JP2011002254A - Fluorescence observation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform time-lapse fluorescence observation for a long time without missing quick motion of a cell, while reducing a damage inflicted on the cell.SOLUTION: This fluorescence observation device 1 includes a light source 2 for irradiating a living cell A with excitation light, an image acquisition part 3 for acquiring an image by photographing fluorescence generated from the living cell A as a result of irradiation of the excitation light emitted from the light source 2, a cell state detection part 4 for detecting a state of the living cell A, and a period switching means 5 for switching an irradiation period of the excitation light from the light source 2 and an image acquisition period by the image acquisition part 3 based on the state of the living cell A detected by the cell state detection part 4.

Description

  The present invention relates to a fluorescence observation apparatus.

Conventionally, in cell observation, a specific physiological phenomenon is detected, or a reaction to an external stimulus such as light or a drug is observed (for example, see Patent Documents 1 to 3). In these cases, in order to observe without missing the occurrence of a specific physiological phenomenon or reaction, it is necessary to continue observation for a long time before the occurrence of the physiological phenomenon or reaction.
And, there are magnitudes of speed and magnitudes of changes in cell responses and morphological changes. In addition, the physiological phenomenon of cells often proceeds three-dimensionally.

  In order to record these changes, for example, it is necessary to continue to observe the cells in a short imaging cycle if the movement is fast, and to observe the cells at a high resolution in order to capture the changes in detail. There is. In addition, in order to capture a three-dimensional reaction, it is necessary to repeatedly observe the cross-sectional image of the cell in the optical axis direction.

JP 2007-309776 A JP-A-2005-230202 JP 2005-128086 A

However, when such an observation method is adopted, although the fast movement can be taken without missing, there is a disadvantage that the cell must be irradiated with excitation light unnecessarily, and the cell is damaged. is there. In addition, when such an observation method is adopted, the change in the cell can be captured in high definition and three-dimensionally, but as described above, the cell must be irradiated with excitation light unnecessarily, resulting in damage to the cell. There is an inconvenience of giving.
The present invention has been made in view of the circumstances described above, and provides a fluorescence observation apparatus capable of performing time-lapse fluorescence observation over a long period of time without losing changes in cells while reducing damage to cells. The purpose is that.

In order to achieve the above object, the present invention provides the following means.
The present invention includes a light source that irradiates live cells with excitation light, and an image acquisition unit that acquires images by photographing fluorescence generated from live cells as a result of irradiation with excitation light emitted from the light sources; A cell state detection unit for detecting a state of a living cell, and a cycle for switching an irradiation period of excitation light by the light source and an image acquisition period by the image acquisition unit based on the state of the living cell detected by the cell state detection unit Provided is a fluorescence observation apparatus comprising switching means, resolution switching means for switching the resolution of an image to be acquired, or dimension switching means for switching a dimension to be observed.

  According to the present invention, when the excitation light emitted from the light source is irradiated to the living cell, the fluorescent substance existing in the living cell is excited to generate fluorescence, and the generated fluorescence is photographed by the image acquisition unit. Thus, a fluorescent image is acquired. In this case, the cell state detection unit detects the state of the living cell, and the cycle switching unit switches the excitation light irradiation cycle and the image acquisition cycle based on the state of the living cell, or the resolution switching unit Switching the acquisition resolution based on the state, or switching the number of dimensions based on the state of the cell by the dimension switching means, thereby acquiring a fluorescence image with an image acquisition period, resolution or number of dimensions according to the state of the living cell Can do.

Here, the state of a living cell is a cell cycle (G1, S, G2, M, and M phases) until a daughter cell generated by cell division becomes a mother cell again to undergo cell division and become a new daughter cell. ) And states of each process and molecular bonding.
Thus, for example, when it is desired to detect the S phase, G2 phase, and M phase of the cell cycle, the change in the state of the living cells up to that time progresses slowly, so imaging is performed with a relatively long image acquisition cycle. By switching the image acquisition cycle shortly when the S phase, the G2 phase, and the M phase are detected, it is possible to take a picture without missing the rapid change of the cells in the S phase, the G2 phase, and the M phase. Therefore, when the morphological change of cells proceeds slowly, it is not necessary to excessively irradiate the living cells with the excitation light from the light source, and damage to the living cells can be reduced.

In the above invention, the period switching unit may switch a frame rate by the image acquisition unit.
In this way, it is possible to switch the frame rate in accordance with the speed of change of the state of the living cell, to prevent unnecessary excitation light irradiation and to acquire a fluorescence image at a necessary frequency.

