#0097 Screening of preservatives and evaluation of sterilized cellulose nanofibers for toxicity studies
Nanocellulose: can a new sterilization method improve safety assessments?
Cellulose is a polymer material found in plant cell walls, enabling them to stay strong and maintaining the plant upright, yet with enough pores to let water through easily, making them a preferred material to make paper, resins and a wide array of super-absorbent materials from. Cellulose nanofibers (CNFs) are industrially extracted small subunits of cellulose that can be integrated into nanomaterials to make them more absorbent, transparent, or heat resistant. However, little is known about the potential toxicity of CNFs. Many pathogens, such as fungi and bacteria, are known to feed on cellulose. Contamination in non-sterile environments, therefore, is very likely, with potential life-threatening effects if the material is used or consumed by humans. Sterilizing the supply chain is thus necessary to avoid contamination.
There are two common methods used for sterilization: using radiation or high temperatures to kill potential organic contaminants. However, because cellulose is also organic, high temperatures and radiation can also damage it irreparably. We need a method that safety eliminates contamination, while leaving the chemical and physical properties of CNF intact.
With this in mind, a team of Japanese researchers imagined a different sterilization process. They settled on a solution involving preservatives, often added to cellulose materials to enhance desired properties. In this case, they tested different antiseptic preservatives and examined their effect on CNFs at different concentrations. They judged treatment success on two criteria: how well it prevented contamination (how many bacteria/fungi and other toxins were present on the treated sample) and whether the CNFs’ physical and chemical properties remained unchanged.
After comparing their results, they were able to pinpoint the most effective dose and combination of preservatives for a safe sterilization process. The winning treatments involved either 10 µg/mL of benzalkonium chloride, or a combination of 250 µg/mL methyl parahydroxybenzoate and 250 µg/mL propyl parahydroxybenzoate.
Despite their success, the scientists suggest caution. Because CNFs are a relatively new material, their potential effects on human health are not well understood. They advocate for more research to evaluate their safety, highlighting the need to conduct animal testing first.
Link to the original journal article:
https://onlinelibrary.wiley.com/doi/10.1002/1348-9585.12176
Title of the paper:
Screening of preservatives and evaluation of sterilized cellulose nanofibers for toxicity studies
Authors:
Takafumi Sai, Junko Maru, Sawae Obara, Shigehisa Endoh, Hideo Kajihara, Katsuhide Fujita
