JP4861121B2 - Hollow needle inspection device, hollow needle inspection method, and microinjection system - Google Patents

Description

  The present invention relates to a hollow needle inspection device, a hollow needle inspection method, and a microinjection system for inspecting a hollow needle, and more particularly, a hollow needle inspection that enables a total inspection of hollow needles by inspecting the hollow needle without destroying it. The present invention relates to a device, a hollow needle inspection method, and a microinjection system.

  Microinjection is a technique for introducing a gene solution and a drug solution (hereinafter collectively referred to as an introduction liquid) into cells and cell-like fine particles (hereinafter collectively referred to as cells) using a needle (for example, Non-Patent Document 1). And 2).

In fields such as regenerative medicine and new drug development, opportunities to introduce substances into cells and verify their effectiveness are increasing. Many substance introduction techniques have been used so far, but in the future, it will be necessary to conduct many patterns of experiments using a small amount of cells and introduction liquid. From such a background, there is a demand for a technique for ascertaining and reliably assembling a predetermined amount of introduced liquid into individual particles in a large number.

  A needle used for microinjection is a glass hollow needle (hereinafter referred to as a capillary). In order to puncture general somatic cells often having a diameter of several tens of μm, the tip of the capillary is squeezed to 1 μm or less. In general, the pressure required to push out the liquid filled in the circular pipe is inversely proportional to the fourth power of the radius of the circular pipe, and therefore the inner diameter of the tip sharply affects the pressure management. For this reason, it is important to measure and manage the inner diameter of the created capillary.

"SUTTER INSTRUMENT", [searched on September 12, 2006], Internet <URL: http://www.shoshinem.com/puller-ivf.htm> "Automatic microinjection device", [Search September 12, 2006], Internet <URL: http://jp.fujitsu.com/group/automation/services/cellinjector>

  There are two methods for measuring the tip diameter of the capillary. One is a method of directly measuring with an image. In the case of an optical microscope, a capillary is attached to the stage and magnified observation is performed. However, in order to observe the tip shape of 1 μm or less, the optical microscope has a limit in terms of resolution. In observation with an electron microscope (SEM), there is a limit to the models that can accommodate the capillary length (50 mm or more). Therefore, in many cases, since the capillary is cut and mounted on the stage, a sampling inspection is performed. In addition, it is not a simple measurement method because pretreatment by sputtering is necessary to obtain a good image.

  The other is a method in which a capillary is put in the liquid and gas is discharged from the tip for measurement. The tip of the capillary is immersed in a container filled with ethanol, and air or nitrogen is released from the inside. This is a method of recording the pressure when bubbles start to emerge from the tip and calculating the tip inner diameter by calculation. However, in this measurement method, since the capillary is immersed in a liquid, the capillary once used for measurement cannot be used as a product, and must be subjected to a sampling inspection.

  As described above, in the conventional measurement and inspection of the tip diameter of the capillary, it is unavoidable to be a sampling inspection. However, the capillary has a large variation in the tip diameter due to its manufacturing principle, so the measurement accuracy is not high in the sampling inspection. There is a problem.

  The present invention has been made in order to solve the above-described problems caused by the prior art, and is a hollow needle inspection device that can inspect all the hollow needles by inspecting the hollow needles such as capillaries without breaking them. An object of the present invention is to provide a hollow needle inspection method and a microinjection system.

In order to solve the above-described problems and achieve the object, the present invention provides a first pressure chamber connected to a pipe used for gas supply, and the first pressure chamber is connected via a valve. A second pressure chamber, a regulator that adjusts the pressure of the gas supplied using the pipe, and a second pressure that is separated from the first pressure chamber by the valve that is closed after pressure adjustment by the regulator. A differential pressure sensor for measuring a pressure difference generated between the first pressure chamber and the second pressure chamber when the hollow needle connected to the chamber leaks gas in the second pressure chamber; and the differential pressure sensor calculating the rate of increase in the differential pressure from the pressure difference measured by, Ru and an inner diameter calculating means for calculating a tip inner diameter of the hollow needle from the rising speed of the calculated.

According to the present invention, the first pressure chamber connected to the pipe used for gas supply, the second pressure chamber connected to the first pressure chamber via the valve, and the pipe A regulator for adjusting the pressure of the supplied gas, and a hollow needle connected to a second pressure chamber separated from the first pressure chamber by a valve closed after pressure adjustment by the regulator is provided in the second pressure chamber. Since the hollow needle inspection device is configured with the differential pressure sensor that measures the pressure difference generated between the first pressure chamber and the second pressure chamber when the gas leaks, by measuring the pressure difference multiple times The time change of the pressure difference can be calculated.

