Method for preparing karyotype

Abstract

The invention discloses a method for preparing a chromosome karyotype, which comprises the following steps: adopting a cell culture chamber glass slide, culturing antenatal villus and amniotic fluid cells on the chamber glass slide in situ, then carrying out cell hypotonic and chromosome fixing operations, dispersing chromosomes by using hot steam, uniformly dispersing chromosome suspension on the chamber glass slide, and preparing the chromosome karyotype. And a proper chromosome dispersion effect and a clear and complete karyotype are obtained. According to the method, the cell culture time is shortened, the loss of the cells is reduced to the greatest extent, the efficiency and accuracy of karyotype analysis are effectively improved, and the method has a very good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of genetics, and particularly relates to a method for culturing cells on an in-situ chamber slide and preparing chromosome karyotypes by thermal steam dispersion of chromosomes. Background Art

[0002] As the "gold standard" of prenatal diagnostic genetics, karyotype analysis is based on the preparation of all chromosomes of cells, and arranges them according to morphological characteristics such as chromosome length, size, and centromere position. The chromosomal aberrations in the metaphase of cell division are observed and analyzed through a microscope, including chromosomal number and structural variations. In addition to clarifying aneuploid changes, karyotype analysis can also directly detect chromosomal structural aberrations such as deletions, duplications, inversions, translocations, rings, and isochromosomes. With the implementation of the three-level prevention and control strategy for birth defects, the number of prenatal karyotype analyses is increasing day by day, and at the same time, new prenatal detection technologies are constantly evolving. How to meet clinical needs and improve the quality of slide preparation and analysis efficiency is extremely urgent. Of course, rich cell clones, a large number of metaphase figures, complete chromosome dispersion, moderate length, clear bands, and few overlaps are the requirements for high-quality slide preparation, so as to perform karyotype analysis under a microscope efficiently and accurately. Therefore, culturing chorionic and amniotic fluid cells and chromosome dispersion are both crucial for chromosome karyotype analysis.

[0003] Traditional culture flask methods and in-situ slide methods require a large amount of amniotic fluid samples, more amniotic fluid culture media, and karyotype preparation reagents. Among them, the culture flask method also requires a long culture time and uses trypsin digestion or scraping of cells, resulting in large cell loss and serious chromosome loss. In addition, the dispersion of chromosomes prepared by these two methods is too dependent on laboratory environmental factors, namely temperature and humidity. The slide method usually places the slide in a chromosome disperser, sets appropriate temperature and humidity, and takes it out until the slide is completely dry; while the culture flask method directly drops the cell suspension onto a dry or wet slide, places it in a chromosome disperser, and takes it out after the slide is completely dry. These methods are difficult to control the expansion and flow of surface liquid, resulting in uneven dispersion, and there are situations of excessive chromosome dispersion or insufficient dispersion, resulting in unclear karyotypes and affecting subsequent karyotype analysis. Summary of the Invention

[0004] The present invention aims to solve the technical problems of long cell culture time, large cell loss, poor chromosome dispersion, and unclear karyotypes in the current traditional prenatal chorionic and amniotic fluid cell culture and karyotype preparation. A method for preparing chromosome karyotypes is provided. This method cultures cells on an in-situ chamber slide and disperses chromosomes by thermal steam, not only shortening the cell culture time, saving the use of chorionic and amniotic fluid samples, culture media and other reagents, expanding the gestational age range of prenatal puncture, and avoiding cell loss, but also having a large number of cell division phases, good chromosome dispersion effect, and complete karyotype, which can significantly improve the efficiency and accuracy of karyotype analysis.

