English
A cell factory is a consumable for cell culture that consists of one or multiple layers. During the cell culture process, it is crucial to monitor the growth status of the cells in order to proceed with the next steps. The number of viable cells can be detected using the Trypan Blue staining method. The specific procedure is as follows:
For adherent cells, remove the culture medium and add digestive solution. Incubate for an appropriate amount of time. Once the cells round up, add a volume of culture medium equal to or greater than the volume of the digestive solution to stop the digestion. Centrifuge and resuspend the cells in culture medium to form a cell suspension.
Mix 0.5 ml of Trypan Blue solution, 0.3 ml of PBS, and 0.2 ml of cell suspension thoroughly. Allow the mixture to stand for 1-2 minutes. Using a capillary pipette or a 10 µl pipette tip, take a small amount of the mixture and inject it into a hemocytometer.
Count at least 1000 cells, and record the number of stained cells.
Clean the hemocytometer and cover glass with ultrapure water and 75% ethanol.
Normal cells do not stain; only dead cells, which have increased membrane permeability, will take up the Trypan Blue and appear blue. The mixture should not be left for too long, as viable cells may also take up the dye, affecting the accuracy of the count.
Cell viability (%) = (Total number of cells - Number of stained cells) / Total number of cells * 100.
The Trypan Blue staining method, similar to cell counting, has a large margin of error. It can only detect early-stage apoptosis levels and does not clearly show differences between the control and experimental groups.
During the cell culture process in a cell factory, some cells will inevitably die due to various reasons. Understanding the number of viable cells and cell viability is a key operation in cell culture experiments and is essential for ensuring the progress of the experiment.
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.