Specimen tray fixer

Abstract

The utility model discloses a specimen tray fixer which is used for fixed slicing of brain tissue, the specimen tray fixer comprises a horizontal bottom plate and a baffle vertically arranged at the top of the bottom plate, one end of the bottom plate is provided with a clamping groove, the clamping groove is connected with the side wall of a bath of a vibration slicing machine in a clamping mode, and a specimen tray is arranged in the middle of the inside of the bath. The other end of the bottom plate extends to the top of the specimen tray and is supported by the specimen tray, the agarose block is placed on one side of the baffle in an attached mode, the abdominal side face of the brain tissue is placed on the side, away from the baffle, of the agarose block in an attached mode, and the cross section of the agarose block and the cross section of the brain tissue are fixed to the bottom plate in a limited mode through fixing needles; a blade of the vibration slicer is located on the back side face of the brain tissue and is perpendicular to the baffle. By the adoption of the fixing device, use of 502 glue can be avoided, the specimen fixing process is simplified, secondary fixing adjustment is facilitated, the stability and accuracy of a brain slice are improved, and the neuron survival state of the brain slice is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of biological experimental equipment, in particular to a specimen tray fixer. Background Art

[0002] With the rapid advancement of basic neuroscience research, patch-clamp electrophysiology remains one of the most critical techniques for recording the electrical activity of single neurons and ion channel function in isolated brain slices. The successful implementation of this technique relies on the preparation of good fresh brain slices. Currently, fresh animal brains are typically dried and attached upright to one side of an agarose block. The brain tissue and the agarose base are then secured to the specimen tray of a vibratome using 502 glue. Frozen sectioning fluid is then quickly added to an ice bath until the specimen is submerged, followed by vibratome sectioning. Finally, the slices are transferred to pre-oxygenated artificial cerebrospinal fluid for incubation.

[0003] Due to the particularity of fresh brain slice preparation, the main problems are: (1) brain tissue is extremely intolerant to hypoxic damage after removal, and needs to be fixed and sliced on the specimen tray in the shortest possible time until the brain slice is transferred to pre-oxygenated artificial cerebrospinal fluid for incubation; (2) the amount and timing of applying quick-drying glue are extremely difficult to control, especially when agarose is soaked in slicing fluid, it is difficult to form a firm connection with the specimen tray, causing the brain tissue to float with the agarose during slicing. After floating, there is no time to dry and fix it again, resulting in slicing failure; (3) quick-drying glue often forms glue floating objects when it comes into contact with frozen slicing fluid. These substances may have toxic effects on newly prepared brain slices; (4) even if the agarose is temporarily fixed manually with curved tweezers, it is extremely difficult to stably fix the position of the agarose and brain tissue. The movement of the specimen will cause the slices to be of different thicknesses, resulting in poor cell status during subsequent oxygenation and incubation, affecting subsequent electrophysiological recordings. (3) It usually takes more than 2 hours from vibrating slices, incubation to patch clamping cells to observe whether the cell state of the prepared brain slice is good. Therefore, failed specimen fixation is bound to waste a lot of experimental time and labor costs; and sometimes when preparing precious transgenic mouse brain tissue, the experimental cycle is affected even longer. Obviously, the current brain slice preparation process still needs to thoroughly solve the problems of specimen placement and fixation stability, accuracy, and slicing convenience. These not only increase the difficulty of the experiment, but also seriously affect the credibility and accuracy of subsequent electrophysiological experiments. Utility Model Content

[0004] 1. Technical problems to be solved:

[0005] In view of the above technical problems, the utility model provides a specimen tray holder.

[0006] 2. Technical solution:

[0007] A specimen tray holder is used for fixed slicing of brain tissue, comprising a horizontal base plate and a baffle arranged vertically on the top of the base plate; one end of the base plate is provided with a slot, which is engaged with the side wall of the bath of a vibrating microtome; a specimen tray is provided in the middle of the bath; the other end of the base plate extends to the top of the specimen tray and is supported by the specimen tray; an agarose block is placed against one side of the baffle, and the ventral side of the brain tissue is placed against the side of the agarose block away from the baffle; the agarose block and the cross-section of the brain tissue are fixed to the base plate by fixing pins; the blade of the vibrating microtome is located on the dorsal side of the brain tissue and remains perpendicular to the baffle.

[0008] Furthermore, a pressure plate is hinged on the top of the baffle, and the pressure plate can press on the top of the agarose block when it rotates toward the fixed needle.

[0009] Furthermore, the pressing plate includes an L-shaped connecting plate and a passivation pressing head, the passivation pressing head can be pressed on the top of the agarose block, the passivation pressing head is fixedly connected to one end of the L-shaped connecting plate, and the other end of the L-shaped connecting plate is hinged to the baffle through a hinge structure.