[0005] To solve the above technical problems, the present invention is implemented through the following technical solutions:

[0006] In one aspect of the present invention, a method for preparing a chromosome karyotype is provided, comprising the following steps:

[0007] Drop a suspension containing villus cells or amniotic fluid cells onto a chamber slide, place it in an incubator for culturing for several days. After multiple clone cell populations proliferate on the chamber slide, harvest the chamber slide with villus cells or amniotic fluid cells growing thereon;

[0008] Add colchicine to the chamber slide, place it in an incubator for 0.75 - 1.25 hours, discard the supernatant; add hypotonic solution to the chamber slide, let it stand for 25 - 40 minutes; add fixative to the chamber slide multiple times for pre - fixation and fixation respectively;

[0009] Place hot steam under the chamber slide, align the steam flow to the bottom of the chamber slide. After steam treatment, make the cell chromosome suspension on the front of the slide evenly disperse on the surface of the slide;

[0010] Transfer the chamber slide after steam treatment to a baking machine. After the chamber slide is dried, remove the movable chamber, place the slide in an oven, and bake at 70 - 80 °C for 2.5 - 3.5 hours;

[0011] Take out the slide, perform chromosome staining using the G - banding staining method, and obtain the chromosome karyotype of villus cells or amniotic fluid cells.

[0012] In another aspect of the present invention, a chromosome karyotype analysis slide is also provided. The preparation method of the slide comprises the following steps:

[0013] Drop a suspension containing villus cells or amniotic fluid cells onto a chamber slide, place it in an incubator for culturing for several days. After multiple clone cell populations proliferate on the chamber slide, harvest the chamber slide with villus cells or amniotic fluid cells growing thereon;

[0014] Add colchicine to the chamber slide, place it in an incubator for 0.75 - 1.25 hours, discard the supernatant; add hypotonic solution to the chamber slide, let it stand for 25 - 40 minutes; add fixative to the chamber slide multiple times for pre - fixation and fixation respectively;

[0015] Place hot steam under the chamber slide, align the steam flow to the bottom of the chamber slide. After steam treatment, make the cell chromosome suspension on the front of the slide evenly disperse on the surface of the slide;

[0016] Transfer the steam-treated chamber slide to a roasting machine. After the chamber slide is dried, remove the movable chamber, and place the slide in an oven. Bake the slide at 70-80 °C for 2.5-3.5 hours.

[0017] Take out the slide and perform chromosome staining using the G-banding staining method to obtain a slide for chromosome karyotype analysis.

[0018] Preferably, the preparation steps of the suspension containing villus cells include: transferring the isolated prenatal villus tissue into a centrifuge tube, adding trypsin, digesting in an incubator for 20-40 minutes, then adding collagenase to the centrifuge tube, digesting in an incubator for 20-40 minutes, adding amniotic fluid medium to the centrifuge tube to terminate digestion, centrifuging at room temperature to obtain a villus cell precipitate, and adding amniotic fluid medium to the cell precipitate and mixing well to obtain a suspension containing villus cells.

[0019] Preferably, the villus tissue is villi with a length of about 1 cm and more than 5 roots obtained by an 18G biopsy puncture needle.

[0020] In an embodiment of the present invention, the preparation steps of the suspension containing villus cells include: transferring the isolated prenatal villus tissue into a centrifuge tube, adding 2 ml of trypsin with a concentration of 0.05%, digesting in an incubator (37 °C, 5% CO2) for 30 minutes, then adding 2 ml of collagenase with a concentration of 1 mg / ml to the centrifuge tube, digesting in an incubator for 30 minutes, adding 4 ml of amniotic fluid medium to the centrifuge tube to terminate digestion, centrifuging at room temperature to obtain a villus cell precipitate, and adding 1 ml of amniotic fluid medium to the cell precipitate and mixing well to obtain a suspension containing villus cells.

[0021] Preferably, the preparation steps of the suspension containing amniotic fluid cells include: centrifuging the aseptically collected amniotic fluid cells at room temperature to obtain an amniotic fluid cell precipitate, and adding amniotic fluid medium to the cell precipitate and mixing well to obtain a suspension containing amniotic fluid cells.

[0022] Preferably, the concentration of colchicine is 10 μg / ml, the hypotonic solution is sodium citrate with a concentration of 0.7%, and the fixing solution is a methanol-glacial acetic acid solution with a volume ratio of 3:1.

[0023] In one embodiment of the present invention, 27 - 30 μl of colchicine with a concentration of 10 μg / ml was added to the cells cultured on the in-situ chamber slide, shaken well, placed in an incubator for 1 hour, and the supernatant was discarded; 2 ml of pre-warmed 0.7% sodium citrate hypotonic solution at 37°C was slowly added to the chamber slide, and left standing at room temperature for 30 - 35 min; 1 ml of freshly prepared fixative (methanol - glacial acetic acid solution with a volume ratio of 3:1) was added to the chamber slide for pre-fixation, and the supernatant was discarded after 5 min at room temperature; 2 ml of freshly prepared fixative (methanol - glacial acetic acid solution with a volume ratio of 3:1) was added to the cell chamber slide for fixation, and the supernatant was discarded after leaving standing at room temperature for 10 min; the previous step of the fixation procedure was repeated.

