Effect of laboratory freeze dryer

The laboratory freeze dryer is a small freeze dryer used for freeze drying a small amount of samples in the laboratory. The freeze dryer directly sublimates the solvent from the solid sample to the gaseous state in a vacuum state to achieve the purpose of drying. Since the sample is dried at normal or even low temperature, it does not affect the biological activity of the sample, and the processed sample is in a loose and porous state and is easy to dissolve. So freeze-drying is a good way to preserve biologically active samples.

The pre-freezing of materials is a key step in the freeze-drying process, and the quality of the pre-freezing process directly affects the quality of freeze-dried products. The material pre-freezing process can be basically divided into slow freezing and fast freezing. Users can flexibly operate the equipment according to specific needs to achieve effective pre-freezing of materials.

During the drying process of freeze dryer, the impact of drying on cell viability is mainly concentrated in the second stage of drying. When the freeze dryer is working, the surface of the sample loses water quickly, which can easily make the sample partially overdry and destroy the water molecule protective layer of biological macromolecules. This will not only damage the activity of cell biologically active substances, but also leads to oxidation of lipids or proteins, generating free radicals, thus affecting cell activity.

In the experiment, it is found that freezing during the freeze-drying process of vacuum freeze dryer is the main cause of damage, and the damage caused by the drying process is relatively small. There are many factors that affect the freeze-drying effect, including the cell size, cell concentration, pH value, cryoprotectant, pre-freezing temperature, cooling rate, freeze-drying conditions, and cell water content.