A culture dish is a glass or plastic round vessel used to hold liquid culture medium or solid agar culture medium for cell culture. The culture dish consists of a bottom and a cover. It is a chemical device used to culture bacteria. The main material is glass or plastic.
The texture of the culture dish is fragile and easy to break, so you should be careful and handle it with care when cleaning and handling. It is best to clean the culture dish in time after use and store it in a safe and fixed place to prevent damage and breakage.
Classification of culture dishes
According to the different uses of culture dishes, they can be divided into cell culture dishes and bacterial culture dishes;
According to the different manufacturing materials, they can be divided into plastic culture dishes and glass culture dishes, but imported culture dishes and disposable culture dishes are mostly plastic materials.
According to the different sizes, they can usually be divided into culture dishes with diameters of 35mm, 60mm, 90mm, and 150mm;
According to the different partitions, they can be divided into 2-partition culture dishes, 3-partition culture dishes, etc.;
The materials of culture dishes are basically divided into two categories, mainly plastic and glass. Glass can be used for plant materials,
microorganism culture and animal cell attachment. The plastic ones may be made of polyethylene, which can be disposable or reusable. They are suitable for laboratory inoculation, streaking, and bacterial isolation operations, and can be used for the cultivation of plant materials.
The difference between a culture dish and an evaporating dish
The culture dish consists of a bottom and a cover, and is generally used for culture experiments. It is usually made of glass or plastic. The upper cover has the function of heat preservation and moisture retention. The evaporating dish has no cover and is a vessel used to evaporate concentrated solutions or burn solids. It has a large mouth and a shallow bottom, and there are two types: round bottom and flat bottom with handles. The most commonly used evaporating dish is a porcelain evaporating dish, and there are also ones made of glass, quartz, platinum, etc. Different materials have different corrosion resistance, and should be appropriately selected according to the properties of the solution and solid.
Uses of culture dishes
Suitable for quarantine stations, hospitals, biological products, food industry, pharmaceutical industry and other units, for bacterial isolation and culture, antibiotic potency testing and qualitative testing and analysis. In scientific research such as agriculture and aquatic products, it is used for artificial cultivation and hatching research on seed germination, plants, insects, and fish species. It is used as a vessel in the electronics industry or other industries.
Guide to using petri dishes
Petri dishes are usually made of solid culture media for flat culture (the origin of the name of flat dishes). To make a flat culture medium, the sterilized agar culture medium that has been installed is dissolved in warm water (sterile), the cotton plug of the test tube is removed, the tube mouth is passed over the flame of the alcohol lamp, and then the sterilized petri dish cover is slightly opened so that the mouth of the test tube can go deep. After pouring in the culture medium, it can be covered tightly, and then the poured culture medium is gently shaken to make it evenly distributed on the bottom of the dish and condensed, and the flat culture medium is obtained.
Since the reproduction, development and growth of bacteria are directly related to the culture medium (nutrients) provided, especially for quantitative testing and analysis, the amount of nutrients provided is decisive. When culturing bacteria, the amount of nutrients provided, whether it is uniform, and whether the bottom of the petri dish is flat are extremely important. If the bottom of the petri dish is uneven, the distribution of the agar culture medium will be thick or thin depending on whether the bottom of the petri dish is flat, and the thin part will have insufficient nutrition supply, which is closely related to quantitative analysis. However, if general qualitative analysis (testing bacteria, colony growth, reproduction, etc.) is performed, ordinary petri dishes can be used.
Bacteria isolation and culture, usually several kinds of bacteria are mixed in the specimen at the same time, such as oral and pharyngeal bacteria and ear secretions, sputum, urine, feces, etc. All bacteria that need to be studied must first be cultured by separation and culture to make them pure. Through pure culture of bacteria, use gravy plus 2% agar solid culture medium, filter through a heat preservation funnel with degreased cotton, and inject into a test tube. After two days, check that there are no new bacteria, and then put it into the culture dish. First make a flat plate and inoculate under sterile conditions. After inoculation, turn the culture dish upside down and move it into a constant temperature box at 25-35℃ (inversion is to avoid water vapor condensing into liquid droplets and falling into the bottom of the dish, affecting the growth of the colony). Through cultivation, further observe the morphology and color of bacteria, study pathogenic bacteria, and the effect of chemical prevention and control.
Precautions for the use of culture dishes
1. Clean and disinfect before use. Whether the culture dish is clean or not has a great impact on the work, which can affect the pH value of the culture medium. If certain chemicals are present, it will inhibit bacterial growth.
2. Newly purchased culture dishes should be rinsed with hot water first, then soaked in a hydrochloric acid solution with a mass fraction of 1% or 2% for several hours to remove free alkaline substances, and then rinsed with distilled water twice.
3. If you want to culture bacteria, sterilize with high-pressure steam (generally 6.8*105Pa high-pressure steam) at 120℃ for 30min, and dry at room temperature; or use dry heat sterilization, that is, place the culture dish in an oven and maintain the temperature at around 120℃ for 2h to kill the bacterial cells.
4. Only sterilized culture dishes can be used for inoculation and culture;
5. Why do you turn the culture dish upside down when culturing on a plate:
Reason: During the culture, more water vapor will be generated in the culture dish, and the water vapor will condense on the cover to produce water droplets. If the culture dish is placed upright, the water droplets will disperse the colony. In this case, a large colony may be dispersed into many small colonies, which will cause great trouble for the cultivation and counting of bacteria. If it is inverted, the culture medium is on top and the cover is on the bottom, and water drops will not drip onto the colonies.
Cleaning of culture dishes
1 Soaking
New or used glassware should be soaked in clean water first to soften and dissolve the attachments. Before using new glassware, it should be simply brushed with tap water and then soaked in 5% hydrochloric acid overnight; used glassware often has a lot of protein and grease attached, which is not easy to brush off after drying, so it should be immediately immersed in clean water for brushing after use.
2 Brushing
Put the soaked glassware in detergent water and brush it repeatedly with a soft brush. Do not leave dead corners and prevent damage to the surface finish of the vessel. Wash and dry the cleaned glassware for acid dipping.
3 Acid dipping
Acid dipping is to soak the above-mentioned vessels in cleaning liquid, also known as acid solution, and remove possible residual substances on the surface of the vessel through the strong oxidizing effect of the acid solution. Acid dipping should not be less than six hours, usually overnight or longer. Be careful when placing and removing vessels.
4 Rinsing
The vessels after brushing and acid dipping must be fully rinsed with water. Whether the vessels are rinsed clean after acid dipping directly affects the success or failure of cell culture. When washing the vessels after acid dipping manually, each vessel must be repeatedly filled and emptied for at least 15 times, and finally rinsed with re-distilled water for 2-3 times, and then dried or baked before packaging for later use.
Post time: Jun-27-2024