[0010] Preferably, the passivation indenter is cylindrical and has a certain counterweight.

[0011] Furthermore, when the brain tissue is placed on the bottom plate, the highest point of the top is not higher than the side wall height of the bathtub.

[0012] Furthermore, the area on the bottom plate where the agarose block and brain tissue are placed is located on the top of the specimen tray.

[0013] Preferably, the pressing plate is elastically hinged, and the elastic force acts on the pressing plate to provide a pre-tightening force for squeezing the agarose block.

[0014] 3.Beneficial effects:

[0015] (1) The use of 502 glue can be avoided; when the fixator of the utility model is used, the baffle is placed behind the agarose block, and the fixing needle is vertically inserted into the brain tissue and the agarose block, ensuring that the brain tissue and the agarose block will not move in the front-back direction during the process of cutting and retracting the knife. When the pressing plate is pressed on the agarose block, the fixing effect of the agarose block on the bottom plate is further strengthened;

[0016] (2) It can simplify the specimen fixation process and facilitate secondary fixation adjustment: When using the fixator of the utility model, there is no need to accurately seize the time window for drying glue, and it also avoids the situation where the specimen is not firmly adhered and floats after being fixed with glue. Even if the initial fixation position is not satisfactory, it is only necessary to slightly lift the brain tissue and agarose block, and due to the vertical fixation advantage of the fixation needle, it can be dropped to the ideal position again and fixed. The adjustment process will hardly prolong the slicing time;

[0017] (3) Improve the stability and accuracy of brain slices; because the specimen is stably fixed to the base during slicing, the vibrating microtome can cut brain slices according to the preset thickness;

[0018] (5) Improve the survival of neurons: Since the predetermined slice thickness can be guaranteed during slicing, and the slice thickness is uniform, it can ensure that neurons and oxygen are fully exchanged during the subsequent brain slice incubation, thereby ensuring the activity of neurons and improving the experimental fault tolerance rate. In addition, since the use of 502 glue is avoided, the potential toxic threat to the brain slice caused by the floating of residual glue after the addition of slicing liquid can also be avoided, which further ensures the survival of neurons. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a three-dimensional structural diagram of the specimen tray holder of the utility model;

[0020] Figure 2 This is a schematic diagram of the cross-sectional structure of the specimen tray holder of the utility model in use;

[0021] The accompanying drawings are marked as follows: 1-bath, 2-specimen tray, 3-bottom plate, 4-baffle, 5-pressing plate, 6-hinge structure, 7-fixing needle, 8-slot, 9-brain tissue, and agarose block 10. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings.

[0023] As attached Figure 1 To the attached Figure 2 As shown,

[0024] Example:

[0025] The specimen tray holder is used for fixed sectioning of brain tissue 9, and includes a horizontal base plate 3 and a baffle 4 vertically arranged on the top of the base plate 3. The base plate body is composed of a flat metal strip. One end of the base plate 3 is provided with a slot 8, which is engaged with the side wall of the bath 1 of the vibration microtome. A specimen tray 2 is provided in the middle of the bath 1. The other end of the base plate 3 extends to the top of the specimen tray 2 and is supported by the specimen tray 2. An agarose block 10 is placed against one side of the baffle 4, and the ventral side of the brain tissue 9 is placed against the side of the agarose block 10 away from the baffle 4. The agarose block 10 and the cross-section of the brain tissue 9 are fixed to the base plate 3 by fixing pins 7. The blade of the vibration microtome is located on the dorsal side of the brain tissue 9 and remains perpendicular to the baffle 4.

[0026] A pressure plate 5 is hinged on the top of the baffle 4. When the pressure plate 5 is rotated toward the fixing needle 7, it can press on the top of the agarose block 10. The pressure plate 5 itself has a certain weight to squeeze and fix the agarose block, or the pressure plate 5 is elastically hinged, and the elastic force acting on the pressure plate 5 provides a preload force for squeezing the agarose block 10.

[0027] The pressing plate 5 comprises an L-shaped connecting plate and a blunting press head. The blunting press head is capable of pressing against the top of the agarose block 10. The blunting press head is fixedly connected to one end of the L-shaped connecting plate, while the other end of the L-shaped connecting plate is hingedly connected to the baffle 4 via a hinge structure 6. The blunting press head has a smooth surface, which more evenly distributes pressure on the agarose block 10, preventing it from being crushed and securing the block. Preferably, the blunting press head is cylindrical and has a counterweight.

[0028] Preferably, when the brain tissue 9 is placed on the bottom plate 3 , the highest point of the top thereof is not higher than the side wall height of the bathtub 1 .

