There are mainly the following common types of sample preservation solutions for the virus transportation system:

Virus Preservation Solution

• Non-inactivated Type
  • Composition: It usually contains components such as the Hanks’ solution base, amino acids, vitamins, bovine serum albumin (BSA) and other nutrients, as well as a buffer system like HEPES and phosphates. Antibiotics such as penicillin and streptomycin may also be added to prevent microbial contamination. Some may also add reducing agents like dithiothreitol (DTT) to maintain the biological activity of the virus.
  • Principle of Action: It provides the nutrients and a stable environment required for the survival of the virus, maintains the complete structure and activity of the virus, enabling the virus to temporarily maintain its biological characteristics in vitro, which is convenient for subsequent detection, culture and other operations.
  • Application Scenarios: It is mainly used for the isolation and culture of viruses, the preservation of samples before viral nucleic acid detection, etc. It is suitable for situations where it is necessary to retain the activity of the virus for further research or diagnosis, such as the research of new viruses in scientific research institutions and the development of viral vaccines.
• Inactivated Type
  • Composition: It mainly consists of guanidine salts, such as guanidine isothiocyanate and guanidine hydrochloride. It may also contain Tris buffer solution, surfactants such as Triton X-100 or NP-40, and a certain concentration of proteinase K.
  • Principle of Action: Guanidine salts can rapidly denature proteins, disrupt the protein shell of the virus, making the virus lose its infectivity. At the same time, they can protect the viral nucleic acid from degradation. Surfactants help to lyse the virus particles and release the nucleic acid, and proteinase K can further degrade the possible nucleases, ensuring the integrity of the nucleic acid.
  • Application Scenarios: It is widely used in the collection and transportation of samples for viral nucleic acid detection, such as the large-scale screening of nucleic acid detection for the novel coronavirus. It can effectively prevent the spread of the virus, ensure the safety of operators, and at the same time stably preserve the viral nucleic acid to meet the detection requirements.

Cell Preservation Solution

• Universal Cell Preservation Solution
  • Composition: It generally includes components of cell culture media such as MEM and DMEM. Fetal bovine serum or calf serum is added to provide nutrients. Antibiotics such as penicillin and streptomycin are added to prevent bacterial contamination, and antifungal drugs such as amphotericin B are added to prevent fungal contamination. In addition, buffers such as HEPES are included to maintain the stability of pH.
  • Principle of Action: It simulates the survival environment of cells in vivo, provides necessary nutrients and growth factors for cells, maintains the metabolism and physiological functions of cells, inhibits the growth of microorganisms, and ensures that cells can survive for a certain period of time in vitro, maintaining the morphology and biological characteristics of cells.
  • Application Scenarios: It is suitable for the preservation and transportation of various cell types, such as peripheral blood mononuclear cells and tumor cells. It is often used in fields such as cell biology research, cell therapy, and immunological detection, for example, in the collection and transportation of cells in CAR-T cell therapy.
• Dedicated Cell Preservation Solution
  • Composition: The formula is adjusted according to the specific needs of different cell types. For example, the preservation solution for stem cells may add some specific cytokines, such as stem cell factor (SCF) and epidermal growth factor (EGF), etc., to maintain the stemness of stem cells. The preservation solution for lymphocytes may contain more immunomodulatory factors.
  • Principle of Action: Aiming at the biological characteristics and needs of specific cells, it provides precise nutrients and regulatory substances, promotes the survival and function maintenance of cells, inhibits cell differentiation or apoptosis, and maintains the specific phenotype and function of cells.
  • Application Scenarios: It is specially used for the preservation and transportation of specific types of cells, such as the preservation of umbilical cord blood stem cells and the preservation of samples for lymphocyte subset analysis. It is of great significance for precision medical fields such as cell therapy and immunotherapy.

Tissue Preservation Solution

• Formalin Fixative Solution
  • Composition: The main component is a 4% formaldehyde solution. Usually, a phosphate buffer solution is also added to adjust the pH value, keeping it at around 7.0 to ensure the fixing effect.
  • Principle of Action: Formaldehyde can react with the proteins in the tissue to form methylene bridges, thus connecting the protein molecules to each other, fixing the morphology and structure of the tissue, preventing tissue autolysis and putrefaction. At the same time, it can preserve the antigen components in the tissue, which is convenient for subsequent pathological sectioning, immunohistochemistry and other detections.
  • Application Scenarios: It is widely used in the fixation and preservation of tissue samples in pathological diagnosis, such as tumor tissue biopsy samples and surgically resected tissues. It is one of the most commonly used tissue preservation solutions in the clinical pathology department.
• Paraformaldehyde Fixative Solution
  • Composition: It is generally a 2% – 4% paraformaldehyde solution. A buffer solution is also needed to adjust the pH value, and the commonly used one is PBS buffer solution.
  • Principle of Action: Paraformaldehyde will gradually depolymerize into formaldehyde in water and play a fixing role similar to that of formaldehyde. However, the fixing effect of paraformaldehyde is relatively milder and more stable, which can better preserve the ultrastructure and antigenicity of the tissue, and has a good fixing effect on biological macromolecules such as proteins and nucleic acids in cells.
  • Application Scenarios: It is often used in experiments and diagnoses with high requirements for the preservation of tissue ultrastructure and antigens, such as immunohistochemistry, immunofluorescence, and electron microscopy observation, for example, studying the expression distribution of specific proteins in tissues and observing the subcellular structure.