[0024] Preferably, the steam is water vapor.

[0025] Preferably, the G-banding staining includes the following steps: placing the slide in trypsin digestion solution for 8 - 10 seconds, then in calf serum termination digestion solution for 9 - 12 seconds, and then treating with Giemsa staining solution for 2 - 3 minutes.

[0026] The trypsin digestion solution in the G-banding staining step is 2.5% trypsin and Earle's balanced salt solution with a volume ratio of 1:50, the termination digestion solution is calf serum and phosphate buffer solution with a pH of 6.8 with a volume ratio of 3:50, and the Giemsa staining solution is Giemsa stock solution and phosphate buffer solution with a pH of 6.8 with a volume ratio of 1:2.

[0027] In another aspect of the present invention, there is also provided the use of the above-mentioned chromosome karyotype analysis slide in the preparation of prenatal chromosome genetic diagnosis products.

[0028] In another aspect of the present invention, there is also provided the use of the chamber slide in the preparation of prenatal chromosome genetic diagnosis products.

[0029] The method for preparing chromosome karyotype in the present invention, for prenatal chorionic villi and amniotic fluid cells, prepares chromosome karyotype by culturing cells on an in-situ chamber slide and dispersing chromosomes with hot steam, and has the following beneficial effects:

[0030] (1) The present invention requires less prenatal chorionic villus tissue and amniotic fluid, has a high success rate of cell culture, reduces the loss during the cell harvesting process, is also applicable to the preparation of amniotic fluid samples with small gestational weeks (13 weeks) and large gestational weeks (32 weeks), does not affect the prenatal diagnosis procedure, effectively improves the timeliness of prenatal diagnosis, and minimizes the harm to pregnant women.

[0031] (2) The present invention reduces the use of amniotic fluid culture medium and chromosome preparation reagents, and reduces costs.

[0032] (3) The present invention uses the chamber slide as an in situ culture tool, simplifying the experimental process and steps.

[0033] (4) The present invention is not affected by the ambient temperature and humidity. The hot steam evenly disperses the chromosome suspension on the chamber slide, resulting in rich cell clones, many metaphase division phases, good chromosome dispersion and integrity, a small number of chromosome overlaps, and a clear karyotype, which effectively improves the effect of subsequent karyotype analysis.

[0034] (5) The chromosome karyotype preparation method of the present invention has good stability and simplified operation. After preparation, the slides are equipped with a Beian fully automatic scanning platform to realize the automation of prenatal karyotype analysis, which greatly improves the work efficiency of the laboratory. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic diagram of the cell culture chamber slide in Example 1 of the present invention;

[0036] Figure 2 This is a graph of amniotic fluid cell growth on a chamber slide after banding staining in Example 1 of the present invention;

[0037] Figure 3 This is a graph of villous cell growth on a chamber slide after band staining in Example 1 of the present invention. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments (unless otherwise specified, the reagents of the present invention are purchased from Wuxi Nice Life Science Co., Ltd.; the amniotic fluid culture medium is AmnioMAX from GIBCO). TM C-100 Basal Medium).

[0039] The present invention provides a chromosome karyotype analysis slide prepared by culturing cells on an in situ chamber slide and dispersing chromosomes with hot steam. The slide has a clear and complete karyotype and can significantly improve the efficiency and accuracy of karyotype analysis. The preparation method comprises the following steps:

[0040] Dropping a suspension containing chorionic villus cells or amniotic fluid cells onto a chamber slide, culturing the suspension in an incubator for several days, and harvesting the chamber slide containing the chorionic villus cells or amniotic fluid cells after multiple clone cell groups proliferate on the chamber slide;

[0041] Adding colchicine to the chamber slide, placing it in an incubator for 0.75-1.25 hours, and discarding the supernatant; adding hypotonic solution to the chamber slide, and letting it stand for 25-40 minutes; adding fixative to the chamber slide multiple times for pre-fixation and fixation respectively;

[0042] Place hot steam below the chamber slide, align the steam flow with the bottom of the chamber slide, and through steam treatment, evenly disperse the cell chromosome suspension on the front of the slide on the surface of the slide.