Moreover, the present invention is characterized in that, in the above invention, the regulator adjusts the pressure of the gas when the valve is closed to a range between a predetermined lower limit value and an upper limit value.

According to the present invention, since the pressure of the gas when the valve is closed is adjusted to the predetermined lower limit value and upper limit value range, the first pressure chamber and the second pressure chamber are The resulting pressure differential can be measured appropriately.

Moreover, the present invention is characterized in that, in the above invention, the first pressure chamber and the second pressure chamber are cut out from the same member.

According to the present invention, since the first pressure chamber and the second pressure chamber are cut out from the same member, the pressure difference generated between the first pressure chamber and the second pressure chamber can be accurately determined. Can be measured.

According to the present invention, the pressure increase rate is calculated from the pressure difference measured by the differential pressure sensor, and the tip inner diameter of the hollow needle is calculated from the calculated speed increase. It can be calculated easily.

Further, according to the present invention, in the above invention, the inner diameter calculation among a plurality of differential pressure increasing speeds calculated by repeatedly adjusting an atmospheric pressure by the regulator, closing a valve, calculating a differential pressure increasing speed, and opening a valve. The means is characterized in that the tip inner diameter of the hollow needle is calculated excluding the initial differential pressure increase rate.

According to the present invention, the first differential pressure increase speed among the plurality of differential pressure increase speeds calculated by repeatedly adjusting the air pressure by the regulator, closing the valve, calculating the differential pressure increase speed, and opening the valve is obtained. In addition, since the tip inner diameter of the hollow needle is calculated, an initial error when calculating the differential pressure increase speed can be excluded.

Further, the present invention provides a second pressure chamber to which a hollow needle is connected and a first pressure chamber connected to the second pressure chamber via a valve by opening the valve with a predetermined pressure. A gas supply step to supply; after filling the first pressure chamber and the second pressure chamber with a gas of a predetermined pressure by the gas supply step and closing the valve, the first pressure chamber and the second pressure chamber; A differential pressure increase rate calculation step for measuring the differential pressure between the two and calculating the differential pressure increase rate, and a tip inner diameter of the hollow needle based on the differential pressure increase rate calculated by the differential pressure increase rate calculation step And a tip inner diameter calculating step for calculating.

According to the present invention, a gas having a predetermined pressure is supplied to the second pressure chamber connected to the hollow needle and the first pressure chamber connected to the second pressure chamber via the valve by opening the valve. Then, after filling the first pressure chamber and the second pressure chamber and closing the valve, the differential pressure between the first pressure chamber and the second pressure chamber is measured to calculate the differential pressure increase rate. Since the tip inner diameter of the hollow needle is calculated based on the calculated differential pressure increase rate, the tip inner diameter can be calculated without destroying the hollow needle.

Further, the present invention is a microinjection system using a capillary, wherein a first pressure chamber connected to a pipe used for gas supply and the first pressure chamber are connected via a valve. A second pressure chamber that is partitioned from the first pressure chamber by the valve closed after the pressure adjustment by the regulator, and a regulator that adjusts the pressure of the gas supplied using the pipe A differential pressure sensor for measuring a pressure difference generated between the first pressure chamber and the second pressure chamber when the capillary connected to the gas leaks gas in the second pressure chamber, and measured by the differential pressure sensor And an inner diameter calculating means for calculating an increasing speed of the differential pressure from the calculated pressure difference and calculating an inner diameter of the tip of the capillary from the calculated increasing speed.

According to the present invention, the first pressure chamber connected to the pipe used for gas supply, the second pressure chamber connected to the first pressure chamber via the valve, and the pipe A regulator that adjusts the pressure of the supplied gas, and a capillary connected to the second pressure chamber that is partitioned from the first pressure chamber by a valve that is closed after pressure adjustment by the regulator is the gas in the second pressure chamber Since the microinjection system is equipped with a differential pressure sensor that measures the pressure difference generated between the first pressure chamber and the second pressure chamber when leaking It is possible to calculate.

  According to the present invention, since it is possible to calculate the time change of the pressure difference generated between the first pressure chamber and the second pressure chamber, the correspondence between the time change of the pressure difference and the tip inner diameter of the hollow needle It is possible to accurately obtain the tip inner diameter of each hollow needle using the.

  In addition, according to the present invention, since the pressure difference generated between the first pressure chamber and the second pressure chamber is appropriately measured, it is possible to accurately calculate the time change of the pressure difference. .

