Why do you invert the culture dish when conducting biological experiments with the culture dish?

When culturing in an inverted Petri dish, since the air in the Petri dish is not easy to flow, the infection of foreign bacteria can be reduced as much as possible, and the contamination of the culture medium and culture by bacteria can be avoided. Through experimental observation, it is found that if the culture dish is placed in the correct direction, it is easy to grow contaminated bacterial colonies around the culture dish. When the culture conditions require ventilation, the inverted culture dish can reduce the air flow on the surface of the culture medium, slow down the evaporation of water in the culture medium, keep the water in solid medium such as agar, and fully maintain the elasticity of the culture medium. Agar and other coagulants can prolong the time of medium rupture. Therefore, reverse culture is conducive to the propagation and survival of bacteria. If the culture dish is placed vertically, the medium will lose water and break in a few days. It can be seen that it is very important to prevent water loss during the cultivation process. When opening the incubator to take out and place the Petri dish, it is easy to knock off the lid of the accidentally placed Petri dish. Although the inverted Petri dish can keep its original shape when it is removed, it is not easy to separate the bottom of the dish from the lid, thus avoiding the contamination of bacteria in the environment. After inverting the culture dish, since the culture medium still has a residual temperature and has just solidified, the water content is relatively high and the humidity is relatively high, and some water drops fall on the dish cover. If the culture dish is placed, the condensed water droplets will flow into the culture medium, which will not only cause pollution, but also separate the culture medium from the culture dish, so that it is easy to slide. This is one of the reasons why the culture medium cannot adhere firmly. If the water in the culture medium is very large when the culture dish is laid, the bacteria in the culture medium will flow around during the inoculation and culture, and the grown bacterial membranes will be connected together and cannot be counted. The main purpose of dish culture is to separate single-cell colonies for observation and identification. Inverting the dish can prevent condensed water from dropping onto the culture medium and being polluted by bacteria. It is also conducive to the growth, reproduction and counting of bacterial species.


Some knowledge points of suction head

Generally, the pipette tip is made of pure PP without plasticizer and release agent, otherwise the dissolved matter will affect the experimental results. High dimensional accuracy, otherwise it will lead to poor sealing consistency; The inner wall is required to be smooth and free of flow marks, and the front end is required to be free of notches and burrs, otherwise the drainage will be inaccurate; It is clean and free of biological pollution, and it is required to be manufactured in an ultra clean environment. Although most standard pipette tips do not require conductivity, tips used for liquid treatment in drug detection systems need not only conductivity, but also excellent physical properties and chemical resistance. In addition, as the pipette tip becomes longer and larger in design, the conductive compound used to make the tip needs to flow more easily to accommodate a narrower processing window. The pipette suction head is mainly packaged in bags and boxes. In the relatively mature market, boxed products account for the majority; In the Chinese market, bagging is the mainstream at present - the main reason is that bagging is cheap. Bagging is to put the suction heads in plastic bags with 500 or 1000 suction heads in each bag (the number of suction heads in each bag will be much smaller if the number of suction heads is large). Most customers will buy a bag of suction heads, and then manually put them into the suction head box, and then sterilize them with a high-pressure steam sterilizer. The adaptability of pipette tip is a problem that users are more and more concerned about. Why? Because not all suction heads can be used on the pipette of the corresponding range of any brand, customers must pay attention to the adaptability of the suction head when purchasing the suction head. We can discuss the adaptability of the desorption head from the following aspects: 1. Specificity of pipette tip: some pipettes of some brands can only use their own standard pipette tip, while others cannot. 2. Adaptability of suction head: it is common that a pipette can use multiple suction heads, but the pipetting effect is different after installing different suction heads. 3. The range of the suction head and the pipette shall be compatible: generally, the volume of the suction head shall be greater than or equal to the Zui range of the pipette. For example, the 200L suction head can be used for pipettes with ranges of 20L, 100L and 200L; The above are some knowledge points about the suction head. I hope I can help you.


Medical devices are supported by policies

According to the sample survey statistics of the medical device branch of China Medical Materials Association, the sales scale of China's medical device market in 2015 was about 308 billion yuan, an increase of 52.4 billion yuan over the 255.6 billion yuan in 2014, with an average growth rate of about 20.05%. With the aggravation of the aging population, the pharmaceutical industry has been paid more and more attention, especially the subdivided industry - medical devices. From 2009 to 2014, the overall scale of the high-tech industry in China's medical device manufacturing industry increased by 2.32 times, which indicates the rapid development of the medical device industry. From the performance of listed companies related to a shares, the medical device sector has delivered a beautiful report card this year. In the first quarter, among the 23 medical device companies, 15 had increased performance. Of the 3 companies that issued the interim performance forecast, 2 reported good results. From the policy point of view, the state also strongly supports the medical device industry. The general office of the State Council issued the guiding opinions on promoting the healthy development of the pharmaceutical industry, which has a close connection with the medical device industry, mainly focusing on strengthening technological innovation, accelerating quality upgrading, optimizing industrial structure, deepening foreign cooperation, and cultivating new business forms.

< 1 > proceed page