[0043] Transfer the chamber slide after steam treatment to a roasting machine. After the chamber slide is dried, remove the movable chamber, and then place the slide in an oven and roast at 70 - 80 °C for 2.5 - 3.5 hours.

[0044] Take out the slide and perform chromosome staining using the G-banding staining method to obtain a slide for chromosome karyotype analysis.

[0045] Example 1

[0046] A method for preparing chromosomes of prenatal chorionic villi and amniotic fluid cells, comprising the following steps:

[0047] (1) Cultivate cells on an in-situ chamber slide

[0048] ① Obtain cell precipitate of prenatal sample: Place the aseptically collected chorionic villi tissue under a dissecting microscope, rinse with physiological saline to remove blood clots, transfer the separated chorionic villi tissue to a 15 ml centrifuge tube, add 2 ml of trypsin (0.05%), digest in an incubator (37 °C, 5% CO2) for 30 min, then add 2 ml of collagenase (1 mg / ml) to the centrifuge tube and digest in the incubator for 30 min, and then add 4 ml of amniotic fluid medium to the centrifuge tube to terminate digestion, and centrifuge at 1500 rpm at room temperature for 8 min to obtain chorionic villi cell precipitate; In each amniotic fluid sample, aseptically collect 10 - 12 ml of amniotic fluid cell specimen, and centrifuge at 1500 rpm at room temperature for 8 min to obtain amniotic fluid cell precipitate.

[0049] ② Inoculation: Discard the supernatant, add 1 ml of amniotic fluid medium to the cell precipitate and mix well, take 0.5 ml of the suspension and drop it onto the chamber slide ( Figure 1 ), slowly shake, spread evenly, and place in an incubator for cultivation (37 °C, 5% CO2). Prepare two chamber slides for each sample for double-line cultivation; Add 2 - 3 ml of fresh amniotic fluid medium to the culture dish every other day and place it back in the incubator for cultivation.

[0050] ③ Medium change: When the cells are cultured for 5 - 6 days, discard the medium, add 3 ml of fresh amniotic fluid medium to each culture dish, observe the cell growth progress under an inverted microscope on the fourth day, and when 4 - 5 clone cell groups proliferate, the clone cell groups are large in area and there are more translucent cells, the chamber slides of chorionic villi and amniotic fluid cells can be harvested.

[0051] (2) Harvesting and slide preparation: Add colchicine (10 μg / ml, 27 - 30 μl) to the in-situ culture chamber slide, shake well, place it in a 5% CO2, 37°C incubator for 0.75 - 1.25 h, and discard the supernatant;

[0052] (3) Hypotonic treatment: Slowly add 2 ml of pre-warmed (37°C) hypotonic solution (0.7% sodium citrate) to the chamber slide, and let it stand at room temperature for 25 - 40 min;

[0053] (4) Pre-fixation: Add 1 ml of freshly prepared fixative (methanol - glacial acetic acid solution with a volume ratio of 3:1) to the chamber slide, discard the supernatant after 5 min at room temperature;

[0054] (5) Fixation: Add another 2 ml of freshly prepared fixative to the chamber slide, let it stand at room temperature for 10 min, and discard the supernatant;

[0055] (6) Repeat step (5);

[0056] (7) Heat steam dispersion of chromosomes: Lay a stainless steel baking net flat on the mouth of the beaker. When the water in the beaker is heated to boiling, place the chamber slide in the center of the baking net, and direct the hot steam flow from the boiling water in the beaker towards the bottom of the chamber slide. The hot steam slowly diffuses the liquid particles on the surface of the chamber slide, and connections are formed between the liquid particles, creating a strong and uniform liquid expansion and flow on the surface, which suspends the cell chromosome suspension evenly, and further enables the cell chromosomes to be evenly dispersed on the surface of the slide; After 10 - 12 s of steam treatment, move the chamber slide to the slide dryer to evenly disperse and dry the cell chromosome suspension on the front of the slide;