[0029] Preferably, the area on the bottom plate 3 where the agarose block 10 and the brain tissue 9 are placed is located on the top of the specimen tray 2 .

[0030] The structure of the bath 1 and specimen tray 2 of the present invention is similar to that of existing vibrating microtomes. When in use, first snap the specimen tray holder's slot 8 onto the side wall of the bath 1. At this point, the other end of the base plate 3 extends exactly to the top of the specimen tray 2. Adjust the base plate 3 to the middle of the specimen tray 2. Take the process of preparing mouse brain slices as an example:

[0031] Cut an agarose block 10 of appropriate size and set aside. After perfusing the mouse with frozen sectioning solution, complete brain removal. Immediately trim the brain tissue 9, dry the surface water, and immediately place it on the agarose block 10. Transfer the entire block to the bottom plate 3 above the specimen tray. Secure the agarose block 10 against one side of the baffle 4 using pins 7 and a pressure plate 5. Another pin 7 is used to position the brain tissue. If coronal sectioning is desired, position the brain tissue 9 with the coronal surface facing the bottom plate 3. Pour frozen sectioning solution into the bath 1 until the brain tissue is submerged for sectioning.

[0032] Once the above steps are completed, it can be ensured that during the vibrating sectioning process, when the blade vibration is transmitted to the brain tissue 9, the baffle 4 and agarose block 10 will prevent the brain tissue 9 from moving toward the agarose block 10. The agarose block 10 is fixed to a defined initial position by the fixing pins 7 and the pressing plate 5. After the brain tissue 9 is fixed by the fixing pins 7, it can be prevented from floating when the frozen sectioning solution is added, which requires re-fixing, thereby wasting a lot of experimental time and affecting the cell state of the prepared brain slice. The vibrating blade can move along the length of the baffle 4 during slicing. Since the slicing is performed on one side of the baffle 4, when the vibration is transmitted to the brain tissue 9, it will push the brain tissue toward the baffle 4. This displacement is limited by the agarose block 10, and the vibration is absorbed by the agarose block 10. The vibrating agarose block 10 is an elastic material with the same shock-absorbing effect as elastic materials such as rubber pads. It can ensure the slicing effect of brain tissue and is non-biotoxic and will not have a toxic effect on brain tissue.

[0033] Even if the initial fixation is poor during the operation, only a slight adjustment is needed to achieve the desired effect, with little impact on the entire experiment time. The entire process no longer relies on the fixation effect of 502 glue. After the sectioning is completed, only the brain tissue and agarose block on the bottom plate need to be cleaned to complete the sectioning process.

[0034] Although the present invention has been disclosed above in terms of preferred embodiments, they are not intended to limit the present invention. Anyone skilled in the art can make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined by the claims of this application.

Claims

1. Specimen tray holder, used for fixing slices of brain tissue, characterized in that: The specimen tray holder includes a horizontal base plate and a baffle vertically arranged on the top of the base plate. A slot is provided at one end of the base plate, which is engaged with the side wall of the bathtub of the vibration microtome. A specimen tray is provided in the middle of the bathtub. The other end of the base plate extends to the top of the specimen tray and is supported by the specimen tray. An agarose block is placed against one side of the baffle, and the ventral side of the brain tissue is placed against the side of the agarose block away from the baffle. The cross-section of the agarose block and the brain tissue is fixed to the base plate by fixing pins. The blade of the vibration microtome is located on the dorsal side of the brain tissue and remains perpendicular to the baffle.

2. The specimen tray holder according to claim 1, characterized in that: A pressing plate is hinged on the top of the baffle, and the pressing plate can press on the top of the agarose block when it rotates toward the fixed needle.

3. The specimen tray holder according to claim 2, characterized in that: The pressing plate includes an L-shaped connecting plate and a passivation pressing head. The passivation pressing head can be pressed on the top of the agarose block. The passivation pressing head is fixedly connected to one end of the L-shaped connecting plate, and the other end of the L-shaped connecting plate is hinged to the baffle through a hinge structure.

4. The specimen tray holder according to claim 3, characterized in that: The passivation indenter is cylindrical and has a certain counterweight.

5. The specimen tray holder according to claim 1, wherein: When the brain tissue is placed on the bottom plate, the highest point of the top of the brain tissue is no higher than the side wall height of the bathtub.

6. The specimen tray holder according to claim 1, characterized in that: The bottom plate houses the agarose block and the area for the brain tissue is located on top of the specimen tray.

7. The specimen tray holder according to claim 2, wherein: The pressing plate is elastically hinged, and the elastic force acts on the pressing plate to provide a pre-tightening force for squeezing the agarose block.

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