  In addition, according to the present invention, since the pressure difference generated between the first pressure chamber and the second pressure chamber is accurately measured, the time change of the pressure difference can be calculated with high accuracy. .

  In addition, according to the present invention, since the tip inner diameter of the hollow needle is easily calculated, there is an effect that the total number inspection of the hollow needle can be performed with a small burden.

  In addition, according to the present invention, since the initial error when calculating the differential pressure increase rate is excluded, it is possible to improve the accuracy of the tip inner diameter of the hollow needle calculated from the differential pressure increase rate.

  In addition, according to the present invention, since the tip inner diameter is calculated without destroying the hollow needle, the tip inner diameter can be calculated for each hollow needle.

  Further, according to the present invention, it is possible to calculate the tip inner diameter of the capillary by the microinjection system itself, so that it is possible to accurately calculate the tip inner diameter of the capillary at the time of injection.

  Exemplary embodiments of a hollow needle inspection apparatus, a hollow needle inspection method, and a microinjection system according to the present invention will be described below in detail with reference to the accompanying drawings.

  First, the configuration of the capillary inspection apparatus according to this embodiment will be described. FIG. 1 is a diagram illustrating a configuration of a capillary inspection apparatus according to the present embodiment. As shown in the figure, in this capillary inspection apparatus 100, the capillary 1 is mounted on the capillary mounting portion 2 by screws or appropriate mounting means. From the capillary mounting part 2 to the second pressure chamber 3, the first pressure chamber 7, the valve 8, the regulator unit 10 and the filter 11, all are internally connected by piping 9 or formed integrally.

  Between the first and second pressure chambers, there is provided an electromagnetic valve 5 for blocking both pressure chambers to generate a differential pressure. Here, in order to reduce the overall dimensions, a diaphragm type electromagnetic valve is used as the electromagnetic valve 5, but other types of electromagnetic valves can also be used.

  The pressure generated between the two pressure chambers is measured by the differential pressure sensor 4. The differential pressure sensor 4 can detect a fine differential pressure with a minimum resolution of 0.1 Pa. Separately from the differential pressure sensor 4, the pressure in the first pressure chamber is measured by the pressure sensor 6. The pressure sensor 6 is used as an index when the regulator unit 10 adjusts the original pressure.

  In the inspection by the capillary inspection apparatus 100, nitrogen or air cleaned through the filter 11 is filled in the first pressure chamber 7 and the second pressure chamber 3 connected to the capillary 1, and both pressure chambers are electromagnetic valves. Isolate at 5. Then, the differential pressure sensor 4 measures the pressure difference between the two pressure chambers over several minutes, and the inner diameter calculation device 12 calculates and displays the tip inner diameter of the capillary 1 from the rate of change in the differential pressure. The inner diameter calculating device 12 stores the correspondence between the change rate of the differential pressure increase and the tip inner diameter of the capillary 1 and calculates the tip inner diameter of the capillary 1 from the change rate of the differential pressure increase using the stored correspondence. .

  In microinjection, the internal volume of the object to be measured (= capillary) is as small as 0.1 cc or less. For this reason, the structure which suppresses the internal volume of a measuring device and excludes the connection piping in an apparatus is calculated | required. Therefore, here, the pressure difference between the pressure chamber and the capillary is directly measured by the differential pressure sensor 4. Further, the pressure chamber and the capillary mounting portion 2 are manufactured with the same parts so as to suppress leakage from other than the measurement place.

Next, the measurement of the differential pressure using the capillary inspection apparatus 100 will be described. FIG. 2 is a diagram illustrating a state until the capillary is mounted on the capillary inspection apparatus 100. The operator sets the supply source pressure to zero on the basis of the indication value of the pressure sensor 6 with the electromagnetic valve 5 released. This means that the source pressure supply line is equivalent to the atmospheric pressure (P ₀ ). In this state, the operator removes and replaces the capillary 1.

  Note that these operations are performed in a state where the solenoid valve 5 is released because the differential pressure sensor 4 connecting the two pressure chambers is subjected to a differential pressure exceeding the measurement range due to a change in the original pressure or a change in the internal pressure due to screwing of the capillary 1. This is to prevent the differential pressure sensor 4 from being damaged.