[0057] (8) Slide baking: After the chamber slide is dry, remove the movable chamber, and then place the slide in an oven at 70 - 80°C for baking for 2.5 h - 3.5 h;

[0058] (9) G-banding staining: After taking out the slide, perform chromosome staining using the G-banding staining method. Treat it with room temperature trypsin digestion solution for 8 - 10 s, treat it in calf serum termination digestion solution for 10 s, and treat it with Giemsa stain solution for 2 min 20 s. The trypsin digestion solution is 2.5% trypsin and Earle's balanced salt solution with a volume ratio of 1:50, the termination digestion solution is calf serum and phosphate buffer solution with a pH of 6.8 with a volume ratio of 3:50, and the Giemsa stain solution is Giemsa stock solution and phosphate buffer solution with a pH of 6.8 with a volume ratio of 1:2;

[0059] (10) Scanning karyotype: Take pictures of the slides of villus and amniotic fluid cells using a microscope, and collect the chromosome karyotype with the BeiAng full-automatic chromosome microscopic image scanning system.

[0060] The slide after completing the banding staining is as Figure 2and Figure 3 as shown Figure 2 is the growth diagram of amniotic fluid cells on a slide after banding staining Figure 3 is the growth diagram of chorionic villus cells on a chamber slide after banding staining, and by Figure 2 , 3 It can be seen that there are multiple fixed cells on the slide, and the preparation effect is good, indicating the success of culturing cells on the in-situ chamber slide of the present invention; putting this slide into the BeiAng full-automatic chromosome microscopic image scanning system for image collection and analysis, the results show that there are many metaphase figures, the chromosomes are well dispersed, the karyotype is complete, the banding is clear, and the analysis reliability is high, indicating that in the present invention, hot steam is used to disperse chromosomes, making the prepared chromosome karyotype complete and clear, and making karyotype analysis more accurate and efficient. In Figure 2 , a: the cloning growth situation of amniotic fluid cells on the slide; b: a large number of metaphase figures of amniotic fluid cells under a high-power microscope (100-fold magnification); c: a metaphase figure with appropriate dispersion. In Figure 3 , a: the cloning growth situation of chorionic villus cells on the slide; b: the metaphase figures of chorionic villus cells under a high-power microscope (100-fold magnification); c: a metaphase figure with appropriate dispersion.

[0061] As can be seen from the above embodiments, the method for preparing chromosome karyotype in the present invention prepares chromosome karyotype by culturing cells on an in-situ chamber slide for prenatal chorionic villi and amniotic fluid cells and dispersing chromosomes with hot steam, and has achieved very good results. The present invention can (1) reduce the amount of chorionic tissue and amniotic fluid used for culture, with a high success rate of cell culture, and is also applicable to the preparation of amniotic fluid samples in the early pregnancy (13 weeks) and late pregnancy (32 weeks), without affecting the prenatal diagnosis procedure, effectively improving the timeliness of prenatal diagnosis and minimizing the harm to pregnant women; (2) reduce the usage amount of amniotic fluid culture medium and chromosome preparation reagents, reducing costs; (3) use the chamber slide as an in-situ culture tool, simplifying the experimental process and steps; (4) not affected by environmental temperature and humidity, the hot steam makes the chromosome suspension evenly dispersed on the chamber slide, obtaining rich cell clones, many metaphase figures, good integrity of chromosome dispersion, few overlapping chromosomes, clear karyotype, and effectively improving the effect of subsequent karyotype analysis. (5) The karyotype preparation method has good stability, simplifies the operation, and after preparation, the slide can be automatically adjusted for focus and automatically scanned and captured through the currently equipped BeiAng full-automatic chromosome microscopic image scanning system according to the slide thickness, realizing the automation of prenatal karyotype analysis and greatly improving the working efficiency of the laboratory.

