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Bioparticle observation apparatus and bioparticle observation method

Foreign code F200010110
File No. 6211
Posted date May 18, 2020
Country United States of America
Application number 201916436338
Gazette No. 20190376947
Date of filing Jun 10, 2019
Gazette Date Dec 12, 2019
Priority data
  • P2018-111342 (Jun 11, 2018) JP
Title Bioparticle observation apparatus and bioparticle observation method
Abstract A bioparticle observation apparatus includes a dielectrophoresis electrode that outputs a first signal causing a dielectrophoresis force to act on a bioparticle, a sensor electrode that detects an impedance difference between the bioparticle and the liquid, and a control circuit that controls the first signal so that the detected impedance difference is fixed.
Outline of related art and contending technology BACKGROUND
1. Field
The present disclosure relates to a bioparticle observation apparatus and a bioparticle observation method that are used to observe fine bioparticles in liquid.
2. Description of the Related Art
In accordance with an existence form in cell culture, cells, which are one kind of bioparticle, are roughly classified into one kind called adherent cells, which adhere to a culture container and grow, and another kind called suspended cells, which grow in a state of being suspended in a medium.
When observing a suspended cell such as a hematopoietic cell by using a microscope to trace a growth pattern, an observation target is to be fixed at a predetermined position. For observing the suspended cell under the microscope, a method of setting aside the suspended cell, which is in a medium, in a dish or the like for observation is considered, but when culture and observation using the microscope are performed for a long time, a suspended state is not maintained and the cells are thus greatly damaged.
On the other hand, as a proposal for fixing the suspended cells, as illustrated in FIG. 7, a method of forming a fixing agent 201, such as a protein or a polymer, that has excellent compatibility with a surface of a cell 200 in solution 203 and thereby fixing the cell surface to a dish 202 or the like is known. Since a cell wall of the cell 200 is not directly bonded to a bottom surface of the dish 202 or the like, a suspended state is maintained, even after culture and observation are performed for a long time. The observation is performed through a lid 204 such as a cover glass. According to the aforementioned configuration, less damage to the cell is expected. For example, Japanese Unexamined Patent Application Publication No. 2005-80579 (published on Mar. 31, 2005) proposes a method in which the fixing agent 201 has a phosphorylcholine-like group and a hydrazide group. With the method, a protein that fixes the suspended cell to the dish or the like is modified in advance and is bonded and mixed with the surface of the suspended cell for fixation. This makes it possible to fix the surface of the cell 200 to the dish 202 or the like.
However, with the method of fixing the suspended cell according to the related art disclosed in Japanese Unexamined Patent Application Publication No. 2005-80579 described above, it is difficult to selectively fix a type of cell among a plurality of types of cell by using protein to be modified or to fix only a single cell, which poses a problem of fixing a plurality of cells at the same time in many cases. The method of fixing the suspended cell according to the related art also has problems in which it is difficult to observe behavior of a single cell under the microscope and in which there is a concern about damage to the cells because a plurality of cells are intensively fixed.
An aspect of the disclosure is made in view of the problems of the related art described above and provides a bioparticle observation apparatus and the like that are able to reduce damage to bioparticles and facilitate observation of a single bioparticle.
Scope of claims [claim1]
1. A bioparticle observation apparatus usable for observation of a bioparticle in liquid, the bioparticle observation apparatus comprising:
a dielectrophoresis electrode that outputs a first signal causing a dielectrophoresis force to act on the bioparticle;
a sensor electrode that detects an impedance difference between the bioparticle and the liquid; and
a control circuit that controls the first signal so that the detected impedance difference is fixed.

[claim2]
2. The bioparticle observation apparatus according to claim 1, wherein
the control circuit controls an amplitude or a frequency of the first signal.

[claim3]
3. The bioparticle observation apparatus according to claim 1, wherein
the dielectrophoresis electrode has a circular shape or a polygonal shape to surround a periphery of the sensor electrode with the sensor electrode located at a center and outputs a signal, which provides a negative dielectrophoresis force, as the first signal to the bioparticle.

[claim4]
4. The bioparticle observation apparatus according to claim 1, wherein
the dielectrophoresis electrode includes a plurality of electrodes arranged to surround a periphery of the sensor electrode with the sensor electrode located at a center and outputs a signal, which provides a negative dielectrophoresis force, as the first signal to the bioparticle.

[claim5]
5. The bioparticle observation apparatus according to claim 1, wherein
the sensor electrode is a single electrode or a differential electrode.

[claim6]
6. The bioparticle observation apparatus according to claim 1, wherein
the sensor electrode is connected to a switch and is able to switch, through the switch, between a function of detecting the impedance difference and a function of outputting a signal, which provides a positive dielectrophoresis force, to the bioparticle.

[claim7]
7. The bioparticle observation apparatus according to claim 1, wherein
a second signal that provides a positive dielectrophoresis force is output from the sensor electrode.

[claim8]
8. The bioparticle observation apparatus according to claim 1, further comprising
a microscope that enables observation from outside of a state where the bioparticle stays at a predetermined position.

[claim9]
9. The bioparticle observation apparatus according to claim 1, further comprising
a microfluidic channel in which the bioparticle flows.

[claim10]
10. A bioparticle observation method, comprising:
causing a bioparticle to stay at a predetermined position in liquid by using the bioparticle observation apparatus according to claim 1, and
observing a state where the bioparticle stays at the predetermined position from outside by using a microscope.
  • Inventor, and Inventor/Applicant
  • MITSUNAKA TAKESHI
  • OGAWA YUICHI
  • KYOTO UNIVERSITY
  • SHARP CORPORATION
IPC(International Patent Classification)
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