Determining the appropriate concentration of virus preservation liquid requires comprehensive consideration of multiple factors. The following are some common methods and key points:

Consulting Literature: Different types of viruses have significant differences in their requirements for the components and concentrations of preservation liquids. For example, influenza viruses, the novel coronavirus, HIV viruses, etc., all have their own suitable preservation liquid formulations and concentration ranges. By referring to relevant scientific literature, research reports, and professional virology books, you can understand the research results and recommended solutions regarding the concentration of virus preservation liquids by predecessors and use them as reference bases.
Preliminary Experiments for Exploration: Under laboratory conditions, conduct small-scale preliminary experiments for specific viruses. Set up different concentration gradients of preservation liquids, add virus samples to them respectively, and preserve them under the same preservation conditions (such as temperature, time, etc.). Then regularly detect the activity, titer, and other indicators of the viruses, and observe the survival status of the viruses in preservation liquids with different concentrations to preliminarily determine a more appropriate concentration range.

Short-Term Preservation: If virus samples only need to be preserved for a short period (such as a few hours to a few days), the requirements for the concentration of the preservation liquid are relatively low. At this time, the focus is on maintaining the basic stability of the viruses and preventing them from degrading or being inactivated in the short term. The concentrations of some components, such as protein stabilizers and antibacterial agents, can be appropriately reduced, but it must be ensured that the basic preservation requirements can be met.
Long-Term Preservation: For virus samples that need to be preserved for a long time (several weeks, months, or even years), in order to better protect the activity and integrity of the viruses, the preservation liquid usually requires a higher concentration and a more complete formulation. For example, it may be necessary to increase the concentration of cryoprotectants such as glycerol to prevent virus damage during cryopreservation. Meanwhile, increase the concentration of antibacterial agents to ensure that the stability of the viruses will not be affected by bacterial contamination over a long period.

Sample Types: Virus samples from different sources, such as clinical swab samples, cell cultures, animal tissue samples, etc., have different compositions and impurity contents, and their requirements for the concentration of the preservation liquid also vary. For example, clinical swab samples may contain more host cell components and secretions, and it is necessary to appropriately adjust the concentrations of certain components in the preservation liquid to avoid interference with virus preservation.
Sample Processing: Whether the samples have undergone pretreatment after collection and the processing methods will also affect the selection of the preservation liquid and the determination of its concentration. If the samples have gone through complex processing procedures, such as centrifugation and lysis, the state of the viruses may change. It is necessary to adjust the concentration of the preservation liquid according to the post-processing situation to better protect the viruses.

Activity Testing: Use methods such as virus titer determination and cell infection experiments to detect the activity of viruses in the preservation liquid. By comparing the changes in virus activity in preservation liquids with different concentrations, determine the concentration range that can maintain virus activity to the greatest extent.
Stability Testing: Observe the stability of viruses in preservation liquids with different concentrations under different preservation conditions, including physical stability (such as whether aggregation or precipitation occurs) and chemical stability (such as whether nucleic acids are degraded). Select the concentration of the preservation liquid that enables the viruses to maintain good stability.
Compatibility Testing: If the virus preservation liquid needs to be used in conjunction with other reagents or detection systems later, such as nucleic acid extraction reagents and PCR reaction systems, compatibility testing is also required to ensure that the preservation liquid at the corresponding concentration will not have an adverse impact on subsequent detection or operations.