  Generally, the inner diameter of the glass tube portion of the capillary 1 is about 0.6 mm, the length including the capillary mounting portion 2 is about 50 mm, and the total volume inside the capillary is about 15 μL. In order to detect the internal pressure fluctuation, it is necessary to suppress the volume of the pipe connected to the capillary 1 and the pressure chamber as much as possible. Here, the total volume on the capillary side from the solenoid valve 5 including the capillary mounting portion 2 and the second pressure chamber 3 is suppressed to about 100 μL by designing the piping to be short.

  In addition, a device that packs high-pressure gas into the part to be measured and measures the pressure change from it to detect the presence or absence of an opening is called a leak tester. In a normal leak tester, the only thing that can be detected is the presence or absence of a leak. The volume of the detection object is often on the order of mL to L. In this type of measurement, it is usual to prepare a part having the same shape (leak master) that is guaranteed to have no leakage, and to measure the differential pressure between this part and the detection part.

  However, in the case of this capillary inspection apparatus 100, since the measurement object is a very small volume, the sensor cannot be directly installed on the leak master, and the slight leak that occurs when the master is connected is not allowed. Use is conversely inefficient. Therefore, here, a technique is adopted in which the differential pressure sensor 4 is installed between the first and second pressure chambers and the difference between the original pressure and the capillary internal pressure is directly measured.

  After the capillary is mounted, the operator operates the regulator unit 10 while confirming the indication value of the differential pressure sensor 4 while the electromagnetic valve 5 is open, and gradually increases the pressure of the entire apparatus. This is shown in FIG. The setting of the source pressure needs to be determined by the load applied to the solenoid valve 5 and the pressure to be measured. However, the source pressure is appropriately about 80 kPa or more and about 100 kPa under general conditions. In addition, the electromagnetic valve 5 is opened and closed several times before the measurement in order to distribute the pressure uniformly throughout the electromagnetic valve 5 and the like, such as in the differential pressure sensor and the tip of the capillary.

As soon as the solenoid valve 5 is closed, the operator starts measurement. A state during measurement is shown in FIG. By discharging the filled compressed air (or nitrogen) from the opening at the tip of the capillary, the internal pressure of the second pressure chamber 3 decreases. When the internal pressure of the first pressure chamber 7 is P _H and the internal pressure of the second pressure chamber 3 is P _L , P _H −P _L appears in the differential pressure sensor 4. The value gradually increases due to leakage from the capillary tip.

  The inner diameter calculation device 12 records the value with time. Recording is performed for about 60 seconds every 1-2 seconds, but 120 seconds or more if possible. Since it is necessary to wait for the thermal equilibrium of the entire apparatus, the increase rate of the differential pressure is unstable for several tens of seconds after the start of measurement, but thereafter, the increase of the differential pressure becomes almost linear with respect to time, The value of the slope of the straight line (hereinafter referred to as the decompression rate) can be obtained.

  Further, since the pressure reduction rate increases as the tip inner diameter increases, the inner diameter calculation device 12 stores the measurement result of the pressure reduction rate for a plurality of capillaries whose tip inner diameters are known, thereby calculating the tip inner diameter from the pressure reduction rate. Can be calculated.

  FIG. 5 shows five times of “measurement of pressure reduction rate for 60 seconds and refilling gas by opening / closing the electromagnetic valve for 10 seconds” for a capillary of the same lot five times. Measurement results from the same capillary are connected by a line. According to this, it can be seen that the measurement error in the same capillary is at most 1 Pa / s after the second measurement.

  In this embodiment, ensuring airtightness is extremely important. Therefore, it is necessary to connect the capillary 1 and the second pressure chamber 3 while maintaining airtightness. Therefore, in this embodiment, as shown in FIG. 6A, the capillary 1 and the second pressure chamber 3 are connected by a screw. If there seems to be a problem with the airtightness of the female thread portion cut into the second pressure chamber 3, the corresponding portion is filled with putty or the like.

  Further, the capillary inspection apparatus 100 according to the present embodiment can also be applied to a capillary having a structure that can be automatically attached to and detached from the injection manipulator. For simplicity, an airtight holding material such as an O-ring is arranged in the second pressure chamber 3, and a capillary having the shape shown in FIG. 6B is attached to the second pressure chamber 3. Airtightness can be secured by fastening the jig with screws. In FIG. 6 (b), the connection is manual, but automatic attachment / detachment is also possible.

  In addition, due to insufficient airtightness, gas may leak from other than the capillary tip. In this case, it is known from experimental results that the rate of increase in the value sensed by the differential pressure sensor is clearly different from that without leakage. Specifically, the measurement limit of the sensor is exceeded in a few seconds to a few dozen seconds. For this reason, if the sensor value change immediately after the start of measurement is as described above, it is possible to detect leaks due to insufficient airtightness of the mounting part by adopting a structure that notifies the operator by appropriate means such as an alarm sound or a message. Is possible.

