What about the viral safety of chitosan? Here, we would like to present an interesting publication about the viral safety of chitosan. Chitosan can be applied as a virus-free biopolymer for medical products in human, as the deacetylation process of chitin is sufficient for virus inactivation, shown by Park et al (2015). The researchers from Korea used chitin from Heppe Medical Chitosan to show that viruses are efficiently inactivated during the deacetylation process from chitin to chitosan.
Inactivation efficiency of DNA and RNA viruses during chitin-to-chitosan conversion.
Park, J.P., Koh, MY., Sung, P.S. et al. (2015) Macromol. Res.23: 505. doi:10.1007/s13233-015-3081-6
Viral contamination of biomaterials for medical products is a major concern. As for chitosan production non viable material of animal origin (chitin) is applied, the viral safety of chitosan should be assessed. HMC is using chitin from snow crabs (Chionoecetes opilio) shells for chitosan production.
In the study, inactivation of white spot syndrome virus (WSSV) and Hepatitis A virus (HAV), both viruses relevant for chitin, was examined. The double-stranded DNA virus WSSV infects a wide range of crustacean hosts like crabs . Infection with single-stranded RNA virus HAV is linked to consumption of shellfish harvested from fecal contaminated water. To demonstrate inactivation of viruses through the chitin deacetylation process, 100 µl virus stock solution and 400 µl 50% NaOH were inoculated to 10 mg chitin and incubated at 90 °C for 2h. Before and after this process viral titer was determined by quantitative PCR.
- Viral genome equivalents of both viruses were strongly reduced by nearly 100% (reduction factors see table below)
|Inoculated||3.83 x 107||1.30 x 108|
|Recovered||1.07 x 10||2.27 x 103|
|Reduction factor [log10]||6.55||4.78|
Additionally, an infectivity test was performed. HAV-permissive human hepatoma cell line (Huh-7.5) were infected with HAV-chitin/chitosan-solution and incubated for 72 h. HAV-infected cells were identified by immunohistochemistry.
- Infectivity test showed the loss of infectivity of HAV after the deacetylation process:
- A high number of cells were infected, when inoculated with solution before deacetylation
- No cells were infected, when inoculated with solution after deacetylation
In conclusion, high pH and high temperature treatments can be considered as efficient steps for virus inactivation, as demonstrated with model viruses WSSV and HAV by Park et al. (2015). Based on the results of the study it can be assumed that viruses are efficiently eliminated/reduced by the manufacturing process and no further inactivation step is required.
 Lightner, D. V. (1996). A handbook of shrimp pathology and diagnostic procedures for diseases of cultured penaeid shrimp. World Aquaculture Society, Baton Rouge, Louisiana, USA.