Moreover, in the said invention, the said image acquisition part is provided with multiple types of imaging part from which an image acquisition period differs, and the said period switching means is based on the state of the living cell detected by the said cell state detection part. You may switch the imaging part which comprises an acquisition part.
By doing in this way, an imaging part can be switched according to the speed of change of the state of a living cell, and irradiation of unnecessary excitation light can be prevented and a fluorescent image can be acquired at a necessary frequency.

The image acquisition unit may increase the resolution of an image to be acquired in order to capture cell changes with high definition when the cycle switching unit switches the image acquisition cycle to be shorter.
The image acquisition unit may increase the number of dimensions of an image to be acquired in order to capture a reaction in a three-dimensional space when the dimension switching unit is switched to shorten the image acquisition cycle.

  In this way, when the speed of change of the state of the living cell is increased and the image acquisition cycle is switched to be shortened, by increasing the resolution of the image to be acquired, a higher-definition image can be obtained. Can be acquired. Further, by increasing the number of dimensions of the acquired image, it is possible to capture the cell reaction in a three-dimensional space. Thereby, the important operation | movement of a living cell can be observed three-dimensionally clearly.

  According to the present invention, it is possible to perform time-lapse fluorescence observation over a long period of time without reducing changes in cells while reducing damage to cells.

It is a block diagram which shows the fluorescence observation apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the modification of the fluorescence observation apparatus of FIG. It is a block diagram which shows the other modification of the fluorescence observation apparatus of FIG.

A fluorescence observation apparatus according to an embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the fluorescence observation apparatus 1 according to this embodiment includes a light source 2 that generates excitation light, and a living cell A that is irradiated with excitation light emitted from the light source 2. Based on the state of the living cell A detected by the cell state detecting unit 4, the cell state detecting unit 4 that detects the state of the living cell A, the image acquisition unit 3 that captures fluorescence generated from the light source 2 and And a control unit 5 that controls the image acquisition unit 3.

The light source 2 outputs excitation light of a predetermined wavelength band with a predetermined intensity over a predetermined time according to a command signal from the control unit 5.
The image acquisition unit 3 irradiates the living cells A with the scanner 6 that two-dimensionally scans the excitation light emitted from the light source 2 and the excitation light scanned by the scanner 6, and the fluorescence generated in the living cells A Based on the objective lens 7 for condensing light, the photodetector 8 for detecting the fluorescence condensed by the objective lens 7, the scanning position by the scanner 6 and the intensity of the fluorescence detected by the photodetector 8. And an image generation unit 9 that generates a two-dimensional image of the cell A. In the figure, reference numeral 10 denotes a dichroic mirror that passes excitation light and reflects fluorescence, and reference numeral 11 denotes a storage unit that stores an image generated by the image generation unit 9.

The scanner 6 is operated over a time range in which excitation light from the light source 2 is output in response to a command signal from the control unit 5.
The cell state detection unit 4 is a color of a fluorescent probe (Fucci: Fluorescent, ubiquitination-based cell cycle indicator) that is administered to the living cell A from the image generated by the image generation unit 9 and visualizes the cell cycle progression. Is monitored to detect the differentiation process in the cell cycle (G1 phase, S phase, G2 phase, M phase).

  When the cell state detection unit 4 detects the G1 phase of the cell cycle, that is, when the color of the fluorescent probe administered to the living cell A is red, the control unit (cycle switching means) 5 A relatively long image acquisition cycle, for example, 30 minutes is commanded to the light source 2 and the image acquisition unit 3. In addition, when the cell state detection unit 4 detects the S phase, the G2 phase, and the M phase in the cell cycle, that is, the color of the fluorescent probe administered to the living cell A has changed from red to green. In some cases, the light source 2 and the image acquisition unit 3 are instructed to have a relatively short image acquisition cycle, for example, 30 seconds.

In addition, when the cell state detection unit 4 detects the S phase, the G2 phase, and the M phase in the cell cycle, the control unit 5 delays the operation of the scanner 6 to increase the fluorescence intensity in the same image acquisition range. The number to be acquired, that is, the resolution is controlled to increase.
In addition, when the cell state detection unit 4 detects the S phase, the G2 phase, and the M phase in the cell cycle, the control unit 5 performs a microscope stage or objective every time an XY plane image of the cell is acquired. The lens is moved in the direction of the optical axis, and a cross-sectional image of the cell is acquired, that is, control is performed to increase the number of dimensions.