  As shown in FIG. 7, the capillary inspection apparatus according to this embodiment can be mounted as a part of the injection system. The minimum components for realizing the capillary inspection apparatus according to this embodiment are the first and second pressure chambers, the electromagnetic valve, and the differential pressure sensor. Since the injection system has a function to control the supply pressure, these components are mounted on the manipulator, and the needle volume is grasped in real time on the injection system, so that the discharge amount can be controlled more precisely. Can do.

  As described above, in this embodiment, the capillary 1 is connected to the second pressure chamber 3, and compressed air or compressed nitrogen adjusted to a predetermined pressure by the regulator unit 10 is used as the first pressure chamber 7 and the second pressure chamber 3. The pressure sensor 4 measures the pressure difference between the two pressure chambers with the solenoid valve 5 closed after the pressure chamber 3 is filled, and the inner diameter calculation device 12 determines the tip of the capillary 1 from the rate of change of the pressure difference. Since the inner diameter is calculated, the inner diameter of the tip can be obtained without destroying the capillary 1.

  In this embodiment, the case where the tip inner diameter of the capillary 1 is calculated has been described. However, the present invention is not limited to this, and the same applies to the case where the tip inner diameter of a general hollow needle is calculated. be able to.

  In this embodiment, the operator opens / closes the solenoid valve and operates the regulator unit. However, the present invention is not limited to this, and controls the solenoid valve, the regulator unit, and the differential pressure sensor. The present invention can be similarly applied to a case where a control device is provided and the tip inner diameter is calculated by measuring a differential pressure between the first pressure chamber and the second pressure chamber based on an instruction from the control device.

(Appendix 1) a first pressure chamber connected to a pipe used for gas supply;
A second pressure chamber connected via a valve to the first pressure chamber;
A regulator for adjusting the pressure of the gas supplied using the pipe;
The first pressure when the hollow needle connected to the second pressure chamber separated from the first pressure chamber by the valve closed after the pressure adjustment by the regulator leaks the gas in the second pressure chamber. A differential pressure sensor for measuring a pressure difference generated between the chamber and the second pressure chamber;
A hollow needle inspection apparatus comprising:

(Additional remark 2) The said regulator adjusts the pressure of the gas at the time of a valve being closed to the range of a predetermined | prescribed lower limit and upper limit, The hollow needle inspection apparatus of Additional remark 1 characterized by the above-mentioned.

(Supplementary note 3) The hollow needle inspection apparatus according to supplementary note 1 or 2, wherein the first pressure chamber and the second pressure chamber are cut out from the same member.

(Additional remark 4) It further provided with the internal diameter calculation means which calculates the raise speed | rate of a differential pressure from the pressure difference measured by the said differential pressure sensor, and calculates the front-end | tip internal diameter of the said hollow needle from this calculated rise speed, The hollow needle inspection apparatus according to Supplementary Note 1, 2, or 3.

(Additional remark 5) The said hollow needle is a capillary, The hollow needle inspection apparatus as described in any one of additional marks 1-4 characterized by the above-mentioned.

(Additional remark 6) The said hollow needle is connected to a 2nd pressure chamber with a screw | thread, The hollow needle inspection apparatus of Additional remark 5 characterized by the above-mentioned.

(Supplementary note 7) Among the plurality of differential pressure increase speeds calculated by repeatedly adjusting the pressure by the regulator, closing the valve, calculating the differential pressure increase speed, and opening the valve, the inner diameter calculating means is the first difference The hollow needle inspection apparatus according to appendix 4, wherein a tip inner diameter of the hollow needle is calculated excluding a pressure increasing speed.

(Supplementary Note 8) A gas having a predetermined pressure is supplied to the second pressure chamber connected to the hollow needle and the first pressure chamber connected to the second pressure chamber via the valve by opening the valve. A gas supply step;
After the gas supply step, the first pressure chamber and the second pressure chamber are filled with a gas having a predetermined pressure and the valve is closed, and then the differential pressure between the first pressure chamber and the second pressure chamber is measured. A differential pressure increase rate calculating step for calculating the increase rate of the differential pressure;
A tip inner diameter calculating step for calculating a tip inner diameter of the hollow needle based on the differential pressure increasing speed calculated by the differential pressure increasing speed calculating step;
A hollow needle inspection method characterized by comprising:

