Cell culture involves cell inoculation, cultivation, harvesting and other processes. The cells in the cell culture flasks have grown to a certain extent and the cells need to be harvested. At this time, the cells on the flask wall need to be digested with trypsin and then harvested. The digestion time must be controlled during the use of pancreatin.
Trypsin is a heterogeneous protease, which can degrade the protein on the cell membrane and the cell culture flasks. By degrading the protein at a specific location, the protein at the junction between the proteins is degraded, and the cells become spherical due to the tension of their internal cytoskeleton, thereby separating the cells. The degree of trypsin digestion is a key step in cell culture: excessively digested cell debris increases, black scum increases, cells will fall off in pieces, which seriously affects cell viability, and some cells float and lose with the discarded trypsin; digestion Insufficient, cells are difficult to blow down from the bottle wall, repeated pipetting will also damage cell viability.
Different tissues or cells react differently to the action of pancreatin. The activity of pancreatin dispersed cells is also related to its concentration, temperature and action time. When the pH is 8.0 and the temperature is 37, the action ability of the pancreatin solution is relatively strong. When using pancreatin, the concentration, temperature and time should be controlled to avoid cell damage caused by over-digestion. Because Ca2+, Mg2+, serum and protein can reduce the activity of pancreatin, BSS without Ca2+ and Mg2+ should be used when preparing pancreatin solution, such as D-Hanks solution. When terminating digestion, use serum-containing culture medium or trypsin inhibitor to stop the effect of pancreatin on cells.
In addition, if it is a newly purchased cell, you can first use a low concentration of trypsin to find out the digestion time, and observe whether the cells are round every minute and make a record. In short, when harvesting the cells in the cell culture flasks, the trypsin digestion time must be controlled so as to maintain the cell viability.
The FAI climbed 5.9 percent year-on-year in the first 11 months of 2018, quickening from the 5.7-percent growth in Jan-Oct, the National Bureau of Statistics (NBS) said Friday in an online statement.
The key indicator of investment, dubbed a major growth driver, hit the bottom in August and has since started to rebound steadily.
In the face of emerging economic challenges home and abroad, China has stepped up efforts to stabilize investment, in particular rolling out measures to motivate private investors and channel funds into infrastructure.
Friday's data showed private investment, accounting for more than 60 percent of the total FAI, expanded by a brisk 8.7 percent.
NBS spokesperson Mao Shengyong said funds into weak economic links registered rapid increases as investment in environmental protection and agriculture jumped 42 percent and 12.5 percent respectively, much faster than the average.
In breakdown, investment in high-tech and equipment manufacturing remained vigorous with 16.1-percent and 11.6-percent increases respectively in the first 11 months. Infrastructure investment gained 3.7 percent, staying flat. Investment in property development rose 9.7 percent, also unchanged.