specifically, for example, as illustrated inFIG.5, when the 100% number of events is 25 with respect to the event (EPS5′) in a steady state after the fifth boost (Bst5), for example, 15 can be set to be a threshold for the number of events. When the number of events is not greater than the threshold, the controller45causes the vibrator25to restart vibrating (VB).

Further, when the vibrator25is continuously or intermittently driven at a specified drive voltage also after boosting, the controller45may increase the drive voltage when the number of events is not greater than a threshold. Furthermore, in the case of intermittent driving of the vibrator25, the controller45may change the intermittent driving to continuous driving when the number of events is not greater than the threshold. Moreover, the change to the continuous driving and the increase in drive voltage may be combined.

Regarding the threshold described above, the number of thresholds is not limited to one, but a plurality of thresholds may be gradually set, and the controller45may perform an optical control according to the number of detected events.

The automatic control performed by the controller45described above makes it possible to perform a sample measurement efficiently and properly.

Note that, in the description above, information regarding the number of detected samples is fed back to the controller45from the analyzer41. However, for example, when a device that receives information detected by the detector20is a device other than the analyzer41, the information regarding the number of samples may be fed back to the controller45from the device other than the analyzer41.

4. Modification

The present technology is not limited to the embodiments described above. For example, in the embodiments described above, the strength and the timing of the vibration are controlled by the controller45, but they may be controlled by a manual operation performed by a man.

The sample liquid-sending apparatuses according to the respective embodiments described above each include a single vibrator25, but they may each include a plurality of vibrators25respectively arranged in different positions.

In the first embodiment described above, the controller45causes a vibration using the vibrator25before boosting, and then stops the vibration. However, as described above, the controller45may also cause a vibration continuously or intermittently using the vibrator25after boosting, or the controller45may cause a vibration continuously or intermittently regardless of the timing of boosting.

The waveform of the drive voltage illustrated inFIG.3or6is rectangular, but it may be, for example, trapezoidal or triangular, or the wave of the drive voltage may exhibit a ramp form only at one of the rising and the falling.

The sample liquid-sending apparatus according to the present technology can be applied as a sorter.

For example, as illustrated inFIG.12, the sample liquid-sending apparatus may include a cleaning unit70that cleans the nozzle15. The cleaning unit70is connected to an up-and-down mechanism76, and is configured to be moved by the up-and-down mechanism76in parallel with a direction of a length of, for example, the nozzle15. For example, the cleaning unit70moves in a state of being in contact with an outer periphery of the nozzle15, so as to clean the outer periphery.

Regarding how to clean, for example, the cleaning unit70includes a contact member that comes in contact with the outer periphery of the nozzle15. Cleaning is performed by the contact member being moved up and down by the up-and-down mechanism76. The contact member is made of, for example, resin. Alternatively, instead of the contact member, the cleaning unit70may include a mechanism that supplies a cleaning solution to the outer periphery of the nozzle15, or the cleaning unit70may have a configuration in which the contact member is supplied with the cleaning solution.

FIG.13is a top view of the above-described cleaning unit70provided with a vibrator. As illustrated in the figure, a vibrator75may be provided instead of, or in addition to the vibrator25illustrated inFIGS.1and2. The vibrator75includes a function similar to that of the vibrator25, and plays a role similar to that of the vibrator25. As described above, the position at which a vibrator is provided can be changed as appropriate.

The sample liquid-sending apparatus may be provided with a plurality of vibrators respectively provided at different positions of the sample liquid-sending apparatus. In this case, for example, the nozzle15and the nozzle arm26may each be provided with the vibrator, or the nozzle arm26and the cleaning unit70may each be provided with the vibrator.

At least two of the features in the embodiments described above may be combined.

Note that the present technology may also take the following configurations.

(1) A sample liquid-sending apparatus including:

a placement portion in which a sample container is placed, the sample container containing a suspension of a sample;

a suction mechanism that includes a nozzle configured to be inserted into the sample container placed in the placement portion, the suction mechanism suctioning the sample through the nozzle; and

a vibrator that vibrates the nozzle.

(2) The sample liquid-sending apparatus according to (1), further including

a nozzle support that supports the nozzle, in which

the vibrator is provided to the nozzle support.

(3) The sample liquid-sending apparatus according to (1), in which the vibrator is provided to the nozzle.

(4) The sample liquid-sending apparatus according to any one of (1) to (3), further including a controller that is configured to control at least one of a strength of a vibration caused by the vibrator or a length of time of the vibration.

(5) The sample liquid-sending apparatus according to (4), in which the controller is configured to cause the vibrator to vibrate, and then to cause the suction mechanism to start an operation of suctioning the sample.

(6) The sample liquid-sending apparatus according to (5), in which the controller is configured to cause the vibrator to vibrate, to stop the vibrator from vibrating, and then to cause the suction mechanism to start the operation of suctioning the sample.

(7) The sample liquid-sending apparatus according to (4), in which the controller causes the vibrator to vibrate continuously or intermittently.

(8) The sample liquid-sending apparatus according to any one of (4) to (7), further including a detector that detects the sample suctioned by the suction mechanism, in which

the controller is configured to control, according to a threshold, at least one of the strength of the vibration or the length of time of the vibration, the threshold being set with respect to the number of the samples detected by the detector.

(9) The sample liquid-sending apparatus according to (1), further including a cleaning unit that cleans the nozzle.

(10) The sample liquid-sending apparatus according to (9), in which the vibrator is provided to the cleaning unit.

(11) The sample liquid-sending apparatus according to (9), further including a nozzle support that supports the nozzle, in which

a plurality of the vibrators is provided, and

at least two of the plurality of the vibrators are respectively provided to the nozzle support and the cleaning unit.

(12) The sample liquid-sending apparatus according to (2), in which a plurality of the vibrators is provided, and

at least two of the plurality of the vibrators are respectively provided to the nozzle and the nozzle support.

(13) A flow cytometer including:

a placement portion in which a sample container is placed, the sample container containing a suspension of a sample;

a suction mechanism that includes a nozzle configured to be inserted into the sample container placed in the placement portion, the suction mechanism suctioning the sample through the nozzle;

a vibrator that vibrates the nozzle;

a detector that detects the sample suctioned by the suction mechanism; and an analyzer that analyzes characteristics of the detected sample.

(14) A sample liquid-sending method including:

inserting a nozzle into a sample container containing a suspension of a sample, the nozzle being included in a suction mechanism, the sample container being placed in a placement portion;

vibrating the nozzle; and

suctioning the sample through the nozzle using the suction mechanism.

REFERENCE SIGNS LIST

15,65nozzle20detector25,75vibrator26nozzle arm30placement portion38sample tube41analyzer45controller50,150sample liquid-sending apparatus63mounting portion70cleaning unit100flow cytometer