The operation of the fluorescence observation apparatus 1 according to this embodiment configured as described above will be described below.
In order to perform time-lapse observation of living cells A over a long period of time using the fluorescence observation apparatus 1 according to this embodiment, excitation light is emitted from the light source 2 in a state in which a fluorescent probe such as Fucci is administered to the living cells A, A fluorescence image of the living cell A is acquired by the image acquisition unit 3.

  Excitation light emitted from the light source 2 is scanned by the scanner 6 and irradiated to the living cells A by the objective lens 7. Since a fluorescent substance is present in the living cell A in addition to the fluorescent probe, fluorescence is generated when the fluorescent substance is excited by excitation light. The generated fluorescence is collected by the objective lens 7 and detected by the photodetector 8. By storing the scanning position of the excitation light by the scanner 6 and the intensity of the fluorescence detected by the light detector 8 in association with each other, a two-dimensional image can be generated by the image generation unit 9.

  The image generated in the image generation unit 9 is sent to the cell state detection unit 4 where the color of the fluorescent probe is monitored. When the color of the fluorescent probe is red, the state of the living cell A is considered to be in the G1 phase of the cell cycle, and the operation of the living cell A is relatively slow in those processes. And in this state, since the control part 5 sets the image acquisition period by the image acquisition part 3 comparatively long, the irradiation frequency of the excitation light to the living cell A by the light source 2 and the scanner 6 is reduced, and excessive excitation light This prevents the living cells A from being excessively damaged. That is, it is possible to perform time-lapse observation over a long period while maintaining the living cells A in a healthy state.

  Further, when the color of the fluorescent probe detected by the cell state detection unit 4 changes from red to green, the state of the living cell A is considered to be in the S phase, G2 phase, and M phase of the cell cycle. In this process, the operation of the living cell A is relatively agile. And in this state, since the control part 5 sets the image acquisition period by the image acquisition part 3 comparatively short, many fluorescence images can be acquired. Thereby, it is possible to observe without missing agile movement such as cell division of the living cell A.

  Furthermore, in the present embodiment, as described above, when the state of the living cell A is considered to be in the S phase, G2 phase, or M phase of the cell cycle by the cell state detection unit 4, the control unit 5 The scanner 6 is controlled to increase the resolution of the fluorescent image acquired by the image acquisition unit 3. Thereby, a high-resolution fluorescent image can be acquired in the S period, the G2 period, and the M period where detailed observation is required.

  For example, if an image obtained with 512 × 512 pixels in the same field of view is switched to 1024 × 1024 pixels after detection of a change in the state of living cells A, the number of pixels is 4 because the fluorescence photometric time of one pixel is almost the same. When the magnification is doubled, the laser irradiation time is also quadrupled, but damage to the living cells A can be reduced as compared with the case where images are always acquired with 1024 × 1024 pixels.

  Furthermore, in the present embodiment, as described above, when the state of the living cell A is considered to be in the S phase, G2 phase, or M phase of the cell cycle by the cell state detection unit 4, the control unit 5 Increase the number of dimensions. Thereby, the change can be captured three-dimensionally in the S period, the G2 period, and the M period where detailed observation is required.

  For example, when an XY plane image is acquired at a specific Z-direction position, when switching to XYZ image acquisition in order to observe the state of a three-dimensional change of a specimen after detecting a change in the state of a living cell A, the same Since a plurality of images are acquired in the Z direction with respect to the region, the laser irradiation time is increased, but damage to the living cells A can be reduced as compared with the case where the XYZ images are continuously acquired.

As described above, according to the fluorescence observation apparatus 1 according to the present embodiment, the image acquisition cycle is adjusted according to the state of the living cell A based on the fluorescence image acquired by the image acquisition unit 3. Even without always waiting in front of the fluorescence observation apparatus 1, high-definition and three-dimensional observation can be performed without missing the phenomenon that occurs in the living cells A in the target S phase, G2 phase, and M phase. There is an advantage.
Moreover, according to the fluorescence observation apparatus 1 according to the present embodiment, an XY plane image is acquired with a long image acquisition cycle in the G1 phase of the cell cycle in which the operation of the living cell A is slow, and thus an image to be acquired The number of data can be reduced, and the amount of data in a less important period can be reduced.