(Supplementary note 9) A microinjection system using a capillary,
A first pressure chamber connected to a pipe used for gas supply;
A second pressure chamber connected via a valve to the first pressure chamber;
A regulator for adjusting the pressure of the gas supplied using the pipe;
When the capillary connected to the second pressure chamber separated from the first pressure chamber by the valve closed after the pressure adjustment by the regulator leaks the gas in the second pressure chamber, the first pressure chamber A differential pressure sensor for measuring a pressure difference generated between the first pressure chamber and the second pressure chamber;
A microinjection system characterized by comprising:

  As described above, the hollow needle inspection device, the hollow needle inspection method, and the microinjection system according to the present invention are useful when introducing a drug solution into cells in regenerative medicine or new drug development, and in particular, the tip inner diameter of the capillary This is suitable when it is necessary to accurately obtain the value.

It is a figure which shows the structure of the capillary inspection apparatus which concerns on a present Example. It is a figure which shows the state until capillary mounting. It is a figure which shows the state at the time of original pressure application. It is a figure which shows the state at the time of a differential pressure measurement. It is a figure which shows the relationship (example) of the frequency | count of a measurement in the same lot capillary, and a pressure reduction rate actual value. It is a figure which shows the structural example of a capillary mounting part. It is a figure which shows the example of mounting to the injection system main body of the capillary inspection apparatus which concerns on a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capillary 2 Capillary mounting part 3 2nd pressure chamber 4 Differential pressure sensor 5 Electromagnetic valve 6 Pressure sensor 7 1st pressure chamber 8 Valve (for source pressure supply)
9 Piping 10 Regulator unit 11 Filter 12 Inner diameter calculation device 100 Capillary inspection device

Claims (6)

A first pressure chamber connected to a pipe used for gas supply;
A second pressure chamber connected via a valve to the first pressure chamber;
A regulator for adjusting the pressure of the gas supplied using the pipe;
The first pressure when the hollow needle connected to the second pressure chamber separated from the first pressure chamber by the valve closed after the pressure adjustment by the regulator leaks the gas in the second pressure chamber. A differential pressure sensor for measuring a pressure difference generated between the chamber and the second pressure chamber;
A hollow needle inspection comprising: an inner diameter calculating means for calculating a rising speed of a differential pressure from a pressure difference measured by the differential pressure sensor and calculating a tip inner diameter of the hollow needle from the calculated rising speed. apparatus.   The hollow needle inspection apparatus according to claim 1, wherein the regulator adjusts a gas pressure when the valve is closed to a range between a predetermined lower limit value and an upper limit value.   The hollow needle inspection apparatus according to claim 1 or 2, wherein the first pressure chamber and the second pressure chamber are cut out from the same member. Among the plurality of differential pressure increase speeds calculated by adjusting the atmospheric pressure by the regulator, closing the valve, calculating the differential pressure increase speed, and repeatedly opening the valve, the inner diameter calculating means determines the initial differential pressure increase speed. The hollow needle inspection apparatus according to claim 1, wherein the tip inner diameter of the hollow needle is calculated except for the above. A gas supply step of supplying a gas of a predetermined pressure to the second pressure chamber connected to the hollow needle and the first pressure chamber connected to the second pressure chamber via a valve by opening the valve; ,
  After the gas supply step, the first pressure chamber and the second pressure chamber are filled with a gas having a predetermined pressure and the valve is closed, and then the differential pressure between the first pressure chamber and the second pressure chamber is measured. A differential pressure increase rate calculating step for calculating the increase rate of the differential pressure;
  A tip inner diameter calculating step for calculating a tip inner diameter of the hollow needle based on the differential pressure increasing speed calculated by the differential pressure increasing speed calculating step;
  A hollow needle inspection method characterized by comprising: A microinjection system using a capillary,
  A first pressure chamber connected to a pipe used for gas supply;
  A second pressure chamber connected via a valve to the first pressure chamber;
  A regulator for adjusting the pressure of the gas supplied using the pipe;
  When the capillary connected to the second pressure chamber separated from the first pressure chamber by the valve closed after the pressure adjustment by the regulator leaks the gas in the second pressure chamber, the first pressure chamber A differential pressure sensor for measuring a pressure difference generated between the first pressure chamber and the second pressure chamber;
  An inner diameter calculating means for calculating an increase rate of the differential pressure from the pressure difference measured by the differential pressure sensor, and calculating an inner diameter of the tip of the capillary from the calculated increase rate;
  A microinjection system characterized by comprising:

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