[0062] The embodiments described above merely represent the implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. A method for preparing a chromosome karyotype, characterized in that, It includes the following steps: Drop the suspension containing villus cells or amniotic fluid cells onto a chamber slide, place it in an incubator for culturing for several days. After multiple clone cell populations proliferate on the chamber slide, harvest the slide with villus cells or amniotic fluid cells grown on it. Add colchicine to the chamber slide, place it in the incubator for 0.75 - 1.25 hours, discard the supernatant. Add hypotonic solution to the chamber slide, let it stand for 25 - 40 minutes. Add fixative multiple times to the chamber slide for pre - fixation and fixation respectively. Place hot steam under the chamber slide, align the steam flow to the bottom of the chamber slide. After steam treatment, make the cell chromosome suspension on the front of the slide evenly disperse on the surface of the slide. Transfer the steam - treated chamber slide to a baking machine. After the chamber slide is dried, remove the movable chamber, place the slide in an oven, and bake at 70 - 80 °C for 2.5 - 3.5 hours. Take out the slide, perform chromosome staining using the G - banding staining method, and obtain the chromosome karyotype of villus cells or amniotic fluid cells.

2. A chromosome karyotype analysis slide, characterized in that, The preparation method of the slide includes the following steps: Drop the suspension containing villus cells or amniotic fluid cells onto a chamber slide, place it in an incubator for culturing for several days. After multiple clone cell populations proliferate on the chamber slide, harvest the chamber slide with villus cells or amniotic fluid cells grown on it. Add colchicine to the chamber slide, place it in the incubator for 0.75 - 1.25 hours, discard the supernatant. Add hypotonic solution to the chamber slide, let it stand for 25 - 40 minutes. Add fixative multiple times to the chamber slide for pre - fixation and fixation respectively. Place hot steam under the chamber slide, align the steam flow to the bottom of the chamber slide. After steam treatment, make the cell chromosome suspension on the front of the slide evenly disperse on the surface of the slide. Transfer the steam - treated chamber slide to a baking machine. After the chamber slide is dried, remove the movable chamber, place the slide in an oven, and bake at 70 - 80 °C for 2.5 - 3.5 hours. Take out the slide, perform chromosome staining using the G - banding staining method, and obtain the slide for chromosome karyotype analysis.

3. The karyotype analysis slide according to claim 2, wherein The preparation steps of the suspension containing villus cells include: Transfer the isolated prenatal villus tissue into a centrifuge tube, add trypsin, digest in an incubator for 20 - 40 minutes. Then add collagenase to the centrifuge tube, digest in an incubator for 20 - 40 minutes. Then add amniotic fluid medium to the centrifuge tube to terminate digestion, centrifuge at room temperature to obtain villus cell precipitate, and add amniotic fluid medium to the cell precipitate and mix well to obtain the suspension containing villus cells.

4. The karyotype analysis slide according to claim 3, characterized in that, The concentration of the trypsin is 0.05%, and the concentration of the collagenase is 1 mg / ml.

5. The karyotype analysis slide according to claim 2, wherein, The preparation steps of the suspension containing amniotic fluid cells include: Centrifuge the aseptically collected amniotic fluid cells at room temperature to obtain amniotic fluid cell precipitate, and add amniotic fluid medium to the cell precipitate and mix well to obtain the suspension containing amniotic fluid cells.

6. The chromosomal karyotype analysis slide according to claim 2, wherein The concentration of the colchicine is 10 μg / ml, the hypotonic solution is sodium citrate with a concentration of 0.7%, and the fixative is a methanol - glacial acetic acid solution with a volume ratio of 3:

1.

7. The karyotype analysis slide according to claim 2, wherein The G-banding staining includes the following steps: placing the slide in trypsin digestion solution for 8 - 10 seconds, then in calf serum termination digestion solution for 9 - 12 seconds, and then treating with Giemsa staining solution for 2 - 3 minutes.

8. The karyotype analysis slide according to claim 7, wherein, The trypsin digestion solution is 2.5% trypsin and Earle's balanced salt solution with a volume ratio of 1:50, the termination digestion solution is calf serum and phosphate buffer solution with a pH of 6.8 with a volume ratio of 3:50, and the Giemsa staining solution is Giemsa stock solution and phosphate buffer solution with a pH of 6.8 with a volume ratio of 1:

2.

9. Application of the chromosome karyotype analysis slide according to any one of claims 2 - 8 in the preparation of a prenatal chromosome genetic diagnosis product.

10. Application of the chamber slide in the preparation of a prenatal chromosome genetic diagnosis product.

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