  In the present embodiment, the case where the image acquisition unit 3 includes the single scanner 6 has been described. Instead, as illustrated in FIG. 6 ′ may be provided, and the scanners 6 and 6 ′ may be switched according to the state of the living cell A. In the figure, reference numerals 12 and 13 denote mirrors.

  Further, as shown in FIG. 3, by providing an imaging means such as a surface illumination light source 14 and a CCD 15 on an optical path different from that of the scanner, living cells in the S phase, G2 phase, and M phase, which move quickly, are provided. A may be switched so that an image is acquired instantaneously by the CCD 15. In the figure, reference numeral 16 denotes a dichroic mirror, and reference numeral 17 denotes a mirror.

  In addition, the cell cycle is detected by monitoring the color of the fluorescence generated from the fluorescent probe administered to the living cell A. Instead, the brightness of the living cell A and the shape of the living cell A in the fluorescence image are detected. The state of the living cell A may be detected by monitoring the dynamics of the living cell A, the wavelength of the fluorescence generated from the living cell A, or the speed of the living cell A.

  In addition, when the living cell A is in the S phase, the G2 phase, or the M phase, the period for acquiring the fluorescent image is changed or the resolution of the acquired fluorescent image is increased. The position and range of the fluorescent image may be switched.

  In the present embodiment, the cell cycle is detected and the image acquisition cycle is switched. Alternatively, the frame rate may be switched. That is, an image is acquired at a low frame rate during a period of low importance, and an image is acquired at a high frame rate like the video rate during a period of high importance.

Furthermore, instead of detecting the cell cycle and switching the image acquisition cycle, other events, for example, binding of molecules may be detected to switch the image acquisition cycle. Monitoring the concentration change of Ca ²⁺ induced by the binding of molecules to the living cell A to be observed, and acquiring an image at a high frame rate such as a video rate when the Ca ²⁺ concentration change occurs. You can do it. Thereby, there exists an advantage that the living cell A can be observed corresponding to different reaction rates, such as a movement of a molecule ^| numerator, and a Ca2 ⁺ density ^| concentration change.

In addition, the scan image is generated by detecting the fluorescence returning through the scanner 6, but instead, when the light source is composed of femtosecond pulse laser light, the scanner 6 and the objective lens 7 are used. Alternatively, the non-scanned image may be generated by detecting the fluorescence branched from between the two.
Further, as the imaging device, a CMOS may be employed instead of the CCD 15.

  In the present embodiment, the control unit 5 shortens the time interval for image acquisition, increases the resolution of the acquired image, and increases the number of dimensions of the acquired image. Only one or two of these may be performed.

A Live cell 1 Fluorescence observation apparatus 2 Light source 3 Image acquisition part 4 Cell state detection part 5 Control part (period switching means)
8 Photodetector (imaging part)
15 CCD (imaging part)

Claims (6)

A light source that irradiates live cells with excitation light;
As a result of irradiating the excitation light emitted from the light source, an image acquisition unit for capturing an image by capturing fluorescence generated from living cells;
A cell state detection unit for detecting a state of a living cell;
A fluorescence observation apparatus comprising: cycle switching means for switching an image acquisition cycle by the image acquisition unit based on a state of a living cell detected by the cell state detection unit. A light source that irradiates live cells with excitation light;
As a result of irradiating the excitation light emitted from the light source, an image acquisition unit for capturing an image by capturing fluorescence generated from living cells;
A cell state detection unit for detecting a state of a living cell;
A fluorescence observation apparatus comprising: a resolution switching unit that switches a resolution of an image acquired by the image acquisition unit based on a state of a living cell detected by the cell state detection unit. A light source that irradiates live cells with excitation light;
As a result of irradiating the excitation light emitted from the light source, an image acquisition unit for capturing an image by capturing fluorescence generated from living cells;
A cell state detection unit for detecting a state of a living cell;
A fluorescence observation apparatus comprising: a dimension number switching unit that switches a dimension number of an image acquired by the image acquisition unit based on a state of a living cell detected by the cell state detection unit.   The fluorescence observation apparatus according to claim 1, wherein the cycle switching unit switches a frame rate by the image acquisition unit. The image acquisition unit includes a plurality of types of imaging units having different image acquisition cycles,
The fluorescence observation apparatus according to claim 1, wherein the cycle switching unit switches an imaging unit configuring the image acquisition unit based on a state of a living cell detected by the cell state detection unit.   The said image acquisition part increases the resolution of the image to acquire, when it switches so that an image acquisition period may become short by the said period switching means. Fluorescence observation device.

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